CYTRX CORP
8-K, 1997-11-06
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
Previous: RAYTECH CORP, 10-Q, 1997-11-06
Next: CFX CORP, SC 13D, 1997-11-06



<PAGE>   1



                              

                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549

                                 ----------------

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(D) OF THE
                         SECURITIES EXCHANGE ACT OF 1934



       Date of Report (Date of earliest event reported): October 22, 1997
                                                         ----------------


                                CYTRX CORPORATION
                                -----------------
               (Exact Name of Registrant as Specified in Charter)

                                        
   Delaware                      000-15237                     58-1642740
- ---------------                 ------------               -------------------
(State or Other                 Commission                  (IRS Employer
Jurisdiction of                 File Number                 Identification No.)


                             154 Technology Parkway
                             Norcross, Georgia 30092
                             ----------------------- 
         (Addresses of Principal Executive Offices, including Zip Code)


                                 (770) 368-9500
                             ----------------------- 
              (Registrant's Telephone Number, including Area Code)







                               Page 1 of 6 Pages
                        Exhibit Index appears on Page 5

<PAGE>   2
ITEM 5.    OTHER EVENTS.

         On October 22, 1997 (the "Closing Date"), pursuant to the Private
Securities Subscription Agreements, dated as of October 22, 1997, (the
"Subscription Agreements" attached hereto as Exhibits 2.1 - 2.5 and incorporated
herein by reference) by and between CytRx Corporation (the "Corporation") and
each of GUNDYCO in trust for R.R.S.P. 550-98866-19, Excalibur Limited
Partnership, Pine Street Asset Management, Charles N. Eckert and David Kosloff
(together, the "Investors"), the Corporation privately placed two million
dollars of certain debentures (the "Debentures" attached hereto as Exhibits 3.1
- - 3.5 and incorporated herein by reference), convertible into shares of common
stock of the Corporation (the "Shares"), and certain share purchase warrants
(the"Warrants" attached hereto as Exhibits 4.1 - 4.5 and incorporated herein by
reference) (the Subscription Agreements, the Debentures and the Warrants,
collectively, are hereinafter called the "Transaction Documents").

         The Debentures were sold at par and will bear interest at the rate of 
6% per annum. The Debentures are not convertible into Shares for sixty (60)
days after the Closing Date. Thereafter, the Investors have the option of
converting the Debentures at the lesser of eighty-five percent (85%) of the
average closing bid price for the ten (10) trading days preceding such
conversion or $5.68 per Share. If the conversion price is below four dollars
($4.00), the Corporation has the right to redeem the Debentures at one hundred
ten percent (110%) of par. The Warrants allow the Investors to purchase 40,000
Shares at a price of $5.68 per share. Furthermore, the Corporation also has the
option of selling the Investors an additional two million dollars ($2,0000,000)
of debentures at any time between ninety (90) and two hundred seventy (270)
days after the shelf registration statement, required to be filed with the
Securities and Exchange Commission (the "Commission") pursuant to Rule 415 of
the Securities Act of 1933 and in accordance with the Registration Rights
Agreement, dated October 22, 1997, entered into by and among the Corporation
and the Investors (the "Registration Rights Agreement" attached hereto as
Exhibit 5.1 and incorporated herein by reference), has been declared effective
by the Commission subject to certain conditions.  If the Corporation issues
additional debentures, then it will also issue warrants to purchase an
additional 40,000 Shares.


ITEM 7.    FINANCIAL STATEMENTS, PRO FORMA FINANCIAL INFORMATION, AND EXHIBITS.

         No financial statements are required to be filed as part of this
Report. The following exhibits are filed as part of this Report:

<TABLE>
<CAPTION>


               EXHIBITS
               -------- 
               <S>       <C>

               2.1       Private Securities and Subscription Agreement dated as
                         of October 22, 1997 by and between CytRx Corporation
                         and GUNDYCO in trust for R.R.S.P. 550-98866-19

               2.2       Private Securities and Subscription Agreement dated as
                         of October 22, 1997 by and between CytRx Corporation
                         and Excalibur Limited Partnership

               2.3       Private Securities and Subscription Agreement dated as
                         of October 22, 1997 by and between CytRx Corporation
                         and Pine Street Asset Management

               2.4       Private Securities and Subscription Agreement dated as
                         of October 22, 1997 by and between CytRx Corporation
                         and Charles N. Eckert

               2.5       Private Securities and Subscription Agreement dated as
                         of October 22, 1997 by and between CytRx Corporation
                         and David Kosloff 

</TABLE>

                                      -2-
<PAGE>   3

<TABLE>
               <S>       <C>
               3.1       CytRx Corporation 6% Convertible Debenture dated as of
                         October 22, 1997 in favor of GUNDYCO in trust for
                         R.R.S.P. 550-98866-19


               3.2       CytRx Corporation 6% Convertible Debenture dated as of
                         October 22, 1997 in favor of Excalibur Limited
                         Partnership

               3.3       CytRx Corporation 6% Convertible Debenture dated as of
                         October 22, 1997 in favor of Pine Street Asset
                         Management

               3.4       CytRx Corporation 6% Convertible Debenture dated as of
                         October 22, 1997 in favor of Charles N. Eckert

               3.5       CytRx Corporation 6% Convertible Debenture dated as of
                         October 22, 1997 in favor of David Kosloff

               4.1       CytRx Corporation Stock Purchase Warrant dated as of
                         October 22, 1997 in favor of GUNDYCO in trust for
                         R.R.S.P. 550-98866-19

               4.2       CytRx Corporation Stock Purchase Warrant dated as of
                         October 22, 1997 in favor of Excalibur Limited
                         Partnership

               4.3       CytRx Corporation Stock Purchase Warrant dated as of
                         October 22, 1997 in favor of Pine Street Asset
                         Management

               4.4       CytRx Corporation Stock Purchase Warrant dated as of
                         October 22, 1997 in favor of Charles N. Eckert

               4.5       CytRx Corporation Stock Purchase Warrant dated as of
                         October 22, 1997 in favor of David Kosloff

               5.1       Registration Rights Agreement dated as of October 22,
                         1997 by and among CytRx Corporation, GUNDYCO in trust
                         for 550-98866-19, Excalibur Limited Partnership, Pine
                         Street Asset Management, Charles N. Eckert and David
                         Kosloff

               5.2       Press Release dated October 22, 1997

</TABLE>

                                      -3-
<PAGE>   4


                                    SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the Registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                    CYTRX CORPORATION
                                    (REGISTRANT)


<TABLE>
<S>                                       <C>
Date: November 6, 1997                    By: /s/ Jack J. Luchese
                                              ------------------------
                                          Jack J. Luchese, Chairman, President and Chief
                                          Executive Officer (Principal Executive Officer)
</TABLE>

                                      -4-
<PAGE>   5



                                INDEX TO EXHIBITS
                                -----------------
<TABLE>
<CAPTION>
                                                                                        
                                                                                SEQUENTIAL
EXHIBIT                                                                         PAGE NO.
- -------                                                                         --------
<S>             <C>                                                             <C>     
2.1             Private Securities and Subscription Agreement dated as of
                October 22, 1997 by and between CytRx Corporation and
                GUNDYCO in trust for R.R.S.P. 550-98866-19

2.2             Private Securities and Subscription Agreement dated as of
                October 22, 1997 by and between CytRx Corporation and
                Excalibur Limited Partnership

2.3             Private Securities and Subscription Agreement dated
                as of October 22, 1997 by and between CytRx
                Corporation and Pine Street Asset Management

2.4             Private Securities and Subscription Agreement dated as of
                October 22, 1997 by and between CytRx Corporation and
                Charles N. Eckert

2.5             Private Securities and Subscription Agreement dated as of
                October 22, 1997 by and between CytRx Corporation and
                David Kosloff

3.1             CytRx Corporation 6% Convertible Debenture dated as
                of October 22, 1997 in favor of GUNDYCO in trust for
                R.R.S.P. 550-98866-19

3.2             CytRx Corporation 6% Convertible Debenture dated as of
                October 22, 1997 in favor of Excalibur Limited Partnership

3.3             CytRx Corporation 6% Convertible Debenture dated as of
                October 22, 1997 in favor of Pine Street Asset Management

3.4             CytRx Corporation 6% Convertible Debenture dated as of
                October 22, 1997 in favor of Charles N. Eckert

3.5             CytRx Corporation 6% Convertible Debenture dated as of
                October 22, 1997 in favor of David Kosloff
</TABLE>

<PAGE>   6


<TABLE>
<S>            <C>
4.1            CytRx Corporation Stock Purchase Warrant dated as of October 22,
               1997 in favor of GUNDYCO in trust for R.R.S.P. 550-98866-19

4.2            CytRx Corporation Stock Purchase Warrant dated as of October 22,
               1997 in favor of Excalibur Limited Partnership

4.3            CytRx Corporation Stock Purchase Warrant dated as of October 22,
               1997 in favor of Pine Street Asset Management

4.4            CytRx Corporation Stock Purchase Warrant dated as of October 22,
               1997 in favor of Charles N. Eckert

4.5            CytRx Corporation Stock Purchase Warrant dated as of October 22,
               1997 in favor of David Kosloff

5.1            Registration Rights Agreement dated as of October 22, 1997 by 
               and among CytRx Corporation, GUNDYCO in trust for 550-98866-19,
               Excalibur Limited Partnership, Pine Street Asset Management,
               Charles N. Eckert and David Kosloff

5.2            Press Release dated October 22, 1997

</TABLE>





<PAGE>   1
                                                                     EXHIBIT 2.1
                    PRIVATE SECURITIES SUBSCRIPTION AGREEMENT
                                CYTRX CORPORATION
                                (REGULATION "D")


         THIS PRIVATE SECURITIES SUBSCRIPTION AGREEMENT (hereinafter the
"Agreement") has been executed by the undersigned in connection with the
purchase in a private placement pursuant to Section 4(2) of the Securities Act
of 1933, as amended (the "Securities Act"), of certain debentures (hereinafter
the "Debentures"), convertible into shares of common stock (hereinafter the
"Shares"), and certain share purchase warrants (hereinafter the "Warrants") from
CytRx Corporation ("CYTR") 154 Technology Parkway, Technology Parkway, Atlanta,
Georgia, 30092, USA, a corporation organized under the laws of Delaware
(hereinafter the "COMPANY" or "SELLER") by Name: Gundyco in trust for R.R.S.P.
550-98866-19 located at 4120 Yonge Street, Suite 416; City: North York;
Province/State; Ontario; Zip/Postal Code: M2P 2B8; Country: Canada a trust
organized under the laws of Ontario and Canada (hereinafter "BUYER"). SELLER and
BUYER (hereinafter collectively the "parties") each hereby represents, warrants
and agrees as follows:


         1.       AGREEMENT TO SUBSCRIBE; PURCHASE PRICE:

                  (i)   SELLER and BUYER are executing and delivering this
         Agreement in reliance upon the exemption from securities registration
         afforded by Rule 506 under Regulation D ("Regulation D") as promulgated
         by the United States Securities and Exchange Commission (the
         "Commission") under the Securities Act; and

                  (ii)  BUYER hereby subscribes for Four Hundred Thousand 
         Dollars (USD $400,000) U.S. principal amount of Debentures,
         substantially in the form attached as Exhibit A to and forming an
         integral part of this Agreement.

                  (iii) BUYER will receive 8,000 Warrants substantially in the
         form attached as Exhibit B to and forming an integral part of this
         Agreement. Each Warrant will entitle BUYER to purchase one treasury
         Common Share at the price of $5.68. The Warrants will expire two (2)
         years after the Closing; and

                  (iv)  BUYER shall on or before the Closing execute a copy of
         the Registration Rights Agreement (the "Registration Rights Agreement")
         substantially in the form attached as Exhibit "A" to and forming an
         integral part of this Agreement.

<PAGE>   2

         2.       BUYER'S REPRESENTATIONS

                  BUYER represents and warrants follows:

                  (i)   Authorization: Such BUYER has full power and authority 
         to enter into this Agreement, the Debenture, the Warrant and the
         Registration Rights Agreement (collectively, the "Transaction
         Documents") and that the Transaction Documents, when executed and
         delivered will constitute a valid and legally binding obligation of
         BUYER in accordance with their terms, subject to (A) bankruptcy,
         insolvency, fraudulent conveyance, reorganization, moratorium and
         similar laws now or hereafter in effect relating to creditors' rights
         and (B) that the remedy of specific performance and injunctive and
         other forms of equitable relief may be subject to equitable defenses
         and to the discretion of the court before which any proceedings
         therefor may be brought and (C) to the extent that the indemnification
         provisions contained in the Registration Rights Agreement may be
         limited by applicable laws.

                  (ii)  Purchase Entirely for Own Account. This Agreement is 
         made with BUYER in reliance upon BUYER'S representation to the Company,
         which by such BUYER'S execution of this Agreement BUYER hereby
         confirms, that the Debentures and Warrants to be purchased by BUYER and
         the Common Stock issuable upon conversion thereof (collectively, the
         "Securities") will be acquired for investment for BUYERS own account,
         not a nominee as agent, and not with a view to the resale or
         distribution of any part thereof. By execution of this Agreement, Buyer
         further represents that Buyer does not have any contract, undertaking,
         agreement or arrangement with any person, to sell, transfer or grant
         participation to such person or to any third person, with respect to
         any of the Securities.

                  (iii) Reliance Upon BUYER'S Representations. BUYER understands
         that the Debentures and the Warrants are not, and any Common Stock
         acquired on conversion thereof at the time of issuance may not be,
         registered under the Securities Act on the ground that the sale
         provided for in this Agreement and the issuance of securities hereunder
         is exempt from registration under the Securities Act pursuant to
         Section 4(2) thereof and that the Company's reliance on such exemption
         is predicated on the BUYERS' representations set forth herein. Buyer
         also understands that no prospectus or offering memorandum has been
         received by Buyer or filed by the Seller with any Canadian securities
         commission or similar authority in connection with the sale of the
         Debentures and Warrants, and that no prospectus or offering memorandum
         shall be received by the Seller or so filed by Buyer in connection with
         any sale of Shares issued on the conversion of the Debentures or
         Warrants, and that as a result the Buyer will be unable to rely upon
         civil or contractual remedies that might otherwise be available to it
         if the Debentures, Warrants and/or Shares had been issued by the Seller
         by way of a prospectus or offering memorandum, respectively, and the
         prospectus or offering 

                                      -2-

<PAGE>   3

         memorandum, as the case may be, contained a misrepresentation as that 
         term is defined in the Securities Act (Ontario).

                  (iv)  Buyer is not a corporation, syndicate, partnership or
         other form of unincorporated entity or corporation created solely to
         permit the purchase of the Securities by a group of individuals who
         individual share in the aggregate acquisition cost of the Securities is
         less than $150,000 and Buyer is not purchasing the Securities as the
         result of an advertisement of the Securities, including an
         advertisement in printed media of general and regular paid circulation,
         radio or television.

                  (v)   BUYER believes BUYER has received all the information
         BUYER considers necessary or appropriate for deciding whether to
         purchase any of the Securities. BUYER further represents that BUYER has
         had an opportunity to ask questions and receive answers from the
         Company regarding the terms and conditions of the offering any of the
         Securities and the business, properties, prospects, and financial
         condition of the Company and to obtain additional information (to the
         extent the Company possessed such information or could acquire it
         without reasonable effort or expense) necessary to verify the accuracy
         of any information furnished to BUYER or to which BUYER had access.

                  (vi)  BUYER represents that BUYER is experienced in evaluating
         and investing in private placement transactions of securities of
         companies in a similar stage of development and acknowledges that BUYER
         is able to fend for himself, herself or itself, can bear the economic
         risk of BUYER'S investment, and has such knowledge and experience in
         financial and business matters that BUYER is capable of evaluating the
         merits and risks of the investment in the Debentures and Warrants. If
         other than an individual, BUYER also represents BUYER has not been
         organized for the purpose of acquiring the Debentures and Warrants.

                  (vii) The BUYER represents that BUYER is an Accredited
         Investor.

                  The term "Accredited Investor" as used herein refers to:

                  (1)      A person or entity who is a direct or executive 
                           officer of the Company;

                  (2)      Any bank as defined in Section 3(a)(2) of the
                           Securities Act, or any savings and loan association
                           or other institution as defined in section 3(a)(5)(A)
                           of the Securities Act whether acting in its
                           individual or fiduciary capacity; any broker or
                           dealer registered pursuant to Section 15 of the
                           Securities Exchange Act of 1934; any insurance
                           company as defined in Section 2(13) of the Securities
                           Act; any investment company registered under the
                           Investment Company Act of 1940 or a business
                           development company as 

                                      -3-

<PAGE>   4

                         defined in Section 2(a(48) of that Act; any Small 
                         Business Investment Company licensed by the U.S. Small
                         Business Administration under Section 301 (c) or (d) of
                         the Small Business Investment Act of 1958; any plan
                         established and maintained by a state, its political
                         subdivisions, or any agency or instrumentality of a
                         state or its political subdivisions, for the benefit of
                         its employees, if such plan has total assets in excess
                         of $5,000,000; any employee benefit plan within the
                         meaning of Title I of the Employee Retirement Income
                         Security Act of 1974, if the investment decision is
                         made by a plan fiduciary, as defined in Section 3(21)of
                         such Act, which is either a bank, savings and loan
                         association, insurance company or registered investment
                         adviser, or if the employee benefit plan has total
                         assets in excess of $5,000,000 or, if a self-directed
                         plan, with investment decisions made solely by the
                         persons that are Accredited Investors.

                  (3)    Any private business  development  company as defined 
                         in section 202(a)(22) of the Investment Advisers Act of
                         1940;

                  (4)    Any organization described in Section 501(c)(3) of
                         the Internal Revenue Code, corporation, Massachusetts
                         or similar business trust, or partnership, not formed
                         for the specific purpose of acquiring the securities
                         offered, with total assets in excess of $5,000,000;

                  (5)    Any natural person whose individual net worth, or
                         joint net worth with that person's spouse, at the
                         time of the purchase exceeds $1,000,000;

                  (6)    Any natural person who had an individual income in
                         excess of $200,000 in each of the two most recent
                         years or joint income with that person's spouse in
                         excess of $300,000 in each of those years and has a
                         reasonable expectation of reaching the same income
                         level in the current year;

                  (7)    Any trust, with total assets in excess of $5,000,000,
                         not formed for the specific purpose of acquiring the
                         securities offered, whose purchase is directed by a
                         person who has such knowledge and experience in
                         financial and business matters that he or she is
                         capable of evaluating the merits and risks of the
                         prospective investment; or

                  (8)    Any entity in which all of the equity owners are
                         Accredited Investors.

                                      -4-

<PAGE>   5

         As used in this Paragraph 3.(vii) the term "net worth" means the
         excesses of total assets over total liabilities. For the purpose of
         determining a person's net worth, the principal residence owned by an
         individual should be valued at fair market value, including the cost of
         improvements, net of current encumbrances. As used in this paragraph
         "income" means actual economic income, which may differ from adjusted
         gross income for income tax purposes. Accordingly, Buyer should
         consider whether Buyer should add any or all of the following items to
         Buyer's adjusted gross income for income tax purposes in order to
         reflect more accurately Buyer's actual economic income; any amounts
         attributable to tax-exempt income received, losses claimed as a limited
         partner in any limited partnership, deductions claimed for depletion,
         contributions an IRA or keogh retirement plan, and alimony payments.

                  (viii) BUYER understands that the Securities may not be sold,
         transferred or otherwise disposed of in the United States without
         registration under the Securities Act or an exemption therefrom, and
         that in the absence of an effective registration statement covering any
         of the Securities or an available exemption from registration under the
         Securities Act, the Securities must be held indefinitely. In
         particular, BUYER is aware that the Securities may not be sold pursuant
         to Rule 144 promulgated under the Securities Act unless all of the
         condition of that Rule are met. BUYER also understands that any resale
         of the Securities must be conducted in accordance with the applicable
         requirements of the Securities Act (Ontario).

                  (ix)   Buyer acknowledges that no person has made to Buyer any
         written or oral representations:

                  (i)    that any person will resell or repurchase the 
         Securities;

                  (ii)   that any person will refund the purchase price of the 
         Securities; and

                  (iii)  as to the future price or value of the Securities.


         3.       SELLER'S REPRESENTATIONS

                  SELLER represents and warrants as follows:

                  (i)    SELLER has not conducted any general solicitation or 
         general advertising (as defined in Regulation D) with respect to any 
         of the Securities offered hereby;

                  (ii)   The Debentures, when issued and delivered pursuant to 
         the terms of this Agreement, will have been duly authorized, executed,
         issued and delivered and will constitute valid and legally binding
         obligations of the Company in 

                                      -5-

<PAGE>   6

         accordance with their terms, subject to (A) bankruptcy, insolvency,
         fraudulent conveyance, reorganization, moratorium and similar laws now
         or hereafter in effect relating to creditors' rights and (B) that the
         remedy of specific performance and injunctive and other forms of
         equitable relief may be subject to equitable defenses and to the
         discretion of the court before which any proceedings therefor may be
         brought and (C) to the extent that the indemnification provisions
         contained in the Registration Rights Agreement may be limited by
         applicable laws.

                  (iii) The Shares, when issued and delivered upon conversion of
         the Debentures in accordance with their terms, will be duly and validly
         authorized and issued, fully-paid and non assessable and will not
         subject the holders thereof to personal liability by reason of being
         such holders. There are no preemptive rights of any shareholder of
         SELLER with respect to the Shares contained in SELLER'S Certificate of
         Incorporation or any agreement to which SELLER is a party;

                  (iv)  This Agreement has been duly authorized, validly 
         executed and delivered on behalf of SELLER and is a valid and binding
         agreement of SELLER in accordance with its terms, subject to (A)
         bankruptcy, insolvency, fraudulent conveyance, reorganization,
         moratorium and similar laws now or hereafter in effect relating to
         creditors' rights and (B) that the remedy of specific performance and
         injunctive and other forms of equitable relief may be subject to
         equitable defenses and to the discretion of the court before which any
         proceedings therefor may be brought and (C) to the extent that the
         indemnification provisions contained in the Registration Rights
         Agreement may be limited by applicable laws.

                  (v)   The execution and delivery of this Agreement and the
         consummation of the transactions contemplated by this Agreement do not
         and will not conflict with or result in a breach by SELLER of any of
         the terms or provisions of, or constitute a default under, the
         certificate of incorporation (or charter) or by-laws of SELLER, or any
         indenture, mortgage, deed of trust or other material agreement or
         instrument to which SELLER is a party or by which it or any of its
         properties or assets are bound, or any existing applicable decree,
         judgment or order of any court, federal or state regulatory body,
         administrative agency or other governmental body having jurisdiction
         over SELLER or any of its properties or assets;

                  (vi)  No authorization, approval or consent of or filing with
         any federal, state or local governmental body of the United States is
         legally required for the issuance and sale of the Debentures and
         (provided no commission or other remuneration is paid or given directly
         or indirectly by SELLER for soliciting such conversion) the issuance of
         the Shares upon conversion of the Debentures in accordance with their
         terms, as contemplated by this Agreement, except the filing of a Form D
         with the Commission;

                                      -6-
<PAGE>   7


                  (vii)  To the best of the Company's knowledge after reasonable
         investigation, the information contained in the Company's Annual Report
         on Form 10K for the year ended December 31, 1996, Proxy statement
         relating to the Annual Meeting of Shareholders held on June 26, 1997 or
         Quarterly Report on Form 10-Q for the quarter ended June 30, 1997, as
         filed with the Commission does not contain any untrue statement of a
         material fact or omit to state any material fact necessary in order to
         make the statements therein, in the light of the circumstance under
         which they are made, not misleading. Since September 30, 1997, there
         has been no material adverse development in the business, properties,
         operations, financial condition or results of operations of SELLER.

                  (viii) SELLER will issue one or more certificates representing
         the Debentures in the name of BUYER in such denominations (in multiples
         of $25,000) to be specified by BUYER prior to closing and will issue
         one or more certificates representing the Shares in such denominations
         to be specified by Buyer upon conversion of the Debentures. SELLER
         further warrants that the Debentures and the Shares shall be
         transferable on the books and records of SELLER as and to the extent
         provided in the Transaction Documents, subject to compliance with
         Federal and State securities laws. Nothing in this Section shall affect
         in any way BUYER'S obligations and agreement to comply with all
         applicable securities laws upon resale of the Securities.


         4.       CLOSING. Debentures and Warrants shall be delivered to BUYER 
          and the funds therefor shall be delivered to SELLER on the 22nd day of
          October, 1997 (the "Closing") or at such time to be mutually agreed in
          accordance with the following procedures.

                  SELLER shall execute the appropriate copies of the Transaction
         Documents (the "Seller's Closing Documents") and deliver the executed
         documents to Gowling, Strathy & Henderson, counsel for BUYER, with
         instructions to hold the documents in trust and not to release the
         documents to BUYER until advised to do so by SELLER. BUYER shall
         execute the appropriate copies of the Transaction Documents (the
         "BUYER'S Closing Documents") and deliver the executed documents to
         Alston & Bird, counsel for SELLER, with instructions to hold the
         documents in trust and not to release the documents to SELLER until
         advised to do so by BUYER.

                  Immediately after BUYER has confirmed that its counsel has
         received the SELLER'S Closing Documents executed by SELLER, then BUYER
         shall pay to SELLER the principal amount of the Debentures for which
         BUYER subscribed (the "Purchase Price"). BUYER shall pay the Purchase
         Price, less all appropriate legal fees and commissions by wire transfer
         of immediately available funds in accordance with the following
         instructions:

                                      -7-

<PAGE>   8

                  Mellon Bank, Pittsburgh, P.A.
                  ABA# 0430-0026-1
                  Credit: Merrill Lynch
                  Acct# 101-1730
                  For further credit to CytRx Corporation
                  Acct# 701-96D69

                  On the banking day that SELLER has confirmed that its counsel
         has received the BUYER'S Closing Documents and is credited with having
         received the Purchase Price (the "Closing Date"), SELLER shall advise
         BUYER. Immediately thereafter, SELLER shall advise Gowling, Strathy &
         Henderson to release the SELLER'S Closing Documents to BUYER and BUYER
         shall advise Alston & Bird to release the BUYER'S Closing Documents to
         SELLER. The Transaction Documents shall not be deemed to have been
         delivered except in accordance with the procedure described in this
         Section 4.

                  If the Closing Date does not occur before October 23, 1997,
         then either party may terminate this Agreement immediately upon written
         notice to the other party and all Transaction Documents shall be deemed
         to be null and void.


         5.       CONDITIONS TO CLOSING

                  (i)  BUYER understands that SELLER'S obligation to sell the
         Debentures and the Warrants is conditioned upon the receipt in
         immediately available funds of the amount set forth in Paragraph 1
         hereof and an opinion of counsel substantially in the form attached as
         D to and forming an integral part of this Agreement, SELLER shall have
         the right to reject any given Agreement which is tendered to SELLER,
         for the reason that SELLER reasonably believes any representations and
         warranties of BUYER to be untrue and in such event SELLER shall provide
         BUYER written notice of such rejection and the reason therefore and
         shall provide reasonable opportunity for a response to such stated
         reason. Also, SELLER may decline to accept this Agreement for any other
         reason which in the sole discretion of SELLER may materially affect
         SELLER.

                  (ii) SELLER understands that BUYER'S obligation to purchase
         the Debentures is conditioned upon delivery of certificate(s)
         representing Debentures as described in Paragraph 1(ii) hereto and
         provision of an opinion of counsel attached as Exhibit E substantially
         in the form and forming an integral part of this Agreement.


         6.       SELLER'S OPTION ADDITIONAL $2,000,000 TO BUYER AND
                  OTHER CONCURRENT BUYERS CONVERSION AND
                  WARRANT PRICE

                                      -8-

<PAGE>   9

         SELLER shall have the option (the "Option") to require BUYER to
         purchase Four Hundred Thousand Dollars (USD $400,000) of additional
         Debentures at any time between 90 and 270 days (the "Option Period")
         after the Shelf Registration (as defined in the Rights Registration
         Agreement) has been declared effective by the Commission subject to the
         following conditions:

                  (i)   The ten day Average Closing Bid Price of the Shares 
         shall not be below $3.50 per share on (a) the day SELLER gives BUYER
         notice of SELLER'S election to exercise this Option and (b) the day
         before the closing of the Option;

                  (ii)  SELLER shall not be in default under any material
         borrowings from any financial institution or other persons;

                  (iii) the class of common stock into which the Debentures are
         convertible shall continue to be listed by Nasdaq; or

                  (iv)  the Company shall not have been convicted of any fraud 
         in the sale of its securities.

         The closing of the purchase of the additional Debentures will take
         place 10 business days after the day of SELLER'S notice to BUYER.

         With the exception of any further option in favour of SELLER, and the
         Conversion Price and Warrant Price and the maturity dates which will
         have to be reset, the terms and conditions in connection with the
         funding and closing of the Option will be the same as those relating to
         the initial funding of October, 1997.

         Provided however if the Black-Out Period as defined in Section 1(ii) of
         the Debenture is invoked, then the actual number of days of the
         Black-Out Period shall be added to each of the 90 and 270 days
         comprising the Option Period.

         If the Option is completed:

         "Average Closing Bid Price" for the purposes of this Section 6 means
         the average of the daily last bid price for the shares of Common Stock
         for the five (5) or ten (10), as the case may be, consecutive trading
         days on which such shares are actually traded as over-the-counter
         securities and quoted on Nasdaq National Market (as reported by
         Bloomberg Business News, or, if not reported thereby, any other
         authoritative source selected by the Company ending at the close of the
         trading on the trading day immediately preceding the measurement date.

         "Conversion Price" shall mean the lessor of (A:) one hundred ten
         percent (110%) of the five day Average Closing Bid Price, calculated
         using the closing date as the measurement date, or (B) eighty five
         percent (85%) of the ten day Average 

                                      -9-

<PAGE>   10

          Closing Bid Price calculated using the date of conversion as the
          measurement date, provided, however, but if the holder will have
          delivered a Forbearance Request to the Company in accordance with what
          is presently Section 5(ii) of the Debenture used in the October 1997
          Closing, within twenty-four (24) hours before it will have delivered a
          conversion notice of the Company in accordance with what is presently
          Section 4.3.1 of the Debenture, then the ten day Average Closing Bid
          Price for the portion of the debenture that the Holder will have
          identified in the Forbearance Request shall be calculated using either
          the date of conversion or the date the Company actually received such
          Forbearance Request as the measurement date, whichever results in a
          lower Conversion Price.

          "Exercise Price" for per share under each Warrant shall be one hundred
          ten percent (110%) of the five day Average Closing Bid Price
          calculated as of the Closing Date of the Option. The Exercise Price
          shall be paid in cash.

          "Right of First Refusal Period" shall mean the period that begins on
          the Closing Date and ends on the earlier of (a) the closing date of
          the Option, (b) the refusal of Buyer to purchase the Debentures
          covered by the Option because Seller failed to meet the conditions set
          forth in clauses (i) to (iv) above, or (c) the end of the Option
          Period.

          The "closing date" means the closing date of the Option.

          If, during the Right of First Refusal Period, but only ninety (90)
          days after the Closing Date the Company proposes to undertake an
          issuance of any securities pursuant to Regulations D or S promulgated
          under the Securities Act (the "New Securities"), then the Company
          shall give written notice of the Company's intention to BUYER,
          describing the type of the securities, and their price and the general
          terms upon which the Company proposes to issue the same. The Debenture
          is being issued in connection with debentures on similar terms to
          Charles N. Eckert, David Kosloff, Pine Street Asset Management and
          Gundyco in trust for R.R.S.P. 550-98866-19 (collectively, the "Other
          Buyers"). Each of the BUYER and the Other Buyer who remain Accredited
          Investors ("Qualified Buyer") shall have twenty (20) days after any
          such notice is mailed or delivered to agree to purchase all of such
          New Securities for the price and upon the terms specified in the
          notice by giving written notice to the Company and stating therein the
          quantity of New Securities to be purchased. Each of the Qualified
          Buyers shall be entitled to purchase New Securities in the proportion
          of its purchase of Debentures and if one or more buyers decline, or is
          not qualified, to so purchase, then the others, as the case may be,
          shall be entitled to purchase the New Securities not taken by the
          Qualified Buyer(s), as the case may be within the original twenty (20)
          day period.

          "New Securities" does not include (i) securities issued pursuant to
          the acquisition of another business entity or segment of any such
          entity by the Company by merger, asset purchase, stock purchase or
          otherwise, (ii) any borrowings, direct or

                                      -10-

<PAGE>   11

          indirect, from financial institutions or other persons by the Company,
          whether or not presently authorized, including any type of loan or
          payment evidenced by any type of debt instrument, provided such
          borrowings do not have any equity features including warrants, options
          or other rights to purchase capital stock and are not convertible into
          capital stock of the Company, (iii) securities issued to employees,
          consultants, officers or directors of the Company pursuant to any
          stock option, stock purchase or stock bonus plan, agreement or
          arrangement, (iv) securities issued to vendors or customers or to
          other persons in similar commercial situations with the Company, (v)
          securities issued in connection with obtaining lease financing,
          whether issued to a lessor, guarantor or other person, (vi) securities
          issued in connection with any stock split, stock dividend or
          recapitalization of the Company, or (vi) securities issued in
          connection with corporate partnering transactions.

          If the Qualified Buyers fail to exercise fully the right of first
          refusal within the prescribed twenty (20) day period, then the Company
          shall have one hundred twenty (120) days thereafter to sell or enter
          into an agreement to sell the New Securities, at a price and on terms
          no more favourable to the purchasers thereof than specified in the
          notice to the Qualified Buyers. If the Company has not sold or entered
          into an agreement to sell the New Securities in accordance with the
          foregoing within the one hundred twenty (120) day period, then the
          Company shall not thereafter issue or sell any New Securities, without
          first again offering such securities to the Qualified Buyers in
          accordance with this Section 6.


          7.       GOVERNING LAW; INTERPRETATION AND DISPUTES.
          This Agreement shall be governed by and construed under the laws of
          the State of Delaware and the laws applicable therein without regard
          to its choice of law principles.


          8.       ARBITRATION
          All disputes arising under this Agreement (other than claims in
          equity) shall be resolved by arbitration in accordance with the
          Commercial Arbitration Rules of the American Arbitration Association.
          Arbitration shall be by a single arbitrator experienced in the matters
          at issue and selected by the SELLER and BUYER in accordance with the
          Commercial Arbitration Rules of the American Arbitration Association.
          The arbitration shall be held in such place in New York, New York, as
          may be specified by the arbitrator (or any place agreed to by SELLER,
          BUYER and the arbitrator). The decision of the arbitrator shall be
          final and binding as to any matters submitted under this Agreement,
          provided, however, if necessary, such decision and satisfaction
          procedure may be enforced by either SELLER or BUYER in any court of
          record having jurisdiction over the subject matter or over any of the
          parties to this Agreement. All costs and expenses incurred in
          connection with any such arbitration proceeding (including reasonable
          attorneys fees) shall be borne by 

                                      -11-

<PAGE>   12

          the party against which the decision is rendered, or, if no decision
          is rendered, such costs and expenses shall be home equally by SELLER
          as one party and BUYER as the other party. If the arbitrator's
          decision is a compromise, the determination of which party or parties
          bears the costs and expenses incurred in connection with any such
          arbitration proceeding shall be made by the arbitrator on the basis of
          the arbitrator's assessment of the relative merits of the parties'
          positions.


          9.      CONFIDENTIALITY.

          The parties hereto agree to maintain the confidentiality of this
          Agreement and not to disclose to any person or entity information
          concerning the transaction contemplated hereby unless required by law
          to do so.


          10.     ENTIRE AGREEMENT.
          This Agreement constitutes the entire agreement among the parties
          hereof with respect to the subject matter hereof and supersedes any
          and all prior or contemporaneous representations, warranties,
          agreements and understandings in connection therewith. This Agreement
          may be amended only by a writing executed by all parties hereto. This
          Agreement may be executed in counterparts and the facsimile
          transmission of an executed counterpart to this Agreement shall be
          effective as an original.

          [Signatures begin on next page]


          11.     FULL NAME AND ADDRESS OF BUYER FOR REGISTRATION
                  PURPOSES:

          NAME:             Gundyco, in trust for R.R.S.P. 550-98866-19

          ADDRESS:          4120 Yonge Street

                            Suite 416

                            North York, Ontario M2P 2B8

          Tel.  No.         (416) 225-7980

          Fax.  No.         (416) 225-7950

          Contact Name:     Mark Shoom

                                      -12-

<PAGE>   13

         12.      DELIVERY INSTRUCTIONS: (IF DIFFERENT FROM REGISTRATION NAME):

         NAME:            
                                 -------------------------------
         ADDRESS:        
                                 -------------------------------

                                 -------------------------------

                                 -------------------------------
                                   


         Tel. No.       
                                 -------------------------------     
         Fax. No.                 
                                 -------------------------------
         Contact Name:     
                                 -------------------------------

         Special Instructions:      
                                 -------------------------------

                                 -------------------------------

                                 -------------------------------

                                      -13-

<PAGE>   14


         IN WITNESS WHEREOF, this Agreement was duly executed or the date first
written below.


Dated this 21st day of the month of October, 1997.


Company Name:         Gundyco, in trust for
                      R.R.S.P. 550-98866-19
                      by its Owner, Mark Shoom


By:               
                      ------------------------------
                      Mark Shoom

Title:                Owner

Country of Execution: Canada


                                CYTRX CORPORATION

                      By: 
                         ------------------------------------


         I have the full authority to bind CYTRX CORPORATION _________ (initial)

Name:             Jack J. Luchese

Title:            President

                                      -14-



<PAGE>   1
                                                                     EXHIBIT 2.2
                    PRIVATE SECURITIES SUBSCRIPTION AGREEMENT
                                CYTRX CORPORATION
                                (REGULATION "D")


         THIS PRIVATE SECURITIES SUBSCRIPTION AGREEMENT (hereinafter the
"Agreement") has been executed by the undersigned in connection with the
purchase in a private placement pursuant to Section 4(2) of the Securities Act
of 1933, as amended (the "Securities Act"), of certain debentures (hereinafter
the "Debentures"), convertible into shares of common stock (hereinafter the
"Shares"), and certain share purchase warrants (hereinafter the "Warrants") from
CytRx Corporation ("CYTR") 154 Technology Parkway, Technology Parkway, Atlanta,
Georgia, 30092, USA, a corporation organized under the laws of Delaware
(hereinafter the "COMPANY" or "SELLER") by Name: Excalibur Limited Partnership,
c/o H&H Securities Limited located at: 205 Vesta Drive; City: Toronto;
Province/State: Ontario; Zip/Postal Code: M5P 3A1; Country: Canada a limited
partnership organized under the laws of Ontario and Canada (hereinafter
"Buyer"). SELLER and BUYER (hereinafter collectively the "parties") each hereby
represents, warrants and agrees as follows:


         1.       AGREEMENT TO SUBSCRIBE; PURCHASE PRICE:

                  (i)   SELLER and BUYER are executing and delivering this
         Agreement in reliance upon the exemption from securities registration
         afforded by Rule 506 under Regulation D ("Regulation D") as promulgated
         by the United States Securities and Exchange Commission (the
         "Commission") under the Securities Act; and

                  (ii)  BUYER hereby subscribes for Four Hundred Thousand 
         Dollars (USD $400,000) U.S. principal amount of Debentures,
         substantially in the form attached as Exhibit A to and forming an
         integral part of this Agreement.

                  (iii) BUYER will receive 8,000 Warrants substantially in the
         form attached as Exhibit B to and forming an integral part of this
         Agreement. Each Warrant will entitle BUYER to purchase one treasury
         Common Share at the price of $5.68. The Warrants will expire two (2)
         years after the Closing; and

                  (iv)  BUYER shall on or before the Closing execute a copy of
         the Registration Rights Agreement (the "Registration Rights Agreement")
         substantially in the form attached as Exhibit "A" to and forming an
         integral part of this Agreement.

<PAGE>   2

         2.       BUYER'S REPRESENTATIONS

                  BUYER represents and warrants follows:

                  (i)    Authorization: Such BUYER has full power and authority 
         to enter into this Agreement, the Debenture, the Warrant and the
         Registration Rights Agreement (collectively, the "Transaction
         Documents") and that the Transaction Documents, when executed and
         delivered will constitute a valid and legally binding obligation of
         BUYER in accordance with their terms, subject to (A) bankruptcy,
         insolvency, fraudulent conveyance, reorganization, moratorium and
         similar laws now or hereafter in effect relating to creditors' rights
         and (B) that the remedy of specific performance and injunctive and
         other forms of equitable relief may be subject to equitable defenses
         and to the discretion of the court before which any proceedings
         therefor may be brought and (C) to the extent that the indemnification
         provisions contained in the Registration Rights Agreement may be
         limited by applicable laws.

                  (ii)   Purchase Entirely for Own Account. This Agreement is 
         made with BUYER in reliance upon BUYER'S representation to the Company,
         which by such BUYER'S execution of this Agreement BUYER hereby
         confirms, that the Debentures and Warrants to be purchased by BUYER and
         the Common Stock issuable upon conversion thereof (collectively, the
         "Securities") will be acquired for investment for BUYERS own account,
         not a nominee as agent, and not with a view to the resale or
         distribution of any part thereof. By execution of this Agreement, Buyer
         further represents that Buyer does not have any contract, undertaking,
         agreement or arrangement with any person, to sell, transfer or grant
         participation to such person or to any third person, with respect to
         any of the Securities.

                  (iii)  Reliance Upon BUYER'S Representations. BUYER 
         understands that the Debentures and the Warrants are not, and any
         Common Stock acquired on conversion thereof at the time of issuance may
         not be, registered under the Securities Act on the ground that the sale
         provided for in this Agreement and the issuance of securities hereunder
         is exempt from registration under the Securities Act pursuant to
         Section 4(2) thereof and that the Company's reliance on such exemption
         is predicated on the BUYERS' representations set forth herein. Buyer
         also understands that no prospectus or offering memorandum has been
         received by Buyer or filed by the Seller with any Canadian securities
         commission or similar authority in connection with the sale of the
         Debentures and Warrants, and that no prospectus or offering memorandum
         shall be received by the Seller or so filed by Buyer in connection with
         any sale of Shares issued on the conversion of the Debentures or
         Warrants, and that as a result the Buyer will be unable to rely upon
         civil or contractual remedies that might otherwise be available to it
         if the Debentures, Warrants and/or Shares had been issued by the Seller
         by way of a prospectus or offering memorandum, respectively, and the
         prospectus or offering 

<PAGE>   3

          memorandum, as the case may be, contained a misrepresentation as that
          term is defined in the Securities Act (Ontario).

                  (iv)   Buyer is not a corporation, syndicate, partnership or
          other form of unincorporated entity or corporation created solely to
          permit the purchase of the Securities by a group of individuals who
          individual share in the aggregate acquisition cost of the Securities
          is less than $150,000 and Buyer is not purchasing the Securities as
          the result of an advertisement of the Securities, including an
          advertisement in printed media of general and regular paid
          circulation, radio or television.

                  (v)    BUYER believes BUYER has received all the information
          BUYER considers necessary or appropriate for deciding whether to
          purchase any of the Securities. BUYER further represents that BUYER
          has had an opportunity to ask questions and receive answers from the
          Company regarding the terms and conditions of the offering any of the
          Securities and the business, properties, prospects, and financial
          condition of the Company and to obtain additional information (to the
          extent the Company possessed such information or could acquire it
          without reasonable effort or expense) necessary to verify the accuracy
          of any information furnished to BUYER or to which BUYER had access.

                  (vi)   BUYER represents that BUYER is experienced in 
         evaluating and investing in private placement transactions of
         securities of companies in a similar stage of development and
         acknowledges that BUYER is able to fend for himself, herself or itself,
         can bear the economic risk of BUYER'S investment, and has such
         knowledge and experience in financial and business matters that BUYER
         is capable of evaluating the merits and risks of the investment in the
         Debentures and Warrants. If other than an individual, BUYER also
         represents BUYER has not been organized for the purpose of acquiring
         the Debentures and Warrants.

                  (vii)  The BUYER represents that BUYER is an Accredited
         Investor.

                  The term "Accredited Investor" as used herein refers to:

                  (1)      A person or entity who is a direct or executive 
                           officer of the Company;

                  (2)      Any bank as defined in Section 3(a)(2) of the
                           Securities Act, or any savings and loan association
                           or other institution as defined in section 3(a)(5)(A)
                           of the Securities Act whether acting in its
                           individual or fiduciary capacity; any broker or
                           dealer registered pursuant to Section 15 of the
                           Securities Exchange Act of 1934; any insurance
                           company as defined in Section 2(13) of the Securities
                           Act; any investment company registered under the
                           Investment Company Act of 1940 or a business
                           development company as 

                                      -3-

<PAGE>   4

                    defined in Section 2(a(48) of that Act; any Small Business
                    Investment Company licensed by the U.S. Small Business
                    Administration under Section 301 (c) or (d) of the Small
                    Business Investment Act of 1958; any plan established and
                    maintained by a state, its political subdivisions, or any
                    agency or instrumentality of a state or its political
                    subdivisions, for the benefit of its employees, if such plan
                    has total assets in excess of $5,000,000; any employee
                    benefit plan within the meaning of Title I of the Employee
                    Retirement Income Security Act of 1974, if the investment
                    decision is made by a plan fiduciary, as defined in Section
                    3(21)of such Act, which is either a bank, savings and loan
                    association, insurance company or registered investment
                    adviser, or if the employee benefit plan has total assets in
                    excess of $5,000,000 or, if a self-directed plan, with
                    investment decisions made solely by the persons that are
                    Accredited Investors.

           (3)      Any private business development company as defined in
                    section 202(a)(22) of the Investment Advisers Act of 1940;

           (4)      Any organization described in Section 501(c)(3) of the
                    Internal Revenue Code, corporation, Massachusetts or similar
                    business trust, or partnership, not formed for the specific
                    purpose of acquiring the securities offered, with total
                    assets in excess of $5,000,000;

           (5)      Any natural person whose individual net worth, or joint net
                    worth with that person's spouse, at the time of the purchase
                    exceeds $1,000,000;

           (6)      Any natural person who had an individual income in excess of
                    $200,000 in each of the two most recent years or joint
                    income with that person's spouse in excess of $300,000 in
                    each of those years and has a reasonable expectation of
                    reaching the same income level in the current year;

           (7)      Any trust, with total assets in excess of $5,000,000, not
                    formed for the specific purpose of acquiring the securities
                    offered, whose purchase is directed by a person who has such
                    knowledge and experience in financial and business matters
                    that he or she is capable of evaluating the merits and risks
                    of the prospective investment; or

           (8)      Any entity in which all of the equity owners are Accredited
                    Investors.

                                      -4-

<PAGE>   5

         As used in this Paragraph 3.(vii) the term "net worth" means the
         excesses of total assets over total liabilities. For the purpose of
         determining a person's net worth, the principal residence owned by an
         individual should be valued at fair market value, including the cost of
         improvements, net of current encumbrances. As used in this paragraph
         "income" means actual economic income, which may differ from adjusted
         gross income for income tax purposes. Accordingly, Buyer should
         consider whether Buyer should add any or all of the following items to
         Buyer's adjusted gross income for income tax purposes in order to
         reflect more accurately Buyer's actual economic income; any amounts
         attributable to tax-exempt income received, losses claimed as a limited
         partner in any limited partnership, deductions claimed for depletion,
         contributions an IRA or keogh retirement plan, and alimony payments.

                  (viii) BUYER understands that the Securities may not be sold,
         transferred or otherwise disposed of in the United States without
         registration under the Securities Act or an exemption therefrom, and
         that in the absence of an effective registration statement covering any
         of the Securities or an available exemption from registration under the
         Securities Act, the Securities must be held indefinitely. In
         particular, BUYER is aware that the Securities may not be sold pursuant
         to Rule 144 promulgated under the Securities Act unless all of the
         condition of that Rule are met. BUYER also understands that any resale
         of the Securities must be conducted in accordance with the applicable
         requirements of the Securities Act (Ontario).

                  (ix)   Buyer acknowledges that no person has made to Buyer any
         written or oral representations:

                  (i)    that any person will resell or repurchase the 
         Securities;

                  (ii)   that any person will refund the purchase price of the 
         Securities; and

                  (iii)  as to the future price or value of the Securities.


         3.       SELLER'S REPRESENTATIONS

                  SELLER represents and warrants as follows:

                  (i)    SELLER has not conducted any general solicitation or 
         general advertising (as defined in Regulation D) with respect to any 
         of the Securities offered hereby;

                  (ii)   The Debentures, when issued and delivered pursuant to 
         the terms of this Agreement, will have been duly authorized, executed,
         issued and delivered and will constitute valid and legally binding
         obligations of the Company in 

                                      -5-

<PAGE>   6

          accordance with their terms, subject to (A) bankruptcy, insolvency,
          fraudulent conveyance, reorganization, moratorium and similar laws now
          or hereafter in effect relating to creditors' rights and (B) that the
          remedy of specific performance and injunctive and other forms of
          equitable relief may be subject to equitable defenses and to the
          discretion of the court before which any proceedings therefor may be
          brought and (C) to the extent that the indemnification provisions
          contained in the Registration Rights Agreement may be limited by
          applicable laws.

                  (iii) The Shares, when issued and delivered upon conversion
          of the Debentures in accordance with their terms, will be duly and
          validly authorized and issued, fully-paid and non assessable and will
          not subject the holders thereof to personal liability by reason of
          being such holders. There are no preemptive rights of any shareholder
          of SELLER with respect to the Shares contained in SELLER'S Certificate
          of Incorporation or any agreement to which SELLER is a party;

                  (iv)  This Agreement has been duly authorized, validly 
          executed and delivered on behalf of SELLER and is a valid and binding
          agreement of SELLER in accordance with its terms, subject to (A)
          bankruptcy, insolvency, fraudulent conveyance, reorganization,
          moratorium and similar laws now or hereafter in effect relating to
          creditors' rights and (B) that the remedy of specific performance and
          injunctive and other forms of equitable relief may be subject to
          equitable defenses and to the discretion of the court before which any
          proceedings therefor may be brought and (C) to the extent that the
          indemnification provisions contained in the Registration Rights
          Agreement may be limited by applicable laws.

                  (v)   The execution and delivery of this Agreement and the
          consummation of the transactions contemplated by this Agreement do not
          and will not conflict with or result in a breach by SELLER of any of
          the terms or provisions of, or constitute a default under, the
          certificate of incorporation (or charter) or by-laws of SELLER, or any
          indenture, mortgage, deed of trust or other material agreement or
          instrument to which SELLER is a party or by which it or any of its
          properties or assets are bound, or any existing applicable decree,
          judgment or order of any court, federal or state regulatory body,
          administrative agency or other governmental body having jurisdiction
          over SELLER or any of its properties or assets;

                  (vi)  No authorization, approval or consent of or filing with
          any federal, state or local governmental body of the United States is
          legally required for the issuance and sale of the Debentures and
          (provided no commission or other remuneration is paid or given
          directly or indirectly by SELLER for soliciting such conversion) the
          issuance of the Shares upon conversion of the Debentures in accordance
          with their terms, as contemplated by this Agreement, except the filing
          of a Form D with the Commission;

                                      -6-

<PAGE>   7

                  (vii)  To the best of the Company's knowledge after reasonable
          investigation, the information contained in the Company's Annual
          Report on Form 10K for the year ended December 31, 1996, Proxy
          statement relating to the Annual Meeting of Shareholders held on June
          26, 1997 or Quarterly Report on Form 10-Q for the quarter ended June
          30, 1997, as filed with the Commission does not contain any untrue
          statement of a material fact or omit to state any material fact
          necessary in order to make the statements therein, in the light of the
          circumstance under which they are made, not misleading. Since
          September 30, 1997, there has been no material adverse development in
          the business, properties, operations, financial condition or results
          of operations of SELLER.

                  (viii) SELLER will issue one or more certificates representing
          the Debentures in the name of BUYER in such denominations (in
          multiples of $25,000) to be specified by BUYER prior to closing and
          will issue one or more certificates representing the Shares in such
          denominations to be specified by Buyer upon conversion of the
          Debentures. SELLER further warrants that the Debentures and the Shares
          shall be transferable on the books and records of SELLER as and to the
          extent provided in the Transaction Documents, subject to compliance
          with Federal and State securities laws. Nothing in this Section shall
          affect in any way BUYER'S obligations and agreement to comply with all
          applicable securities laws upon resale of the Securities.


          4.      CLOSING. Debentures and Warrants shall be delivered to BUYER 
          and the funds therefor shall be delivered to SELLER on the 22nd day of
          October, 1997 (the "Closing") or at such time to be mutually agreed in
          accordance with the following procedures.

                  SELLER shall execute the appropriate copies of the     
          Transaction Documents (the "Seller's Closing Documents") and
          deliver the executed documents to Gowling, Strathy & Henderson,
          counsel for BUYER, with instructions to hold the documents in trust
          and not to release the documents to BUYER until advised to do so by
          SELLER. BUYER shall execute the appropriate copies of the Transaction
          Documents (the "BUYER'S Closing Documents") and deliver the executed
          documents to Alston & Bird, counsel for SELLER, with instructions to
          hold the documents in trust and not to release the documents to
          SELLER until advised to do so by BUYER.

                  Immediately after BUYER has confirmed that its counsel has
          received the SELLER'S Closing Documents executed by SELLER, then BUYER
          shall pay to SELLER the principal amount of the Debentures for which
          BUYER subscribed (the "Purchase Price"). BUYER shall pay the Purchase
          Price, less all appropriate legal fees and commissions by wire
          transfer of immediately available funds in accordance with the
          following instructions:

                                      -7-

<PAGE>   8

                  Mellon Bank, Pittsburgh, P.A.
                  ABA# 0430-0026-1
                  Credit: Merrill Lynch
                  Acct# 101-1730
                  For further credit to CytRx Corporation
                  Acct# 701-96D69

                  On the banking day that SELLER has confirmed that its counsel
         has received the BUYER'S Closing Documents and is credited with having
         received the Purchase Price (the "Closing Date"), SELLER shall advise
         BUYER. Immediately thereafter, SELLER shall advise Gowling, Strathy &
         Henderson to release the SELLER'S Closing Documents to BUYER and BUYER
         shall advise Alston & Bird to release the BUYER'S Closing Documents to
         SELLER. The Transaction Documents shall not be deemed to have been
         delivered except in accordance with the procedure described in this
         Section 4.

                  If the Closing Date does not occur before October 23, 1997,
         then either party may terminate this Agreement immediately upon written
         notice to the other party and all Transaction Documents shall be deemed
         to be null and void.


         5.       CONDITIONS TO CLOSING

                  (i)  BUYER understands that SELLER'S obligation to sell the
         Debentures and the Warrants is conditioned upon the receipt in
         immediately available funds of the amount set forth in Paragraph 1
         hereof and an opinion of counsel substantially in the form attached as
         D to and forming an integral part of this Agreement, SELLER shall have
         the right to reject any given Agreement which is tendered to SELLER,
         for the reason that SELLER reasonably believes any representations and
         warranties of BUYER to be untrue and in such event SELLER shall provide
         BUYER written notice of such rejection and the reason therefore and
         shall provide reasonable opportunity for a response to such stated
         reason. Also, SELLER may decline to accept this Agreement for any other
         reason which in the sole discretion of SELLER may materially affect
         SELLER.

                  (ii) SELLER understands that BUYER'S obligation to purchase
         the Debentures is conditioned upon delivery of certificate(s)
         representing Debentures as described in Paragraph 1(ii) hereto and
         provision of an opinion of counsel attached as Exhibit E substantially
         in the form and forming an integral part of this Agreement.


         6.       SELLER'S OPTION ADDITIONAL $2,000,000 TO BUYER AND
                  OTHER CONCURRENT BUYERS CONVERSION AND
                  WARRANT PRICE

                                      -8-

<PAGE>   9


         SELLER shall have the option (the "Option") to require BUYER to
         purchase Four Hundred Thousand Dollars (USD $400,000) of additional
         Debentures at any time between 90 and 270 days (the "Option Period")
         after the Shelf Registration (as defined in the Rights Registration
         Agreement) has been declared effective by the Commission subject to the
         following conditions:

                  (i)   The ten day Average Closing Bid Price of the Shares 
         shall not be below $3.50 per share on (a) the day SELLER gives BUYER 
         notice of SELLER'S election to exercise this Option and (b) the day 
         before the closing of the Option;

                  (ii)  SELLER shall not be in default under any material
         borrowings from any financial institution or other persons;

                  (iii) the class of common stock into which the Debentures are
         convertible shall continue to be listed by Nasdaq; or

                  (iv)  the Company shall not have been convicted of any fraud 
         in the sale of its securities.

         The closing of the purchase of the additional Debentures will take
         place 10 business days after the day of SELLER'S notice to BUYER.

         With the exception of any further option in favour of SELLER, and the
         Conversion Price and Warrant Price and the maturity dates which will
         have to be reset, the terms and conditions in connection with the
         funding and closing of the Option will be the same as those relating to
         the initial funding of October, 1997.

         Provided however if the Black-Out Period as defined in Section 1(ii) of
         the Debenture is invoked, then the actual number of days of the
         Black-Out Period shall be added to each of the 90 and 270 days
         comprising the Option Period.

         If the Option is completed:

         "Average Closing Bid Price" for the purposes of this Section 6 means
         the average of the daily last bid price for the shares of Common Stock
         for the five (5) or ten (10), as the case may be, consecutive trading
         days on which such shares are actually traded as over-the-counter
         securities and quoted on Nasdaq National Market (as reported by
         Bloomberg Business News, or, if not reported thereby, any other
         authoritative source selected by the Company ending at the close of the
         trading on the trading day immediately preceding the measurement date.

         "Conversion Price" shall mean the lessor of (A:) one hundred ten
         percent (110%) of the five day Average Closing Bid Price, calculated
         using the closing date as the measurement date, or (B) eighty five
         percent (85%) of the ten day Average 

                                      -9-

<PAGE>   10

          Closing Bid Price calculated using the date of conversion as the
          measurement date, provided, however, but if the holder will have
          delivered a Forbearance Request to the Company in accordance with what
          is presently Section 5(ii) of the Debenture used in the October 1997
          Closing, within twenty-four (24) hours before it will have delivered a
          conversion notice of the Company in accordance with what is presently
          Section 4.3.1 of the Debenture, then the ten day Average Closing Bid
          Price for the portion of the debenture that the Holder will have
          identified in the Forbearance Request shall be calculated using either
          the date of conversion or the date the Company actually received such
          Forbearance Request as the measurement date, whichever results in a
          lower Conversion Price.

          "Exercise Price" for per share under each Warrant shall be one hundred
          ten percent (110%) of the five day Average Closing Bid Price
          calculated as of the Closing Date of the Option. The Exercise Price
          shall be paid in cash.

          "Right of First Refusal Period" shall mean the period that begins on
          the Closing Date and ends on the earlier of (a) the closing date of
          the Option, (b) the refusal of Buyer to purchase the Debentures
          covered by the Option because Seller failed to meet the conditions set
          forth in clauses (i) to (iv) above, or (c) the end of the Option
          Period.

          The "closing date" means the closing date of the Option.

          If, during the Right of First Refusal Period, but only ninety (90)
          days after the Closing Date the Company proposes to undertake an
          issuance of any securities pursuant to Regulations D or S promulgated
          under the Securities Act (the "New Securities"), then the Company
          shall give written notice of the Company's intention to BUYER,
          describing the type of the securities, and their price and the general
          terms upon which the Company proposes to issue the same. The Debenture
          is being issued in connection with debentures on similar terms to
          Charles N. Eckert, David Kosloff, Pine Street Asset Management and
          Gundyco in trust for R.R.S.P. 550-98866-19 (collectively, the "Other
          Buyers"). Each of the BUYER and the Other Buyer who remain Accredited
          Investors ("Qualified Buyer") shall have twenty (20) days after any
          such notice is mailed or delivered to agree to purchase all of such
          New Securities for the price and upon the terms specified in the
          notice by giving written notice to the Company and stating therein the
          quantity of New Securities to be purchased. Each of the Qualified
          Buyers shall be entitled to purchase New Securities in the proportion
          of its purchase of Debentures and if one or more buyers decline, or is
          not qualified, to so purchase, then the others, as the case may be,
          shall be entitled to purchase the New Securities not taken by the
          Qualified Buyer(s), as the case may be within the original twenty (20)
          day period.

          "New Securities" does not include (i) securities issued pursuant to
          the acquisition of another business entity or segment of any such
          entity by the Company by merger, asset purchase, stock purchase or
          otherwise, (ii) any borrowings, direct or

                                      -10-

<PAGE>   11

          indirect, from financial institutions or other persons by the Company,
          whether or not presently authorized, including any type of loan or
          payment evidenced by any type of debt instrument, provided such
          borrowings do not have any equity features including warrants, options
          or other rights to purchase capital stock and are not convertible into
          capital stock of the Company, (iii) securities issued to employees,
          consultants, officers or directors of the Company pursuant to any
          stock option, stock purchase or stock bonus plan, agreement or
          arrangement, (iv) securities issued to vendors or customers or to
          other persons in similar commercial situations with the Company, (v)
          securities issued in connection with obtaining lease financing,
          whether issued to a lessor, guarantor or other person, (vi) securities
          issued in connection with any stock split, stock dividend or
          recapitalization of the Company, or (vi) securities issued in
          connection with corporate partnering transactions.

          If the Qualified Buyers fail to exercise fully the right of first
          refusal within the prescribed twenty (20) day period, then the Company
          shall have one hundred twenty (120) days thereafter to sell or enter
          into an agreement to sell the New Securities, at a price and on terms
          no more favourable to the purchasers thereof than specified in the
          notice to the Qualified Buyers. If the Company has not sold or entered
          into an agreement to sell the New Securities in accordance with the
          foregoing within the one hundred twenty (120) day period, then the
          Company shall not thereafter issue or sell any New Securities, without
          first again offering such securities to the Qualified Buyers in
          accordance with this Section 6.


          7.       GOVERNING LAW; INTERPRETATION AND DISPUTES.
          This Agreement shall be governed by and construed under the laws of
          the State of Delaware and the laws applicable therein without regard
          to its choice of law principles.


          8.       ARBITRATION
          All disputes arising under this Agreement (other than claims in
          equity) shall be resolved by arbitration in accordance with the
          Commercial Arbitration Rules of the American Arbitration Association.
          Arbitration shall be by a single arbitrator experienced in the matters
          at issue and selected by the SELLER and BUYER in accordance with the
          Commercial Arbitration Rules of the American Arbitration Association.
          The arbitration shall be held in such place in New York, New York, as
          may be specified by the arbitrator (or any place agreed to by SELLER,
          BUYER and the arbitrator). The decision of the arbitrator shall be
          final and binding as to any matters submitted under this Agreement,
          provided, however, if necessary, such decision and satisfaction
          procedure may be enforced by either SELLER or BUYER in any court of
          record having jurisdiction over the subject matter or over any of the
          parties to this Agreement. All costs and expenses incurred in
          connection with any such arbitration proceeding (including reasonable
          attorneys fees) shall be borne by 

                                      -11-

<PAGE>   12

          the party against which the decision is rendered, or, if no decision
          is rendered, such costs and expenses shall be home equally by SELLER
          as one party and BUYER as the other party. If the arbitrator's
          decision is a compromise, the determination of which party or parties
          bears the costs and expenses incurred in connection with any such
          arbitration proceeding shall be made by the arbitrator on the basis of
          the arbitrator's assessment of the relative merits of the parties'
          positions.


          9.      CONFIDENTIALITY.
          The parties hereto agree to maintain the confidentiality of this
          Agreement and not to disclose to any person or entity information
          concerning the transaction contemplated hereby unless required by law
          to do so.


          10.     ENTIRE AGREEMENT.
          This Agreement constitutes the entire agreement among the parties
          hereof with respect to the subject matter hereof and supersedes any
          and all prior or contemporaneous representations, warranties,
          agreements and understandings in connection therewith. This Agreement
          may be amended only by a writing executed by all parties hereto. This
          Agreement may be executed in counterparts and the facsimile
          transmission of an executed counterpart to this Agreement shall be
          effective as an original.

          [Signatures begin on next page]


          11.     FULL NAME AND ADDRESS OF BUYER FOR REGISTRATION
                  PURPOSES:

          NAME:             Excalibur Limited Partnership

          ADDRESS:          c/o H&H Securities Limited

                            205 Vesta Drive

                            Toronto, Ontario M5P 3AI

          Tel. No.          (416) 964-9077

          Fax. No.          (416) 964-8868

          Contact Name:     William S. Hechter


          12.     DELIVERY INSTRUCTIONS: (IF DIFFERENT FROM REGISTRATION NAME):

                                      -12-

<PAGE>   13


         NAME:             
                                -----------------------------

         ADDRESS:          
                                -----------------------------

                                -----------------------------

                                -----------------------------

         Tel.  No.                  
                                -----------------------------
         Fax.  No.                 
                                -----------------------------
         Contact Name:    
                                -----------------------------
         Special Instructions:  
                                -----------------------------

                                -----------------------------

                                -----------------------------

                                      -13-

<PAGE>   14



         IN WITNESS WHEREOF, this Agreement was duly executed or the date first
         written below.


Dated this 21st day of the month of October, 1997.


Company Name:         Excalibur Limited Partnership.
                      by its General Partner,
                      Excalibur Capital Management Inc.


By:                      
                      -------------------------------
                      William S. Hechter

Title:                President

Country of Execution: Canada


                                CYTRX CORPORATION

                        By: 
                           ----------------------------------

     I have the full authority to bind CYTRX CORPORATION _________ (initial)

Name:    Jack J. Luchese

Title:   President





<PAGE>   1

                                                                     EXHIBIT 2.3

                    PRIVATE SECURITIES SUBSCRIPTION AGREEMENT
                                CYTRX CORPORATION
                                (REGULATION "D")


         THIS PRIVATE SECURITIES SUBSCRIPTION AGREEMENT (hereinafter the
"Agreement") has been executed by the undersigned in connection with the
purchase in a private placement pursuant to Section 4(2) of the Securities Act
of 1933, as amended (the "Securities Act"), of certain debentures (hereinafter
the "Debentures"), convertible into shares of common stock (hereinafter the
"Shares"), and certain share purchase warrants (hereinafter the "Warrants") from
CytRx Corporation ("CYTR") 154 Technology Parkway, Technology Parkway, Atlanta,
Georgia, 30092, USA, a corporation organized under the laws of Delaware
(hereinafter the "COMPANY" or "SELLER") by Name: Pine Asset Management located
at: c/o Shipley Raidy Capital Partners, One Tower Bridge, Suite 1370; City: West
Conshohocken; Province/State: Pennsylvania; Zip/Postal 19428; Country: U.S.A. a
limited partnership organized under the laws of the State of Pennsylvania and
the U.S.A. (hereinafter "BUYER"). SELLER and BUYER (hereinafter collectively the
"parties") each hereby represents, warrants and agrees as follows:


         1.       AGREEMENT TO SUBSCRIBE; PURCHASE PRICE:

                  (i)   SELLER and BUYER are executing and delivering this
         Agreement in reliance upon the exemption from securities registration
         afforded by Rule 506 under Regulation D ("Regulation D") as promulgated
         by the United States Securities and Exchange Commission (the
         "Commission") under the Securities Act; and

                  (ii)  BUYER hereby subscribes for Four Hundred Thousand
         Dollars (USD $400,000) U.S. principal amount of Debentures,
         substantially in the form attached as Exhibit A to and forming an
         integral part of this Agreement.

                  (iii) BUYER will receive 8,000 Warrants substantially in the
         form attached as Exhibit B to and forming an integral part of this
         Agreement. Each Warrant will entitle BUYER to purchase one treasury
         Common Share at the price of $5.68. The Warrants will expire two (2)
         years after the Closing; and

                  (iv)  BUYER shall on or before the Closing execute a copy of
         the Registration Rights Agreement (the "Registration Rights Agreement")
         substantially in the form attached as Exhibit "A" to and forming an
         integral part of this Agreement.


<PAGE>   2

         2.       BUYER'S REPRESENTATIONS

                  BUYER represents and warrants follows:

                  (i)   Authorization: Such BUYER has full power and authority
         to enter into this Agreement, the Debenture, the Warrant and the
         Registration Rights Agreement (collectively, the "Transaction
         Documents") and that the Transaction Documents, when executed and
         delivered will constitute a valid and legally binding obligation of
         BUYER in accordance with their terms, subject to (A) bankruptcy,
         insolvency, fraudulent conveyance, reorganization, moratorium and
         similar laws now or hereafter in effect relating to creditors' rights
         and (B) that the remedy of specific performance and injunctive and
         other forms of equitable relief may be subject to equitable defenses
         and to the discretion of the court before which any proceedings
         therefor may be brought and (C) to the extent that the indemnification
         provisions contained in the Registration Rights Agreement may be
         limited by applicable laws.

                  (ii)  Purchase Entirely for Own Account. This Agreement is
         made with BUYER in reliance upon BUYER'S representation to the Company,
         which by such BUYER'S execution of this Agreement BUYER hereby
         confirms, that the Debentures and Warrants to be purchased by BUYER and
         the Common Stock issuable upon conversion thereof (collectively, the
         "Securities") will be acquired for investment for BUYERS own account,
         not a nominee as agent, and not with a view to the resale or
         distribution of any part thereof. By execution of this Agreement, Buyer
         further represents that Buyer does not have any contract, undertaking,
         agreement or arrangement with any person, to sell, transfer or grant
         participation to such person or to any third person, with respect to
         any of the Securities.

                  (iii) Reliance Upon BUYER'S Representations. BUYER understands
         that the Debentures and the Warrants are not, and any Common Stock
         acquired on conversion thereof at the time of issuance may not be,
         registered under the Securities Act on the ground that the sale
         provided for in this Agreement and the issuance of securities hereunder
         is exempt from registration under the Securities Act pursuant to
         Section 4(2) thereof and that the Company's reliance on such exemption
         is predicated on the BUYERS' representations set forth herein. Buyer
         also understands that no prospectus or offering memorandum has been
         received by Buyer or filed by the Seller with any Canadian securities
         commission or similar authority in connection with the sale of the
         Debentures and Warrants, and that no prospectus or offering memorandum
         shall be received by the Seller or so filed by Buyer in connection with
         any sale of Shares issued on the conversion of the Debentures or
         Warrants, and that as a result the Buyer will be unable to rely upon
         civil or contractual remedies that might otherwise be available to it
         if the Debentures, Warrants and/or Shares had been issued by the Seller
         by way of a prospectus or offering memorandum, respectively, and the
         prospectus or offering 


                                      -2-

<PAGE>   3

         memorandum, as the case may be, contained a misrepresentation as that
         term is defined in the Securities Act (Ontario).

                  (iv)  Buyer is not a corporation, syndicate, partnership or
         other form of unincorporated entity or corporation created solely to
         permit the purchase of the Securities by a group of individuals who
         individual share in the aggregate acquisition cost of the Securities is
         less than $150,000 and Buyer is not purchasing the Securities as the
         result of an advertisement of the Securities, including an
         advertisement in printed media of general and regular paid circulation,
         radio or television.

                  (v)   BUYER believes BUYER has received all the information
         BUYER considers necessary or appropriate for deciding whether to
         purchase any of the Securities. BUYER further represents that BUYER has
         had an opportunity to ask questions and receive answers from the
         Company regarding the terms and conditions of the offering any of the
         Securities and the business, properties, prospects, and financial
         condition of the Company and to obtain additional information (to the
         extent the Company possessed such information or could acquire it
         without reasonable effort or expense) necessary to verify the accuracy
         of any information furnished to BUYER or to which BUYER had access.

                  (vi)  BUYER represents that BUYER is experienced in evaluating
         and investing in private placement transactions of securities of
         companies in a similar stage of development and acknowledges that BUYER
         is able to fend for himself, herself or itself, can bear the economic
         risk of BUYER'S investment, and has such knowledge and experience in
         financial and business matters that BUYER is capable of evaluating the
         merits and risks of the investment in the Debentures and Warrants. If
         other than an individual, BUYER also represents BUYER has not been
         organized for the purpose of acquiring the Debentures and Warrants.

                  (vii) The BUYER represents that BUYER is an Accredited
         Investor.

                  The term "Accredited Investor" as used herein refers to:

                  (1)      A person or entity who is a direct or executive
                           officer of the Company;

                  (2)      Any bank as defined in Section 3(a)(2) of the
                           Securities Act, or any savings and loan association
                           or other institution as defined in section 3(a)(5)(A)
                           of the Securities Act whether acting in its
                           individual or fiduciary capacity; any broker or
                           dealer registered pursuant to Section 15 of the
                           Securities Exchange Act of 1934; any insurance
                           company as defined in Section 2(13) of the Securities
                           Act; any investment company registered under the
                           Investment Company Act of 1940 or a business
                           development company as 


                                      -3-

<PAGE>   4

                           defined in Section 2(a(48) of that Act; any Small
                           Business Investment Company licensed by the U.S.
                           Small Business Administration under Section 301 (c)
                           or (d) of the Small Business Investment Act of 1958;
                           any plan established and maintained by a state, its
                           political subdivisions, or any agency or
                           instrumentality of a state or its political
                           subdivisions, for the benefit of its employees, if
                           such plan has total assets in excess of $5,000,000;
                           any employee benefit plan within the meaning of Title
                           I of the Employee Retirement Income Security Act of
                           1974, if the investment decision is made by a plan
                           fiduciary, as defined in Section 3(21)of such Act,
                           which is either a bank, savings and loan association,
                           insurance company or registered investment adviser,
                           or if the employee benefit plan has total assets in
                           excess of $5,000,000 or, if a self-directed plan,
                           with investment decisions made solely by the persons
                           that are Accredited Investors.

                  (3)      Any private business development company as defined
                           in section 202(a)(22) of the Investment Advisers Act
                           of 1940;

                  (4)      Any organization described in Section 501(c)(3) of
                           the Internal Revenue Code, corporation, Massachusetts
                           or similar business trust, or partnership, not formed
                           for the specific purpose of acquiring the securities
                           offered, with total assets in excess of $5,000,000;

                  (5)      Any natural person whose individual net worth, or
                           joint net worth with that person's spouse, at the
                           time of the purchase exceeds $1,000,000;

                  (6)      Any natural person who had an individual income in
                           excess of $200,000 in each of the two most recent
                           years or joint income with that person's spouse in
                           excess of $300,000 in each of those years and has a
                           reasonable expectation of reaching the same income
                           level in the current year;

                  (7)      Any trust, with total assets in excess of $5,000,000,
                           not formed for the specific purpose of acquiring the
                           securities offered, whose purchase is directed by a
                           person who has such knowledge and experience in
                           financial and business matters that he or she is
                           capable of evaluating the merits and risks of the
                           prospective investment; or

                  (8)      Any entity in which all of the equity owners are
                           Accredited Investors.


                                      -4-

<PAGE>   5


         As used in this Paragraph 3.(vii) the term "net worth" means the
         excesses of total assets over total liabilities. For the purpose of
         determining a person's net worth, the principal residence owned by an
         individual should be valued at fair market value, including the cost of
         improvements, net of current encumbrances. As used in this paragraph
         "income" means actual economic income, which may differ from adjusted
         gross income for income tax purposes. Accordingly, Buyer should
         consider whether Buyer should add any or all of the following items to
         Buyer's adjusted gross income for income tax purposes in order to
         reflect more accurately Buyer's actual economic income; any amounts
         attributable to tax-exempt income received, losses claimed as a limited
         partner in any limited partnership, deductions claimed for depletion,
         contributions an IRA or keogh retirement plan, and alimony payments.

                  (viii) BUYER understands that the Securities may not be sold,
         transferred or otherwise disposed of in the United States without
         registration under the Securities Act or an exemption therefrom, and
         that in the absence of an effective registration statement covering any
         of the Securities or an available exemption from registration under the
         Securities Act, the Securities must be held indefinitely. In
         particular, BUYER is aware that the Securities may not be sold pursuant
         to Rule 144 promulgated under the Securities Act unless all of the
         condition of that Rule are met. BUYER also understands that any resale
         of the Securities must be conducted in accordance with the applicable
         requirements of the Securities Act (Ontario).

                  (ix)   Buyer acknowledges that no person has made to Buyer any
         written or oral representations:

                  (i)    that any person will resell or repurchase the
                         Securities;

                  (ii)   that any person will refund the purchase price of the
                         Securities; and

                  (iii)  as to the future price or value of the Securities.


         3.       SELLER'S REPRESENTATIONS

                  SELLER represents and warrants as follows:

                  (i)    SELLER has not conducted any general solicitation or
         general advertising (as defined in Regulation D) with respect to any of
         the Securities offered hereby;

                  (ii)   The Debentures, when issued and delivered pursuant to 
         the terms of this Agreement, will have been duly authorized, executed,
         issued and delivered and will constitute valid and legally binding
         obligations of the Company in 


                                      -5-

<PAGE>   6

         accordance with their terms, subject to (A) bankruptcy, insolvency,
         fraudulent conveyance, reorganization, moratorium and similar laws now
         or hereafter in effect relating to creditors' rights and (B) that the
         remedy of specific performance and injunctive and other forms of
         equitable relief may be subject to equitable defenses and to the
         discretion of the court before which any proceedings therefor may be
         brought and (C) to the extent that the indemnification provisions
         contained in the Registration Rights Agreement may be limited by
         applicable laws.

                  (iii) The Shares, when issued and delivered upon conversion of
         the Debentures in accordance with their terms, will be duly and validly
         authorized and issued, fully-paid and non assessable and will not
         subject the holders thereof to personal liability by reason of being
         such holders. There are no preemptive rights of any shareholder of
         SELLER with respect to the Shares contained in SELLER'S Certificate of
         Incorporation or any agreement to which SELLER is a party;

                  (iv)  This Agreement has been duly authorized, validly
         executed and delivered on behalf of SELLER and is a valid and binding
         agreement of SELLER in accordance with its terms, subject to (A)
         bankruptcy, insolvency, fraudulent conveyance, reorganization,
         moratorium and similar laws now or hereafter in effect relating to
         creditors' rights and (B) that the remedy of specific performance and
         injunctive and other forms of equitable relief may be subject to
         equitable defenses and to the discretion of the court before which any
         proceedings therefor may be brought and (C) to the extent that the
         indemnification provisions contained in the Registration Rights
         Agreement may be limited by applicable laws.

                  (v)   The execution and delivery of this Agreement and the
         consummation of the transactions contemplated by this Agreement do not
         and will not conflict with or result in a breach by SELLER of any of
         the terms or provisions of, or constitute a default under, the
         certificate of incorporation (or charter) or by-laws of SELLER, or any
         indenture, mortgage, deed of trust or other material agreement or
         instrument to which SELLER is a party or by which it or any of its
         properties or assets are bound, or any existing applicable decree,
         judgment or order of any court, federal or state regulatory body,
         administrative agency or other governmental body having jurisdiction
         over SELLER or any of its properties or assets;

                  (vi)  No authorization, approval or consent of or filing with
         any federal, state or local governmental body of the United States is
         legally required for the issuance and sale of the Debentures and
         (provided no commission or other remuneration is paid or given directly
         or indirectly by SELLER for soliciting such conversion) the issuance of
         the Shares upon conversion of the Debentures in accordance with their
         terms, as contemplated by this Agreement, except the filing of a Form D
         with the Commission;


                                      -6-

<PAGE>   7

                  (vii)  To the best of the Company's knowledge after reasonable
         investigation, the information contained in the Company's Annual Report
         on Form 10K for the year ended December 31, 1996, Proxy statement
         relating to the Annual Meeting of Shareholders held on June 26, 1997 or
         Quarterly Report on Form 10-Q for the quarter ended June 30, 1997, as
         filed with the Commission does not contain any untrue statement of a
         material fact or omit to state any material fact necessary in order to
         make the statements therein, in the light of the circumstance under
         which they are made, not misleading. Since September 30, 1997, there
         has been no material adverse development in the business, properties,
         operations, financial condition or results of operations of SELLER.

                  (viii) SELLER will issue one or more certificates representing
         the Debentures in the name of BUYER in such denominations (in multiples
         of $25,000) to be specified by BUYER prior to closing and will issue
         one or more certificates representing the Shares in such denominations
         to be specified by Buyer upon conversion of the Debentures. SELLER
         further warrants that the Debentures and the Shares shall be
         transferable on the books and records of SELLER as and to the extent
         provided in the Transaction Documents, subject to compliance with
         Federal and State securities laws. Nothing in this Section shall affect
         in any way BUYER'S obligations and agreement to comply with all
         applicable securities laws upon resale of the Securities.


         4.       CLOSING. Debentures and Warrants shall be delivered to BUYER
         and the funds therefor shall be delivered to SELLER on the 22nd day 
         of October, 1997 (the "Closing") or at such time to be mutually agreed
         in accordance with the following procedures.

                  SELLER shall execute the appropriate copies of the Transaction
         Documents (the "SELLER'S Closing Documents") and deliver the executed
         documents to Gowling, Strathy & Henderson, counsel for BUYER, with
         instructions to hold the documents in trust and not to release the
         documents to BUYER until advised to do so by SELLER. BUYER shall
         execute the appropriate copies of the Transaction Documents (the
         "BUYER'S Closing Documents") and deliver the executed documents to
         Alston & Bird, counsel for SELLER, with instructions to hold the
         documents in trust and not to release the documents to SELLER until
         advised to do so by BUYER.

                  Immediately after BUYER has confirmed that its counsel has
         received the SELLER'S Closing Documents executed by SELLER, then BUYER
         shall pay to SELLER the principal amount of the Debentures for which
         BUYER subscribed (the "Purchase Price"). BUYER shall pay the Purchase
         Price, less all appropriate legal fees and commissions by wire transfer
         of immediately available funds in accordance with the following
         instructions:


                                      -7-

<PAGE>   8

                  Mellon Bank, Pittsburgh, P.A.
                  ABA# 0430-0026-1
                  Credit: Merrill Lynch
                  Acct# 101-1730
                  For further credit to CytRx Corporation
                  Acct# 701-96D69

                  On the banking day that SELLER has confirmed that its counsel
         has received the BUYER'S Closing Documents and is credited with having
         received the Purchase Price (the "Closing Date"), SELLER shall advise
         BUYER. Immediately thereafter, SELLER shall advise Gowling, Strathy &
         Henderson to release the SELLER'S Closing Documents to BUYER and BUYER
         shall advise Alston & Bird to release the BUYER'S Closing Documents to
         SELLER. The Transaction Documents shall not be deemed to have been
         delivered except in accordance with the procedure described in this
         Section 4.

                  If the Closing Date does not occur before October 23, 1997,
         then either party may terminate this Agreement immediately upon written
         notice to the other party and all Transaction Documents shall be deemed
         to be null and void.


         5.       CONDITIONS TO CLOSING

                  (i)  BUYER understands that SELLER'S obligation to sell the
         Debentures and the Warrants is conditioned upon the receipt in
         immediately available funds of the amount set forth in Paragraph 1
         hereof and an opinion of counsel substantially in the form attached as
         D to and forming an integral part of this Agreement, SELLER shall have
         the right to reject any given Agreement which is tendered to SELLER,
         for the reason that SELLER reasonably believes any representations and
         warranties of BUYER to be untrue and in such event SELLER shall provide
         BUYER written notice of such rejection and the reason therefore and
         shall provide reasonable opportunity for a response to such stated
         reason. Also, SELLER may decline to accept this Agreement for any other
         reason which in the sole discretion of SELLER may materially affect
         SELLER.

                  (ii) SELLER understands that BUYER'S obligation to purchase
         the Debentures is conditioned upon delivery of certificate(s)
         representing Debentures as described in Paragraph 1(ii) hereto and
         provision of an opinion of counsel attached as Exhibit E substantially
         in the form and forming an integral part of this Agreement.


         6.       SELLER'S OPTION ADDITIONAL $2,000,000 TO BUYER AND
                  OTHER CONCURRENT BUYERS CONVERSION AND
                  WARRANT PRICE


                                      -8-

<PAGE>   9

         SELLER shall have the option (the "Option") to require BUYER to
         purchase Four Hundred Thousand Dollars (USD $400,000) of additional
         Debentures at any time between 90 and 270 days (the "Option Period")
         after the Shelf Registration (as defined in the Rights Registration
         Agreement) has been declared effective by the Commission subject to the
         following conditions:

                  (i)   The ten day Average Closing Bid Price of the Shares
         shall not be below $3.50 per share on (a) the day SELLER gives BUYER
         notice of SELLER'S election to exercise this Option and (b) the day
         before the closing of the Option;

                  (ii)  SELLER shall not be in default under any material
         borrowings from any financial institution or other persons;

                  (iii) the class of common stock into which the Debentures are
         convertible shall continue to be listed by Nasdaq; or

                  (iv)  the Company shall not have been convicted of any fraud
         in the sale of its securities.

         The closing of the purchase of the additional Debentures will take
         place 10 business days after the day of SELLER'S notice to BUYER.

         With the exception of any further option in favour of SELLER, and the
         Conversion Price and Warrant Price and the maturity dates which will
         have to be reset, the terms and conditions in connection with the
         funding and closing of the Option will be the same as those relating to
         the initial funding of October, 1997.

         Provided however if the Black-Out Period as defined in Section 1(ii) of
         the Debenture is invoked, then the actual number of days of the
         Black-Out Period shall be added to each of the 90 and 270 days
         comprising the Option Period.

         If the Option is completed:

         "Average Closing Bid Price" for the purposes of this Section 6 means
         the average of the daily last bid price for the shares of Common Stock
         for the five (5) or ten (10), as the case may be, consecutive trading
         days on which such shares are actually traded as over-the-counter
         securities and quoted on Nasdaq National Market (as reported by
         Bloomberg Business News, or, if not reported thereby, any other
         authoritative source selected by the Company ending at the close of the
         trading on the trading day immediately preceding the measurement date.

         "Conversion Price" shall mean the lessor of (A:) one hundred ten
         percent (110%) of the five day Average Closing Bid Price, calculated
         using the closing date as the measurement date, or (B) eighty five
         percent (85%) of the ten day Average


                                      -9-

<PAGE>   10

         Closing Bid Price calculated using the date of conversion as the
         measurement date, provided, however, but if the holder will have
         delivered a Forbearance Request to the Company in accordance with what
         is presently Section 5(ii) of the Debenture used in the October 1997
         Closing, within twenty-four (24) hours before it will have delivered a
         conversion notice of the Company in accordance with what is presently
         Section 4.3.1 of the Debenture, then the ten day Average Closing Bid
         Price for the portion of the debenture that the Holder will have
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

         "Exercise Price" for per share under each Warrant shall be one hundred
         ten percent (110%) of the five day Average Closing Bid Price calculated
         as of the Closing Date of the Option. The Exercise Price shall be paid
         in cash.

         "Right of First Refusal Period" shall mean the period that begins on
         the Closing Date and ends on the earlier of (a) the closing date of the
         Option, (b) the refusal of Buyer to purchase the Debentures covered by
         the Option because Seller failed to meet the conditions set forth in
         clauses (i) to (iv) above, or (c) the end of the Option Period.

         The "closing date" means the closing date of the Option.

         If, during the Right of First Refusal Period, but only ninety (90) days
         after the Closing Date the Company proposes to undertake an issuance of
         any securities pursuant to Regulations D or S promulgated under the
         Securities Act (the "New Securities"), then the Company shall give
         written notice of the Company's intention to BUYER, describing the type
         of the securities, and their price and the general terms upon which the
         Company proposes to issue the same. The Debenture is being issued in
         connection with debentures on similar terms to Charles N. Eckert, David
         Kosloff, Pine Street Asset Management and Gundyco in trust for R.R.S.P.
         550-98866-19 (collectively, the "Other Buyers"). Each of the BUYER and
         the Other Buyer who remain Accredited Investors ("Qualified Buyer")
         shall have twenty (20) days after any such notice is mailed or
         delivered to agree to purchase all of such New Securities for the price
         and upon the terms specified in the notice by giving written notice to
         the Company and stating therein the quantity of New Securities to be
         purchased. Each of the Qualified Buyers shall be entitled to purchase
         New Securities in the proportion of its purchase of Debentures and if
         one or more buyers decline, or is not qualified, to so purchase, then
         the others, as the case may be, shall be entitled to purchase the New
         Securities not taken by the Qualified Buyer(s), as the case may be
         within the original twenty (20) day period.

         "New Securities" does not include (i) securities issued pursuant to the
         acquisition of another business entity or segment of any such entity by
         the Company by merger, asset purchase, stock purchase or otherwise,
         (ii) any borrowings, direct or 


                                      -10-


<PAGE>   11

         indirect, from financial institutions or other persons by the Company,
         whether or not presently authorized, including any type of loan or
         payment evidenced by any type of debt instrument, provided such
         borrowings do not have any equity features including warrants, options
         or other rights to purchase capital stock and are not convertible into
         capital stock of the Company, (iii) securities issued to employees,
         consultants, officers or directors of the Company pursuant to any stock
         option, stock purchase or stock bonus plan, agreement or arrangement,
         (iv) securities issued to vendors or customers or to other persons in
         similar commercial situations with the Company, (v) securities issued
         in connection with obtaining lease financing, whether issued to a
         lessor, guarantor or other person, (vi) securities issued in connection
         with any stock split, stock dividend or recapitalization of the
         Company, or (vi) securities issued in connection with corporate
         partnering transactions.

         If the Qualified Buyers fail to exercise fully the right of first
         refusal within the prescribed twenty (20) day period, then the Company
         shall have one hundred twenty (120) days thereafter to sell or enter
         into an agreement to sell the New Securities, at a price and on terms
         no more favourable to the purchasers thereof than specified in the
         notice to the Qualified Buyers. If the Company has not sold or entered
         into an agreement to sell the New Securities in accordance with the
         foregoing within the one hundred twenty (120) day period, then the
         Company shall not thereafter issue or sell any New Securities, without
         first again offering such securities to the Qualified Buyers in
         accordance with this Section 6.


         7.       GOVERNING LAW; INTERPRETATION AND DISPUTES.
         This Agreement shall be governed by and construed under the laws of the
         State of Delaware and the laws applicable therein without regard to its
         choice of law principles.


         8.       ARBITRATION
         All disputes arising under this Agreement (other than claims in equity)
         shall be resolved by arbitration in accordance with the Commercial
         Arbitration Rules of the American Arbitration Association. Arbitration
         shall be by a single arbitrator experienced in the matters at issue and
         selected by the SELLER and BUYER in accordance with the Commercial
         Arbitration Rules of the American Arbitration Association. The
         arbitration shall be held in such place in New York, New York, as may
         be specified by the arbitrator (or any place agreed to by SELLER, BUYER
         and the arbitrator). The decision of the arbitrator shall be final and
         binding as to any matters submitted under this Agreement, provided,
         however, if necessary, such decision and satisfaction procedure may be
         enforced by either SELLER or BUYER in any court of record having
         jurisdiction over the subject matter or over any of the parties to this
         Agreement. All costs and expenses incurred in connection with any such
         arbitration proceeding (including reasonable attorneys fees) shall be
         borne by 


                                      -11-


<PAGE>   12

         the party against which the decision is rendered, or, if no decision is
         rendered, such costs and expenses shall be home equally by SELLER as
         one party and BUYER as the other party. If the arbitrator's decision is
         a compromise, the determination of which party or parties bears the
         costs and expenses incurred in connection with any such arbitration
         proceeding shall be made by the arbitrator on the basis of the
         arbitrator's assessment of the relative merits of the parties'
         positions.


         9.  CONFIDENTIALITY.
         The parties hereto agree to maintain the confidentiality of this
         Agreement and not to disclose to any person or entity information
         concerning the transaction contemplated hereby unless required by law
         to do so.


         10. ENTIRE AGREEMENT.
         This Agreement constitutes the entire agreement among the parties
         hereof with respect to the subject matter hereof and supersedes any and
         all prior or contemporaneous representations, warranties, agreements
         and understandings in connection therewith. This Agreement may be
         amended only by a writing executed by all parties hereto. This
         Agreement may be executed in counterparts and the facsimile
         transmission of an executed counterpart to this Agreement shall be
         effective as an original.

         [Signatures begin on next page]


         11. FULL NAME AND ADDRESS OF BUYER FOR REGISTRATION
             PURPOSES:

         NAME:             Pine Street Asset Management

         ADDRESS:          One Tower Bridge

                           Suite 1370

                           West Conshohocken, Pennsylvania 19428 U.S.A.

         Tel. No.          (610) 941-9090

         Fax. No.          (610) 828-4131

         Contact Name:     Kevin Raidy


                                      -12-


<PAGE>   13

         12.      DELIVERY INSTRUCTIONS: (IF DIFFERENT FROM REGISTRATION NAME):

         NAME:
                                    ----------------------------

         ADDRESS:
                                    ----------------------------

                                    ----------------------------

                                    ----------------------------


         Tel. No.
                                    ----------------------------
         Fax. No.
                                    ----------------------------
         Contact Name:
                                    ----------------------------

         Special Instructions:
                                    ----------------------------

                                    ----------------------------

                                    ----------------------------


                                      -13-

<PAGE>   14


         IN WITNESS WHEREOF, this Agreement was duly executed or the date first
         written below.


Dated this 21st day of the month of October, 1997.


Company Name:              Pine Street Asset Management
                           by its General Partner, Samuel Shipley


By:
                           --------------------------------------
                           Samuel Shipley

Title:                     General Partner

Country of Execution:      U.S.A.


                                CYTRX CORPORATION

                        By: 
                            -----------------------------


         I have the full authority to bind CYTRX CORPORATION _________ (initial)

Name:             Jack J. Luchese

Title:            President


                                      -14-


<PAGE>   1
                                                                     EXHIBIT 2.4

                    PRIVATE SECURITIES SUBSCRIPTION AGREEMENT
                                CYTRX CORPORATION
                                (REGULATION "D")


         THIS PRIVATE SECURITIES SUBSCRIPTION AGREEMENT (hereinafter the
"Agreement") has been executed by the undersigned in connection with the
purchase in a private placement pursuant to Section 4(2) of the Securities Act
of 1933, as amended (the "Securities Act"), of certain debentures (hereinafter
the "Debentures"), convertible into shares of common stock (hereinafter the
"Shares"), and certain share purchase warrants (hereinafter the "Warrants") from
CytRx Corporation ("CYTR") 154 Technology Parkway, Technology Parkway, Atlanta,
Georgia, 30092, USA, a corporation organized under the laws of Delaware
(hereinafter the "COMPANY" or "SELLER") by Name: Charles N. Eckert located at:
c/o Shipley Raidy Capital Partners, One Tower Bridge, Suite 1370; City: West
Conshohocken; Province/State: Pennsylvania; Zip/Postal Code: 19428; Country:
U.S.A., an individual resident in the State of Pennsylvania (hereinafter
"BUYER"). SELLER and BUYER (hereinafter collectively the "parties") each hereby
represents, warrants and agrees as follows:


         1.       AGREEMENT TO SUBSCRIBE; PURCHASE PRICE:

                  (i)   SELLER and BUYER are executing and delivering this
         Agreement in reliance upon the exemption from securities registration
         afforded by Rule 506 under Regulation D ("Regulation D") as promulgated
         by the United States Securities and Exchange Commission (the
         "Commission") under the Securities Act; and

                  (ii)  BUYER hereby subscribes for Four Hundred Thousand 
         Dollars (USD $400,000) U.S. principal amount of Debentures, 
         substantially in the form attached as Exhibit A to and forming an 
         integral part of this Agreement.

                  (iii) BUYER will receive 8,000 Warrants substantially in the
         form attached as Exhibit B to and forming an integral part of this
         Agreement. Each Warrant will entitle BUYER to purchase one treasury
         Common Share at the price of $5.68. The Warrants will expire two (2)
         years after the Closing; and

                  (iv)  BUYER shall on or before the Closing execute a copy of
         the Registration Rights Agreement (the "Registration Rights Agreement")
         substantially in the form attached as Exhibit "A" to and forming an
         integral part of this Agreement.


<PAGE>   2


         2.       BUYER'S REPRESENTATIONS

                  BUYER represents and warrants follows:

                  (i)   Authorization: Such BUYER has full power and authority
         to enter into this Agreement, the Debenture, the Warrant and the
         Registration Rights Agreement (collectively, the "Transaction
         Documents") and that the Transaction Documents, when executed and
         delivered will constitute a valid and legally binding obligation of
         BUYER in accordance with their terms, subject to (A) bankruptcy,
         insolvency, fraudulent conveyance, reorganization, moratorium and
         similar laws now or hereafter in effect relating to creditors' rights
         and (B) that the remedy of specific performance and injunctive and
         other forms of equitable relief may be subject to equitable defenses
         and to the discretion of the court before which any proceedings
         therefor may be brought and (C) to the extent that the indemnification
         provisions contained in the Registration Rights Agreement may be
         limited by applicable laws.

                  (ii)  Purchase Entirely for Own Account. This Agreement is 
         made with BUYER in reliance upon BUYER'S representation to the Company,
         which by such BUYER'S execution of this Agreement BUYER hereby
         confirms, that the Debentures and Warrants to be purchased by BUYER and
         the Common Stock issuable upon conversion thereof (collectively, the
         "Securities") will be acquired for investment for BUYERS own account,
         not a nominee as agent, and not with a view to the resale or
         distribution of any part thereof. By execution of this Agreement, Buyer
         further represents that Buyer does not have any contract, undertaking,
         agreement or arrangement with any person, to sell, transfer or grant
         participation to such person or to any third person, with respect to
         any of the Securities.

                  (iii) Reliance Upon BUYER'S Representations. BUYER understands
         that the Debentures and the Warrants are not, and any Common Stock
         acquired on conversion thereof at the time of issuance may not be,
         registered under the Securities Act on the ground that the sale
         provided for in this Agreement and the issuance of securities hereunder
         is exempt from registration under the Securities Act pursuant to
         Section 4(2) thereof and that the Company's reliance on such exemption
         is predicated on the BUYERS' representations set forth herein. Buyer
         also understands that no prospectus or offering memorandum has been
         received by Buyer or filed by the Seller with any Canadian securities
         commission or similar authority in connection with the sale of the
         Debentures and Warrants, and that no prospectus or offering memorandum
         shall be received by the Seller or so filed by Buyer in connection with
         any sale of Shares issued on the conversion of the Debentures or
         Warrants, and that as a result the Buyer will be unable to rely upon
         civil or contractual remedies that might otherwise be available to it
         if the Debentures, Warrants and/or Shares had been issued by the Seller
         by way of a prospectus or offering memorandum, respectively, and the
         prospectus or offering 


                                       -2-

<PAGE>   3

         memorandum, as the case may be, contained a misrepresentation as that
         term is defined in the Securities Act (Ontario).

                  (iv)  Buyer is not a corporation, syndicate, partnership or
         other form of unincorporated entity or corporation created solely to
         permit the purchase of the Securities by a group of individuals who
         individual share in the aggregate acquisition cost of the Securities is
         less than $150,000 and Buyer is not purchasing the Securities as the
         result of an advertisement of the Securities, including an
         advertisement in printed media of general and regular paid circulation,
         radio or television.

                  (v)   BUYER believes BUYER has received all the information
         BUYER considers necessary or appropriate for deciding whether to
         purchase any of the Securities. BUYER further represents that BUYER has
         had an opportunity to ask questions and receive answers from the
         Company regarding the terms and conditions of the offering any of the
         Securities and the business, properties, prospects, and financial
         condition of the Company and to obtain additional information (to the
         extent the Company possessed such information or could acquire it
         without reasonable effort or expense) necessary to verify the accuracy
         of any information furnished to BUYER or to which BUYER had access.

                  (vi)  BUYER represents that BUYER is experienced in evaluating
         and investing in private placement transactions of securities of
         companies in a similar stage of development and acknowledges that BUYER
         is able to fend for himself, herself or itself, can bear the economic
         risk of BUYER'S investment, and has such knowledge and experience in
         financial and business matters that BUYER is capable of evaluating the
         merits and risks of the investment in the Debentures and Warrants. If
         other than an individual, BUYER also represents BUYER has not been
         organized for the purpose of acquiring the Debentures and Warrants.

                  (vii) The BUYER represents that BUYER is an Accredited
         Investor.

                  The term "Accredited Investor" as used herein refers to:

                  (1)      A person or entity who is a direct or executive
                           officer of the Company;

                  (2)      Any bank as defined in Section 3(a)(2) of the
                           Securities Act, or any savings and loan association
                           or other institution as defined in section 3(a)(5)(A)
                           of the Securities Act whether acting in its
                           individual or fiduciary capacity; any broker or
                           dealer registered pursuant to Section 15 of the
                           Securities Exchange Act of 1934; any insurance
                           company as defined in Section 2(13) of the Securities
                           Act; any investment company registered under the
                           Investment Company Act of 1940 or a business
                           development company as 


                                      -3-

<PAGE>   4

                           defined in Section 2(a(48) of that Act; any Small
                           Business Investment Company licensed by the U.S.
                           Small Business Administration under Section 301 (c)
                           or (d) of the Small Business Investment Act of 1958;
                           any plan established and maintained by a state, its
                           political subdivisions, or any agency or
                           instrumentality of a state or its political
                           subdivisions, for the benefit of its employees, if
                           such plan has total assets in excess of $5,000,000;
                           any employee benefit plan within the meaning of Title
                           I of the Employee Retirement Income Security Act of
                           1974, if the investment decision is made by a plan
                           fiduciary, as defined in Section 3(21)of such Act,
                           which is either a bank, savings and loan association,
                           insurance company or registered investment adviser,
                           or if the employee benefit plan has total assets in
                           excess of $5,000,000 or, if a self-directed plan,
                           with investment decisions made solely by the persons
                           that are Accredited Investors.

                  (3)      Any private business development company as defined
                           in section 202(a)(22) of the Investment Advisers Act
                           of 1940;

                  (4)      Any organization described in Section 501(c)(3) of
                           the Internal Revenue Code, corporation, Massachusetts
                           or similar business trust, or partnership, not formed
                           for the specific purpose of acquiring the securities
                           offered, with total assets in excess of $5,000,000;

                  (5)      Any natural person whose individual net worth, or
                           joint net worth with that person's spouse, at the
                           time of the purchase exceeds $1,000,000;

                  (6)      Any natural person who had an individual income in
                           excess of $200,000 in each of the two most recent
                           years or joint income with that person's spouse in
                           excess of $300,000 in each of those years and has a
                           reasonable expectation of reaching the same income
                           level in the current year;

                  (7)      Any trust, with total assets in excess of $5,000,000,
                           not formed for the specific purpose of acquiring the
                           securities offered, whose purchase is directed by a
                           person who has such knowledge and experience in
                           financial and business matters that he or she is
                           capable of evaluating the merits and risks of the
                           prospective investment; or

                  (8)      Any entity in which all of the equity owners are
                           Accredited Investors.


                                      -4-


<PAGE>   5

         As used in this Paragraph 3.(vii) the term "net worth" means the
         excesses of total assets over total liabilities. For the purpose of
         determining a person's net worth, the principal residence owned by an
         individual should be valued at fair market value, including the cost of
         improvements, net of current encumbrances. As used in this paragraph
         "income" means actual economic income, which may differ from adjusted
         gross income for income tax purposes. Accordingly, Buyer should
         consider whether Buyer should add any or all of the following items to
         Buyer's adjusted gross income for income tax purposes in order to
         reflect more accurately Buyer's actual economic income; any amounts
         attributable to tax-exempt income received, losses claimed as a limited
         partner in any limited partnership, deductions claimed for depletion,
         contributions an IRA or keogh retirement plan, and alimony payments.

                  (viii) BUYER understands that the Securities may not be sold,
         transferred or otherwise disposed of in the United States without
         registration under the Securities Act or an exemption therefrom, and
         that in the absence of an effective registration statement covering any
         of the Securities or an available exemption from registration under the
         Securities Act, the Securities must be held indefinitely. In
         particular, BUYER is aware that the Securities may not be sold pursuant
         to Rule 144 promulgated under the Securities Act unless all of the
         condition of that Rule are met. BUYER also understands that any resale
         of the Securities must be conducted in accordance with the applicable
         requirements of the Securities Act (Ontario).

                  (ix)   Buyer acknowledges that no person has made to Buyer any
         written or oral representations:

                  (i)    that any person will resell or repurchase the
                         Securities;

                  (ii)   that any person will refund the purchase price of the
                         Securities; and

                  (iii)  as to the future price or value of the Securities.


         3.       SELLER'S REPRESENTATIONS

                  SELLER represents and warrants as follows:

                  (i)    SELLER has not conducted any general solicitation or
         general advertising (as defined in Regulation D) with respect to any of
         the Securities offered hereby;

                  (ii)   The Debentures, when issued and delivered pursuant to 
         the terms of this Agreement, will have been duly authorized, executed,
         issued and delivered and will constitute valid and legally binding
         obligations of the Company in 


                                      -5-


<PAGE>   6

         accordance with their terms, subject to (A) bankruptcy, insolvency,
         fraudulent conveyance, reorganization, moratorium and similar laws now
         or hereafter in effect relating to creditors' rights and (B) that the
         remedy of specific performance and injunctive and other forms of
         equitable relief may be subject to equitable defenses and to the
         discretion of the court before which any proceedings therefor may be
         brought and (C) to the extent that the indemnification provisions
         contained in the Registration Rights Agreement may be limited by
         applicable laws.

                  (iii) The Shares, when issued and delivered upon conversion of
         the Debentures in accordance with their terms, will be duly and validly
         authorized and issued, fully-paid and non assessable and will not
         subject the holders thereof to personal liability by reason of being
         such holders. There are no preemptive rights of any shareholder of
         SELLER with respect to the Shares contained in SELLER'S Certificate of
         Incorporation or any agreement to which SELLER is a party;

                  (iv)  This Agreement has been duly authorized, validly
         executed and delivered on behalf of SELLER and is a valid and binding
         agreement of SELLER in accordance with its terms, subject to (A)
         bankruptcy, insolvency, fraudulent conveyance, reorganization,
         moratorium and similar laws now or hereafter in effect relating to
         creditors' rights and (B) that the remedy of specific performance and
         injunctive and other forms of equitable relief may be subject to
         equitable defenses and to the discretion of the court before which any
         proceedings therefor may be brought and (C) to the extent that the
         indemnification provisions contained in the Registration Rights
         Agreement may be limited by applicable laws.

                  (v)   The execution and delivery of this Agreement and the
         consummation of the transactions contemplated by this Agreement do not
         and will not conflict with or result in a breach by SELLER of any of
         the terms or provisions of, or constitute a default under, the
         certificate of incorporation (or charter) or by-laws of SELLER, or any
         indenture, mortgage, deed of trust or other material agreement or
         instrument to which SELLER is a party or by which it or any of its
         properties or assets are bound, or any existing applicable decree,
         judgment or order of any court, federal or state regulatory body,
         administrative agency or other governmental body having jurisdiction
         over SELLER or any of its properties or assets;

                  (vi)  No authorization, approval or consent of or filing with
         any federal, state or local governmental body of the United States is
         legally required for the issuance and sale of the Debentures and
         (provided no commission or other remuneration is paid or given directly
         or indirectly by SELLER for soliciting such conversion) the issuance of
         the Shares upon conversion of the Debentures in accordance with their
         terms, as contemplated by this Agreement, except the filing of a Form D
         with the Commission;


                                      -6-

<PAGE>   7

                  (vii) To the best of the Company's knowledge after reasonable
         investigation, the information contained in the Company's Annual Report
         on Form 10K for the year ended December 31, 1996, Proxy statement
         relating to the Annual Meeting of Shareholders held on June 26, 1997 or
         Quarterly Report on Form 10-Q for the quarter ended June 30, 1997, as
         filed with the Commission does not contain any untrue statement of a
         material fact or omit to state any material fact necessary in order to
         make the statements therein, in the light of the circumstance under
         which they are made, not misleading. Since September 30, 1997, there
         has been no material adverse development in the business, properties,
         operations, financial condition or results of operations of SELLER.

                  (viii) SELLER will issue one or more certificates representing
         the Debentures in the name of BUYER in such denominations (in multiples
         of $25,000) to be specified by BUYER prior to closing and will issue
         one or more certificates representing the Shares in such denominations
         to be specified by Buyer upon conversion of the Debentures. SELLER
         further warrants that the Debentures and the Shares shall be
         transferable on the books and records of SELLER as and to the extent
         provided in the Transaction Documents, subject to compliance with
         Federal and State securities laws. Nothing in this Section shall affect
         in any way BUYER'S obligations and agreement to comply with all
         applicable securities laws upon resale of the Securities.


         4. CLOSING. Debentures and Warrants shall be delivered to BUYER and the
         funds therefor shall be delivered to SELLER on the 22nd day of October,
         1997 (the "Closing") or at such time to be mutually agreed in
         accordance with the following procedures.

                  SELLER shall execute the appropriate copies of the Transaction
         Documents (the "SELLER'S Closing Documents") and deliver the executed
         documents to Gowling, Strathy & Henderson, counsel for BUYER, with
         instructions to hold the documents in trust and not to release the
         documents to BUYER until advised to do so by SELLER. BUYER shall
         execute the appropriate copies of the Transaction Documents (the
         "BUYER'S Closing Documents") and deliver the executed documents to
         Alston & Bird, counsel for SELLER, with instructions to hold the
         documents in trust and not to release the documents to SELLER until
         advised to do so by BUYER.

                  Immediately after BUYER has confirmed that its counsel has
         received the SELLER'S Closing Documents executed by SELLER, then BUYER
         shall pay to SELLER the principal amount of the Debentures for which
         BUYER subscribed (the "Purchase Price"). BUYER shall pay the Purchase
         Price, less all appropriate legal fees and commissions by wire transfer
         of immediately available funds in accordance with the following
         instructions:


                                      -7-

<PAGE>   8

                  Mellon Bank, Pittsburgh, P.A.
                  ABA# 0430-0026-1
                  Credit: Merrill Lynch
                  Acct# 101-1730
                  For further credit to CytRx Corporation
                  Acct# 701-96D69

                  On the banking day that SELLER has confirmed that its counsel
         has received the BUYER'S Closing Documents and is credited with having
         received the Purchase Price (the "Closing Date"), SELLER shall advise
         BUYER. Immediately thereafter, SELLER shall advise Gowling, Strathy &
         Henderson to release the SELLER'S Closing Documents to BUYER and BUYER
         shall advise Alston & Bird to release the BUYER'S Closing Documents to
         SELLER. The Transaction Documents shall not be deemed to have been
         delivered except in accordance with the procedure described in this
         Section 4.

                  If the Closing Date does not occur before October 23, 1997,
         then either party may terminate this Agreement immediately upon written
         notice to the other party and all Transaction Documents shall be deemed
         to be null and void.


         5.       CONDITIONS TO CLOSING

                  (i)  BUYER understands that SELLER'S obligation to sell the
         Debentures and the Warrants is conditioned upon the receipt in
         immediately available funds of the amount set forth in Paragraph 1
         hereof and an opinion of counsel substantially in the form attached as
         D to and forming an integral part of this Agreement, SELLER shall have
         the right to reject any given Agreement which is tendered to Seller,
         for the reason that SELLER reasonably believes any representations and
         warranties of BUYER to be untrue and in such event SELLER shall provide
         BUYER written notice of such rejection and the reason therefore and
         shall provide reasonable opportunity for a response to such stated
         reason. Also, SELLER may decline to accept this Agreement for any other
         reason which in the sole discretion of SELLER may materially affect
         SELLER.

                  (ii) SELLER understands that BUYER'S obligation to purchase
         the Debentures is conditioned upon delivery of certificate(s)
         representing Debentures as described in Paragraph 1(ii) hereto and
         provision of an opinion of counsel attached as Exhibit E substantially
         in the form and forming an integral part of this Agreement.


         6.       SELLER'S OPTION ADDITIONAL $2,000,000 TO BUYER AND
                  OTHER CONCURRENT BUYERS CONVERSION AND
                  WARRANT PRICE


                                      -8-

<PAGE>   9


         SELLER shall have the option (the "Option") to require BUYER to
         purchase Four Hundred Thousand Dollars (USD $400,000) of additional
         Debentures at any time between 90 and 270 days (the "Option Period")
         after the Shelf Registration (as defined in the Rights Registration
         Agreement) has been declared effective by the Commission subject to the
         following conditions:

                  (i)   The ten day Average Closing Bid Price of the Shares 
         shall not be below $3.50 per share on (a) the day SELLER gives BUYER
         notice of SELLER'S election to exercise this Option and (b) the day
         before the closing of the Option;

                  (ii)  SELLER shall not be in default under any material
         borrowings from any financial institution or other persons;

                  (iii) the class of common stock into which the Debentures are
         convertible shall continue to be listed by Nasdaq; or

                  (iv)  the Company shall not have been convicted of any fraud
         in the sale of its securities.

         The closing of the purchase of the additional Debentures will take
         place 10 business days after the day of SELLER'S notice to BUYER.

         With the exception of any further option in favour of SELLER, and the
         Conversion Price and Warrant Price and the maturity dates which will
         have to be reset, the terms and conditions in connection with the
         funding and closing of the Option will be the same as those relating to
         the initial funding of October, 1997.

         Provided however if the Black-Out Period as defined in Section 1(ii) of
         the Debenture is invoked, then the actual number of days of the
         Black-Out Period shall be added to each of the 90 and 270 days
         comprising the Option Period.

         If the Option is completed:

         "Average Closing Bid Price" for the purposes of this Section 6 means
         the average of the daily last bid price for the shares of Common Stock
         for the five (5) or ten (10), as the case may be, consecutive trading
         days on which such shares are actually traded as over-the-counter
         securities and quoted on Nasdaq National Market (as reported by
         Bloomberg Business News, or, if not reported thereby, any other
         authoritative source selected by the Company ending at the close of the
         trading on the trading day immediately preceding the measurement date.

         "Conversion Price" shall mean the lessor of (A:) one hundred ten
         percent (110%) of the five day Average Closing Bid Price, calculated
         using the closing date as the measurement date, or (B) eighty five
         percent (85%) of the ten day Average 


                                      -9-

<PAGE>   10

         Closing Bid Price calculated using the date of conversion as the
         measurement date, provided, however, but if the holder will have
         delivered a Forbearance Request to the Company in accordance with what
         is presently Section 5(ii) of the Debenture used in the October 1997
         Closing, within twenty-four (24) hours before it will have delivered a
         conversion notice of the Company in accordance with what is presently
         Section 4.3.1 of the Debenture, then the ten day Average Closing Bid
         Price for the portion of the debenture that the Holder will have
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

         "Exercise Price" for per share under each Warrant shall be one hundred
         ten percent (110%) of the five day Average Closing Bid Price calculated
         as of the Closing Date of the Option. The Exercise Price shall be paid
         in cash.

         "Right of First Refusal Period" shall mean the period that begins on
         the Closing Date and ends on the earlier of (a) the closing date of the
         Option, (b) the refusal of Buyer to purchase the Debentures covered by
         the Option because Seller failed to meet the conditions set forth in
         clauses (i) to (iv) above, or (c) the end of the Option Period.

         The "closing date" means the closing date of the Option.

         If, during the Right of First Refusal Period, but only ninety (90) days
         after the Closing Date the Company proposes to undertake an issuance of
         any securities pursuant to Regulations D or S promulgated under the
         Securities Act (the "New Securities"), then the Company shall give
         written notice of the Company's intention to BUYER, describing the type
         of the securities, and their price and the general terms upon which the
         Company proposes to issue the same. The Debenture is being issued in
         connection with debentures on similar terms to Charles N. Eckert, David
         Kosloff, Pine Street Asset Management and Gundyco in trust for R.R.S.P.
         550-98866-19 (collectively, the "Other Buyers"). Each of the BUYER and
         the Other Buyer who remain Accredited Investors ("Qualified Buyer")
         shall have twenty (20) days after any such notice is mailed or
         delivered to agree to purchase all of such New Securities for the price
         and upon the terms specified in the notice by giving written notice to
         the Company and stating therein the quantity of New Securities to be
         purchased. Each of the Qualified Buyers shall be entitled to purchase
         New Securities in the proportion of its purchase of Debentures and if
         one or more buyers decline, or is not qualified, to so purchase, then
         the others, as the case may be, shall be entitled to purchase the New
         Securities not taken by the Qualified Buyer(s), as the case may be
         within the original twenty (20) day period.

         "New Securities" does not include (i) securities issued pursuant to the
         acquisition of another business entity or segment of any such entity by
         the Company by merger, asset purchase, stock purchase or otherwise,
         (ii) any borrowings, direct or 


                                      -10-

<PAGE>   11

         indirect, from financial institutions or other persons by the Company,
         whether or not presently authorized, including any type of loan or
         payment evidenced by any type of debt instrument, provided such
         borrowings do not have any equity features including warrants, options
         or other rights to purchase capital stock and are not convertible into
         capital stock of the Company, (iii) securities issued to employees,
         consultants, officers or directors of the Company pursuant to any stock
         option, stock purchase or stock bonus plan, agreement or arrangement,
         (iv) securities issued to vendors or customers or to other persons in
         similar commercial situations with the Company, (v) securities issued
         in connection with obtaining lease financing, whether issued to a
         lessor, guarantor or other person, (vi) securities issued in connection
         with any stock split, stock dividend or recapitalization of the
         Company, or (vi) securities issued in connection with corporate
         partnering transactions.

         If the Qualified Buyers fail to exercise fully the right of first
         refusal within the prescribed twenty (20) day period, then the Company
         shall have one hundred twenty (120) days thereafter to sell or enter
         into an agreement to sell the New Securities, at a price and on terms
         no more favourable to the purchasers thereof than specified in the
         notice to the Qualified Buyers. If the Company has not sold or entered
         into an agreement to sell the New Securities in accordance with the
         foregoing within the one hundred twenty (120) day period, then the
         Company shall not thereafter issue or sell any New Securities, without
         first again offering such securities to the Qualified Buyers in
         accordance with this Section 6.


         7.       GOVERNING LAW; INTERPRETATION AND DISPUTES.
         This Agreement shall be governed by and construed under the laws of the
         State of Delaware and the laws applicable therein without regard to its
         choice of law principles.


         8.       ARBITRATION
         All disputes arising under this Agreement (other than claims in equity)
         shall be resolved by arbitration in accordance with the Commercial
         Arbitration Rules of the American Arbitration Association. Arbitration
         shall be by a single arbitrator experienced in the matters at issue and
         selected by the SELLER and BUYER in accordance with the Commercial
         Arbitration Rules of the American Arbitration Association. The
         arbitration shall be held in such place in New York, New York, as may
         be specified by the arbitrator (or any place agreed to by SELLER, BUYER
         and the arbitrator). The decision of the arbitrator shall be final and
         binding as to any matters submitted under this Agreement, provided,
         however, if necessary, such decision and satisfaction procedure may be
         enforced by either SELLER or BUYER in any court of record having
         jurisdiction over the subject matter or over any of the parties to this
         Agreement. All costs and expenses incurred in connection with any such
         arbitration proceeding (including reasonable attorneys fees) shall be
         borne by 


                                      -11-

<PAGE>   12

         the party against which the decision is rendered, or, if no decision is
         rendered, such costs and expenses shall be home equally by SELLER as
         one party and BUYER as the other party. If the arbitrator's decision is
         a compromise, the determination of which party or parties bears the
         costs and expenses incurred in connection with any such arbitration
         proceeding shall be made by the arbitrator on the basis of the
         arbitrator's assessment of the relative merits of the parties'
         positions.


         9.  CONFIDENTIALITY.
         The parties hereto agree to maintain the confidentiality of this
         Agreement and not to disclose to any person or entity information
         concerning the transaction contemplated hereby unless required by law
         to do so.


         10. ENTIRE AGREEMENT.
         This Agreement constitutes the entire agreement among the parties
         hereof with respect to the subject matter hereof and supersedes any and
         all prior or contemporaneous representations, warranties, agreements
         and understandings in connection therewith. This Agreement may be
         amended only by a writing executed by all parties hereto. This
         Agreement may be executed in counterparts and the facsimile
         transmission of an executed counterpart to this Agreement shall be
         effective as an original.

         [Signatures begin on next page]


         11. FULL NAME AND ADDRESS OF BUYER FOR REGISTRATION
             PURPOSES:

         NAME:             Charles N. Eckert

         ADDRESS:          One Tower Bridge

                           Suite 1370

                           West Conshohocken, Pennsylvania 19428 U.S.A.

         Tel. No.          (610) 941-9090

         Fax. No.          (610) 828-4131

         Contact Name:     Charles N. Eckert


                                      -12-

<PAGE>   13


         12.      DELIVERY INSTRUCTIONS: (IF DIFFERENT FROM REGISTRATION NAME):

         NAME:             
                                    ----------------------------

         ADDRESS:          
                                    ----------------------------

                                    ----------------------------

                                    ----------------------------

         Tel.  No.        
                                    ----------------------------
         Fax.  No.        
                                    ----------------------------
         Contact Name:    
                                    ----------------------------

         Special Instructions:
                                    ----------------------------

                                    ----------------------------

                                    ----------------------------


                                      -13-

<PAGE>   14


         IN WITNESS WHEREOF, this Agreement was duly executed or the date first
         written below.


Dated this 21st day of the month of October, 1997.


Name:
                           ----------------------------
                           Charles N. Eckert


Country of Execution:      U.S.A.


                                CYTRX CORPORATION

                       By: 
                           ----------------------------


         I have the full authority to bind CYTRX CORPORATION _________ (initial)

Name:             Jack J. Luchese

Title:            President



                                      -14-


<PAGE>   1
                                                                     EXHIBIT 2.5

                    PRIVATE SECURITIES SUBSCRIPTION AGREEMENT
                                CYTRX CORPORATION
                                (REGULATION "D")


         THIS PRIVATE SECURITIES SUBSCRIPTION AGREEMENT (hereinafter the
"Agreement") has been executed by the undersigned in connection with the
purchase in a private placement pursuant to Section 4(2) of the Securities Act
of 1933, as amended (the "Securities Act"), of certain debentures (hereinafter
the "Debentures"), convertible into shares of common stock (hereinafter the
"Shares"), and certain share purchase warrants (hereinafter the "Warrants") from
CytRx Corporation ("CYTR") 154 Technology Parkway, Technology Parkway, Atlanta,
Georgia, 30092, USA, a corporation organized under the laws of Delaware
(hereinafter the "COMPANY" or "SELLER") by Name: David Kosloff located at c/o
Shipley Raidy Capital Partners, One Tower Bridge, Suite 1370; City: West
Conshohocken; Province/State: Pennsylvania; Zip/Postal 19428; Country: U.S.A. an
individual resident of the State of Pennsylvania (hereinafter "BUYER"). SELLER
and BUYER (hereinafter collectively the "parties") each hereby represents,
warrants and agrees as follows:


         1.       AGREEMENT TO SUBSCRIBE; PURCHASE PRICE:

                  (i)   SELLER and BUYER are executing and delivering this
         Agreement in reliance upon the exemption from securities registration
         afforded by Rule 506 under Regulation D ("Regulation D") as promulgated
         by the United States Securities and Exchange Commission (the
         "Commission") under the Securities Act; and

                  (ii)  BUYER hereby subscribes for Four Hundred Thousand
         Dollars (USD $400,000) U.S. principal amount of Debentures,
         substantially in the form attached as Exhibit A to and forming an
         integral part of this Agreement.

                  (iii) BUYER will receive 8,000 Warrants substantially in the
         form attached as Exhibit B to and forming an integral part of this
         Agreement. Each Warrant will entitle BUYER to purchase one treasury
         Common Share at the price of $5.68. The Warrants will expire two (2)
         years after the Closing; and

                  (iv)  BUYER shall on or before the Closing execute a copy of
         the Registration Rights Agreement (the "Registration Rights Agreement")
         substantially in the form attached as Exhibit "A" to and forming an
         integral part of this Agreement.


<PAGE>   2

         2.       BUYER'S REPRESENTATIONS

                  BUYER represents and warrants follows:

                  (i)   Authorization: Such BUYER has full power and authority 
         to enter into this Agreement, the Debenture, the Warrant and the
         Registration Rights Agreement (collectively, the "Transaction
         Documents") and that the Transaction Documents, when executed and
         delivered will constitute a valid and legally binding obligation of
         BUYER in accordance with their terms, subject to (A) bankruptcy,
         insolvency, fraudulent conveyance, reorganization, moratorium and
         similar laws now or hereafter in effect relating to creditors' rights
         and (B) that the remedy of specific performance and injunctive and
         other forms of equitable relief may be subject to equitable defenses
         and to the discretion of the court before which any proceedings
         therefor may be brought and (C) to the extent that the indemnification
         provisions contained in the Registration Rights Agreement may be
         limited by applicable laws.

                  (ii)  Purchase Entirely for Own Account. This Agreement is
         made with BUYER in reliance upon BUYER'S representation to the Company,
         which by such BUYER'S execution of this Agreement BUYER hereby
         confirms, that the Debentures and Warrants to be purchased by BUYER and
         the Common Stock issuable upon conversion thereof (collectively, the
         "Securities") will be acquired for investment for BUYERS own account,
         not a nominee as agent, and not with a view to the resale or
         distribution of any part thereof. By execution of this Agreement, Buyer
         further represents that Buyer does not have any contract, undertaking,
         agreement or arrangement with any person, to sell, transfer or grant
         participation to such person or to any third person, with respect to
         any of the Securities.

                  (iii) Reliance Upon BUYER'S Representations. BUYER understands
         that the Debentures and the Warrants are not, and any Common Stock
         acquired on conversion thereof at the time of issuance may not be,
         registered under the Securities Act on the ground that the sale
         provided for in this Agreement and the issuance of securities hereunder
         is exempt from registration under the Securities Act pursuant to
         Section 4(2) thereof and that the Company's reliance on such exemption
         is predicated on the BUYERS' representations set forth herein. Buyer
         also understands that no prospectus or offering memorandum has been
         received by Buyer or filed by the Seller with any Canadian securities
         commission or similar authority in connection with the sale of the
         Debentures and Warrants, and that no prospectus or offering memorandum
         shall be received by the Seller or so filed by Buyer in connection with
         any sale of Shares issued on the conversion of the Debentures or
         Warrants, and that as a result the Buyer will be unable to rely upon
         civil or contractual remedies that might otherwise be available to it
         if the Debentures, Warrants and/or Shares had been issued by the Seller
         by way of a prospectus or offering memorandum, respectively, and the
         prospectus or offering 


                                      -2-

<PAGE>   3

         memorandum, as the case may be, contained a misrepresentation as that
         term is defined in the Securities Act (Ontario).

                  (iv)  Buyer is not a corporation, syndicate, partnership or
         other form of unincorporated entity or corporation created solely to
         permit the purchase of the Securities by a group of individuals who
         individual share in the aggregate acquisition cost of the Securities is
         less than $150,000 and Buyer is not purchasing the Securities as the
         result of an advertisement of the Securities, including an
         advertisement in printed media of general and regular paid circulation,
         radio or television.

                  (v)   BUYER believes BUYER has received all the information
         BUYER considers necessary or appropriate for deciding whether to
         purchase any of the Securities. BUYER further represents that BUYER has
         had an opportunity to ask questions and receive answers from the
         Company regarding the terms and conditions of the offering any of the
         Securities and the business, properties, prospects, and financial
         condition of the Company and to obtain additional information (to the
         extent the Company possessed such information or could acquire it
         without reasonable effort or expense) necessary to verify the accuracy
         of any information furnished to BUYER or to which BUYER had access.

                  (vi)  BUYER represents that BUYER is experienced in evaluating
         and investing in private placement transactions of securities of
         companies in a similar stage of development and acknowledges that BUYER
         is able to fend for himself, herself or itself, can bear the economic
         risk of BUYER'S investment, and has such knowledge and experience in
         financial and business matters that BUYER is capable of evaluating the
         merits and risks of the investment in the Debentures and Warrants. If
         other than an individual, BUYER also represents BUYER has not been
         organized for the purpose of acquiring the Debentures and Warrants.

                  (vii) The BUYER represents that BUYER is an Accredited
         Investor.

                  The term "Accredited Investor" as used herein refers to:

                  (1)   A  person or entity who is a direct or executive
                        officer of the Company;

                  (2)   Any  bank as defined in Section 3(a)(2) of the
                        Securities Act, or any savings and loan association
                        or other institution as defined in section 3(a)(5)(A)
                        of the Securities Act whether acting in its
                        individual or fiduciary capacity; any broker or
                        dealer registered pursuant to Section 15 of the
                        Securities Exchange Act of 1934; any insurance
                        company as defined in Section 2(13) of the Securities
                        Act; any investment company registered under the
                        Investment Company Act of 1940 or a business
                        development company as 


                                      -3-


<PAGE>   4

                           defined in Section 2(a(48) of that Act; any Small
                           Business Investment Company licensed by the U.S.
                           Small Business Administration under Section 301 (c)
                           or (d) of the Small Business Investment Act of 1958;
                           any plan established and maintained by a state, its
                           political subdivisions, or any agency or
                           instrumentality of a state or its political
                           subdivisions, for the benefit of its employees, if
                           such plan has total assets in excess of $5,000,000;
                           any employee benefit plan within the meaning of Title
                           I of the Employee Retirement Income Security Act of
                           1974, if the investment decision is made by a plan
                           fiduciary, as defined in Section 3(21)of such Act,
                           which is either a bank, savings and loan association,
                           insurance company or registered investment adviser,
                           or if the employee benefit plan has total assets in
                           excess of $5,000,000 or, if a self-directed plan,
                           with investment decisions made solely by the persons
                           that are Accredited Investors.

                  (3)      Any private business development company as defined
                           in section 202(a)(22) of the Investment Advisers Act
                           of 1940;

                  (4)      Any organization described in Section 501(c)(3) of
                           the Internal Revenue Code, corporation, Massachusetts
                           or similar business trust, or partnership, not formed
                           for the specific purpose of acquiring the securities
                           offered, with total assets in excess of $5,000,000;

                  (5)      Any natural person whose individual net worth, or
                           joint net worth with that person's spouse, at the
                           time of the purchase exceeds $1,000,000;

                  (6)      Any natural person who had an individual income in
                           excess of $200,000 in each of the two most recent
                           years or joint income with that person's spouse in
                           excess of $300,000 in each of those years and has a
                           reasonable expectation of reaching the same income
                           level in the current year;

                  (7)      Any trust, with total assets in excess of $5,000,000,
                           not formed for the specific purpose of acquiring the
                           securities offered, whose purchase is directed by a
                           person who has such knowledge and experience in
                           financial and business matters that he or she is
                           capable of evaluating the merits and risks of the
                           prospective investment; or

                  (8)      Any entity in which all of the equity owners are
                           Accredited Investors.


                                      -4-


<PAGE>   5

         As used in this Paragraph 3.(vii) the term "net worth" means the
         excesses of total assets over total liabilities. For the purpose of
         determining a person's net worth, the principal residence owned by an
         individual should be valued at fair market value, including the cost of
         improvements, net of current encumbrances. As used in this paragraph
         "income" means actual economic income, which may differ from adjusted
         gross income for income tax purposes. Accordingly, Buyer should
         consider whether Buyer should add any or all of the following items to
         Buyer's adjusted gross income for income tax purposes in order to
         reflect more accurately Buyer's actual economic income; any amounts
         attributable to tax-exempt income received, losses claimed as a limited
         partner in any limited partnership, deductions claimed for depletion,
         contributions an IRA or keogh retirement plan, and alimony payments.

                  (viii) BUYER understands that the Securities may not be sold,
         transferred or otherwise disposed of in the United States without
         registration under the Securities Act or an exemption therefrom, and
         that in the absence of an effective registration statement covering any
         of the Securities or an available exemption from registration under the
         Securities Act, the Securities must be held indefinitely. In
         particular, BUYER is aware that the Securities may not be sold pursuant
         to Rule 144 promulgated under the Securities Act unless all of the
         condition of that Rule are met. BUYER also understands that any resale
         of the Securities must be conducted in accordance with the applicable
         requirements of the Securities Act (Ontario).

                  (ix)   Buyer acknowledges that no person has made to Buyer any
         written or oral representations:

                  (i)    that any person will resell or repurchase the
                         Securities;

                  (ii)   that any person will refund the purchase price of the
                         Securities; and

                  (iii)  as to the future price or value of the Securities.


         3.       SELLER'S REPRESENTATIONS

                  SELLER represents and warrants as follows:

                  (i)    SELLER has not conducted any general solicitation or
         general advertising (as defined in Regulation D) with respect to any of
         the Securities offered hereby;

                  (ii)   The Debentures, when issued and delivered pursuant to 
         the terms of this Agreement, will have been duly authorized, executed,
         issued and delivered and will constitute valid and legally binding
         obligations of the Company in 


                                      -5-

<PAGE>   6

         accordance with their terms, subject to (A) bankruptcy, insolvency,
         fraudulent conveyance, reorganization, moratorium and similar laws now
         or hereafter in effect relating to creditors' rights and (B) that the
         remedy of specific performance and injunctive and other forms of
         equitable relief may be subject to equitable defenses and to the
         discretion of the court before which any proceedings therefor may be
         brought and (C) to the extent that the indemnification provisions
         contained in the Registration Rights Agreement may be limited by
         applicable laws.

                  (iii) The Shares, when issued and delivered upon conversion of
         the Debentures in accordance with their terms, will be duly and validly
         authorized and issued, fully-paid and non assessable and will not
         subject the holders thereof to personal liability by reason of being
         such holders. There are no preemptive rights of any shareholder of
         SELLER with respect to the Shares contained in SELLER'S Certificate of
         Incorporation or any agreement to which SELLER is a party;

                  (iv)  This Agreement has been duly authorized, validly
         executed and delivered on behalf of SELLER and is a valid and binding
         agreement of SELLER in accordance with its terms, subject to (A)
         bankruptcy, insolvency, fraudulent conveyance, reorganization,
         moratorium and similar laws now or hereafter in effect relating to
         creditors' rights and (B) that the remedy of specific performance and
         injunctive and other forms of equitable relief may be subject to
         equitable defenses and to the discretion of the court before which any
         proceedings therefor may be brought and (C) to the extent that the
         indemnification provisions contained in the Registration Rights
         Agreement may be limited by applicable laws.

                  (v)   The execution and delivery of this Agreement and the
         consummation of the transactions contemplated by this Agreement do not
         and will not conflict with or result in a breach by SELLER of any of
         the terms or provisions of, or constitute a default under, the
         certificate of incorporation (or charter) or by-laws of SELLER, or any
         indenture, mortgage, deed of trust or other material agreement or
         instrument to which SELLER is a party or by which it or any of its
         properties or assets are bound, or any existing applicable decree,
         judgment or order of any court, federal or state regulatory body,
         administrative agency or other governmental body having jurisdiction
         over SELLER or any of its properties or assets;

                  (vi)  No authorization, approval or consent of or filing with
         any federal, state or local governmental body of the United States is
         legally required for the issuance and sale of the Debentures and
         (provided no commission or other remuneration is paid or given directly
         or indirectly by SELLER for soliciting such conversion) the issuance of
         the Shares upon conversion of the Debentures in accordance with their
         terms, as contemplated by this Agreement, except the filing of a Form D
         with the Commission;


                                      -6-

<PAGE>   7

                  (vii)  To the best of the Company's knowledge after reasonable
         investigation, the information contained in the Company's Annual Report
         on Form 10K for the year ended December 31, 1996, Proxy statement
         relating to the Annual Meeting of Shareholders held on June 26, 1997 or
         Quarterly Report on Form 10-Q for the quarter ended June 30, 1997, as
         filed with the Commission does not contain any untrue statement of a
         material fact or omit to state any material fact necessary in order to
         make the statements therein, in the light of the circumstance under
         which they are made, not misleading. Since September 30, 1997, there
         has been no material adverse development in the business, properties,
         operations, financial condition or results of operations of SELLER.

                  (viii) SELLER will issue one or more certificates representing
         the Debentures in the name of BUYER in such denominations (in multiples
         of $25,000) to be specified by BUYER prior to closing and will issue
         one or more certificates representing the Shares in such denominations
         to be specified by Buyer upon conversion of the Debentures. SELLER
         further warrants that the Debentures and the Shares shall be
         transferable on the books and records of SELLER as and to the extent
         provided in the Transaction Documents, subject to compliance with
         Federal and State securities laws. Nothing in this Section shall affect
         in any way BUYER'S obligations and agreement to comply with all
         applicable securities laws upon resale of the Securities.


         4.       CLOSING. Debentures and Warrants shall be delivered to BUYER
         and the funds therefor shall be delivered to SELLER on the 22nd day of
         October, 1997 (the "Closing") or at such time to be mutually agreed in
         accordance with the following procedures.

                  SELLER shall execute the appropriate copies of the Transaction
         Documents (the "SELLER'S Closing Documents") and deliver the executed
         documents to Gowling, Strathy & Henderson, counsel for BUYER, with
         instructions to hold the documents in trust and not to release the
         documents to BUYER until advised to do so by SELLER. BUYER shall
         execute the appropriate copies of the Transaction Documents (the
         "BUYER'S Closing Documents") and deliver the executed documents to
         Alston & Bird, counsel for SELLER, with instructions to hold the
         documents in trust and not to release the documents to SELLER until
         advised to do so by BUYER.

                  Immediately after BUYER has confirmed that its counsel has
         received the SELLER'S Closing Documents executed by SELLER, then BUYER
         shall pay to SELLER the principal amount of the Debentures for which
         BUYER subscribed (the "Purchase Price"). BUYER shall pay the Purchase
         Price, less all appropriate legal fees and commissions by wire transfer
         of immediately available funds in accordance with the following
         instructions:


                                      -7-

<PAGE>   8

                  Mellon Bank, Pittsburgh, P.A.
                  ABA# 0430-0026-1
                  Credit: Merrill Lynch
                  Acct# 101-1730
                  For further credit to CytRx Corporation
                  Acct# 701-96D69

                  On the banking day that SELLER has confirmed that its counsel
         has received the BUYER'S Closing Documents and is credited with having
         received the Purchase Price (the "Closing Date"), SELLER shall advise
         BUYER. Immediately thereafter, SELLER shall advise Gowling, Strathy &
         Henderson to release the SELLER'S Closing Documents to BUYER and BUYER
         shall advise Alston & Bird to release the BUYER'S Closing Documents to
         SELLER. The Transaction Documents shall not be deemed to have been
         delivered except in accordance with the procedure described in this
         Section 4.

                  If the Closing Date does not occur before October 23, 1997,
         then either party may terminate this Agreement immediately upon written
         notice to the other party and all Transaction Documents shall be deemed
         to be null and void.


         5.       CONDITIONS TO CLOSING

                  (i)  BUYER understands that SELLER'S obligation to sell the
         Debentures and the Warrants is conditioned upon the receipt in
         immediately available funds of the amount set forth in Paragraph 1
         hereof and an opinion of counsel substantially in the form attached as
         D to and forming an integral part of this Agreement, SELLER shall have
         the right to reject any given Agreement which is tendered to Seller,
         for the reason that SELLER reasonably believes any representations and
         warranties of BUYER to be untrue and in such event SELLER shall provide
         BUYER written notice of such rejection and the reason therefore and
         shall provide reasonable opportunity for a response to such stated
         reason. Also, SELLER may decline to accept this Agreement for any other
         reason which in the sole discretion of SELLER may materially affect
         SELLER.

                  (ii) SELLER understands that BUYER'S obligation to purchase
         the Debentures is conditioned upon delivery of certificate(s)
         representing Debentures as described in Paragraph 1(ii) hereto and
         provision of an opinion of counsel attached as Exhibit E substantially
         in the form and forming an integral part of this Agreement.


         6.       SELLER'S OPTION ADDITIONAL $2,000,000 TO BUYER AND
                  OTHER CONCURRENT BUYERS CONVERSION AND
                  WARRANT PRICE


                                      -8-

<PAGE>   9

         SELLER shall have the option (the "Option") to require BUYER to
         purchase Four Hundred Thousand Dollars (USD $400,000) of additional
         Debentures at any time between 90 and 270 days (the "Option Period")
         after the Shelf Registration (as defined in the Rights Registration
         Agreement) has been declared effective by the Commission subject to the
         following conditions:

                  (i)   The ten day Average Closing Bid Price of the Shares
         shall not be below $3.50 per share on (a) the day SELLER gives BUYER
         notice of SELLER'S election to exercise this Option and (b) the day
         before the closing of the Option;

                  (ii)  SELLER shall not be in default under any material
         borrowings from any financial institution or other persons;

                  (iii) the class of common stock into which the Debentures are
         convertible shall continue to be listed by Nasdaq; or

                  (iv)  the Company shall not have been convicted of any fraud
         in the sale of its securities.

         The closing of the purchase of the additional Debentures will take
         place 10 business days after the day of SELLER'S notice to BUYER.

         With the exception of any further option in favour of SELLER, and the
         Conversion Price and Warrant Price and the maturity dates which will
         have to be reset, the terms and conditions in connection with the
         funding and closing of the Option will be the same as those relating to
         the initial funding of October, 1997.

         Provided however if the Black-Out Period as defined in Section 1(ii) of
         the Debenture is invoked, then the actual number of days of the
         Black-Out Period shall be added to each of the 90 and 270 days
         comprising the Option Period.

         If the Option is completed:

         "Average Closing Bid Price" for the purposes of this Section 6 means
         the average of the daily last bid price for the shares of Common Stock
         for the five (5) or ten (10), as the case may be, consecutive trading
         days on which such shares are actually traded as over-the-counter
         securities and quoted on Nasdaq National Market (as reported by
         Bloomberg Business News, or, if not reported thereby, any other
         authoritative source selected by the Company ending at the close of the
         trading on the trading day immediately preceding the measurement date.

         "Conversion Price" shall mean the lessor of (A:) one hundred ten
         percent (110%) of the five day Average Closing Bid Price, calculated
         using the closing date as the measurement date, or (B) eighty five
         percent (85%) of the ten day Average


                                      -9-

<PAGE>   10

         Closing Bid Price calculated using the date of conversion as the
         measurement date, provided, however, but if the holder will have
         delivered a Forbearance Request to the Company in accordance with what
         is presently Section 5(ii) of the Debenture used in the October 1997
         Closing, within twenty-four (24) hours before it will have delivered a
         conversion notice of the Company in accordance with what is presently
         Section 4.3.1 of the Debenture, then the ten day Average Closing Bid
         Price for the portion of the debenture that the Holder will have
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

         "Exercise Price" for per share under each Warrant shall be one hundred
         ten percent (110%) of the five day Average Closing Bid Price calculated
         as of the Closing Date of the Option. The Exercise Price shall be paid
         in cash.

         "Right of First Refusal Period" shall mean the period that begins on
         the Closing Date and ends on the earlier of (a) the closing date of the
         Option, (b) the refusal of Buyer to purchase the Debentures covered by
         the Option because Seller failed to meet the conditions set forth in
         clauses (i) to (iv) above, or (c) the end of the Option Period.

         The "closing date" means the closing date of the Option.

         If, during the Right of First Refusal Period, but only ninety (90) days
         after the Closing Date the Company proposes to undertake an issuance of
         any securities pursuant to Regulations D or S promulgated under the
         Securities Act (the "New Securities"), then the Company shall give
         written notice of the Company's intention to BUYER, describing the type
         of the securities, and their price and the general terms upon which the
         Company proposes to issue the same. The Debenture is being issued in
         connection with debentures on similar terms to Charles N. Eckert, David
         Kosloff, Pine Street Asset Management and Gundyco in trust for R.R.S.P.
         550-98866-19 (collectively, the "Other Buyers"). Each of the BUYER and
         the Other Buyer who remain Accredited Investors ("Qualified Buyer")
         shall have twenty (20) days after any such notice is mailed or
         delivered to agree to purchase all of such New Securities for the price
         and upon the terms specified in the notice by giving written notice to
         the Company and stating therein the quantity of New Securities to be
         purchased. Each of the Qualified Buyers shall be entitled to purchase
         New Securities in the proportion of its purchase of Debentures and if
         one or more buyers decline, or is not qualified, to so purchase, then
         the others, as the case may be, shall be entitled to purchase the New
         Securities not taken by the Qualified Buyer(s), as the case may be
         within the original twenty (20) day period.

         "New Securities" does not include (i) securities issued pursuant to the
         acquisition of another business entity or segment of any such entity by
         the Company by merger, asset purchase, stock purchase or otherwise,
         (ii) any borrowings, direct or 


                                      -10-


<PAGE>   11

         indirect, from financial institutions or other persons by the Company,
         whether or not presently authorized, including any type of loan or
         payment evidenced by any type of debt instrument, provided such
         borrowings do not have any equity features including warrants, options
         or other rights to purchase capital stock and are not convertible into
         capital stock of the Company, (iii) securities issued to employees,
         consultants, officers or directors of the Company pursuant to any stock
         option, stock purchase or stock bonus plan, agreement or arrangement,
         (iv) securities issued to vendors or customers or to other persons in
         similar commercial situations with the Company, (v) securities issued
         in connection with obtaining lease financing, whether issued to a
         lessor, guarantor or other person, (vi) securities issued in connection
         with any stock split, stock dividend or recapitalization of the
         Company, or (vi) securities issued in connection with corporate
         partnering transactions.

         If the Qualified Buyers fail to exercise fully the right of first
         refusal within the prescribed twenty (20) day period, then the Company
         shall have one hundred twenty (120) days thereafter to sell or enter
         into an agreement to sell the New Securities, at a price and on terms
         no more favourable to the purchasers thereof than specified in the
         notice to the Qualified Buyers. If the Company has not sold or entered
         into an agreement to sell the New Securities in accordance with the
         foregoing within the one hundred twenty (120) day period, then the
         Company shall not thereafter issue or sell any New Securities, without
         first again offering such securities to the Qualified Buyers in
         accordance with this Section 6.


         7.       GOVERNING LAW; INTERPRETATION AND DISPUTES.
         This Agreement shall be governed by and construed under the laws of the
         State of Delaware and the laws applicable therein without regard to its
         choice of law principles.


         8.       ARBITRATION
         All disputes arising under this Agreement (other than claims in equity)
         shall be resolved by arbitration in accordance with the Commercial
         Arbitration Rules of the American Arbitration Association. Arbitration
         shall be by a single arbitrator experienced in the matters at issue and
         selected by the SELLER and BUYER in accordance with the Commercial
         Arbitration Rules of the American Arbitration Association. The
         arbitration shall be held in such place in New York, New York, as may
         be specified by the arbitrator (or any place agreed to by SELLER, BUYER
         and the arbitrator). The decision of the arbitrator shall be final and
         binding as to any matters submitted under this Agreement, provided,
         however, if necessary, such decision and satisfaction procedure may be
         enforced by either SELLER or BUYER in any court of record having
         jurisdiction over the subject matter or over any of the parties to this
         Agreement. All costs and expenses incurred in connection with any such
         arbitration proceeding (including reasonable attorneys fees) shall be
         borne by 


                                      -11-

<PAGE>   12

         the party against which the decision is rendered, or, if no decision is
         rendered, such costs and expenses shall be home equally by SELLER as
         one party and BUYER as the other party. If the arbitrator's decision is
         a compromise, the determination of which party or parties bears the
         costs and expenses incurred in connection with any such arbitration
         proceeding shall be made by the arbitrator on the basis of the
         arbitrator's assessment of the relative merits of the parties'
         positions.


         9.       CONFIDENTIALITY.
         The parties hereto agree to maintain the confidentiality of this
         Agreement and not to disclose to any person or entity information
         concerning the transaction contemplated hereby unless required by law
         to do so.


         10.      ENTIRE AGREEMENT.
         This Agreement constitutes the entire agreement among the parties
         hereof with respect to the subject matter hereof and supersedes any and
         all prior or contemporaneous representations, warranties, agreements
         and understandings in connection therewith. This Agreement may be
         amended only by a writing executed by all parties hereto. This
         Agreement may be executed in counterparts and the facsimile
         transmission of an executed counterpart to this Agreement shall be
         effective as an original.

         [Signatures begin on next page]


         11.      FULL NAME AND ADDRESS OF BUYER FOR REGISTRATION
                  PURPOSES:

         NAME:             David Kosloff

         ADDRESS:          One Tower Bridge

                           Suite 1370

                           West Conshohocken, Pennsylvania 19428 U.S.A.

         Tel. No.          (610) 941-9090

         Fax. No.          (610) 828-4131

         Contact Name:     David Koslfof


                                      -12-


<PAGE>   13

         12.      DELIVERY INSTRUCTIONS: (IF DIFFERENT FROM REGISTRATION NAME):

         NAME:
                                    ----------------------------
         ADDRESS:
                                    ----------------------------

                                    ----------------------------

                                    ----------------------------

         Tel. No.
                                    ----------------------------
         Fax. No.
                                    ----------------------------
         Contact Name:
                                    ----------------------------

         Special Instructions:
                                    ----------------------------

                                    ----------------------------

                                    ----------------------------


                                      -13-


<PAGE>   14


         IN WITNESS WHEREOF, this Agreement was duly executed or the date first
         written below.


Dated this 21st day of the month of October, 1997.




Name:
                           ----------------------------
                           David Kosloff


Country of Execution: U.S.A.


                                CYTRX CORPORATION

                       By:
                           ----------------------------


         I have the full authority to bind CYTRX CORPORATION _________ (initial)

Name:             Jack J. Luchese

Title:            President


                                      -14-


<PAGE>   1

                                                                     EXHIBIT 3.1

NEITHER THIS DEBENTURE, NOR THE SHARES OF COMMON STOCK FOR WHICH IT MAY BE
CONVERTED, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS DEBENTURE HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS DEBENTURE HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.


                                CYTRX CORPORATION
                            6% CONVERTIBLE DEBENTURE

$1,500,000.00                                         Atlanta, Georgia
                                                      October 22, 1997

CYTRX CORPORATION, a Delaware corporation (the "Company"), the principal office
of which is located at 154 Technology Parkway Technology Park/Atlanta, Norcross,
Georgia 30092, for value received hereby promises to pay to GUNDYCO in trust for
R.R.S.P. 550-98866-19, or its registered assigns, the sum of One Million Five
Hundred Thousand Dollars ($1,500,000.00), or such lesser amount as shall then
equal the outstanding principal amount hereof and any unpaid accrued interest
hereon, as set forth below, shall be due and payable on October ____, 2001, (the
"Maturity Date") (or in the case of redemption in accordance with Section 5
hereof, until the Redemption Payment Date). Payment for all amounts due
hereunder shall be made by mail to the registered address of the Holder. This
Debenture is issued in connection with the transactions described in Section ___
of that certain Subscription Agreement between the Company and the Holder, dated
as of October 22, 1997, as the same may from time to time be amended, modified
or supplemented (the "Purchase Agreement"). The Holder is subject to certain
restrictions set forth in the Purchase Agreement and shall be entitled to
certain rights and privileges set forth in the Purchase Agreement. This
Debenture is the Debenture referred to in the Purchase Agreement.

         The following is a statement of the rights of the Holder of this
Debenture and conditions to which this Debenture is subject, and to which the
Holder hereof, by the acceptance of this Debenture, agrees:


<PAGE>   2


         1. DEFINITIONS. As used in this Debenture, the following terms, unless
the context otherwise requires, have the following meanings:

                  (i)    "Average Closing Bid Price" means the average of the
         daily last bid price for the shares of Common Stock for the ten (10)
         consecutive trading days on which such shares are actually traded as
         over-the-counter securities and quoted on the Nasdaq National Market
         (as reported by Bloomberg Business News or, if not reported thereby,
         any other authoritative source selected by the Company) ending at the
         close of trading on the trading day immediately preceding an identified
         measurement date.

                  (ii)   "Black-Out Period" means the number of days, if any,
         that the Company suspends the rights of the Holder to make sales
         pursuant to the Shelf Registration in accordance with Section 2(h) of
         the Registration Rights Agreement.

                  (iii)  "Closing Date" shall have the meaning given that term
         in the Purchase Agreement.

                  (iv)   "Company" includes any corporation which shall succeed
         to or assume the obligations of the Company under this Debenture.

                  (v)    "Common Stock" shall mean the $.001 par value common
         stock of the Company.

                  (vi)   "Conversion Price" shall mean the lessor of (A) $5.68
         for each share of Common Stock, or (B) eighty-five percent of the
         Average Closing Bid Price calculated using the date of conversion as
         the measurement date; provided, however, but if the Holder delivered a
         Forbearance Request to the Company in accordance with Section 5(ii)
         within twenty-four (24) hours before it delivered a conversion notice
         to the Company in accordance with Section 4.3.1, then the Average
         Closing Bid Price for the portion of the Debenture that the Holder
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

                  (vii)  "Holder," when the context refers to a holder of this
         Debenture, shall mean any person who shall at the time be the
         registered holder of this Debenture.

                  (viii) "Redemption Payment Date" shall mean the day on which
                  the Company is obligated to make the redemption payment to the
                  Holder in accordance with Section 5.3.


                                      -2-

<PAGE>   3

                  (ix) "Registration Rights Agreement" shall mean the
                  Registration Rights Agreement dated as of October 22, 1997,
                  between the Company, the Holder and the other holders of
                  Company securities that are signatories thereto.

                  (x)  "Securities Act" shall mean the Securities Act of 1933,
                  as amended.

                  (xi) "Surrender Date" shall mean the day on which the Company
                  receives the Debenture in accordance with either Section 4.4
                  or 5.3.

         2. INTEREST.

                  (i)  Commencing on December 31, 1997, and on each June 30 and
         December 31 thereafter until the Maturity Date (or in the case of
         redemption in accordance with Section 5 hereof, until the Redemption
         Payment Date, the Company shall pay interest (computed on the basis of
         a 365-day year) at rate of six percent (6%) per annum on the principal
         of this Debenture outstanding during the period beginning on the date
         of issuance of this Debenture and ending on the date that the principal
         amount of this Debenture becomes due and payable.

                  (ii) The Company, at its option, may make any payment of
         interest due hereunder in whole or in part by issuing to the Holder
         shares of Common Stock (the "Interest Shares"). The Interest Shares
         shall be valued at the Average Closing Price, calculated using the date
         on which the interest payment is due as the measurement date. The
         Company shall not be obligated to issue any fractional shares. The
         Company may place such legends, if any, on the certificates for the
         Interest Shares as are required by applicable state and federal
         securities laws in the opinion of counsel to the Company. Applicable
         state and federal securities laws will not require any legends on the
         certificates after the shares have been registered under the Securities
         Act in accordance with the Registration Rights Agreement.

         3. EVENTS OF DEFAULT. If any of the events specified in this Section 3
shall occur (herein individually referred to as an "Event of Default"), the
Holders of more than fifty percent (50%) of the face amount of all then
outstanding Debentures issued pursuant to the Purchase Agreement may, so long as
such condition exists, declare the entire principal and unpaid accrued interest
hereon immediately due and payable, by notice in writing to the Company:

                  (i) Default in the payment of the principal and unpaid accrued
         interest of this Debenture when due and payable if such default is not
         cured by the Company within ten (10) days after the Holder has given
         the Company written notice of such default; or


                                      -3-

<PAGE>   4

                  (ii)  The institution by the Company of proceedings to be
         adjudicated as bankrupt or insolvent, or the consent by it to
         institution of bankruptcy or insolvency proceedings against it or the
         filing by it of a petition or answer or consent seeking reorganization
         or release under the federal Bankruptcy Act, or any other applicable
         federal or state law, or the consent by it to the filing of any such
         petition or the appointment of a receiver, liquidator, assignee,
         trustee or other similar official of the Company, or of any substantial
         part of its property, or the making by it of an assignment for the
         benefit of creditors, or the taking of corporate action by the Company
         in furtherance of any such action; or

                  (iii) If, within sixty (60) days after the commencement of an
         action against the Company (and service of process in connection
         therewith on the Company) seeking any bankruptcy, insolvency,
         reorganization, liquidation, dissolution or similar relief under any
         present or future statute, law or regulation, such action shall not
         have been resolved in favor of the Company or all orders or proceedings
         thereunder affecting the operations or the business of the Company
         stayed, or if the stay of any such order or proceeding shall thereafter
         be set aside, or if, within sixty (60) days after the appointment
         without the consent or acquiescence of the Company of any trustee,
         receiver or liquidator of the Company or of all or any substantial part
         of the properties of the Company, such appointment shall not have been
         vacated.

         4.  CONVERSION.

         4.1 VOLUNTARY CONVERSION. At any time more than sixty (60) days after
the date of this Debenture, the Holder of this Debenture has the right, at the
Holder's option, to convert this Debenture, in accordance with the provisions of
Section 4.3 hereof, in whole or in part, into fully paid and nonassessable
shares of Common Stock; provided, however, that the Holder's right to convert
this Debenture pursuant to this Section 4.1 shall be subject to the Company's
right to redeem this Debenture pursuant to Section 5. The number of shares of
Common Stock into which this Debenture may be converted ("Conversion Shares")
shall be determined by dividing the aggregate principal amount together with all
accrued interest to the date of conversion by the Conversion Price in effect at
the time of such conversion.

         4.2 AUTOMATIC CONVERSION. The entire principal amount of this Debenture
shall be automatically converted into shares of Common Stock at the Conversion
Price at the time in effect immediately prior to any consolidation or merger of
the Company with or into any other corporation or other entity or person, or any
other corporate reorganization in which the Company shall not be the continuing
or surviving entity of such consolidation, merger or reorganization or any
transaction or series of related transactions by the Company in which in excess
of fifty percent (50%) of the Company's voting power is transferred, or a sale
of all or substantially all of the assets of the Company (as presently
constituted, subject to proportionate adjustment in the event of any stock
split, stock dividend, reverse stock split, combination, consolidation,
reclassification or similar event).


                                      -4-

<PAGE>   5

         4.3 CONVERSION PROCEDURE.

                  4.3.1 NOTICE OF CONVERSION PURSUANT TO SECTION 4.1. Before the
Holder shall be entitled to convert this Debenture into shares of Common Stock,
it shall give written notice in accordance with Section 11 to the Company at its
principal corporate office of the election to convert the same pursuant to
Section 4.1, and shall state therein the name or names in which the certificate
or certificates for shares of Common Stock are to be issued. Such conversion
shall be deemed to have been made immediately prior to the close of business on
the date that such notice is actually received; provided, however, that such
notice shall not be effective with respect to, and the Holder shall not have the
right to convert, any portion of this Debenture to be redeemed unless such
notice is actually received by the Company before the close of business on the
day immediately preceding the day on which the Company mails notice of
redemption to the Holder.

                  4.3.2 NOTICE OF CONVERSION PURSUANT TO SECTION 4.2. If this
Debenture is automatically converted, written notice shall be delivered to the
Holder of this Debenture at the address last shown on the records of the Company
for the Holder or given by the Holder to the Company for the purpose of notice
or, if no such address appears or is given, at the place where the principal
executive office of the Company is located, notifying the Holder of the
conversion to be effected, specifying the Conversion Price, the principal amount
of the Debenture to be converted, the amount of accrued interest to be
converted, the date on which such conversion will occur and calling upon such
Holder to surrender to the Company, in the manner and at the place designated,
the Debenture.

         4.4 SURRENDER OF THE DEBENTURE. As promptly as practicable after
conversion of the Debenture (but in no case later than two (2) business days
thereafter), the Holder at its expense shall surrender the Debenture to the
Company, duly endorsed, at the principal offices of the Company. The person or
persons entitled to receive shares of Common Stock issuable upon such conversion
shall be treated for all purposes as the record holder or holders of such shares
of Common Stock immediately prior to the close of business on the Surrender
Date.

         4.5 DELIVERY OF STOCK CERTIFICATES. As promptly as practicable after
the conversion of this Debenture (but in no case later than three (3) business
days thereafter), the Company at its expense will issue and deliver to an
express courier service for delivery to the Holder of this Debenture a
certificate or certificates for the number of full shares of Common Stock
issuable upon such conversion. If the Company fails to delivery to an express
courier service for delivery such certificates to the courier service within ten
(10) days after the conversion of the Debenture, then the Company shall pay to
the Holder, as liquidated damages for such failure, an amount equal to two
hundred and fifty dollars ($250) per day for each twenty-five thousand dollars
($25,000) of principal of the Debenture that was converted until such
certificates are so delivered. Notwithstanding anything to the contrary set
forth herein, the Company shall not be obligated to issue or deliver any
certificates, or to pay any liquidated damages for its failure to deliver such
certificates, unless and until one (1) business day after the Surrender Date.

         4.6 MECHANICS AND EFFECT OF CONVERSION. No fractional shares of Common
Stock shall be issued upon conversion of this Debenture. In lieu of the Company
issuing any fractional 


                                      -5-

<PAGE>   6


shares to the Holder upon the conversion of this Debenture, the Company shall
pay to the Holder the amount of outstanding principal that is not so converted,
such payment to be in the form as provided below. The stock certificates issued
by the Company may bear such legends, if any, as are required by the Purchase
Agreement and applicable state and federal securities laws in the opinion of
counsel to the Company). Applicable state and federal securities laws will not
require any legends on the certificates after the shares have been registered
under the Securities Act in accordance with the Registration Rights Agreement.
Upon conversion of this Debenture, the Company shall be forever released from
all its obligations and liabilities under this Debenture, except that the
Company shall be obligated to pay the Holder, within ten (10) days after the
date of such conversion, any interest accrued and unpaid or unconverted to and
including the date of such conversion, and no more.

         5.  REDEMPTION.

         5.1 REDEMPTION AT THE OPTION OF THE COMPANY. At any time more than two
hundred seventy (270) days after the date of this Debenture, the Company may
redeem the Debenture, in whole or in part, immediately upon mailing written
notice to the Holder at a redemption price equal to one hundred ten percent
(110%) of the principal amount of the Debenture, plus any accrued but unpaid
interest; provided, however, that the Company may not redeem the Debenture
unless and until the shares of Common Stock issuable upon conversion of the
Debenture have been registered under the Securities Act in accordance with the
Registration Rights Agreement for at least two hundred ten (210) days plus any
Black-Out Period that occurs during the two hundred ten (210) days.

         5.2 REDEMPTION IN LIEN OF CONVERSION.

             5.2.1 REDEMPTION RIGHT. If the Holder shall give the Company notice
of the Holder's election to convert all or any part of this Debenture in
accordance with Section 4.1, and the applicable Conversion Price is less than
$4.00, then the Company may redeem this Debenture at a redemption price equal to
one hundred ten percent (110%) of the principal amount of the Debenture, plus
any accrued but unpaid interest.

             5.2.2 FOREBEARANCE REQUEST. The Holder may at any time (but not
more than once each calendar week) give the Company written notice of the
Holder's desire to convert this Debenture (which notice shall state the portion
of this Debenture to be converted) and request that the Company declare its
intention to redeem the Debenture if a notice of conversion is given to the
Company (a "Forbearance Request"). The Company shall respond to the Holder's
Forbearance Request before the close of business on the first business day after
the business day on which the Company actually receives the request. If the
Company states in its response that it will not redeem the Debentures, then the
Company may not redeem the Debenture as a result of the Holder's request to
convert the Debenture to the extent identified in the Holder's Forbearance
Request, provided that the Company receives the conversion notice before the
close of business on the first business day after the business day on which the
Holder actually receives the Company's response to the Holder's Forbearance
Request.


                                      -6-

<PAGE>   7

         5.3 MECHANICS AND EFFECT OF REDEMPTION. As promptly as practicable
after receiving notice of the Company's election to redeem the Debentures (but
in no case later than three (3) business days thereafter), the Holder, at its
expense, shall surrender the Debenture to the Company, duly endorsed, at the
principal offices of the Company. The Company shall make the redemption payment
within fifteen (15) days after (a) the Company gives the Holder notice of
redemption, in the case of a redemption pursuant to Section 5.1, or (b) the
Company actually receives the notice of Holder's election to convert, in the
case of a redemption pursuant to Section 5.2; provided, however, the Company
shall not be obligated to make any redemption payment unless and until one (1)
business day after the Surrender Date. Interest shall continue to accrue on the
Debenture until the Redemption Payment Date. If the Debenture is to be redeemed
in part, then upon surrender of the Debenture, the Company shall deliver to the
Holder a new Debenture in the aggregate principal amount equal to the unredeemed
portion thereof.

         6.  CONVERSION PRICE ADJUSTMENTS.

         6.1 ADJUSTMENTS FOR STOCK SPLITS AND SUBDIVISIONS. In the event the
Company should at any time or from time to time after the date of issuance
hereof fix a record date for the effectuation of a split or subdivision of the
outstanding shares of Common Stock or the determination of holders of Common
Stock entitled to receive a dividend or other distribution payable in additional
shares of Common Stock or other securities or rights convertible into, or
entitling the holder thereof to receive directly or indirectly, additional
shares of Common Stock (hereinafter referred to as "Common Stock Equivalents")
without payment of any consideration by such holder for the additional shares of
Common Stock or the Common Stock Equivalents (including the additional shares of
Common Stock issuable upon conversion or exercise thereof), then, as of such
record date (or the date of such dividend distribution, split or subdivision if
no record date is fixed), the Conversion Price of this Debenture shall be
appropriately decreased so that the number of shares of Common Stock issuable
upon conversion of this Debenture shall be. increased in proportion to such
increase of outstanding shares.

         6.2 ADJUSTMENTS FOR REVERSE STOCK SPLITS. If the number of shares of
Common Stock outstanding at any time after the date hereof is decreased by a
combination of the outstanding shares of Common Stock, then, following the
record date of such combination, the Conversion Price for this Debenture shall
be appropriately increased so that the number of shares of Common Stock issuable
on conversion hereof shall be decreased in proportion to such decrease in out
standing shares.


                                      -7-

<PAGE>   8


         6.3. NOTICES OF RECORD DATE, ETC. In the event of:

                  (i)   Any taking by the Company of a record of the holders of
any class of securities of the Company for the purpose of determining the
holders thereof who are entitled to receive any dividend (other than a cash
dividend payable out of earned surplus at the same rate as that of the last such
cash dividend theretofore paid) or other distribution, or any right to subscribe
for, purchase or otherwise acquire any shares of stock of any class or any other
securities or property, or to receive any other right; or

                  (ii)  Any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
transfer of all or substantially all of the assets of the Company to any other
person or any consolidation or merger involving the Company; or

                  (iii) Any voluntary or involuntary dissolution, liquidation 
or winding up of the Company.

The Company will mail to the holder of this Debenture at least ten (10) days
prior to the earliest date specified therein, a notice specifying (A) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, and the amount and character of such dividend,
distribution or right; and (B) the date on which any such reorganization,
reclassification, transfer, consolidation, merger, dissolution, liquidation or
windingup is expected to become effective and the record date for determining
stockholders entitled to vote thereon.

         6.4 RESERVATION OF STOCK LSSUABLE UPON CONVERSION. The Company shall at
all times reserve and keep available out of its authorized but unissued shares
of Common Stock solely for the purpose of effecting the conversion of the
Debenture such number of its shares of Common Stock as shall from time to time
be sufficient to effect the conversion of the Debenture; and if at any time the
number of authorized but unissued shares of Common Stock shall not be sufficient
to effect the conversion of the entire outstanding principal amount of this
Debenture, in addition to such other remedies as shall be available to the
holder of this Debenture, the Company will use its best efforts to take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock (and shares of its Common
Stock for issuance on conversion of such Common Stock) to such number of shares
as shall be sufficient for such purposes.

         7. ASSIGNMENT. Subject to the restrictions on transfer described in
Section 9 below, the rights and obligations of the Company and the Holder of
this Debenture shall be binding upon and benefit the successors, assigns, heirs,
administrators and transferees of the parties.

         8. WAIVER AND AMENDMENT. Any provision of this Debenture may be
amended, waived or modified upon the written consent of the Company and holders
of at least fifty percent of the face amount of all then outstanding Debentures
issued pursuant to the Purchase Agreement.


                                      -8-

<PAGE>   9

         9. TRANSFER OF THIS DEBENTURE OR SECURITIES ISSUABLE ON CONVERSION
HEREOF. With respect to any offer, sale or other disposition of this Debenture
or securities into which such Debenture may be converted, the Holder will give
written notice to the Company prior thereto, describing briefly the manner
thereof, together with a written opinion of such Holder's counsel, to the effect
that such offer, sale or other distribution may be effected without registration
or qualification (under any federal or state law then in effect). Promptly upon
receiving such written notice and reasonably satisfactory opinion, if so
requested, the Company, as promptly as practicable, shall notify such Holder
that such Holder may sell or otherwise dispose of this Debenture or such
securities, all in accordance with the terms of the notice delivered to the
Company. If a determination has been made pursuant to this Section 9 that the
opinion of counsel for the Holder is not reasonably satisfactory to the Company,
the Company shall so notify the Holder promptly after such determination has
been made. Each Debenture thus transferred and each certificate representing the
securities thus transferred shall bear a legend as to the applicable
restrictions on transferability in order to ensure compliance with the Act,
unless in the opinion of counsel for the Company such legend is not required. in
order to ensure compliance with the Act. The Company may issue stop transfer
instructions to its transfer agent in connection with such restrictions.

         10. TREATMENT OF DEBENTURE. To the extent permitted by generally
accepted accounting principles, the Company will treat, account and report the
Debenture as debt and not equity for accounting purposes and with respect to any
returns filed with federal, state or local tax authorities.

         11. NOTICES. Any notice, request or other communication required or
permitted hereunder shall be in writing and shall be deemed to have been duly
given if made by hand delivery, by an express courier company recognized
nationally in the United States or Canada or by registered or certified mail,
postage prepaid, at the respective addresses of the parties as set forth herein.
Any party hereto may by notice so given change its address for future notice
hereunder. Notice shall conclusively be deemed to have been given as of the date
so delivered when personally delivered, one (1) business day (three (3) business
days in the case of international deliveries) after dispatch if sent for
overnight delivery by an express courier service nationally recognized in the
United States or Canada and five (5) calendar days (seven (7) calendar days in
the case of international deliveries) after mailing if sent by registered or
certified mail in the manner set forth above. A notice of conversion given
pursuant to Section 4.1 and a Forbearance Request given pursuant to Section
5(ii) may be given to the Company by facsimile transmission at 770/448-3357 and
a simultaneous phone call to the Company at 770/453-0121 (or such other number
as the Company shall designate), and shall be deemed to have been given and
received when a legible copy has been actually received. A notice of redemption
given pursuant to Section 4.3.1 and the Company's response to the Holder's
Forebearance Request given pursuant to Section 5.2.2 may be given to the Holder
by facsimile transmission at (___) ___________ and a simultaneous phone call to
the Holder at (___) _______________ (or such other number as the Holder shall
designate) and shall be deemed to have been given and received when a legible
copy has been actually received.


                                      -9-

<PAGE>   10

         12. NO STOCKHOLDER RIGHTS. Nothing contained in this Debenture shall be
construed as conferring upon the Holder or any other person the right to vote or
to consent or to receive notice as a stockholder in respect of meetings of
stockholders for the election of directors of the Company or any other matters
or any rights whatsoever as a stockholder of the Company; and no dividends or
interest shall be payable or accrued in respect of this Debenture or the
interest represented hereby or the Conversion Shares obtainable hereunder until,
and only to the extent that, this Debenture shall have been converted.

         13. GOVERNING LAW; INTERPRETATION. This Debenture shall be governed by
and construed in accordance with the laws of the State of Delaware, USA
excluding that body of law relating to conflict of laws. All references to
dollars are to U.S. dollars.

         14. ARBITRATION. All disputes arising under this Agreement (other than
claims in equity) shall be resolved by arbitration in accordance with the
Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.

         15. HEADING; REFERENCES. All headings used herein are used for
convenience only and shall not be used to construe or interpret this Debenture.
Except where otherwise indicated, all references herein to Sections refer to
Sections hereof.

                    [Signatures Appear on the Following Page]


<PAGE>   11


         IN WITNESS WHEREOF, the Company has caused this Debenture to be issued
this _____ day of October, 1997.

                                             CYTRX CORPORATION

                                             By:
                                                  -----------------------------
                                                  Jack J. Luchese
                                             Its: Chief Executive Officer
                                                  and President

Name of Holder: GUNDYCO in trust for R.R.S.P. 550-98866-19
Address: 4120 Young Street
         Suite 416
         North York, Ontario  M2P2B8
         Canada


                                      -11-

<PAGE>   12


                              NOTICE OF CONVERSION

                (To Be Signed Only Upon Conversion of Debenture)

TO CYTRX CORPORATION

The undersigned, the holder of the foregoing Debenture, hereby surrenders such
Debenture for conversion into shares of Common Stock of CYTRX CORPORATION, to
the extent of $_________ unpaid principal amount of such Debenture, and requests
that the certificates for such shares be issued in the name of, and delivered
to, _________________ whose address is ____________________.

Dated:
      ---------------------

                                             ------------------------------
                                             (Signature must conform in all
                                             respects to name of holder as
                                             specified on the face of the
                                             Debenture)


                                             ------------------------------
                                                      (Address)


                                      -12-


<PAGE>   1

                                                                     EXHIBIT 3.2

NEITHER THIS DEBENTURE, NOR THE SHARES OF COMMON STOCK FOR WHICH IT MAY BE
CONVERTED, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS DEBENTURE HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS DEBENTURE HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.


                                CYTRX CORPORATION
                            6% CONVERTIBLE DEBENTURE

$400,000.00                                           Atlanta, Georgia
                                                      October 22, 1997

CYTRX CORPORATION, a Delaware corporation (the "Company"), the principal office
of which is located at 154 Technology Parkway Technology Park/Atlanta, Norcross,
Georgia 30092, for value received hereby promises to pay to Excalibur Capital
Management, or its registered assigns, the sum of Four Hundred Thousand Dollars
($400,000.00), or such lesser amount as shall then equal the outstanding
principal amount hereof and any unpaid accrued interest hereon, as set forth
below, shall be due and payable on October ____, 2001, (the "Maturity Date") (or
in the case of redemption in accordance with Section 5 hereof, until the
Redemption Payment Date). Payment for all amounts due hereunder shall be made by
mail to the registered address of the Holder. This Debenture is issued in
connection with the transactions described in Section ___ of that certain
Subscription Agreement between the Company and the Holder, dated as of October
22, 1997, as the same may from time to time be amended, modified or supplemented
(the "Purchase Agreement"). The Holder is subject to certain restrictions set
forth in the Purchase Agreement and shall be entitled to certain rights and
privileges set forth in the Purchase Agreement. This Debenture is the Debenture
referred to in the Purchase Agreement.

         The following is a statement of the rights of the Holder of this
Debenture and conditions to which this Debenture is subject, and to which the
Holder hereof, by the acceptance of this Debenture, agrees:


<PAGE>   2

         1. DEFINITIONS. As used in this Debenture, the following terms, unless
the context otherwise requires, have the following meanings:

                  (i)    "Average Closing Bid Price" means the average of the
         daily last bid price for the shares of Common Stock for the ten (10)
         consecutive trading days on which such shares are actually traded as
         over-the-counter securities and quoted on the Nasdaq National Market
         (as reported by Bloomberg Business News or, if not reported thereby,
         any other authoritative source selected by the Company) ending at the
         close of trading on the trading day immediately preceding an identified
         measurement date.

                  (ii)   "Black-Out Period" means the number of days, if any,
         that the Company suspends the rights of the Holder to make sales
         pursuant to the Shelf Registration in accordance with Section 2(h) of
         the Registration Rights Agreement.

                  (iii)  "Closing Date" shall have the meaning given that term
         in the Purchase Agreement.

                  (iv)   "Company" includes any corporation which shall succeed 
         to or assume the obligations of the Company under this Debenture.

                  (v)    "Common Stock" shall mean the $.001 par value common
         stock of the Company.

                  (vi)   "Conversion Price" shall mean the lessor of (A) $5.68
         for each share of Common Stock, or (B) eighty-five percent of the
         Average Closing Bid Price calculated using the date of conversion as
         the measurement date; provided, however, but if the Holder delivered a
         Forbearance Request to the Company in accordance with Section 5(ii)
         within twenty-four (24) hours before it delivered a conversion notice
         to the Company in accordance with Section 4.3.1, then the Average
         Closing Bid Price for the portion of the Debenture that the Holder
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

                  (vii)  "Holder," when the context refers to a holder of this
         Debenture, shall mean any person who shall at the time be the
         registered holder of this Debenture.

                  (viii) "Redemption Payment Date" shall mean the day on which
                  the Company is obligated to make the redemption payment to the
                  Holder in accordance with Section 5.3.


                                      -2-

<PAGE>   3

                  (ix) "Registration Rights Agreement" shall mean the
                  Registration Rights Agreement dated as of October 22, 1997,
                  between the Company, the Holder and the other holders of
                  Company securities that are signatories thereto.

                  (x)  "Securities Act" shall mean the Securities Act of 1933, 
                  as amended.

                  (xi) "Surrender Date" shall mean the day on which the Company
                  receives the Debenture in accordance with either Section 4.4
                  or 5.3.

         2. INTEREST.

                  (i)  Commencing on December 31, 1997, and on each June 30 and
         December 31 thereafter until the Maturity Date (or in the case of
         redemption in accordance with Section 5 hereof, until the Redemption
         Payment Date, the Company shall pay interest (computed on the basis of
         a 365-day year) at rate of six percent (6%) per annum on the principal
         of this Debenture outstanding during the period beginning on the date
         of issuance of this Debenture and ending on the date that the principal
         amount of this Debenture becomes due and payable.

                  (ii) The Company, at its option, may make any payment of
         interest due hereunder in whole or in part by issuing to the Holder
         shares of Common Stock (the "Interest Shares"). The Interest Shares
         shall be valued at the Average Closing Price, calculated using the date
         on which the interest payment is due as the measurement date. The
         Company shall not be obligated to issue any fractional shares. The
         Company may place such legends, if any, on the certificates for the
         Interest Shares as are required by applicable state and federal
         securities laws in the opinion of counsel to the Company. Applicable
         state and federal securities laws will not require any legends on the
         certificates after the shares have been registered under the Securities
         Act in accordance with the Registration Rights Agreement.

         3. EVENTS OF DEFAULT. If any of the events specified in this Section 3
shall occur (herein individually referred to as an "Event of Default"), the
Holders of more than fifty percent (50%) of the face amount of all then
outstanding Debentures issued pursuant to the Purchase Agreement may, so long as
such condition exists, declare the entire principal and unpaid accrued interest
hereon immediately due and payable, by notice in writing to the Company:

                  (i) Default in the payment of the principal and unpaid accrued
         interest of this Debenture when due and payable if such default is not
         cured by the Company within ten (10) days after the Holder has given
         the Company written notice of such default; or


                                      -3-

<PAGE>   4

                  (ii)  The institution by the Company of proceedings to be
         adjudicated as bankrupt or insolvent, or the consent by it to
         institution of bankruptcy or insolvency proceedings against it or the
         filing by it of a petition or answer or consent seeking reorganization
         or release under the federal Bankruptcy Act, or any other applicable
         federal or state law, or the consent by it to the filing of any such
         petition or the appointment of a receiver, liquidator, assignee,
         trustee or other similar official of the Company, or of any substantial
         part of its property, or the making by it of an assignment for the
         benefit of creditors, or the taking of corporate action by the Company
         in furtherance of any such action; or

                  (iii) If, within sixty (60) days after the commencement of an
         action against the Company (and service of process in connection
         therewith on the Company) seeking any bankruptcy, insolvency,
         reorganization, liquidation, dissolution or similar relief under any
         present or future statute, law or regulation, such action shall not
         have been resolved in favor of the Company or all orders or proceedings
         thereunder affecting the operations or the business of the Company
         stayed, or if the stay of any such order or proceeding shall thereafter
         be set aside, or if, within sixty (60) days after the appointment
         without the consent or acquiescence of the Company of any trustee,
         receiver or liquidator of the Company or of all or any substantial part
         of the properties of the Company, such appointment shall not have been
         vacated.

         4.  CONVERSION.

         4.1 VOLUNTARY CONVERSION. At any time more than sixty (60) days after
the date of this Debenture, the Holder of this Debenture has the right, at the
Holder's option, to convert this Debenture, in accordance with the provisions of
Section 4.3 hereof, in whole or in part, into fully paid and nonassessable
shares of Common Stock; provided, however, that the Holder's right to convert
this Debenture pursuant to this Section 4.1 shall be subject to the Company's
right to redeem this Debenture pursuant to Section 5. The number of shares of
Common Stock into which this Debenture may be converted ("Conversion Shares")
shall be determined by dividing the aggregate principal amount together with all
accrued interest to the date of conversion by the Conversion Price in effect at
the time of such conversion.

         4.2 AUTOMATIC CONVERSION. The entire principal amount of this Debenture
shall be automatically converted into shares of Common Stock at the Conversion
Price at the time in effect immediately prior to any consolidation or merger of
the Company with or into any other corporation or other entity or person, or any
other corporate reorganization in which the Company shall not be the continuing
or surviving entity of such consolidation, merger or reorganization or any
transaction or series of related transactions by the Company in which in excess
of fifty percent (50%) of the Company's voting power is transferred, or a sale
of all or substantially all of the assets of the Company (as presently
constituted, subject to proportionate adjustment in the event of any stock
split, stock dividend, reverse stock split, combination, consolidation,
reclassification or similar event).


                                      -4-

<PAGE>   5

         4.3 CONVERSION PROCEDURE.

                  4.3.1 NOTICE OF CONVERSION PURSUANT TO SECTION 4.1. Before the
Holder shall be entitled to convert this Debenture into shares of Common Stock,
it shall give written notice in accordance with Section 11 to the Company at its
principal corporate office of the election to convert the same pursuant to
Section 4.1, and shall state therein the name or names in which the certificate
or certificates for shares of Common Stock are to be issued. Such conversion
shall be deemed to have been made immediately prior to the close of business on
the date that such notice is actually received; provided, however, that such
notice shall not be effective with respect to, and the Holder shall not have the
right to convert, any portion of this Debenture to be redeemed unless such
notice is actually received by the Company before the close of business on the
day immediately preceding the day on which the Company mails notice of
redemption to the Holder.

                  4.3.2 NOTICE OF CONVERSION PURSUANT TO SECTION 4.2. If this
Debenture is automatically converted, written notice shall be delivered to the
Holder of this Debenture at the address last shown on the records of the Company
for the Holder or given by the Holder to the Company for the purpose of notice
or, if no such address appears or is given, at the place where the principal
executive office of the Company is located, notifying the Holder of the
conversion to be effected, specifying the Conversion Price, the principal amount
of the Debenture to be converted, the amount of accrued interest to be
converted, the date on which such conversion will occur and calling upon such
Holder to surrender to the Company, in the manner and at the place designated,
the Debenture.

         4.4 SURRENDER OF THE DEBENTURE. As promptly as practicable after
conversion of the Debenture (but in no case later than two (2) business days
thereafter), the Holder at its expense shall surrender the Debenture to the
Company, duly endorsed, at the principal offices of the Company. The person or
persons entitled to receive shares of Common Stock issuable upon such conversion
shall be treated for all purposes as the record holder or holders of such shares
of Common Stock immediately prior to the close of business on the Surrender
Date.

         4.5 DELIVERY OF STOCK CERTIFICATES. As promptly as practicable after
the conversion of this Debenture (but in no case later than three (3) business
days thereafter), the Company at its expense will issue and deliver to an
express courier service for delivery to the Holder of this Debenture a
certificate or certificates for the number of full shares of Common Stock
issuable upon such conversion. If the Company fails to delivery to an express
courier service for delivery such certificates to the courier service within ten
(10) days after the conversion of the Debenture, then the Company shall pay to
the Holder, as liquidated damages for such failure, an amount equal to two
hundred and fifty dollars ($250) per day for each twenty-five thousand dollars
($25,000) of principal of the Debenture that was converted until such
certificates are so delivered. Notwithstanding anything to the contrary set
forth herein, the Company shall not be obligated to issue or deliver any
certificates, or to pay any liquidated damages for its failure to deliver such
certificates, unless and until one (1) business day after the Surrender Date.

         4.6 MECHANICS AND EFFECT OF CONVERSION. No fractional shares of Common
Stock shall be issued upon conversion of this Debenture. In lieu of the Company
issuing any fractional 


                                      -5-

<PAGE>   6


shares to the Holder upon the conversion of this Debenture, the Company shall
pay to the Holder the amount of outstanding principal that is not so converted,
such payment to be in the form as provided below. The stock certificates issued
by the Company may bear such legends, if any, as are required by the Purchase
Agreement and applicable state and federal securities laws in the opinion of
counsel to the Company). Applicable state and federal securities laws will not
require any legends on the certificates after the shares have been registered
under the Securities Act in accordance with the Registration Rights Agreement.
Upon conversion of this Debenture, the Company shall be forever released from
all its obligations and liabilities under this Debenture, except that the
Company shall be obligated to pay the Holder, within ten (10) days after the
date of such conversion, any interest accrued and unpaid or unconverted to and
including the date of such conversion, and no more.

         5.  REDEMPTION.

         5.1 REDEMPTION AT THE OPTION OF THE COMPANY. At any time more than two
hundred seventy (270) days after the date of this Debenture, the Company may
redeem the Debenture, in whole or in part, immediately upon mailing written
notice to the Holder at a redemption price equal to one hundred ten percent
(110%) of the principal amount of the Debenture, plus any accrued but unpaid
interest; provided, however, that the Company may not redeem the Debenture
unless and until the shares of Common Stock issuable upon conversion of the
Debenture have been registered under the Securities Act in accordance with the
Registration Rights Agreement for at least two hundred ten (210) days plus any
Black-Out Period that occurs during the two hundred ten (210) days.

         5.2 REDEMPTION IN LIEN OF CONVERSION.

             5.2.1 REDEMPTION RIGHT. If the Holder shall give the Company notice
of the Holder's election to convert all or any part of this Debenture in
accordance with Section 4.1, and the applicable Conversion Price is less than
$4.00, then the Company may redeem this Debenture at a redemption price equal to
one hundred ten percent (110%) of the principal amount of the Debenture, plus
any accrued but unpaid interest.

             5.2.2 FOREBEARANCE REQUEST. The Holder may at any time (but not
more than once each calendar week) give the Company written notice of the
Holder's desire to convert this Debenture (which notice shall state the portion
of this Debenture to be converted) and request that the Company declare its
intention to redeem the Debenture if a notice of conversion is given to the
Company (a "Forbearance Request"). The Company shall respond to the Holder's
Forbearance Request before the close of business on the first business day after
the business day on which the Company actually receives the request. If the
Company states in its response that it will not redeem the Debentures, then the
Company may not redeem the Debenture as a result of the Holder's request to
convert the Debenture to the extent identified in the Holder's Forbearance
Request, provided that the Company receives the conversion notice before the
close of business on the first business day after the business day on which the
Holder actually receives the Company's response to the Holder's Forbearance
Request.


                                      -6-

<PAGE>   7

         5.3 MECHANICS AND EFFECT OF REDEMPTION. As promptly as practicable
after receiving notice of the Company's election to redeem the Debentures (but
in no case later than three (3) business days thereafter), the Holder, at its
expense, shall surrender the Debenture to the Company, duly endorsed, at the
principal offices of the Company. The Company shall make the redemption payment
within fifteen (15) days after (a) the Company gives the Holder notice of
redemption, in the case of a redemption pursuant to Section 5.1, or (b) the
Company actually receives the notice of Holder's election to convert, in the
case of a redemption pursuant to Section 5.2; provided, however, the Company
shall not be obligated to make any redemption payment unless and until one (1)
business day after the Surrender Date. Interest shall continue to accrue on the
Debenture until the Redemption Payment Date. If the Debenture is to be redeemed
in part, then upon surrender of the Debenture, the Company shall deliver to the
Holder a new Debenture in the aggregate principal amount equal to the unredeemed
portion thereof.

         6.  CONVERSION PRICE ADJUSTMENTS.

         6.1 ADJUSTMENTS FOR STOCK SPLITS AND SUBDIVISIONS. In the event the
Company should at any time or from time to time after the date of issuance
hereof fix a record date for the effectuation of a split or subdivision of the
outstanding shares of Common Stock or the determination of holders of Common
Stock entitled to receive a dividend or other distribution payable in additional
shares of Common Stock or other securities or rights convertible into, or
entitling the holder thereof to receive directly or indirectly, additional
shares of Common Stock (hereinafter referred to as "Common Stock Equivalents")
without payment of any consideration by such holder for the additional shares of
Common Stock or the Common Stock Equivalents (including the additional shares of
Common Stock issuable upon conversion or exercise thereof), then, as of such
record date (or the date of such dividend distribution, split or subdivision if
no record date is fixed), the Conversion Price of this Debenture shall be
appropriately decreased so that the number of shares of Common Stock issuable
upon conversion of this Debenture shall be. increased in proportion to such
increase of outstanding shares.

         6.2 ADJUSTMENTS FOR REVERSE STOCK SPLITS. If the number of shares of
Common Stock outstanding at any time after the date hereof is decreased by a
combination of the outstanding shares of Common Stock, then, following the
record date of such combination, the Conversion Price for this Debenture shall
be appropriately increased so that the number of shares of Common Stock issuable
on conversion hereof shall be decreased in proportion to such decrease in out
standing shares.


                                      -7-

<PAGE>   8


         6.3. NOTICES OF RECORD DATE, ETC. In the event of:

                  (i)   Any taking by the Company of a record of the holders of
any class of securities of the Company for the purpose of determining the
holders thereof who are entitled to receive any dividend (other than a cash
dividend payable out of earned surplus at the same rate as that of the last such
cash dividend theretofore paid) or other distribution, or any right to subscribe
for, purchase or otherwise acquire any shares of stock of any class or any other
securities or property, or to receive any other right; or

                  (ii)  Any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
transfer of all or substantially all of the assets of the Company to any other
person or any consolidation or merger involving the Company; or

                  (iii) Any voluntary or involuntary dissolution, liquidation or
winding up of the Company.

The Company will mail to the holder of this Debenture at least ten (10) days
prior to the earliest date specified therein, a notice specifying (A) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, and the amount and character of such dividend,
distribution or right; and (B) the date on which any such reorganization,
reclassification, transfer, consolidation, merger, dissolution, liquidation or
windingup is expected to become effective and the record date for determining
stockholders entitled to vote thereon.

         6.4 RESERVATION OF STOCK LSSUABLE UPON CONVERSION. The Company shall at
all times reserve and keep available out of its authorized but unissued shares
of Common Stock solely for the purpose of effecting the conversion of the
Debenture such number of its shares of Common Stock as shall from time to time
be sufficient to effect the conversion of the Debenture; and if at any time the
number of authorized but unissued shares of Common Stock shall not be sufficient
to effect the conversion of the entire outstanding principal amount of this
Debenture, in addition to such other remedies as shall be available to the
holder of this Debenture, the Company will use its best efforts to take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock (and shares of its Common
Stock for issuance on conversion of such Common Stock) to such number of shares
as shall be sufficient for such purposes.

         7. ASSIGNMENT. Subject to the restrictions on transfer described in
Section 9 below, the rights and obligations of the Company and the Holder of
this Debenture shall be binding upon and benefit the successors, assigns, heirs,
administrators and transferees of the parties.

         8. WAIVER AND AMENDMENT. Any provision of this Debenture may be
amended, waived or modified upon the written consent of the Company and holders
of at least fifty percent of the face amount of all then outstanding Debentures
issued pursuant to the Purchase Agreement.


                                      -8-


<PAGE>   9

         9. TRANSFER OF THIS DEBENTURE OR SECURITIES ISSUABLE ON CONVERSION
HEREOF. With respect to any offer, sale or other disposition of this Debenture
or securities into which such Debenture may be converted, the Holder will give
written notice to the Company prior thereto, describing briefly the manner
thereof, together with a written opinion of such Holder's counsel, to the effect
that such offer, sale or other distribution may be effected without registration
or qualification (under any federal or state law then in effect). Promptly upon
receiving such written notice and reasonably satisfactory opinion, if so
requested, the Company, as promptly as practicable, shall notify such Holder
that such Holder may sell or otherwise dispose of this Debenture or such
securities, all in accordance with the terms of the notice delivered to the
Company. If a determination has been made pursuant to this Section 9 that the
opinion of counsel for the Holder is not reasonably satisfactory to the Company,
the Company shall so notify the Holder promptly after such determination has
been made. Each Debenture thus transferred and each certificate representing the
securities thus transferred shall bear a legend as to the applicable
restrictions on transferability in order to ensure compliance with the Act,
unless in the opinion of counsel for the Company such legend is not required. in
order to ensure compliance with the Act. The Company may issue stop transfer
instructions to its transfer agent in connection with such restrictions.

         10. TREATMENT OF DEBENTURE. To the extent permitted by generally
accepted accounting principles, the Company will treat, account and report the
Debenture as debt and not equity for accounting purposes and with respect to any
returns filed with federal, state or local tax authorities.

         11. NOTICES. Any notice, request or other communication required or
permitted hereunder shall be in writing and shall be deemed to have been duly
given if made by hand delivery, by an express courier company recognized
nationally in the United States or Canada or by registered or certified mail,
postage prepaid, at the respective addresses of the parties as set forth herein.
Any party hereto may by notice so given change its address for future notice
hereunder. Notice shall conclusively be deemed to have been given as of the date
so delivered when personally delivered, one (1) business day (three (3) business
days in the case of international deliveries) after dispatch if sent for
overnight delivery by an express courier service nationally recognized in the
United States or Canada and five (5) calendar days (seven (7) calendar days in
the case of international deliveries) after mailing if sent by registered or
certified mail in the manner set forth above. A notice of conversion given
pursuant to Section 4.1 and a Forbearance Request given pursuant to Section
5(ii) may be given to the Company by facsimile transmission at 770/448-3357 and
a simultaneous phone call to the Company at 770/453-0121 (or such other number
as the Company shall designate), and shall be deemed to have been given and
received when a legible copy has been actually received. A notice of redemption
given pursuant to Section 4.3.1 and the Company's response to the Holder's
Forebearance Request given pursuant to Section 5.2.2 may be given to the Holder
by facsimile transmission at (___) ___________ and a simultaneous phone call to
the Holder at (___) _______________ (or such other number as the Holder shall
designate) and shall be deemed to have been given and received when a legible
copy has been actually received.


                                      -9-

<PAGE>   10

         12. NO STOCKHOLDER RIGHTS. Nothing contained in this Debenture shall be
construed as conferring upon the Holder or any other person the right to vote or
to consent or to receive notice as a stockholder in respect of meetings of
stockholders for the election of directors of the Company or any other matters
or any rights whatsoever as a stockholder of the Company; and no dividends or
interest shall be payable or accrued in respect of this Debenture or the
interest represented hereby or the Conversion Shares obtainable hereunder until,
and only to the extent that, this Debenture shall have been converted.

         13. GOVERNING LAW; INTERPRETATION. This Debenture shall be governed by
and construed in accordance with the laws of the State of Delaware, USA
excluding that body of law relating to conflict of laws. All references to
dollars are to U.S. dollars.

         14. ARBITRATION. All disputes arising under this Agreement (other than
claims in equity) shall be resolved by arbitration in accordance with the
Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.

         15. HEADING; REFERENCES. All headings used herein are used for
convenience only and shall not be used to construe or interpret this Debenture.
Except where otherwise indicated, all references herein to Sections refer to
Sections hereof.

                    [Signatures Appear on the Following Page]


                                      -10-

<PAGE>   11


         IN WITNESS WHEREOF, the Company has caused this Debenture to be issued
this 22 day of October, 1997.

                                             CYTRX CORPORATION

                                             By:
                                                -------------------------------
                                                  Jack J. Luchese
                                             Its: Chief Executive Officer
                                                  and President

Name of Holder: EXCALIBUR CAPITAL MANAGEMENT
Address:          c/o H&H Securities Limited
                  205 Vest Drive
                  Toronto, Ontario  MSP3A1
                  Canada


                                      -11-


<PAGE>   12


                              NOTICE OF CONVERSION

                (To Be Signed Only Upon Conversion of Debenture)

TO CYTRX CORPORATION

The undersigned, the holder of the foregoing Debenture, hereby surrenders such
Debenture for conversion into shares of Common Stock of CYTRX CORPORATION, to
the extent of $_________ unpaid principal amount of such Debenture, and requests
that the certificates for such shares be issued in the name of, and delivered
to, _________________ whose address is ____________________.

Dated:
      -------------------------

                                             ------------------------------
                                             (Signature must conform in all
                                             respects to name of holder as
                                             specified on the face of the
                                             Debenture)

                                             ------------------------------
                                                      (Address)


                                      -12-

<PAGE>   1
                                                                     EXHIBIT 3.3

NEITHER THIS DEBENTURE, NOR THE SHARES OF COMMON STOCK FOR WHICH IT MAY BE
CONVERTED, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS DEBENTURE HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(b)(8) OF THE DELAWARE
SECURITIES ACT. THIS DEBENTURE HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.


                                CYTRX CORPORATION
                            6% CONVERTIBLE DEBENTURE

$50,000                                                       Atlanta, Georgia
                                                              October 22, 1997

CYTRX CORPORATION, a Delaware corporation (the "Company"), the principal office
of which is located at 154 Technology Parkway Technology Park/Atlanta, Norcross,
Georgia 30092, for value received hereby promises to pay to Pine Street Asset
Management, or its registered assigns, the sum of Fifty Thousand Dollars
($50,000), or such lesser amount as shall then equal the outstanding principal
amount hereof and any unpaid accrued interest hereon, as set forth below, shall
be due and payable on October ____, 2001, (the "Maturity Date") (or in the case
of redemption in accordance with Section 5 hereof, until the Redemption Payment
Date). Payment for all amounts due hereunder shall be made by mail to the
registered address of the Holder. This Debenture is issued in connection with
the transactions described in Section ___ of that certain Subscription Agreement
between the Company and the Holder, dated as of October 22, 1997, as the same
may from time to time be amended, modified or supplemented (the "Purchase
Agreement"). The Holder is subject to certain restrictions set forth in the
Purchase Agreement and shall be entitled to certain rights and privileges set
forth in the Purchase Agreement. This Debenture is the Debenture referred to in
the Purchase Agreement.

         The following is a statement of the rights of the Holder of this
Debenture and conditions to which this Debenture is subject, and to which the
Holder hereof, by the acceptance of this Debenture, agrees:
<PAGE>   2

         1. Definitions. As used in this Debenture, the following terms, unless
the context otherwise requires, have the following meanings:

                  (i) "Average Closing Bid Price" means the average of the daily
         last bid price for the shares of Common Stock for the ten (10)
         consecutive trading days on which such shares are actually traded as
         over-the-counter securities and quoted on the Nasdaq National Market
         (as reported by Bloomberg Business News or, if not reported thereby,
         any other authoritative source selected by the Company) ending at the
         close of trading on the trading day immediately preceding an identified
         measurement date.

                  (ii) "Black-Out Period" means the number of days, if any, that
         the Company suspends the rights of the Holder to make sales pursuant to
         the Shelf Registration in accordance with Section 2(h) of the
         Registration Rights Agreement.

                  (iii) "Closing Date" shall have the meaning given that term in
         the Purchase Agreement.

                  (iv) "Company" includes any corporation which shall succeed to
         or assume the obligations of the Company under this Debenture.

                  (v)  "Common Stock" shall mean the $.001 par value common
         stock of the Company.

                  (vi) "Conversion Price" shall mean the lessor of (A) $5.68 for
         each share of Common Stock, or (B) eighty-five percent of the Average
         Closing Bid Price calculated using the date of conversion as the
         measurement date; provided, however, but if the Holder delivered a
         Forbearance Request to the Company in accordance with Section 5(ii)
         within twenty-four (24) hours before it delivered a conversion notice
         to the Company in accordance with Section 4.3.1, then the Average
         Closing Bid Price for the portion of the Debenture that the Holder
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

                  (vii) "Holder," when the context refers to a holder of this
         Debenture, shall mean any person who shall at the time be the
         registered holder of this Debenture.

                  (viii)"Redemption Payment Date" shall mean the day on which
         the Company is obligated to make the redemption payment to the Holder
         in accordance with Section 5.3.

                                      - 2-

<PAGE>   3

                  (ix) "Registration Rights Agreement" shall mean the
         Registration Rights Agreement dated as of October 22, 1997, between the
         Company, the Holder and the other holders of Company securities that
         are signatories thereto.

                  (x)  "Securities Act" shall mean the Securities Act of 1933,
         as amended.

                  (xi) "Surrender Date" shall mean the day on which the Company
         receives the Debenture in accordance with either Section 4.4 or 5.3.

         2. Interest.

                  (i)  Commencing on December 31, 1997, and on each June 30 and
         December 31 thereafter until the Maturity Date (or in the case of
         redemption in accordance with Section 5 hereof, until the Redemption
         Payment Date, the Company shall pay interest (computed on the basis of
         a 365-day year) at rate of six percent (6%) per annum on the principal
         of this Debenture outstanding during the period beginning on the date
         of issuance of this Debenture and ending on the date that the principal
         amount of this Debenture becomes due and payable.

                  (ii) The Company, at its option, may make any payment of
         interest due hereunder in whole or in part by issuing to the Holder
         shares of Common Stock (the "Interest Shares"). The Interest Shares
         shall be valued at the Average Closing Price, calculated using the date
         on which the interest payment is due as the measurement date. The
         Company shall not be obligated to issue any fractional shares. The
         Company may place such legends, if any, on the certificates for the
         Interest Shares as are required by applicable state and federal
         securities laws in the opinion of counsel to the Company. Applicable
         state and federal securities laws will not require any legends on the
         certificates after the shares have been registered under the Securities
         Act in accordance with the Registration Rights Agreement.

         3. Events of Default. If any of the events specified in this Section 3
shall occur (herein individually referred to as an "Event of Default"), the
Holders of more than fifty percent (50%) of the face amount of all then
outstanding Debentures issued pursuant to the Purchase Agreement may, so long as
such condition exists, declare the entire principal and unpaid accrued interest
hereon immediately due and payable, by notice in writing to the Company:

                  (i) Default in the payment of the principal and unpaid accrued
         interest of this Debenture when due and payable if such default is not
         cured by the Company within ten (10) days after the Holder has given
         the Company written notice of such default; or


                                     - 3 -

<PAGE>   4

                  (ii)  The institution by the Company of proceedings to be
         adjudicated as bankrupt or insolvent, or the consent by it to
         institution of bankruptcy or insolvency proceedings against it or the
         filing by it of a petition or answer or consent seeking reorganization
         or release under the federal Bankruptcy Act, or any other applicable
         federal or state law, or the consent by it to the filing of any such
         petition or the appointment of a receiver, liquidator, assignee,
         trustee or other similar official of the Company, or of any substantial
         part of its property, or the making by it of an assignment for the
         benefit of creditors, or the taking of corporate action by the Company
         in furtherance of any such action; or

                  (iii) If, within sixty (60) days after the commencement of an
         action against the Company (and service of process in connection
         therewith on the Company) seeking any bankruptcy, insolvency,
         reorganization, liquidation, dissolution or similar relief under any
         present or future statute, law or regulation, such action shall not
         have been resolved in favor of the Company or all orders or proceedings
         thereunder affecting the operations or the business of the Company
         stayed, or if the stay of any such order or proceeding shall thereafter
         be set aside, or if, within sixty (60) days after the appointment
         without the consent or acquiescence of the Company of any trustee,
         receiver or liquidator of the Company or of all or any substantial part
         of the properties of the Company, such appointment shall not have been
         vacated.

         4.  Conversion.

         4.1 Voluntary Conversion. At any time more than sixty (60) days after
the date of this Debenture, the Holder of this Debenture has the right, at the
Holder's option, to convert this Debenture, in accordance with the provisions of
Section 4.3 hereof, in whole or in part, into fully paid and nonassessable
shares of Common Stock; provided, however, that the Holder's right to convert
this Debenture pursuant to this Section 4.1 shall be subject to the Company's
right to redeem this Debenture pursuant to Section 5. The number of shares of
Common Stock into which this Debenture may be converted ("Conversion Shares")
shall be determined by dividing the aggregate principal amount together with all
accrued interest to the date of conversion by the Conversion Price in effect at
the time of such conversion.

         4.2 Automatic Conversion. The entire principal amount of this Debenture
shall be automatically converted into shares of Common Stock at the Conversion
Price at the time in effect immediately prior to any consolidation or merger of
the Company with or into any other corporation or other entity or person, or any
other corporate reorganization in which the Company shall not be the continuing
or surviving entity of such consolidation, merger or reorganization or any
transaction or series of related transactions by the Company in which in excess
of fifty percent (50%) of the Company's voting power is transferred, or a sale
of all or substantially all of the assets of the Company (as presently
constituted, subject to proportionate adjustment in the event of any stock
split, stock dividend, reverse stock split, combination, consolidation,
reclassification or similar event).


                                     - 4 -

<PAGE>   5

         4.3 Conversion Procedure.

                  4.3.1 Notice of Conversion Pursuant to Section 4.1. Before the
Holder shall be entitled to convert this Debenture into shares of Common Stock,
it shall give written notice in accordance with Section 11 to the Company at its
principal corporate office of the election to convert the same pursuant to
Section 4.1, and shall state therein the name or names in which the certificate
or certificates for shares of Common Stock are to be issued. Such conversion
shall be deemed to have been made immediately prior to the close of business on
the date that such notice is actually received; provided, however, that such
notice shall not be effective with respect to, and the Holder shall not have the
right to convert, any portion of this Debenture to be redeemed unless such
notice is actually received by the Company before the close of business on the
day immediately preceding the day on which the Company mails notice of
redemption to the Holder.

                  4.3.2 Notice of Conversion Pursuant to Section 4.2. If this
Debenture is automatically converted, written notice shall be delivered to the
Holder of this Debenture at the address last shown on the records of the Company
for the Holder or given by the Holder to the Company for the purpose of notice
or, if no such address appears or is given, at the place where the principal
executive office of the Company is located, notifying the Holder of the
conversion to be effected, specifying the Conversion Price, the principal amount
of the Debenture to be converted, the amount of accrued interest to be
converted, the date on which such conversion will occur and calling upon such
Holder to surrender to the Company, in the manner and at the place designated,
the Debenture.

         4.4 Surrender of the Debenture. As promptly as practicable after
conversion of the Debenture (but in no case later than two (2) business days
thereafter), the Holder at its expense shall surrender the Debenture to the
Company, duly endorsed, at the principal offices of the Company. The person or
persons entitled to receive shares of Common Stock issuable upon such conversion
shall be treated for all purposes as the record holder or holders of such shares
of Common Stock immediately prior to the close of business on the Surrender
Date.

         4.5 Delivery of Stock Certificates. As promptly as practicable after
the conversion of this Debenture (but in no case later than three (3) business
days thereafter), the Company at its expense will issue and deliver to an
express courier service for delivery to the Holder of this Debenture a
certificate or certificates for the number of full shares of Common Stock
issuable upon such conversion. If the Company fails to delivery to an express
courier service for delivery such certificates to the courier service within ten
(10) days after the conversion of the Debenture, then the Company shall pay to
the Holder, as liquidated damages for such failure, an amount equal to two
hundred and fifty dollars ($250) per day for each twenty-five thousand dollars
($25,000) of principal of the Debenture that was converted until such
certificates are so delivered. Notwithstanding anything to the contrary set
forth herein, the Company shall not be obligated to issue or deliver any
certificates, or to pay any liquidated damages for its failure to deliver such
certificates, unless and until one (1) business day after the Surrender Date.

         4.6 Mechanics and Effect of Conversion. No fractional shares of Common
Stock shall be issued upon conversion of this Debenture. In lieu of the Company
issuing any fractional

                                     - 5 -

<PAGE>   6

shares to the Holder upon the conversion of this Debenture, the Company shall
pay to the Holder the amount of outstanding principal that is not so converted,
such payment to be in the form as provided below. The stock certificates issued
by the Company may bear such legends, if any, as are required by the Purchase
Agreement and applicable state and federal securities laws in the opinion of
counsel to the Company). Applicable state and federal securities laws will not
require any legends on the certificates after the shares have been registered
under the Securities Act in accordance with the Registration Rights Agreement.
Upon conversion of this Debenture, the Company shall be forever released from
all its obligations and liabilities under this Debenture, except that the
Company shall be obligated to pay the Holder, within ten (10) days after the
date of such conversion, any interest accrued and unpaid or unconverted to and
including the date of such conversion, and no more.

         5.  Redemption.

         5.1 Redemption at the Option of the Company. At any time more than two
hundred seventy (270) days after the date of this Debenture, the Company may
redeem the Debenture, in whole or in part, immediately upon mailing written
notice to the Holder at a redemption price equal to one hundred ten percent
(110%) of the principal amount of the Debenture, plus any accrued but unpaid
interest; provided, however, that the Company may not redeem the Debenture
unless and until the shares of Common Stock issuable upon conversion of the
Debenture have been registered under the Securities Act in accordance with the
Registration Rights Agreement for at least two hundred ten (210) days plus any
Black-Out Period that occurs during the two hundred ten (210) days.

         5.2 Redemption in Lien of Conversion.

                  5.2.1 Redemption Right. If the Holder shall give the Company
notice of the Holder's election to convert all or any part of this Debenture in
accordance with Section 4.1, and the applicable Conversion Price is less than
$4.00, then the Company may redeem this Debenture at a redemption price equal to
one hundred ten percent (110%) of the principal amount of the Debenture, plus
any accrued but unpaid interest.

                  5.2.2 Forebearance Request. The Holder may at any time (but
not more than once each calendar week) give the Company written notice of the
Holder's desire to convert this Debenture (which notice shall state the portion
of this Debenture to be converted) and request that the Company declare its
intention to redeem the Debenture if a notice of conversion is given to the
Company (a "Forbearance Request"). The Company shall respond to the Holder's
Forbearance Request before the close of business on the first business day after
the business day on which the Company actually receives the request. If the
Company states in its response that it will not redeem the Debentures, then the
Company may not redeem the Debenture as a result of the Holder's request to
convert the Debenture to the extent identified in the Holder's Forbearance
Request, provided that the Company receives the conversion notice before the
close of business on the first business day after the business day on which the
Holder actually receives the Company's response to the Holder's Forbearance
Request.


                                     - 6 -

<PAGE>   7

         5.3 Mechanics and Effect of Redemption. As promptly as practicable
after receiving notice of the Company's election to redeem the Debentures (but
in no case later than three (3) business days thereafter), the Holder, at its
expense, shall surrender the Debenture to the Company, duly endorsed, at the
principal offices of the Company. The Company shall make the redemption payment
within fifteen (15) days after (a) the Company gives the Holder notice of
redemption, in the case of a redemption pursuant to Section 5.1, or (b) the
Company actually receives the notice of Holder's election to convert, in the
case of a redemption pursuant to Section 5.2; provided, however, the Company
shall not be obligated to make any redemption payment unless and until one (1)
business day after the Surrender Date. Interest shall continue to accrue on the
Debenture until the Redemption Payment Date. If the Debenture is to be redeemed
in part, then upon surrender of the Debenture, the Company shall deliver to the
Holder a new Debenture in the aggregate principal amount equal to the unredeemed
portion thereof.

         6.  Conversion Price Adjustments.

         6.1 Adjustments for Stock Splits and Subdivisions. In the event the
Company should at any time or from time to time after the date of issuance
hereof fix a record date for the effectuation of a split or subdivision of the
outstanding shares of Common Stock or the determination of holders of Common
Stock entitled to receive a dividend or other distribution payable in additional
shares of Common Stock or other securities or rights convertible into, or
entitling the holder thereof to receive directly or indirectly, additional
shares of Common Stock (hereinafter referred to as "Common Stock Equivalents")
without payment of any consideration by such holder for the additional shares of
Common Stock or the Common Stock Equivalents (including the additional shares of
Common Stock issuable upon conversion or exercise thereof), then, as of such
record date (or the date of such dividend distribution, split or subdivision if
no record date is fixed), the Conversion Price of this Debenture shall be
appropriately decreased so that the number of shares of Common Stock issuable
upon conversion of this Debenture shall be. increased in proportion to such
increase of outstanding shares.

         6.2 Adjustments for Reverse Stock Splits. If the number of shares of
Common Stock outstanding at any time after the date hereof is decreased by a
combination of the outstanding shares of Common Stock, then, following the
record date of such combination, the Conversion Price for this Debenture shall
be appropriately increased so that the number of shares of Common Stock issuable
on conversion hereof shall be decreased in proportion to such decrease in out
standing shares.


                                     - 7 -

<PAGE>   8


         6.3. Notices of Record Date, etc. In the event of:

                  (i)   Any taking by the Company of a record of the holders of
any class of securities of the Company for the purpose of determining the
holders thereof who are entitled to receive any dividend (other than a cash
dividend payable out of earned surplus at the same rate as that of the last such
cash dividend theretofore paid) or other distribution, or any right to subscribe
for, purchase or otherwise acquire any shares of stock of any class or any other
securities or property, or to receive any other right; or

                  (ii)  Any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
transfer of all or substantially all of the assets of the Company to any other
person or any consolidation or merger involving the Company; or

                  (iii) Any voluntary or involuntary dissolution, liquidation or
winding up of the Company.

The Company will mail to the holder of this Debenture at least ten (10) days
prior to the earliest date specified therein, a notice specifying (A) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, and the amount and character of such dividend,
distribution or right; and (B) the date on which any such reorganization,
reclassification, transfer, consolidation, merger, dissolution, liquidation or
windingup is expected to become effective and the record date for determining
stockholders entitled to vote thereon.

         6.4 Reservation of Stock lssuable Upon Conversion. The Company shall at
all times reserve and keep available out of its authorized but unissued shares
of Common Stock solely for the purpose of effecting the conversion of the
Debenture such number of its shares of Common Stock as shall from time to time
be sufficient to effect the conversion of the Debenture; and if at any time the
number of authorized but unissued shares of Common Stock shall not be sufficient
to effect the conversion of the entire outstanding principal amount of this
Debenture, in addition to such other remedies as shall be available to the
holder of this Debenture, the Company will use its best efforts to take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock (and shares of its Common
Stock for issuance on conversion of such Common Stock) to such number of shares
as shall be sufficient for such purposes.

         7. Assignment. Subject to the restrictions on transfer described in
Section 9 below, the rights and obligations of the Company and the Holder of
this Debenture shall be binding upon and benefit the successors, assigns, heirs,
administrators and transferees of the parties.

         8. Waiver and Amendment. Any provision of this Debenture may be
amended, waived or modified upon the written consent of the Company and holders
of at least fifty percent of the face amount of all then outstanding Debentures
issued pursuant to the Purchase Agreement.


                                     - 8 -




<PAGE>   9

         9. Transfer of this Debenture or Securities Issuable on Conversion
Hereof. With respect to any offer, sale or other disposition of this Debenture
or securities into which such Debenture may be converted, the Holder will give
written notice to the Company prior thereto, describing briefly the manner
thereof, together with a written opinion of such Holder's counsel, to the effect
that such offer, sale or other distribution may be effected without registration
or qualification (under any federal or state law then in effect). Promptly upon
receiving such written notice and reasonably satisfactory opinion, if so
requested, the Company, as promptly as practicable, shall notify such Holder
that such Holder may sell or otherwise dispose of this Debenture or such
securities, all in accordance with the terms of the notice delivered to the
Company. If a determination has been made pursuant to this Section 9 that the
opinion of counsel for the Holder is not reasonably satisfactory to the Company,
the Company shall so notify the Holder promptly after such determination has
been made. Each Debenture thus transferred and each certificate representing the
securities thus transferred shall bear a legend as to the applicable
restrictions on transferability in order to ensure compliance with the Act,
unless in the opinion of counsel for the Company such legend is not required. in
order to ensure compliance with the Act. The Company may issue stop transfer
instructions to its transfer agent in connection with such restrictions.

         10. Treatment of Debenture. To the extent permitted by generally
accepted accounting principles, the Company will treat, account and report the
Debenture as debt and not equity for accounting purposes and with respect to any
returns filed with federal, state or local tax authorities.

         11. Notices. Any notice, request or other communication required or
permitted hereunder shall be in writing and shall be deemed to have been duly
given if made by hand delivery, by an express courier company recognized
nationally in the United States or Canada or by registered or certified mail,
postage prepaid, at the respective addresses of the parties as set forth herein.
Any party hereto may by notice so given change its address for future notice
hereunder. Notice shall conclusively be deemed to have been given as of the date
so delivered when personally delivered, one (1) business day (three (3) business
days in the case of international deliveries) after dispatch if sent for
overnight delivery by an express courier service nationally recognized in the
United States or Canada and five (5) calendar days (seven (7) calendar days in
the case of international deliveries) after mailing if sent by registered or
certified mail in the manner set forth above. A notice of conversion given
pursuant to Section 4.1 and a Forbearance Request given pursuant to Section
5(ii) may be given to the Company by facsimile transmission at 770/448-3357 and
a simultaneous phone call to the Company at 770/453-0121 (or such other number
as the Company shall designate), and shall be deemed to have been given and
received when a legible copy has been actually received. A notice of redemption
given pursuant to Section 4.3.1 and the Company's response to the Holder's
Forebearance Request given pursuant to Section 5.2.2 may be given to the Holder
by facsimile transmission at (___) ___________ and a simultaneous phone call to
the Holder at (___) _______________ (or such other number as the Holder shall
designate) and shall be deemed to have been given and received when a legible
copy has been actually received.


                                     - 9 -

<PAGE>   10

         12. No Stockholder Rights. Nothing contained in this Debenture shall be
construed as conferring upon the Holder or any other person the right to vote or
to consent or to receive notice as a stockholder in respect of meetings of
stockholders for the election of directors of the Company or any other matters
or any rights whatsoever as a stockholder of the Company; and no dividends or
interest shall be payable or accrued in respect of this Debenture or the
interest represented hereby or the Conversion Shares obtainable hereunder until,
and only to the extent that, this Debenture shall have been converted.

         13. Governing Law; Interpretation. This Debenture shall be governed by
and construed in accordance with the laws of the State of Delaware, USA
excluding that body of law relating to conflict of laws. All references to
dollars are to U.S. dollars.

         14. Arbitration. All disputes arising under this Agreement (other than
claims in equity) shall be resolved by arbitration in accordance with the
Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.

         15. Heading; References. All headings used herein are used for
convenience only and shall not be used to construe or interpret this Debenture.
Except where otherwise indicated, all references herein to Sections refer to
Sections hereof.

                    [Signatures Appear on the Following Page]

                                     - 10 -
<PAGE>   11


         IN WITNESS WHEREOF, the Company has caused this Debenture to be issued
this 22 day of October, 1997.

                                             CYTRX CORPORATION

                                             By:
                                                --------------------------
                                                  Jack J. Luchese
                                             Its: Chief Executive Officer
                                                  and President


Name of Holder:  PINE STREET ASSET MANAGEMENT
Address:         c/o Shipley Raidy Capital Partners, LP
                 One Tower Bridge, Suite 1370
                 West Conshohocken, PA  19428
                 United States of America



                                     - 11 -


<PAGE>   12


                              NOTICE OF CONVERSION

                (To Be Signed Only Upon Conversion of Debenture)

TO CYTRX CORPORATION

The undersigned, the holder of the foregoing Debenture, hereby surrenders such
Debenture for conversion into shares of Common Stock of CYTRX CORPORATION, to
the extent of $_________ unpaid principal amount of such Debenture, and requests
that the certificates for such shares be issued in the name of, and delivered
to, _________________ whose address is ____________________.
Dated:_____________________


                                             -------------------------
                                             (Signature must conform in all
                                             respects to name of holder as
                                             specified on the face of the
                                             Debenture)

                                             -------------------------
                                                      (Address)


                                     - 12 -




<PAGE>   1
                                                                     EXHIBIT 3.4

NEITHER THIS DEBENTURE, NOR THE SHARES OF COMMON STOCK FOR WHICH IT MAY BE
CONVERTED, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS DEBENTURE HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS DEBENTURE HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.


                                CYTRX CORPORATION
                            6% CONVERTIBLE DEBENTURE

$25,000                                                       Atlanta, Georgia
                                                              October 22, 1997

CYTRX CORPORATION, a Delaware corporation (the "Company"), the principal office
of which is located at 154 Technology Parkway Technology Park/Atlanta, Norcross,
Georgia 30092, for value received hereby promises to pay to Charles N. Eckert,
or his registered assigns, the sum of Twenty-Five Thousand Dollars ($25,000), or
such lesser amount as shall then equal the outstanding principal amount hereof
and any unpaid accrued interest hereon, as set forth below, shall be due and
payable on October ____, 2001, (the "Maturity Date") (or in the case of
redemption in accordance with Section 5 hereof, until the Redemption Payment
Date). Payment for all amounts due hereunder shall be made by mail to the
registered address of the Holder. This Debenture is issued in connection with
the transactions described in Section ___ of that certain Subscription Agreement
between the Company and the Holder, dated as of October 22, 1997, as the same
may from time to time be amended, modified or supplemented (the "Purchase
Agreement"). The Holder is subject to certain restrictions set forth in the
Purchase Agreement and shall be entitled to certain rights and privileges set
forth in the Purchase Agreement. This Debenture is the Debenture referred to in
the Purchase Agreement.

         The following is a statement of the rights of the Holder of this
Debenture and conditions to which this Debenture is subject, and to which the
Holder hereof, by the acceptance of this Debenture, agrees:

<PAGE>   2

         1. DEFINITIONS. As used in this Debenture, the following terms, unless
the context otherwise requires, have the following meanings:

                  (i)    "Average Closing Bid Price" means the average of the
         daily last bid price for the shares of Common Stock for the ten (10)
         consecutive trading days on which such shares are actually traded as
         over-the-counter securities and quoted on the Nasdaq National Market
         (as reported by Bloomberg Business News or, if not reported thereby,
         any other authoritative source selected by the Company) ending at the
         close of trading on the trading day immediately preceding an identified
         measurement date.

                  (ii)   "Black-Out Period" means the number of days, if any,
         that the Company suspends the rights of the Holder to make sales
         pursuant to the Shelf Registration in accordance with Section 2(h) of
         the Registration Rights Agreement.

                  (iii)  "Closing Date" shall have the meaning given that term
         in the Purchase Agreement.

                  (iv)   "Company" includes any corporation which shall succeed
         to or assume the obligations of the Company under this Debenture.

                  (v)    "Common Stock" shall mean the $.001 par value common
         stock of the Company.

                  (vi)   "Conversion Price" shall mean the lessor of (A) $5.68
         for each share of Common Stock, or (B) eighty-five percent of the
         Average Closing Bid Price calculated using the date of conversion as
         the measurement date; provided, however, but if the Holder delivered a
         Forbearance Request to the Company in accordance with Section 5(ii)
         within twenty-four (24) hours before it delivered a conversion notice
         to the Company in accordance with Section 4.3.1, then the Average
         Closing Bid Price for the portion of the Debenture that the Holder
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

                  (vii)  "Holder," when the context refers to a holder of this
         Debenture, shall mean any person who shall at the time be the
         registered holder of this Debenture.

                  (viii) "Redemption Payment Date" shall mean the day on which
         the Company is obligated to make the redemption payment to the Holder
         in accordance with Section 5.3.


                                     - 2 -

<PAGE>   3

                  (ix) "Registration Rights Agreement" shall mean the
         Registration Rights Agreement dated as of October 22, 1997, between the
         Company, the Holder and the other holders of Company securities that
         are signatories thereto.

                  (x)  "Securities Act" shall mean the Securities Act of 1933,
         as amended.

                  (xi) "Surrender Date" shall mean the day on which the Company
         receives the Debenture in accordance with either Section 4.4 or 5.3.

         2. INTEREST.

                  (i)  Commencing on December 31, 1997, and on each June 30 and
         December 31 thereafter until the Maturity Date (or in the case of
         redemption in accordance with Section 5 hereof, until the Redemption
         Payment Date, the Company shall pay interest (computed on the basis of
         a 365-day year) at rate of six percent (6%) per annum on the principal
         of this Debenture outstanding during the period beginning on the date
         of issuance of this Debenture and ending on the date that the principal
         amount of this Debenture becomes due and payable.

                  (ii) The Company, at its option, may make any payment of
         interest due hereunder in whole or in part by issuing to the Holder
         shares of Common Stock (the "Interest Shares"). The Interest Shares
         shall be valued at the Average Closing Price, calculated using the date
         on which the interest payment is due as the measurement date. The
         Company shall not be obligated to issue any fractional shares. The
         Company may place such legends, if any, on the certificates for the
         Interest Shares as are required by applicable state and federal
         securities laws in the opinion of counsel to the Company. Applicable
         state and federal securities laws will not require any legends on the
         certificates after the shares have been registered under the Securities
         Act in accordance with the Registration Rights Agreement.

         3. EVENTS OF DEFAULT. If any of the events specified in this Section 3
shall occur (herein individually referred to as an "Event of Default"), the
Holders of more than fifty percent (50%) of the face amount of all then
outstanding Debentures issued pursuant to the Purchase Agreement may, so long as
such condition exists, declare the entire principal and unpaid accrued interest
hereon immediately due and payable, by notice in writing to the Company:

                  (i) Default in the payment of the principal and unpaid accrued
         interest of this Debenture when due and payable if such default is not
         cured by the Company within ten (10) days after the Holder has given
         the Company written notice of such default; or


                                     - 3 -

<PAGE>   4

                  (ii)  The institution by the Company of proceedings to be
         adjudicated as bankrupt or insolvent, or the consent by it to
         institution of bankruptcy or insolvency proceedings against it or the
         filing by it of a petition or answer or consent seeking reorganization
         or release under the federal Bankruptcy Act, or any other applicable
         federal or state law, or the consent by it to the filing of any such
         petition or the appointment of a receiver, liquidator, assignee,
         trustee or other similar official of the Company, or of any substantial
         part of its property, or the making by it of an assignment for the
         benefit of creditors, or the taking of corporate action by the Company
         in furtherance of any such action; or

                  (iii) If, within sixty (60) days after the commencement of an
         action against the Company (and service of process in connection
         therewith on the Company) seeking any bankruptcy, insolvency,
         reorganization, liquidation, dissolution or similar relief under any
         present or future statute, law or regulation, such action shall not
         have been resolved in favor of the Company or all orders or proceedings
         thereunder affecting the operations or the business of the Company
         stayed, or if the stay of any such order or proceeding shall thereafter
         be set aside, or if, within sixty (60) days after the appointment
         without the consent or acquiescence of the Company of any trustee,
         receiver or liquidator of the Company or of all or any substantial part
         of the properties of the Company, such appointment shall not have been
         vacated.

         4.  CONVERSION.

         4.1 VOLUNTARY CONVERSION. At any time more than sixty (60) days after
the date of this Debenture, the Holder of this Debenture has the right, at the
Holder's option, to convert this Debenture, in accordance with the provisions of
Section 4.3 hereof, in whole or in part, into fully paid and nonassessable
shares of Common Stock; provided, however, that the Holder's right to convert
this Debenture pursuant to this Section 4.1 shall be subject to the Company's
right to redeem this Debenture pursuant to Section 5. The number of shares of
Common Stock into which this Debenture may be converted ("Conversion Shares")
shall be determined by dividing the aggregate principal amount together with all
accrued interest to the date of conversion by the Conversion Price in effect at
the time of such conversion.

         4.2 AUTOMATIC CONVERSION. The entire principal amount of this Debenture
shall be automatically converted into shares of Common Stock at the Conversion
Price at the time in effect immediately prior to any consolidation or merger of
the Company with or into any other corporation or other entity or person, or any
other corporate reorganization in which the Company shall not be the continuing
or surviving entity of such consolidation, merger or reorganization or any
transaction or series of related transactions by the Company in which in excess
of fifty percent (50%) of the Company's voting power is transferred, or a sale
of all or substantially all of the assets of the Company (as presently
constituted, subject to proportionate adjustment in the event of any stock
split, stock dividend, reverse stock split, combination, consolidation,
reclassification or similar event).


                                     - 4 -

<PAGE>   5

         4.3 CONVERSION PROCEDURE.

             4.3.1 NOTICE OF CONVERSION PURSUANT TO SECTION 4.1. Before the
Holder shall be entitled to convert this Debenture into shares of Common Stock,
it shall give written notice in accordance with Section 11 to the Company at its
principal corporate office of the election to convert the same pursuant to
Section 4.1, and shall state therein the name or names in which the certificate
or certificates for shares of Common Stock are to be issued. Such conversion
shall be deemed to have been made immediately prior to the close of business on
the date that such notice is actually received; provided, however, that such
notice shall not be effective with respect to, and the Holder shall not have the
right to convert, any portion of this Debenture to be redeemed unless such
notice is actually received by the Company before the close of business on the
day immediately preceding the day on which the Company mails notice of
redemption to the Holder.

             4.3.2 NOTICE OF CONVERSION PURSUANT TO SECTION 4.2. If this
Debenture is automatically converted, written notice shall be delivered to the
Holder of this Debenture at the address last shown on the records of the Company
for the Holder or given by the Holder to the Company for the purpose of notice
or, if no such address appears or is given, at the place where the principal
executive office of the Company is located, notifying the Holder of the
conversion to be effected, specifying the Conversion Price, the principal amount
of the Debenture to be converted, the amount of accrued interest to be
converted, the date on which such conversion will occur and calling upon such
Holder to surrender to the Company, in the manner and at the place designated,
the Debenture.

         4.4 SURRENDER OF THE DEBENTURE. As promptly as practicable after
conversion of the Debenture (but in no case later than two (2) business days
thereafter), the Holder at its expense shall surrender the Debenture to the
Company, duly endorsed, at the principal offices of the Company. The person or
persons entitled to receive shares of Common Stock issuable upon such conversion
shall be treated for all purposes as the record holder or holders of such shares
of Common Stock immediately prior to the close of business on the Surrender
Date.

         4.5 DELIVERY OF STOCK CERTIFICATES. As promptly as practicable after
the conversion of this Debenture (but in no case later than three (3) business
days thereafter), the Company at its expense will issue and deliver to an
express courier service for delivery to the Holder of this Debenture a
certificate or certificates for the number of full shares of Common Stock
issuable upon such conversion. If the Company fails to delivery to an express
courier service for delivery such certificates to the courier service within ten
(10) days after the conversion of the Debenture, then the Company shall pay to
the Holder, as liquidated damages for such failure, an amount equal to two
hundred and fifty dollars ($250) per day for each twenty-five thousand dollars
($25,000) of principal of the Debenture that was converted until such
certificates are so delivered. Notwithstanding anything to the contrary set
forth herein, the Company shall not be obligated to issue or deliver any
certificates, or to pay any liquidated damages for its failure to deliver such
certificates, unless and until one (1) business day after the Surrender Date.

         4.6 MECHANICS AND EFFECT OF CONVERSION. No fractional shares of Common
Stock shall be issued upon conversion of this Debenture. In lieu of the Company
issuing any fractional


                                     - 5 -


<PAGE>   6

shares to the Holder upon the conversion of this Debenture, the Company shall
pay to the Holder the amount of outstanding principal that is not so converted,
such payment to be in the form as provided below. The stock certificates issued
by the Company may bear such legends, if any, as are required by the Purchase
Agreement and applicable state and federal securities laws in the opinion of
counsel to the Company). Applicable state and federal securities laws will not
require any legends on the certificates after the shares have been registered
under the Securities Act in accordance with the Registration Rights Agreement.
Upon conversion of this Debenture, the Company shall be forever released from
all its obligations and liabilities under this Debenture, except that the
Company shall be obligated to pay the Holder, within ten (10) days after the
date of such conversion, any interest accrued and unpaid or unconverted to and
including the date of such conversion, and no more.

         5.  REDEMPTION.

         5.1 REDEMPTION AT THE OPTION OF THE COMPANY. At any time more than two
hundred seventy (270) days after the date of this Debenture, the Company may
redeem the Debenture, in whole or in part, immediately upon mailing written
notice to the Holder at a redemption price equal to one hundred ten percent
(110%) of the principal amount of the Debenture, plus any accrued but unpaid
interest; provided, however, that the Company may not redeem the Debenture
unless and until the shares of Common Stock issuable upon conversion of the
Debenture have been registered under the Securities Act in accordance with the
Registration Rights Agreement for at least two hundred ten (210) days plus any
Black-Out Period that occurs during the two hundred ten (210) days.

         5.2 REDEMPTION IN LIEN OF CONVERSION.

                  5.2.1 REDEMPTION RIGHT. If the Holder shall give the Company
notice of the Holder's election to convert all or any part of this Debenture in
accordance with Section 4.1, and the applicable Conversion Price is less than
$4.00, then the Company may redeem this Debenture at a redemption price equal to
one hundred ten percent (110%) of the principal amount of the Debenture, plus
any accrued but unpaid interest.

                  5.2.2 FOREBEARANCE REQUEST. The Holder may at any time (but
not more than once each calendar week) give the Company written notice of the
Holder's desire to convert this Debenture (which notice shall state the portion
of this Debenture to be converted) and request that the Company declare its
intention to redeem the Debenture if a notice of conversion is given to the
Company (a "Forbearance Request"). The Company shall respond to the Holder's
Forbearance Request before the close of business on the first business day after
the business day on which the Company actually receives the request. If the
Company states in its response that it will not redeem the Debentures, then the
Company may not redeem the Debenture as a result of the Holder's request to
convert the Debenture to the extent identified in the Holder's Forbearance
Request, provided that the Company receives the conversion notice before the
close of business on the first business day after the business day on which the
Holder actually receives the Company's response to the Holder's Forbearance
Request.


                                     - 6 -

<PAGE>   7

         5.3 MECHANICS AND EFFECT OF REDEMPTION. As promptly as practicable
after receiving notice of the Company's election to redeem the Debentures (but
in no case later than three (3) business days thereafter), the Holder, at its
expense, shall surrender the Debenture to the Company, duly endorsed, at the
principal offices of the Company. The Company shall make the redemption payment
within fifteen (15) days after (a) the Company gives the Holder notice of
redemption, in the case of a redemption pursuant to Section 5.1, or (b) the
Company actually receives the notice of Holder's election to convert, in the
case of a redemption pursuant to Section 5.2; provided, however, the Company
shall not be obligated to make any redemption payment unless and until one (1)
business day after the Surrender Date. Interest shall continue to accrue on the
Debenture until the Redemption Payment Date. If the Debenture is to be redeemed
in part, then upon surrender of the Debenture, the Company shall deliver to the
Holder a new Debenture in the aggregate principal amount equal to the unredeemed
portion thereof.

         6.  CONVERSION PRICE ADJUSTMENTS.

         6.1 ADJUSTMENTS FOR STOCK SPLITS AND SUBDIVISIONS. In the event the
Company should at any time or from time to time after the date of issuance
hereof fix a record date for the effectuation of a split or subdivision of the
outstanding shares of Common Stock or the determination of holders of Common
Stock entitled to receive a dividend or other distribution payable in additional
shares of Common Stock or other securities or rights convertible into, or
entitling the holder thereof to receive directly or indirectly, additional
shares of Common Stock (hereinafter referred to as "Common Stock Equivalents")
without payment of any consideration by such holder for the additional shares of
Common Stock or the Common Stock Equivalents (including the additional shares of
Common Stock issuable upon conversion or exercise thereof), then, as of such
record date (or the date of such dividend distribution, split or subdivision if
no record date is fixed), the Conversion Price of this Debenture shall be
appropriately decreased so that the number of shares of Common Stock issuable
upon conversion of this Debenture shall be. increased in proportion to such
increase of outstanding shares.

         6.2 ADJUSTMENTS FOR REVERSE STOCK SPLITS. If the number of shares of
Common Stock outstanding at any time after the date hereof is decreased by a
combination of the outstanding shares of Common Stock, then, following the
record date of such combination, the Conversion Price for this Debenture shall
be appropriately increased so that the number of shares of Common Stock issuable
on conversion hereof shall be decreased in proportion to such decrease in out
standing shares.


                                    - 7 -


<PAGE>   8


         6.3. NOTICES OF RECORD DATE, ETC. In the event of:

                  (i)   Any taking by the Company of a record of the holders of
any class of securities of the Company for the purpose of determining the
holders thereof who are entitled to receive any dividend (other than a cash
dividend payable out of earned surplus at the same rate as that of the last such
cash dividend theretofore paid) or other distribution, or any right to subscribe
for, purchase or otherwise acquire any shares of stock of any class or any other
securities or property, or to receive any other right; or

                  (ii)  Any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
transfer of all or substantially all of the assets of the Company to any other
person or any consolidation or merger involving the Company; or

                  (iii) Any voluntary or involuntary dissolution, liquidation or
winding up of the Company.

The Company will mail to the holder of this Debenture at least ten (10) days
prior to the earliest date specified therein, a notice specifying (A) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, and the amount and character of such dividend,
distribution or right; and (B) the date on which any such reorganization,
reclassification, transfer, consolidation, merger, dissolution, liquidation or
windingup is expected to become effective and the record date for determining
stockholders entitled to vote thereon.

         6.4 RESERVATION OF STOCK LSSUABLE UPON CONVERSION. The Company shall at
all times reserve and keep available out of its authorized but unissued shares
of Common Stock solely for the purpose of effecting the conversion of the
Debenture such number of its shares of Common Stock as shall from time to time
be sufficient to effect the conversion of the Debenture; and if at any time the
number of authorized but unissued shares of Common Stock shall not be sufficient
to effect the conversion of the entire outstanding principal amount of this
Debenture, in addition to such other remedies as shall be available to the
holder of this Debenture, the Company will use its best efforts to take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock (and shares of its Common
Stock for issuance on conversion of such Common Stock) to such number of shares
as shall be sufficient for such purposes.

         7. ASSIGNMENT. Subject to the restrictions on transfer described in
Section 9 below, the rights and obligations of the Company and the Holder of
this Debenture shall be binding upon and benefit the successors, assigns, heirs,
administrators and transferees of the parties.

         8. WAIVER AND AMENDMENT. Any provision of this Debenture may be
amended, waived or modified upon the written consent of the Company and holders
of at least fifty percent of the face amount of all then outstanding Debentures
issued pursuant to the Purchase Agreement.


                                     - 8 -

<PAGE>   9

         9.  TRANSFER OF THIS DEBENTURE OR SECURITIES ISSUABLE ON CONVERSION
HEREOF. With respect to any offer, sale or other disposition of this Debenture
or securities into which such Debenture may be converted, the Holder will give
written notice to the Company prior thereto, describing briefly the manner
thereof, together with a written opinion of such Holder's counsel, to the effect
that such offer, sale or other distribution may be effected without registration
or qualification (under any federal or state law then in effect). Promptly upon
receiving such written notice and reasonably satisfactory opinion, if so
requested, the Company, as promptly as practicable, shall notify such Holder
that such Holder may sell or otherwise dispose of this Debenture or such
securities, all in accordance with the terms of the notice delivered to the
Company. If a determination has been made pursuant to this Section 9 that the
opinion of counsel for the Holder is not reasonably satisfactory to the Company,
the Company shall so notify the Holder promptly after such determination has
been made. Each Debenture thus transferred and each certificate representing the
securities thus transferred shall bear a legend as to the applicable
restrictions on transferability in order to ensure compliance with the Act,
unless in the opinion of counsel for the Company such legend is not required. in
order to ensure compliance with the Act. The Company may issue stop transfer
instructions to its transfer agent in connection with such restrictions.

         10. TREATMENT OF DEBENTURE. To the extent permitted by generally
accepted accounting principles, the Company will treat, account and report the
Debenture as debt and not equity for accounting purposes and with respect to any
returns filed with federal, state or local tax authorities.

         11. NOTICES. Any notice, request or other communication required or
permitted hereunder shall be in writing and shall be deemed to have been duly
given if made by hand delivery, by an express courier company recognized
nationally in the United States or Canada or by registered or certified mail,
postage prepaid, at the respective addresses of the parties as set forth herein.
Any party hereto may by notice so given change its address for future notice
hereunder. Notice shall conclusively be deemed to have been given as of the date
so delivered when personally delivered, one (1) business day (three (3) business
days in the case of international deliveries) after dispatch if sent for
overnight delivery by an express courier service nationally recognized in the
United States or Canada and five (5) calendar days (seven (7) calendar days in
the case of international deliveries) after mailing if sent by registered or
certified mail in the manner set forth above. A notice of conversion given
pursuant to Section 4.1 and a Forbearance Request given pursuant to Section
5(ii) may be given to the Company by facsimile transmission at 770/448-3357 and
a simultaneous phone call to the Company at 770/453-0121 (or such other number
as the Company shall designate), and shall be deemed to have been given and
received when a legible copy has been actually received. A notice of redemption
given pursuant to Section 4.3.1 and the Company's response to the Holder's
Forebearance Request given pursuant to Section 5.2.2 may be given to the Holder
by facsimile transmission at (___) ___________ and a simultaneous phone call to
the Holder at (___) _______________ (or such other number as the Holder shall
designate) and shall be deemed to have been given and received when a legible
copy has been actually received.


                                     - 9 -

<PAGE>   10

         12. NO STOCKHOLDER RIGHTS. Nothing contained in this Debenture shall be
construed as conferring upon the Holder or any other person the right to vote or
to consent or to receive notice as a stockholder in respect of meetings of
stockholders for the election of directors of the Company or any other matters
or any rights whatsoever as a stockholder of the Company; and no dividends or
interest shall be payable or accrued in respect of this Debenture or the
interest represented hereby or the Conversion Shares obtainable hereunder until,
and only to the extent that, this Debenture shall have been converted.

         13. GOVERNING LAW; INTERPRETATION. This Debenture shall be governed by
and construed in accordance with the laws of the State of Delaware, USA
excluding that body of law relating to conflict of laws. All references to
dollars are to U.S. dollars.

         14. ARBITRATION. All disputes arising under this Agreement (other than
claims in equity) shall be resolved by arbitration in accordance with the
Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.

         15. HEADING; REFERENCES. All headings used herein are used for
convenience only and shall not be used to construe or interpret this Debenture.
Except where otherwise indicated, all references herein to Sections refer to
Sections hereof.

                    [Signatures Appear on the Following Page]


                                     - 10 -


<PAGE>   11


         IN WITNESS WHEREOF, the Company has caused this Debenture to be issued
this 22 day of October, 1997.

                                             CYTRX CORPORATION

                                             By:
                                                --------------------------
                                                  Jack J. Luchese
                                             Its: Chief Executive Officer
                                                  and President


Name of Holder:   CHARLES N. ECKERT
Address:          c/o Shipley Raidy Capital Partners, LP
                  One Tower Bridge, Suite 1370
                  West Conshohocken, PA  19428
                  United States of America


                                     - 11 -


<PAGE>   12


                              NOTICE OF CONVERSION

                (To Be Signed Only Upon Conversion of Debenture)

TO CYTRX CORPORATION

The undersigned, the holder of the foregoing Debenture, hereby surrenders such
Debenture for conversion into shares of Common Stock of CYTRX CORPORATION, to
the extent of $_________ unpaid principal amount of such Debenture, and requests
that the certificates for such shares be issued in the name of, and delivered
to, _________________ whose address is ____________________.
Dated:
      ---------------------

                                             -------------------------
                                             (Signature must conform in all
                                             respects to name of holder as
                                             specified on the face of the
                                             Debenture)


                                             -------------------------
                                                    (Address)


                                     - 12 -


<PAGE>   1
                                                                     EXHIBIT 3.5

NEITHER THIS DEBENTURE, NOR THE SHARES OF COMMON STOCK FOR WHICH IT MAY BE
CONVERTED, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS DEBENTURE HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS DEBENTURE HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.


                                CYTRX CORPORATION
                            6% CONVERTIBLE DEBENTURE

$25,000                                                        Atlanta, Georgia
                                                               October 22, 1997

CYTRX CORPORATION, a Delaware corporation (the "Company"), the principal office
of which is located at 154 Technology Parkway Technology Park/Atlanta, Norcross,
Georgia 30092, for value received hereby promises to pay to David Kosloff, or
his registered assigns, the sum of Twenty-Five Thousand Dollars ($25,000), or
such lesser amount as shall then equal the outstanding principal amount hereof
and any unpaid accrued interest hereon, as set forth below, shall be due and
payable on October ____, 2001, (the "Maturity Date") (or in the case of
redemption in accordance with Section 5 hereof, until the Redemption Payment
Date). Payment for all amounts due hereunder shall be made by mail to the
registered address of the Holder. This Debenture is issued in connection with
the transactions described in Section ___ of that certain Subscription Agreement
between the Company and the Holder, dated as of October 22, 1997, as the same
may from time to time be amended, modified or supplemented (the "Purchase
Agreement"). The Holder is subject to certain restrictions set forth in the
Purchase Agreement and shall be entitled to certain rights and privileges set
forth in the Purchase Agreement. This Debenture is the Debenture referred to in
the Purchase Agreement.

         The following is a statement of the rights of the Holder of this
Debenture and conditions to which this Debenture is subject, and to which the
Holder hereof, by the acceptance of this Debenture, agrees:

<PAGE>   2

         1. DEFINITIONS. As used in this Debenture, the following terms, unless
the context otherwise requires, have the following meanings:

                  (i)    "Average Closing Bid Price" means the average of the
         daily last bid price for the shares of Common Stock for the ten (10)
         consecutive trading days on which such shares are actually traded as
         over-the-counter securities and quoted on the Nasdaq National Market
         (as reported by Bloomberg Business News or, if not reported thereby,
         any other authoritative source selected by the Company) ending at the
         close of trading on the trading day immediately preceding an identified
         measurement date.

                  (ii)   "Black-Out Period" means the number of days, if any,
         that the Company suspends the rights of the Holder to make sales
         pursuant to the Shelf Registration in accordance with Section 2(h) of
         the Registration Rights Agreement.

                  (iii)  "Closing Date" shall have the meaning given that term
         in the Purchase Agreement.

                  (iv)   "Company" includes any corporation which shall succeed
         to or assume the obligations of the Company under this Debenture.

                  (v)    "Common Stock" shall mean the $.001 par value common
         stock of the Company.

                  (vi)   "Conversion Price" shall mean the lessor of (A) $5.68
         for each share of Common Stock, or (B) eighty-five percent of the
         Average Closing Bid Price calculated using the date of conversion as
         the measurement date; provided, however, but if the Holder delivered a
         Forbearance Request to the Company in accordance with Section 5(ii)
         within twenty-four (24) hours before it delivered a conversion notice
         to the Company in accordance with Section 4.3.1, then the Average
         Closing Bid Price for the portion of the Debenture that the Holder
         identified in the Forbearance Request shall be calculated using either
         the date of conversion or the date the Company actually received such
         Forbearance Request as the measurement date, whichever results in a
         lower Conversion Price.

                  (vii)  "Holder," when the context refers to a holder of this
         Debenture, shall mean any person who shall at the time be the
         registered holder of this Debenture.

                  (viii) "Redemption Payment Date" shall mean the day on which
         the Company is obligated to make the redemption payment to the Holder
         in accordance with Section 5.3.


                                     - 2 -

<PAGE>   3

                  (ix) "Registration Rights Agreement" shall mean the
         Registration Rights Agreement dated as of October 22, 1997, between the
         Company, the Holder and the other holders of Company securities that
         are signatories thereto.

                  (x)  "Securities Act" shall mean the Securities Act of 1933,
         as amended.

                  (xi) "Surrender Date" shall mean the day on which the Company
         receives the Debenture in accordance with either Section 4.4 or 5.3.

         2. INTEREST.

                  (i)  Commencing on December 31, 1997, and on each June 30 and
         December 31 thereafter until the Maturity Date (or in the case of
         redemption in accordance with Section 5 hereof, until the Redemption
         Payment Date, the Company shall pay interest (computed on the basis of
         a 365-day year) at rate of six percent (6%) per annum on the principal
         of this Debenture outstanding during the period beginning on the date
         of issuance of this Debenture and ending on the date that the principal
         amount of this Debenture becomes due and payable.

                  (ii) The Company, at its option, may make any payment of
         interest due hereunder in whole or in part by issuing to the Holder
         shares of Common Stock (the "Interest Shares"). The Interest Shares
         shall be valued at the Average Closing Price, calculated using the date
         on which the interest payment is due as the measurement date. The
         Company shall not be obligated to issue any fractional shares. The
         Company may place such legends, if any, on the certificates for the
         Interest Shares as are required by applicable state and federal
         securities laws in the opinion of counsel to the Company. Applicable
         state and federal securities laws will not require any legends on the
         certificates after the shares have been registered under the Securities
         Act in accordance with the Registration Rights Agreement.

         3. EVENTS OF DEFAULT. If any of the events specified in this Section 3
shall occur (herein individually referred to as an "Event of Default"), the
Holders of more than fifty percent (50%) of the face amount of all then
outstanding Debentures issued pursuant to the Purchase Agreement may, so long as
such condition exists, declare the entire principal and unpaid accrued interest
hereon immediately due and payable, by notice in writing to the Company:

                  (i)  Default in the payment of the principal and unpaid
         accrued interest of this Debenture when due and payable if such default
         is not cured by the Company within ten (10) days after the Holder has
         given the Company written notice of such default; or


                                     - 3 -

<PAGE>   4

                  (ii)  The institution by the Company of proceedings to be
         adjudicated as bankrupt or insolvent, or the consent by it to
         institution of bankruptcy or insolvency proceedings against it or the
         filing by it of a petition or answer or consent seeking reorganization
         or release under the federal Bankruptcy Act, or any other applicable
         federal or state law, or the consent by it to the filing of any such
         petition or the appointment of a receiver, liquidator, assignee,
         trustee or other similar official of the Company, or of any substantial
         part of its property, or the making by it of an assignment for the
         benefit of creditors, or the taking of corporate action by the Company
         in furtherance of any such action; or

                  (iii) If, within sixty (60) days after the commencement of an
         action against the Company (and service of process in connection
         therewith on the Company) seeking any bankruptcy, insolvency,
         reorganization, liquidation, dissolution or similar relief under any
         present or future statute, law or regulation, such action shall not
         have been resolved in favor of the Company or all orders or proceedings
         thereunder affecting the operations or the business of the Company
         stayed, or if the stay of any such order or proceeding shall thereafter
         be set aside, or if, within sixty (60) days after the appointment
         without the consent or acquiescence of the Company of any trustee,
         receiver or liquidator of the Company or of all or any substantial part
         of the properties of the Company, such appointment shall not have been
         vacated.

         4.  CONVERSION.

         4.1 VOLUNTARY CONVERSION. At any time more than sixty (60) days after
the date of this Debenture, the Holder of this Debenture has the right, at the
Holder's option, to convert this Debenture, in accordance with the provisions of
Section 4.3 hereof, in whole or in part, into fully paid and nonassessable
shares of Common Stock; provided, however, that the Holder's right to convert
this Debenture pursuant to this Section 4.1 shall be subject to the Company's
right to redeem this Debenture pursuant to Section 5. The number of shares of
Common Stock into which this Debenture may be converted ("Conversion Shares")
shall be determined by dividing the aggregate principal amount together with all
accrued interest to the date of conversion by the Conversion Price in effect at
the time of such conversion.

         4.2 AUTOMATIC CONVERSION. The entire principal amount of this Debenture
shall be automatically converted into shares of Common Stock at the Conversion
Price at the time in effect immediately prior to any consolidation or merger of
the Company with or into any other corporation or other entity or person, or any
other corporate reorganization in which the Company shall not be the continuing
or surviving entity of such consolidation, merger or reorganization or any
transaction or series of related transactions by the Company in which in excess
of fifty percent (50%) of the Company's voting power is transferred, or a sale
of all or substantially all of the assets of the Company (as presently
constituted, subject to proportionate adjustment in the event of any stock
split, stock dividend, reverse stock split, combination, consolidation,
reclassification or similar event).


                                     - 4 -

<PAGE>   5

         4.3 CONVERSION PROCEDURE.

                  4.3.1 NOTICE OF CONVERSION PURSUANT TO SECTION 4.1. Before the
Holder shall be entitled to convert this Debenture into shares of Common Stock,
it shall give written notice in accordance with Section 11 to the Company at its
principal corporate office of the election to convert the same pursuant to
Section 4.1, and shall state therein the name or names in which the certificate
or certificates for shares of Common Stock are to be issued. Such conversion
shall be deemed to have been made immediately prior to the close of business on
the date that such notice is actually received; provided, however, that such
notice shall not be effective with respect to, and the Holder shall not have the
right to convert, any portion of this Debenture to be redeemed unless such
notice is actually received by the Company before the close of business on the
day immediately preceding the day on which the Company mails notice of
redemption to the Holder.

                  4.3.2 NOTICE OF CONVERSION PURSUANT TO SECTION 4.2. If this
Debenture is automatically converted, written notice shall be delivered to the
Holder of this Debenture at the address last shown on the records of the Company
for the Holder or given by the Holder to the Company for the purpose of notice
or, if no such address appears or is given, at the place where the principal
executive office of the Company is located, notifying the Holder of the
conversion to be effected, specifying the Conversion Price, the principal amount
of the Debenture to be converted, the amount of accrued interest to be
converted, the date on which such conversion will occur and calling upon such
Holder to surrender to the Company, in the manner and at the place designated,
the Debenture.

         4.4 SURRENDER OF THE DEBENTURE. As promptly as practicable after
conversion of the Debenture (but in no case later than two (2) business days
thereafter), the Holder at its expense shall surrender the Debenture to the
Company, duly endorsed, at the principal offices of the Company. The person or
persons entitled to receive shares of Common Stock issuable upon such conversion
shall be treated for all purposes as the record holder or holders of such shares
of Common Stock immediately prior to the close of business on the Surrender
Date.

         4.5 DELIVERY OF STOCK CERTIFICATES. As promptly as practicable after
the conversion of this Debenture (but in no case later than three (3) business
days thereafter), the Company at its expense will issue and deliver to an
express courier service for delivery to the Holder of this Debenture a
certificate or certificates for the number of full shares of Common Stock
issuable upon such conversion. If the Company fails to delivery to an express
courier service for delivery such certificates to the courier service within ten
(10) days after the conversion of the Debenture, then the Company shall pay to
the Holder, as liquidated damages for such failure, an amount equal to two
hundred and fifty dollars ($250) per day for each twenty-five thousand dollars
($25,000) of principal of the Debenture that was converted until such
certificates are so delivered. Notwithstanding anything to the contrary set
forth herein, the Company shall not be obligated to issue or deliver any
certificates, or to pay any liquidated damages for its failure to deliver such
certificates, unless and until one (1) business day after the Surrender Date.

         4.6 MECHANICS AND EFFECT OF CONVERSION. No fractional shares of Common
Stock shall be issued upon conversion of this Debenture. In lieu of the Company
issuing any fractional


                                    - 5 -


<PAGE>   6

shares to the Holder upon the conversion of this Debenture, the Company shall
pay to the Holder the amount of outstanding principal that is not so converted,
such payment to be in the form as provided below. The stock certificates issued
by the Company may bear such legends, if any, as are required by the Purchase
Agreement and applicable state and federal securities laws in the opinion of
counsel to the Company). Applicable state and federal securities laws will not
require any legends on the certificates after the shares have been registered
under the Securities Act in accordance with the Registration Rights Agreement.
Upon conversion of this Debenture, the Company shall be forever released from
all its obligations and liabilities under this Debenture, except that the
Company shall be obligated to pay the Holder, within ten (10) days after the
date of such conversion, any interest accrued and unpaid or unconverted to and
including the date of such conversion, and no more.

         5.  REDEMPTION.

         5.1 REDEMPTION AT THE OPTION OF THE COMPANY. At any time more than two
hundred seventy (270) days after the date of this Debenture, the Company may
redeem the Debenture, in whole or in part, immediately upon mailing written
notice to the Holder at a redemption price equal to one hundred ten percent
(110%) of the principal amount of the Debenture, plus any accrued but unpaid
interest; provided, however, that the Company may not redeem the Debenture
unless and until the shares of Common Stock issuable upon conversion of the
Debenture have been registered under the Securities Act in accordance with the
Registration Rights Agreement for at least two hundred ten (210) days plus any
Black-Out Period that occurs during the two hundred ten (210) days.

         5.2 REDEMPTION IN LIEN OF CONVERSION.

                  5.2.1 REDEMPTION RIGHT. If the Holder shall give the Company
notice of the Holder's election to convert all or any part of this Debenture in
accordance with Section 4.1, and the applicable Conversion Price is less than
$4.00, then the Company may redeem this Debenture at a redemption price equal to
one hundred ten percent (110%) of the principal amount of the Debenture, plus
any accrued but unpaid interest.

                  5.2.2 FOREBEARANCE REQUEST. The Holder may at any time (but
not more than once each calendar week) give the Company written notice of the
Holder's desire to convert this Debenture (which notice shall state the portion
of this Debenture to be converted) and request that the Company declare its
intention to redeem the Debenture if a notice of conversion is given to the
Company (a "Forbearance Request"). The Company shall respond to the Holder's
Forbearance Request before the close of business on the first business day after
the business day on which the Company actually receives the request. If the
Company states in its response that it will not redeem the Debentures, then the
Company may not redeem the Debenture as a result of the Holder's request to
convert the Debenture to the extent identified in the Holder's Forbearance
Request, provided that the Company receives the conversion notice before the
close of business on the first business day after the business day on which the
Holder actually receives the Company's response to the Holder's Forbearance
Request.


                                     - 6 -

<PAGE>   7

         5.3 MECHANICS AND EFFECT OF REDEMPTION. As promptly as practicable
after receiving notice of the Company's election to redeem the Debentures (but
in no case later than three (3) business days thereafter), the Holder, at its
expense, shall surrender the Debenture to the Company, duly endorsed, at the
principal offices of the Company. The Company shall make the redemption payment
within fifteen (15) days after (a) the Company gives the Holder notice of
redemption, in the case of a redemption pursuant to Section 5.1, or (b) the
Company actually receives the notice of Holder's election to convert, in the
case of a redemption pursuant to Section 5.2; provided, however, the Company
shall not be obligated to make any redemption payment unless and until one (1)
business day after the Surrender Date. Interest shall continue to accrue on the
Debenture until the Redemption Payment Date. If the Debenture is to be redeemed
in part, then upon surrender of the Debenture, the Company shall deliver to the
Holder a new Debenture in the aggregate principal amount equal to the unredeemed
portion thereof.

         6.  CONVERSION PRICE ADJUSTMENTS.

         6.1 ADJUSTMENTS FOR STOCK SPLITS AND SUBDIVISIONS. In the event the
Company should at any time or from time to time after the date of issuance
hereof fix a record date for the effectuation of a split or subdivision of the
outstanding shares of Common Stock or the determination of holders of Common
Stock entitled to receive a dividend or other distribution payable in additional
shares of Common Stock or other securities or rights convertible into, or
entitling the holder thereof to receive directly or indirectly, additional
shares of Common Stock (hereinafter referred to as "Common Stock Equivalents")
without payment of any consideration by such holder for the additional shares of
Common Stock or the Common Stock Equivalents (including the additional shares of
Common Stock issuable upon conversion or exercise thereof), then, as of such
record date (or the date of such dividend distribution, split or subdivision if
no record date is fixed), the Conversion Price of this Debenture shall be
appropriately decreased so that the number of shares of Common Stock issuable
upon conversion of this Debenture shall be. increased in proportion to such
increase of outstanding shares.

         6.2 ADJUSTMENTS FOR REVERSE STOCK SPLITS. If the number of shares of
Common Stock outstanding at any time after the date hereof is decreased by a
combination of the outstanding shares of Common Stock, then, following the
record date of such combination, the Conversion Price for this Debenture shall
be appropriately increased so that the number of shares of Common Stock issuable
on conversion hereof shall be decreased in proportion to such decrease in out
standing shares.


                                     - 7 -

<PAGE>   8


         6.3. NOTICES OF RECORD DATE, ETC. In the event of:

                  (i)   Any taking by the Company of a record of the holders of
any class of securities of the Company for the purpose of determining the
holders thereof who are entitled to receive any dividend (other than a cash
dividend payable out of earned surplus at the same rate as that of the last such
cash dividend theretofore paid) or other distribution, or any right to subscribe
for, purchase or otherwise acquire any shares of stock of any class or any other
securities or property, or to receive any other right; or

                  (ii)  Any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company or any
transfer of all or substantially all of the assets of the Company to any other
person or any consolidation or merger involving the Company; or

                  (iii) Any voluntary or involuntary dissolution, liquidation or
winding up of the Company.

The Company will mail to the holder of this Debenture at least ten (10) days
prior to the earliest date specified therein, a notice specifying (A) the date
on which any such record is to be taken for the purpose of such dividend,
distribution or right, and the amount and character of such dividend,
distribution or right; and (B) the date on which any such reorganization,
reclassification, transfer, consolidation, merger, dissolution, liquidation or
windingup is expected to become effective and the record date for determining
stockholders entitled to vote thereon.

         6.4 RESERVATION OF STOCK LSSUABLE UPON CONVERSION. The Company shall at
all times reserve and keep available out of its authorized but unissued shares
of Common Stock solely for the purpose of effecting the conversion of the
Debenture such number of its shares of Common Stock as shall from time to time
be sufficient to effect the conversion of the Debenture; and if at any time the
number of authorized but unissued shares of Common Stock shall not be sufficient
to effect the conversion of the entire outstanding principal amount of this
Debenture, in addition to such other remedies as shall be available to the
holder of this Debenture, the Company will use its best efforts to take such
corporate action as may, in the opinion of its counsel, be necessary to increase
its authorized but unissued shares of Common Stock (and shares of its Common
Stock for issuance on conversion of such Common Stock) to such number of shares
as shall be sufficient for such purposes.

         7. ASSIGNMENT. Subject to the restrictions on transfer described in
Section 9 below, the rights and obligations of the Company and the Holder of
this Debenture shall be binding upon and benefit the successors, assigns, heirs,
administrators and transferees of the parties.

         8. WAIVER AND AMENDMENT. Any provision of this Debenture may be
amended, waived or modified upon the written consent of the Company and holders
of at least fifty percent of the face amount of all then outstanding Debentures
issued pursuant to the Purchase Agreement.


                                     - 8 -

<PAGE>   9

         9.  TRANSFER OF THIS DEBENTURE OR SECURITIES ISSUABLE ON CONVERSION
HEREOF. With respect to any offer, sale or other disposition of this Debenture
or securities into which such Debenture may be converted, the Holder will give
written notice to the Company prior thereto, describing briefly the manner
thereof, together with a written opinion of such Holder's counsel, to the effect
that such offer, sale or other distribution may be effected without registration
or qualification (under any federal or state law then in effect). Promptly upon
receiving such written notice and reasonably satisfactory opinion, if so
requested, the Company, as promptly as practicable, shall notify such Holder
that such Holder may sell or otherwise dispose of this Debenture or such
securities, all in accordance with the terms of the notice delivered to the
Company. If a determination has been made pursuant to this Section 9 that the
opinion of counsel for the Holder is not reasonably satisfactory to the Company,
the Company shall so notify the Holder promptly after such determination has
been made. Each Debenture thus transferred and each certificate representing the
securities thus transferred shall bear a legend as to the applicable
restrictions on transferability in order to ensure compliance with the Act,
unless in the opinion of counsel for the Company such legend is not required. in
order to ensure compliance with the Act. The Company may issue stop transfer
instructions to its transfer agent in connection with such restrictions.

         10. TREATMENT OF DEBENTURE. To the extent permitted by generally
accepted accounting principles, the Company will treat, account and report the
Debenture as debt and not equity for accounting purposes and with respect to any
returns filed with federal, state or local tax authorities.

         11. NOTICES. Any notice, request or other communication required or
permitted hereunder shall be in writing and shall be deemed to have been duly
given if made by hand delivery, by an express courier company recognized
nationally in the United States or Canada or by registered or certified mail,
postage prepaid, at the respective addresses of the parties as set forth herein.
Any party hereto may by notice so given change its address for future notice
hereunder. Notice shall conclusively be deemed to have been given as of the date
so delivered when personally delivered, one (1) business day (three (3) business
days in the case of international deliveries) after dispatch if sent for
overnight delivery by an express courier service nationally recognized in the
United States or Canada and five (5) calendar days (seven (7) calendar days in
the case of international deliveries) after mailing if sent by registered or
certified mail in the manner set forth above. A notice of conversion given
pursuant to Section 4.1 and a Forbearance Request given pursuant to Section
5(ii) may be given to the Company by facsimile transmission at 770/448-3357 and
a simultaneous phone call to the Company at 770/453-0121 (or such other number
as the Company shall designate), and shall be deemed to have been given and
received when a legible copy has been actually received. A notice of redemption
given pursuant to Section 4.3.1 and the Company's response to the Holder's
Forebearance Request given pursuant to Section 5.2.2 may be given to the Holder
by facsimile transmission at (___) ___________ and a simultaneous phone call to
the Holder at (___) _______________ (or such other number as the Holder shall
designate) and shall be deemed to have been given and received when a legible
copy has been actually received.


                                     - 9 -

<PAGE>   10

         12. NO STOCKHOLDER RIGHTS. Nothing contained in this Debenture shall be
construed as conferring upon the Holder or any other person the right to vote or
to consent or to receive notice as a stockholder in respect of meetings of
stockholders for the election of directors of the Company or any other matters
or any rights whatsoever as a stockholder of the Company; and no dividends or
interest shall be payable or accrued in respect of this Debenture or the
interest represented hereby or the Conversion Shares obtainable hereunder until,
and only to the extent that, this Debenture shall have been converted.

         13. GOVERNING LAW; INTERPRETATION. This Debenture shall be governed by
and construed in accordance with the laws of the State of Delaware, USA
excluding that body of law relating to conflict of laws. All references to
dollars are to U.S. dollars.

         14. ARBITRATION. All disputes arising under this Agreement (other than
claims in equity) shall be resolved by arbitration in accordance with the
Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.

         15. HEADING; REFERENCES. All headings used herein are used for
convenience only and shall not be used to construe or interpret this Debenture.
Except where otherwise indicated, all references herein to Sections refer to
Sections hereof.

                    [Signatures Appear on the Following Page]

                                     - 10 -


<PAGE>   11


         IN WITNESS WHEREOF, the Company has caused this Debenture to be issued
this 22 day of October, 1997.

                                             CYTRX CORPORATION

                                             By:
                                                 -------------------------
                                                  Jack J. Luchese
                                             Its: Chief Executive Officer
                                                  and President

Name of Holder:   DAVID KOSLOFF
Address:          c/o Shipley Raidy Capital Partners, LP
                  One Tower Bridge, Suite 1370
                  West Conshohocken, PA  19428
                  United States of America


                                     - 11 -

<PAGE>   12


                              NOTICE OF CONVERSION

                (To Be Signed Only Upon Conversion of Debenture)

TO CYTRX CORPORATION

The undersigned, the holder of the foregoing Debenture, hereby surrenders such
Debenture for conversion into shares of Common Stock of CYTRX CORPORATION, to
the extent of $_________ unpaid principal amount of such Debenture, and requests
that the certificates for such shares be issued in the name of, and delivered
to, _________________ whose address is ____________________.
Dated:
      ---------------------

                                             -------------------------
                                             (Signature must conform in all
                                             respects to name of holder as
                                             specified on the face of the
                                             Debenture)


                                             -------------------------
                                                     (Address)

                                     - 12 -

<PAGE>   1
                                                                     EXHIBIT 4.1

NEITHER THIS WARRANT, NOR THE SHARES OF COMMON STOCK FOR WHICH IT IS
EXERCISABLE, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS WARRANT HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.



                                CYTRX CORPORATION
                             STOCK PURCHASE WARRANT


         This is to certify that, the Initial Holder (as defined below) or any
successor Holder is entitled upon the due exercise hereof to purchase from CytRx
Corporation, a Delaware Corporation (the "Company") up to 30,000 of the
authorized but unissued shares (subject to adjustment as provided herein) of the
$.001 par value Common Stock of the Company at a price per share as specified in
Section 2 of this Warrant (subject to adjustment as provided herein) and to
exercise the other rights, power and privileges hereinafter provided, all on the
terms and subject to the conditions specified herein.

         SECTION 1. Certain Definitions. Unless the context otherwise requires,
the following terms as used in this Warrant shall have the following meanings:

                  "Affiliate" shall mean any partnership or corporation
controlled by or under common control with the Initial Holder.

                  "Common Stock" shall mean the Company's $.001 par value per
share Common Stock or any stock into which such stock shall have been changed or
any stock resulting from reclassification of such stock.

                  "Company" shall mean CytRx Corporation, a Delaware
corporation, and its successors and assigns.

<PAGE>   2

                  "Exercise Date" has the meaning set forth in Section 3 hereof.

                  "Exercise Price" shall mean the price specified in Section 2
hereof, as the same shall be adjusted from time to time pursuant to the
provisions of this Warrant.

                  "Fair Market Value" shall mean (i) the last sales price for a
share of Common Stock as officially reported on the principal national
securities exchange or domestic over-the-counter market on which the Common
Stock is at the time listed or traded at the time of determination of such Fair
Market Value or (ii) if such Common Stock is not at such time listed on a
national securities exchange or quoted in the domestic over-the-counter market,
the fair market value as determined by the Board of Directors of the Company in
good faith after review of all relevant factors.

                  "Holder" or "Warrant Holder" shall mean the Initial Holder and
its successors and registered assigns of this Warrant.

                  "Initial Holder" shall mean GUNDYCO in trust for R.R.S.P.
550-9886-19, its successors and affiliates.

                  "Subscription Agreement" shall mean that certain Private
Securities Subscription Agreement dated as of October 22, 1997 relating to the
purchase of certain debentures convertible into shares of Common Stock as the
same may be amended and modified from time to time, and "Debenture" shall mean
any of the debentures issued thereunder.

                  "Warrant" means this Warrant dated as of October 22, 1997
issued to Initial Holder hereby and all warrants issued upon the transfer or
division of or in substitution for such Warrant.

         SECTION 2. Exercise Price. The Exercise Price per share shall be $5.68
per share of the Common Stock. The Exercise Price shall be paid in cash.

         SECTION 3. Exercise. Prior to the later of the second anniversary of
the date hereof (the "Expiration Date"), this Warrant may be exercised by the
Holder, as to all or less than all of the shares of Common Stock covered hereby,
by surrender of this Warrant at the Company's principal office (for all purposes
of this Warrant, 154 Technology Parkway, Norcross, Georgia 30092 or such other
address as the Company may advise the registered Holder hereof by notice given
by certified or registered mail) with the form of election to subscribe attached
hereto as Exhibit A duly executed and upon tender of payment to the Company of
the Exercise Price for shares so purchased in cash or by check. Upon the date of
such receipt by the Company (herein called the "Exercise Date"), this Warrant
shall be deemed to have been exercised and the person exercising the same shall
become a holder of record of shares of Common Stock (or of the other securities
or property to which he or it is entitled upon such exercise) purchased
hereunder for all


                                     - 2 -
<PAGE>   3

purposes, and certificates for such shares so purchased shall be delivered to
the Holder or its transferee within a reasonable time (not exceeding 10 days)
after this Warrant shall have been exercised as set forth hereinabove. In the
event that this Warrant is exercised in part, the Company will execute and
deliver a new Warrant of like tenor exerciseable for the number of shares for
which this Warrant may then be exercised. If this Warrant is not exercised on or
prior to the Expiration Date, this Warrant shall become void and all rights of
the Holder hereunder shall cease.

         SECTION 4. Taxes. The Company shall pay all expenses in connection
with, and all taxes and other governmental charges that may be imposed with
respect to the issue or delivery of the shares of Common Stock covered hereby
unless such tax or charge is imposed by law upon the Holder, in which case such
taxes or charges shall be paid by the Holder. The Company shall not be required,
however, to pay any tax or other charge imposed in connection with any transfer
involved in the issue of any certificate for shares of Common Stock issuable
upon exercise of this Warrant in any name other than that of the Holder, and in
such case the Company shall not be required to issue or deliver any stock
certificate until such tax or the charge has been paid or it has been
established to the satisfaction of the Company that no such tax or other charge
is due.

         SECTION 5. Warrant Register. The Company shall at all times while any
portion of this Warrant remains outstanding and exercisable keep and maintain at
its principal office a register (the "Warrant Register") in which the
registration, transfer and exchange of this Warrant shall be recorded. The
Warrant Register shall contain the names and addresses of the Holder or Holders.
Any Holder of this Warrant or any portion thereof may change his or her address
as shown on the Warrant Register by written notice to the Company requesting
such change. Any notice or written communication required or permitted to be
given to the Holder may be delivered or given by mail to such Holder as shown on
the Warrant Register and at the address shown on the Warrant Register. The
Company shall not at any time, except upon the dissolution, liquidation or
winding up of the Company, close such register so as to result in preventing or
delaying the exercise or transfer of this Warrant. If at any time, the Company
shall appoint an agent (the "Warrant Agent") to maintain such register, the
Company shall promptly give notice by certified or registered mail to the
registered Holder hereof of the name of such Warrant Agent and of the place or
places at which this Warrant may be presented for transfer, exchange or
exercise. The terms of the agreement between the Company and any Warrant Agent
at any time in effect will be in conformity with the terms of this Warrant.

         SECTION 6. Transfer. The Company shall register the transfer of any
Warrant upon records to be maintained by the Company for that purpose, upon
surrender of this Warrant, with the form of transfer authorization attached
hereto as Exhibit B duly filled in and signed, to the Company at the office
specified herein. Upon any such registration of transfer, a new Warrant, in
substantially the form of this Warrant, evidencing the Warrant rights so
transferred, shall be issued to the transferee and a new Warrant, in similar
form, evidencing the remaining Warrant rights not so transferred, if any, shall
be issued to the then registered Holder thereof. The Holder understands that
this Warrant has not been


                                     - 3 -
<PAGE>   4

and will not be registered under the Securities Act of 1933, as amended (the
"Securities Act") and that the Warrant and the shares of Common Stock issuable
upon exercise hereof may not be sold, assigned, transferred, pledged or
otherwise encumbered or disposed of in the absence of an effective registration
statement under the Securities Act, relating to such Warrant or shares;
provided, however that this Warrant and the shares of Common Stock issuable upon
exercise hereof may be sold, assigned, transferred, pledged or otherwise
encumbered or disposed of if the holder obtains a written opinion of counsel
acceptable to the Company to the effect that the proposed sale, assignment,
transfer, pledge or other encumbrance or disposition is exempt from registration
under the Securities Act.

         SECTION 7. Exchange. This Warrant is exchangeable, upon the surrender
hereof by the Holder at the principal offices of the Company, together with the
form of transfer authorization attached hereto duly executed, for new warrants
of like tenor and date, in such denominations as the Holder shall designate at
the time of surrender for exchange, representing in the aggregate the right to
subscribe for and purchase the number of shares which may be subscribed for and
purchased hereunder.

         SECTION 8. Covenants of the Company.

                  (a) The Company covenants and agrees that all shares which may
be issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be fully paid and nonassessable, free from preemptive rights, and free
from all taxes, liens, encumbrances and charges with respect to the issue
thereof (other than taxes in respect of any transfer occurring contemporaneously
with such issue). The Company further covenants and agrees that during the
period within which the rights represented by this Warrant may be exercised, the
Company will at all times have authorized and reserved a sufficient number of
shares of Common Stock to provide for the exercise in full of the rights
represented by this Warrant.

                  (b) As long as the Warrant remains outstanding, the Company
shall maintain an office or agency (which may be the principal executive office
of the Company) where the Warrant may be presented for exercise, registration of
transfer, exchange, division or combination as provided in this Warrant.

         SECTION 9. Adjustments for Stock Splits and Subdivisions.

                  (a) In the event the Company should at any time or from time
to time after the date of issuance hereof fix a record date for the effectuation
of a split or subdivision of the outstanding shares of Common Stock or the
determination of holders of Common Stock entitled to receive a dividend or other
distribution payable in additional shares of Common Stock or other securities or
rights convertible into, or entitling the holder thereof to receive directly or
indirectly, additional shares of Common Stock (hereinafter referred to as
"Common Stock Equivalents") without payment of any consideration by such holder
for the additional shares of Common Stock or the Common Stock Equivalents
(including the additional shares of Common Stock issuable upon


                                     - 4 -


<PAGE>   5

conversion or exercise thereof), then, as of such record date (or the date of
such dividend distribution, split or subdivision if no record date is fixed),
the Exercise Price of this Warrant shall be appropriately decreased so that the
number of shares of Common Stock issuable upon exercise of this Warrant shall
be. increased in proportion to such increase of outstanding shares.

                  (b) If the number of shares of Common Stock outstanding at any
time after the date hereof is decreased by a combination of the outstanding
shares of Common Stock, then, following the record date of such combination, the
Exercise Price for this Warrant shall be appropriately increased so that the
number of shares of Common Stock issuable on exercise hereof shall be decreased
in proportion to such decrease in outstanding shares.

         SECTION 10. Holder's Rights. This Warrant shall not entitle the Holder
to any rights of a stockholder of the Company, except that should the Company,
during the period in which this Warrant is exercisable, declare a dividend upon
the Common Stock payable other than in cash out of earnings or surplus (computed
in accordance with generally accepted accounting principles consistently
applied) or other than in Common Stock or securities convertible into Common
Stock, then, thereafter, the Warrant Holder, upon exercise of this Warrant,
shall receive the number of shares of Common Stock purchasable upon such
exercise and, in addition and without further payment, the cash, stock or other
securities and/or other property which the Warrant Holder would have received by
way of dividends (otherwise than in cash out of earnings or earned surplus or in
Common Stock or securities convertible into Common Stock) and/or any other
distributions in respect of the Common Stock as if, continuously since the date
hereof, such Warrant Holder (a) had been the record holder of the number of
shares of Common Stock then being purchased, and (b) had retained all such cash,
stock and other securities (other than dividends in cash out of earnings or
earned surplus or in Common Stock or securities convertible into Common Stock)
and/or other property payable in respect of such Common Stock or in respect of
any stock or securities paid as dividends and originating directly or indirectly
from such Common Stock.

         SECTION 11. Notice of Adjustments. If there shall be any adjustment as
provided in Section 9, the Company shall forthwith cause written notice thereof
to be sent by facsimile, overnight or registered mail, postage prepaid, to the
registered Holder of this Warrant at the address of such Holder shown on the
books of the Company. At the request of Holder and upon surrender of this
Warrant, the Company shall reissue this Warrant in a form conforming to such
adjustments.

         SECTION 12. Cash in Lieu of Fractional Shares. The Company shall not be
required to issue fractional shares upon the exercise of this Warrant. If, by
reason of any change made pursuant to Section 9 or 10 hereof, the Holder of this
Warrant would be entitled, upon the exercise of any rights evidenced hereby, to
receive a fractional interest in a share, the Company shall, upon such exercise,
purchase such fractional interest for an


                                     - 5 -


<PAGE>   6

amount in cash equal to the fair market value of such fractional interest,
determined as of the Exercise Date.

         SECTION 13. Lost, Stolen, Mutilated or Destroyed Warrants. If this
Warrant shall be mutilated, lost, stolen or destroyed, upon request by the
registered Holder of the Warrant, the Company will issue, in exchange for and
upon cancellation of the mutilated Warrant, or in substitution for the lost,
stolen or destroyed Warrant, a new Warrant, in substantially the form of this
Warrant, of like tenor and representing the right to purchase the equivalent
number of the remaining shares of Common Stock issuable upon exercise hereof,
but, in the case of loss, theft or destruction, only upon receipt of evidence
satisfactory to the Company of such loss, theft or destruction of this Warrant
and, if requested by the Company, an indemnification also satisfactory to it (it
being understood that the written agreement of the initial Holder shall be
sufficient indemnity), provided, in the case of mutilation, no indemnity shall
be required if this Warrant in identifiable form is surrendered to the Company
for cancellation.

         SECTION 14. Challenge to Good Faith Determination. Whenever the Board
shall be required to make a determination in good faith of the fair value of any
item under Section 9, such determination may be challenged in good faith by the
Holder, and any dispute shall be resolved by an investment banking firm of
recognized national standing in the United States selected by the Company and
acceptable to the Holder.

         SECTION 15. Certain Limitations. Notwithstanding anything herein to the
contrary, the Company agrees not to enter into any transaction which, by reason
of any adjustment hereunder, would cause the current Exercise Price to be less
than the par value per share of Common Stock.

         SECTION 16. Amendments. Any term of this Warrant may be amended with
the written consent of the Company and the holders of warrants representing more
than fifty percent (50%) of the outstanding warrants issued pursuant to the
Subscription Agreement, even without the consent of the Holder. Any amendment
effected in accordance with this Section 16 shall be binding upon each holder or
any the warrants issued pursuant to the Subscription Agreement, each future
holder of such warrants, and the Company; provided, however, that no special
consideration or inducement may be give to any such holder in connection with
such consent that is not given ratably to all such holders, and that such
amendment must apply to all such holders equally and ratably in accordance with
the number of shares of Common Stock issuable upon exercise of their warrants.
The Company shall promptly give notice to all holders of warrants issued
pursuant to the Subscription Agreement of any amendment effected in accordance
with this Section 16. No waivers of, or exceptions to, any term, condition, or
provision of this Warrant, in any one or more instances, shall be deemed to be,
or construed as, a further or continuing waiver of any such term, condition, or
provision.

         SECTION 17. No Impairment. The Company represents and warrants that
there are no restrictions in the Company's Certificate of Incorporation or
Bylaws which prevent


                                     - 6 -


<PAGE>   7

it from satisfying its obligation to issue the shares of Common Stock issuable
upon exercise of the Warrant. The Company shall not by any action including,
without limitation, amending its Certificate of Incorporation or Bylaws, or
through any reorganization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms of this Warrant,
and will at all times in good faith assist in the carrying out of all such terms
and in the taking of all such actions as may be necessary or appropriate to
protect the rights of the Holder against impairment.

         SECTION 18. Applicable Law; Payments. The validity, interpretation and
performance of this Warrant shall be governed by the laws of the State of
Delaware. All payments shall be in U.S. Dollars by immediately available funds.

         SECTION 19. Successors and Assigns. This Warrant and the rights
evidenced hereby shall inure to the benefit of and be binding upon the
successors and assigns of the Company and the Holder.

         SECTION 20. Headings. Headings of the paragraphs in this Warrant are
for convenience and reference only and shall not, for any purpose, be deemed a
part of this Warrant.

         SECTION 21. Arbitration. All disputes arising under this Agreement
(other than claims in equity) shall be resolved by arbitration in accordance
with the Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.


                                     - 7 -

<PAGE>   8


         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed under seal by its duly authorized officer this 22 day of October,
1997.

                                    CYTRX CORPORATION



                                    By:
                                       -----------------------------------
                                    Name:
                                         ---------------------------------
                                    Title:
                                          --------------------------------

GUNDYCO in trust for
R.R.S.P. 550-98866-19


By:
   -------------------------------
Title:
      ----------------------------


                                     - 8 -

<PAGE>   9


                                    EXHIBIT A

                              FORM OF SUBSCRIPTION


         The undersigned, registered holder or assignee of such registered
holder of the within Warrant, hereby (1) subscribes for _________________ shares
(subject to adjustment as provided herein) which the undersigned is entitled to
purchase under the terms of the within Warrant, (2) makes the full cash payment
called for by the within Warrant, and (3) directs that the shares issuable upon
exercise of said Warrant be issued as follows:


                                    Name:
                                          --------------------------------


                                    By:
                                       -----------------------------------
                                    Title:
                                          --------------------------------



Date:
     -----------------------------

- ----------------------------------



NOTICE: The name and signature on this subscription form must correspond with
the name as written upon the face of the within Warrant, or upon the assignment
form on the reverse thereof, in every particular, without alteration or
enlargement and must be guaranteed by a bank or by a firm having membership on a
registered national securities exchange in the United States.


                                     - 9 -


<PAGE>   10


                                    EXHIBIT B

                               FORM OF ASSIGNMENT


FOR VALUE RECEIVED __________________________ hereby sells, assigns, and
transfers unto __________________, of _________________, the right to purchase
___________ shares (subject to adjustment as provided herein) evidenced by the
within Warrant, and hereby irrevocably constitutes and appoints
__________________ to transfer such right on the books of the Company, with full
power of substitution.

Date: _______________, 19___

                                    Name:
                                         ---------------------------------



                                    By:
                                       -----------------------------------
                                    Title:
                                          --------------------------------



Date:
     -----------------------------

- ----------------------------------


NOTICE: The name and signature on this assignment must correspond with the name
as written upon the face of the within Warrant, or upon any assignment form duly
executed pursuant to the terms of the within Warrant, in every particular,
without alteration or enlargement and must be guaranteed by a bank, or by a firm
having membership on a registered national securities exchange in the United
States.


                                     - 10 -

<PAGE>   1
                                                                    EXHIBIT 4.2 

NEITHER THIS WARRANT, NOR THE SHARES OF COMMON STOCK FOR WHICH IT IS
EXERCISABLE, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS WARRANT HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.



                                CYTRX CORPORATION
                             STOCK PURCHASE WARRANT


         This is to certify that, the Initial Holder (as defined below) or any
successor Holder is entitled upon the due exercise hereof to purchase from CytRx
Corporation, a Delaware Corporation (the "Company") up to 8,000 of the
authorized but unissued shares (subject to adjustment as provided herein) of the
$.001 par value Common Stock of the Company at a price per share as specified in
Section 2 of this Warrant (subject to adjustment as provided herein) and to
exercise the other rights, power and privileges hereinafter provided, all on the
terms and subject to the conditions specified herein.

         SECTION 1. Certain Definitions. Unless the context otherwise requires,
the following terms as used in this Warrant shall have the following meanings:

                  "Affiliate" shall mean any partnership or corporation
controlled by or under common control with the Initial Holder.

                  "Common Stock" shall mean the Company's $.001 par value per
share Common Stock or any stock into which such stock shall have been changed or
any stock resulting from reclassification of such stock.

                  "Company" shall mean CytRx Corporation, a Delaware
corporation, and its successors and assigns.


<PAGE>   2

                  "Exercise Date" has the meaning set forth in Section 3 hereof.

                  "Exercise Price" shall mean the price specified in Section 2
hereof, as the same shall be adjusted from time to time pursuant to the
provisions of this Warrant.

                  "Fair Market Value" shall mean (i) the last sales price for a
share of Common Stock as officially reported on the principal national
securities exchange or domestic over-the-counter market on which the Common
Stock is at the time listed or traded at the time of determination of such Fair
Market Value or (ii) if such Common Stock is not at such time listed on a
national securities exchange or quoted in the domestic over-the-counter market,
the fair market value as determined by the Board of Directors of the Company in
good faith after review of all relevant factors.

                  "Holder" or "Warrant Holder" shall mean the Initial Holder and
its successors and registered assigns of this Warrant.

                  "Initial Holder" shall mean Excalibur Capital Management, its
successors and affiliates.

                  "Subscription Agreement" shall mean that certain Private
Securities Subscription Agreement dated as of October 22, 1997 relating to the
purchase of certain debentures convertible into shares of Common Stock as the
same may be amended and modified from time to time, and "Debenture" shall mean
any of the debentures issued thereunder.

                  "Warrant" means this Warrant dated as of October 22, 1997
issued to Initial Holder hereby and all warrants issued upon the transfer or
division of or in substitution for such Warrant.

         SECTION 2. Exercise Price. The Exercise Price per share shall be $5.68
per share of the Common Stock. The Exercise Price shall be paid in cash.

         SECTION 3. Exercise. Prior to the later of the second anniversary of
the date hereof (the "Expiration Date"), this Warrant may be exercised by the
Holder, as to all or less than all of the shares of Common Stock covered hereby,
by surrender of this Warrant at the Company's principal office (for all purposes
of this Warrant, 154 Technology Parkway, Norcross, Georgia 30092 or such other
address as the Company may advise the registered Holder hereof by notice given
by certified or registered mail) with the form of election to subscribe attached
hereto as Exhibit A duly executed and upon tender of payment to the Company of
the Exercise Price for shares so purchased in cash or by check. Upon the date of
such receipt by the Company (herein called the "Exercise Date"), this Warrant
shall be deemed to have been exercised and the person exercising the same shall
become a holder of record of shares of Common Stock (or of the other securities
or property to which he or it is entitled upon such exercise) purchased
hereunder for all


                                     - 2 -


<PAGE>   3

purposes, and certificates for such shares so purchased shall be delivered to
the Holder or its transferee within a reasonable time (not exceeding 10 days)
after this Warrant shall have been exercised as set forth hereinabove. In the
event that this Warrant is exercised in part, the Company will execute and
deliver a new Warrant of like tenor exerciseable for the number of shares for
which this Warrant may then be exercised. If this Warrant is not exercised on or
prior to the Expiration Date, this Warrant shall become void and all rights of
the Holder hereunder shall cease.

         SECTION 4. Taxes. The Company shall pay all expenses in connection
with, and all taxes and other governmental charges that may be imposed with
respect to the issue or delivery of the shares of Common Stock covered hereby
unless such tax or charge is imposed by law upon the Holder, in which case such
taxes or charges shall be paid by the Holder. The Company shall not be required,
however, to pay any tax or other charge imposed in connection with any transfer
involved in the issue of any certificate for shares of Common Stock issuable
upon exercise of this Warrant in any name other than that of the Holder, and in
such case the Company shall not be required to issue or deliver any stock
certificate until such tax or the charge has been paid or it has been
established to the satisfaction of the Company that no such tax or other charge
is due.

         SECTION 5. Warrant Register. The Company shall at all times while any
portion of this Warrant remains outstanding and exercisable keep and maintain at
its principal office a register (the "Warrant Register") in which the
registration, transfer and exchange of this Warrant shall be recorded. The
Warrant Register shall contain the names and addresses of the Holder or Holders.
Any Holder of this Warrant or any portion thereof may change his or her address
as shown on the Warrant Register by written notice to the Company requesting
such change. Any notice or written communication required or permitted to be
given to the Holder may be delivered or given by mail to such Holder as shown on
the Warrant Register and at the address shown on the Warrant Register. The
Company shall not at any time, except upon the dissolution, liquidation or
winding up of the Company, close such register so as to result in preventing or
delaying the exercise or transfer of this Warrant. If at any time, the Company
shall appoint an agent (the "Warrant Agent") to maintain such register, the
Company shall promptly give notice by certified or registered mail to the
registered Holder hereof of the name of such Warrant Agent and of the place or
places at which this Warrant may be presented for transfer, exchange or
exercise. The terms of the agreement between the Company and any Warrant Agent
at any time in effect will be in conformity with the terms of this Warrant.

         SECTION 6. Transfer. The Company shall register the transfer of any
Warrant upon records to be maintained by the Company for that purpose, upon
surrender of this Warrant, with the form of transfer authorization attached
hereto as Exhibit B duly filled in and signed, to the Company at the office
specified herein. Upon any such registration of transfer, a new Warrant, in
substantially the form of this Warrant, evidencing the Warrant rights so
transferred, shall be issued to the transferee and a new Warrant, in similar
form, evidencing the remaining Warrant rights not so transferred, if any, shall
be issued to the then registered Holder thereof. The Holder understands that
this Warrant has not been


                                     - 3 -


<PAGE>   4

and will not be registered under the Securities Act of 1933, as amended (the
"Securities Act") and that the Warrant and the shares of Common Stock issuable
upon exercise hereof may not be sold, assigned, transferred, pledged or
otherwise encumbered or disposed of in the absence of an effective registration
statement under the Securities Act, relating to such Warrant or shares;
provided, however that this Warrant and the shares of Common Stock issuable upon
exercise hereof may be sold, assigned, transferred, pledged or otherwise
encumbered or disposed of if the holder obtains a written opinion of counsel
acceptable to the Company to the effect that the proposed sale, assignment,
transfer, pledge or other encumbrance or disposition is exempt from registration
under the Securities Act.

         SECTION 7. Exchange. This Warrant is exchangeable, upon the surrender
hereof by the Holder at the principal offices of the Company, together with the
form of transfer authorization attached hereto duly executed, for new warrants
of like tenor and date, in such denominations as the Holder shall designate at
the time of surrender for exchange, representing in the aggregate the right to
subscribe for and purchase the number of shares which may be subscribed for and
purchased hereunder.

         SECTION 8. Covenants of the Company.

                  (a) The Company covenants and agrees that all shares which may
be issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be fully paid and nonassessable, free from preemptive rights, and free
from all taxes, liens, encumbrances and charges with respect to the issue
thereof (other than taxes in respect of any transfer occurring contemporaneously
with such issue). The Company further covenants and agrees that during the
period within which the rights represented by this Warrant may be exercised, the
Company will at all times have authorized and reserved a sufficient number of
shares of Common Stock to provide for the exercise in full of the rights
represented by this Warrant.

                  (b) As long as the Warrant remains outstanding, the Company
shall maintain an office or agency (which may be the principal executive office
of the Company) where the Warrant may be presented for exercise, registration of
transfer, exchange, division or combination as provided in this Warrant.

         SECTION 9. Adjustments for Stock Splits and Subdivisions.

                  (a) In the event the Company should at any time or from time
to time after the date of issuance hereof fix a record date for the effectuation
of a split or subdivision of the outstanding shares of Common Stock or the
determination of holders of Common Stock entitled to receive a dividend or other
distribution payable in additional shares of Common Stock or other securities or
rights convertible into, or entitling the holder thereof to receive directly or
indirectly, additional shares of Common Stock (hereinafter referred to as
"Common Stock Equivalents") without payment of any consideration by such holder
for the additional shares of Common Stock or the Common Stock Equivalents
(including the additional shares of Common Stock issuable upon


                                     - 4 -


<PAGE>   5

conversion or exercise thereof), then, as of such record date (or the date of
such dividend distribution, split or subdivision if no record date is fixed),
the Exercise Price of this Warrant shall be appropriately decreased so that the
number of shares of Common Stock issuable upon exercise of this Warrant shall
be. increased in proportion to such increase of outstanding shares.

                  (b) If the number of shares of Common Stock outstanding at any
time after the date hereof is decreased by a combination of the outstanding
shares of Common Stock, then, following the record date of such combination, the
Exercise Price for this Warrant shall be appropriately increased so that the
number of shares of Common Stock issuable on exercise hereof shall be decreased
in proportion to such decrease in outstanding shares.

         SECTION 10. Holder's Rights. This Warrant shall not entitle the Holder
to any rights of a stockholder of the Company, except that should the Company,
during the period in which this Warrant is exercisable, declare a dividend upon
the Common Stock payable other than in cash out of earnings or surplus (computed
in accordance with generally accepted accounting principles consistently
applied) or other than in Common Stock or securities convertible into Common
Stock, then, thereafter, the Warrant Holder, upon exercise of this Warrant,
shall receive the number of shares of Common Stock purchasable upon such
exercise and, in addition and without further payment, the cash, stock or other
securities and/or other property which the Warrant Holder would have received by
way of dividends (otherwise than in cash out of earnings or earned surplus or in
Common Stock or securities convertible into Common Stock) and/or any other
distributions in respect of the Common Stock as if, continuously since the date
hereof, such Warrant Holder (a) had been the record holder of the number of
shares of Common Stock then being purchased, and (b) had retained all such cash,
stock and other securities (other than dividends in cash out of earnings or
earned surplus or in Common Stock or securities convertible into Common Stock)
and/or other property payable in respect of such Common Stock or in respect of
any stock or securities paid as dividends and originating directly or indirectly
from such Common Stock.

         SECTION 11. Notice of Adjustments. If there shall be any adjustment as
provided in Section 9, the Company shall forthwith cause written notice thereof
to be sent by facsimile, overnight or registered mail, postage prepaid, to the
registered Holder of this Warrant at the address of such Holder shown on the
books of the Company. At the request of Holder and upon surrender of this
Warrant, the Company shall reissue this Warrant in a form conforming to such
adjustments.

         SECTION 12. Cash in Lieu of Fractional Shares. The Company shall not be
required to issue fractional shares upon the exercise of this Warrant. If, by
reason of any change made pursuant to Section 9 or 10 hereof, the Holder of this
Warrant would be entitled, upon the exercise of any rights evidenced hereby, to
receive a fractional interest in a share, the Company shall, upon such exercise,
purchase such fractional interest for an


                                     - 5 -


<PAGE>   6

amount in cash equal to the fair market value of such fractional interest,
determined as of the Exercise Date.

         SECTION 13. Lost, Stolen, Mutilated or Destroyed Warrants. If this
Warrant shall be mutilated, lost, stolen or destroyed, upon request by the
registered Holder of the Warrant, the Company will issue, in exchange for and
upon cancellation of the mutilated Warrant, or in substitution for the lost,
stolen or destroyed Warrant, a new Warrant, in substantially the form of this
Warrant, of like tenor and representing the right to purchase the equivalent
number of the remaining shares of Common Stock issuable upon exercise hereof,
but, in the case of loss, theft or destruction, only upon receipt of evidence
satisfactory to the Company of such loss, theft or destruction of this Warrant
and, if requested by the Company, an indemnification also satisfactory to it (it
being understood that the written agreement of the initial Holder shall be
sufficient indemnity), provided, in the case of mutilation, no indemnity shall
be required if this Warrant in identifiable form is surrendered to the Company
for cancellation.

         SECTION 14. Challenge to Good Faith Determination. Whenever the Board
shall be required to make a determination in good faith of the fair value of any
item under Section 9, such determination may be challenged in good faith by the
Holder, and any dispute shall be resolved by an investment banking firm of
recognized national standing in the United States selected by the Company and
acceptable to the Holder.

         SECTION 15. Certain Limitations. Notwithstanding anything herein to the
contrary, the Company agrees not to enter into any transaction which, by reason
of any adjustment hereunder, would cause the current Exercise Price to be less
than the par value per share of Common Stock.

         SECTION 16. Amendments. Any term of this Warrant may be amended with
the written consent of the Company and the holders of warrants representing more
than fifty percent (50%) of the outstanding warrants issued pursuant to the
Subscription Agreement, even without the consent of the Holder. Any amendment
effected in accordance with this Section 16 shall be binding upon each holder or
any the warrants issued pursuant to the Subscription Agreement, each future
holder of such warrants, and the Company; provided, however, that no special
consideration or inducement may be give to any such holder in connection with
such consent that is not given ratably to all such holders, and that such
amendment must apply to all such holders equally and ratably in accordance with
the number of shares of Common Stock issuable upon exercise of their warrants.
The Company shall promptly give notice to all holders of warrants issued
pursuant to the Subscription Agreement of any amendment effected in accordance
with this Section 16. No waivers of, or exceptions to, any term, condition, or
provision of this Warrant, in any one or more instances, shall be deemed to be,
or construed as, a further or continuing waiver of any such term, condition, or
provision.

         SECTION 17. No Impairment. The Company represents and warrants that
there are no restrictions in the Company's Certificate of Incorporation or
Bylaws which prevent


                                     - 6 -


<PAGE>   7

it from satisfying its obligation to issue the shares of Common Stock issuable
upon exercise of the Warrant. The Company shall not by any action including,
without limitation, amending its Certificate of Incorporation or Bylaws, or
through any reorganization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms of this Warrant,
and will at all times in good faith assist in the carrying out of all such terms
and in the taking of all such actions as may be necessary or appropriate to
protect the rights of the Holder against impairment.

         SECTION 18. Applicable Law; Payments. The validity, interpretation and
performance of this Warrant shall be governed by the laws of the State of
Delaware. All payments shall be in U.S. Dollars by immediately available funds.

         SECTION 19. Successors and Assigns. This Warrant and the rights
evidenced hereby shall inure to the benefit of and be binding upon the
successors and assigns of the Company and the Holder.

         SECTION 20. Headings. Headings of the paragraphs in this Warrant are
for convenience and reference only and shall not, for any purpose, be deemed a
part of this Warrant.

         SECTION 21. Arbitration. All disputes arising under this Agreement
(other than claims in equity) shall be resolved by arbitration in accordance
with the Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.


                                    - 7 -


<PAGE>   8


         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed under seal by its duly authorized officer this 22 day of October,
1997.


                                    CYTRX CORPORATION



                                    By:
                                        ----------------------------------
                                    Name:
                                         ---------------------------------
                                    Title:
                                          --------------------------------


EXCALIBUR CAPITAL MANAGEMENT


By:
   -------------------------------
Title:
      ----------------------------


                                    - 8 -
<PAGE>   9


                                    EXHIBIT A

                              FORM OF SUBSCRIPTION


         The undersigned, registered holder or assignee of such registered
holder of the within Warrant, hereby (1) subscribes for _________________ shares
(subject to adjustment as provided herein) which the undersigned is entitled to
purchase under the terms of the within Warrant, (2) makes the full cash payment
called for by the within Warrant, and (3) directs that the shares issuable upon
exercise of said Warrant be issued as follows:


                                    Name:
                                         -------------------------------



                                    By:
                                       -----------------------------------
                                    Title:
                                          --------------------------------


Date:
     -----------------------------

- ----------------------------------




NOTICE: The name and signature on this subscription form must correspond with
the name as written upon the face of the within Warrant, or upon the assignment
form on the reverse thereof, in every particular, without alteration or
enlargement and must be guaranteed by a bank or by a firm having membership on a
registered national securities exchange in the United States.


                                     - 9 -


<PAGE>   10


                                    EXHIBIT B

                               FORM OF ASSIGNMENT


FOR VALUE RECEIVED __________________________ hereby sells, assigns, and
transfers unto __________________, of _________________, the right to purchase
___________ shares (subject to adjustment as provided herein) evidenced by the
within Warrant, and hereby irrevocably constitutes and appoints
__________________ to transfer such right on the books of the Company, with full
power of substitution.

Date: _______________, 19___

                                    Name:
                                         ---------------------------------




                                    By:
                                       -----------------------------------
                                    Title:
                                          --------------------------------


Date:
      ----------------------------

- ----------------------------------




NOTICE: The name and signature on this assignment must correspond with the name
as written upon the face of the within Warrant, or upon any assignment form duly
executed pursuant to the terms of the within Warrant, in every particular,
without alteration or enlargement and must be guaranteed by a bank, or by a firm
having membership on a registered national securities exchange in the United
States.


                                     - 10 -


<PAGE>   1
                                                                     EXHIBIT 4.3



NEITHER THIS WARRANT, NOR THE SHARES OF COMMON STOCK FOR WHICH IT IS
EXERCISABLE, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS WARRANT HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.



                                CYTRX CORPORATION
                             STOCK PURCHASE WARRANT


         This is to certify that, the Initial Holder (as defined below) or any
successor Holder is entitled upon the due exercise hereof to purchase from CytRx
Corporation, a Delaware Corporation (the "Company") up to 1,000 of the
authorized but unissued shares (subject to adjustment as provided herein) of the
$.001 par value Common Stock of the Company at a price per share as specified in
Section 2 of this Warrant (subject to adjustment as provided herein) and to
exercise the other rights, power and privileges hereinafter provided, all on the
terms and subject to the conditions specified herein.

         SECTION 1. Certain Definitions. Unless the context otherwise requires,
the following terms as used in this Warrant shall have the following meanings:

                  "Affiliate" shall mean any partnership or corporation
controlled by or under common control with the Initial Holder.

                  "Common Stock" shall mean the Company's $.001 par value per
share Common Stock or any stock into which such stock shall have been changed or
any stock resulting from reclassification of such stock.

                  "Company" shall mean CytRx Corporation, a Delaware
corporation, and its successors and assigns.


<PAGE>   2

                  "Exercise Date" has the meaning set forth in Section 3 hereof.

                  "Exercise Price" shall mean the price specified in Section 2
hereof, as the same shall be adjusted from time to time pursuant to the
provisions of this Warrant.

                  "Fair Market Value" shall mean (i) the last sales price for a
share of Common Stock as officially reported on the principal national
securities exchange or domestic over-the-counter market on which the Common
Stock is at the time listed or traded at the time of determination of such Fair
Market Value or (ii) if such Common Stock is not at such time listed on a
national securities exchange or quoted in the domestic over-the-counter market,
the fair market value as determined by the Board of Directors of the Company in
good faith after review of all relevant factors.

                  "Holder" or "Warrant Holder" shall mean the Initial Holder and
its successors and registered assigns of this Warrant.

                  "Initial Holder" shall mean Pine Street Asset Management, its
successors and affiliates.

                  "Subscription Agreement" shall mean that certain Private
Securities Subscription Agreement dated as of October 22, 1997 relating to the
purchase of certain debentures convertible into shares of Common Stock as the
same may be amended and modified from time to time, and "Debenture" shall mean
any of the debentures issued thereunder.

                  "Warrant" means this Warrant dated as of October 22, 1997
issued to Initial Holder hereby and all warrants issued upon the transfer or
division of or in substitution for such Warrant.

         SECTION 2. Exercise Price. The Exercise Price per share shall be $5.68
per share of the Common Stock. The Exercise Price shall be paid in cash.

         SECTION 3. Exercise. Prior to the later of the second anniversary of
the date hereof (the "Expiration Date"), this Warrant may be exercised by the
Holder, as to all or less than all of the shares of Common Stock covered hereby,
by surrender of this Warrant at the Company's principal office (for all purposes
of this Warrant, 154 Technology Parkway, Norcross, Georgia 30092 or such other
address as the Company may advise the registered Holder hereof by notice given
by certified or registered mail) with the form of election to subscribe attached
hereto as Exhibit A duly executed and upon tender of payment to the Company of
the Exercise Price for shares so purchased in cash or by check. Upon the date of
such receipt by the Company (herein called the "Exercise Date"), this Warrant
shall be deemed to have been exercised and the person exercising the same shall
become a holder of record of shares of Common Stock (or of the other securities
or property to which he or it is entitled upon such exercise) purchased
hereunder for all 



                                      -2-
<PAGE>   3

purposes, and certificates for such shares so purchased shall be delivered to
the Holder or its transferee within a reasonable time (not exceeding 10 days)
after this Warrant shall have been exercised as set forth hereinabove. In the
event that this Warrant is exercised in part, the Company will execute and
deliver a new Warrant of like tenor exerciseable for the number of shares for
which this Warrant may then be exercised. If this Warrant is not exercised on or
prior to the Expiration Date, this Warrant shall become void and all rights of
the Holder hereunder shall cease.

         SECTION 4. Taxes. The Company shall pay all expenses in connection
with, and all taxes and other governmental charges that may be imposed with
respect to the issue or delivery of the shares of Common Stock covered hereby
unless such tax or charge is imposed by law upon the Holder, in which case such
taxes or charges shall be paid by the Holder. The Company shall not be required,
however, to pay any tax or other charge imposed in connection with any transfer
involved in the issue of any certificate for shares of Common Stock issuable
upon exercise of this Warrant in any name other than that of the Holder, and in
such case the Company shall not be required to issue or deliver any stock
certificate until such tax or the charge has been paid or it has been
established to the satisfaction of the Company that no such tax or other charge
is due.

         SECTION 5. Warrant Register. The Company shall at all times while any
portion of this Warrant remains outstanding and exercisable keep and maintain at
its principal office a register (the "Warrant Register") in which the
registration, transfer and exchange of this Warrant shall be recorded. The
Warrant Register shall contain the names and addresses of the Holder or Holders.
Any Holder of this Warrant or any portion thereof may change his or her address
as shown on the Warrant Register by written notice to the Company requesting
such change. Any notice or written communication required or permitted to be
given to the Holder may be delivered or given by mail to such Holder as shown on
the Warrant Register and at the address shown on the Warrant Register. The
Company shall not at any time, except upon the dissolution, liquidation or
winding up of the Company, close such register so as to result in preventing or
delaying the exercise or transfer of this Warrant. If at any time, the Company
shall appoint an agent (the "Warrant Agent") to maintain such register, the
Company shall promptly give notice by certified or registered mail to the
registered Holder hereof of the name of such Warrant Agent and of the place or
places at which this Warrant may be presented for transfer, exchange or
exercise. The terms of the agreement between the Company and any Warrant Agent
at any time in effect will be in conformity with the terms of this Warrant.

         SECTION 6. Transfer. The Company shall register the transfer of any
Warrant upon records to be maintained by the Company for that purpose, upon
surrender of this Warrant, with the form of transfer authorization attached
hereto as Exhibit B duly filled in and signed, to the Company at the office
specified herein. Upon any such registration of transfer, a new Warrant, in
substantially the form of this Warrant, evidencing the Warrant rights so
transferred, shall be issued to the transferee and a new Warrant, in similar
form, evidencing the remaining Warrant rights not so transferred, if any, shall
be issued to the then registered Holder thereof. The Holder understands that
this Warrant has not been 



                                      -3-
<PAGE>   4

and will not be registered under the Securities Act of 1933, as amended (the
"Securities Act") and that the Warrant and the shares of Common Stock issuable
upon exercise hereof may not be sold, assigned, transferred, pledged or
otherwise encumbered or disposed of in the absence of an effective registration
statement under the Securities Act, relating to such Warrant or shares;
provided, however that this Warrant and the shares of Common Stock issuable upon
exercise hereof may be sold, assigned, transferred, pledged or otherwise
encumbered or disposed of if the holder obtains a written opinion of counsel
acceptable to the Company to the effect that the proposed sale, assignment,
transfer, pledge or other encumbrance or disposition is exempt from registration
under the Securities Act.

         SECTION 7.  Exchange. This Warrant is exchangeable, upon the surrender
hereof by the Holder at the principal offices of the Company, together with the
form of transfer authorization attached hereto duly executed, for new warrants
of like tenor and date, in such denominations as the Holder shall designate at
the time of surrender for exchange, representing in the aggregate the right to
subscribe for and purchase the number of shares which may be subscribed for and
purchased hereunder.

         SECTION 8.  Covenants of the Company.

                  (a) The Company covenants and agrees that all shares which may
be issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be fully paid and nonassessable, free from preemptive rights, and free
from all taxes, liens, encumbrances and charges with respect to the issue
thereof (other than taxes in respect of any transfer occurring contemporaneously
with such issue). The Company further covenants and agrees that during the
period within which the rights represented by this Warrant may be exercised, the
Company will at all times have authorized and reserved a sufficient number of
shares of Common Stock to provide for the exercise in full of the rights
represented by this Warrant.

                  (b) As long as the Warrant remains outstanding, the Company
shall maintain an office or agency (which may be the principal executive office
of the Company) where the Warrant may be presented for exercise, registration of
transfer, exchange, division or combination as provided in this Warrant.

         SECTION 9.  Adjustments for Stock Splits and Subdivisions.

                  (a) In the event the Company should at any time or from time
to time after the date of issuance hereof fix a record date for the effectuation
of a split or subdivision of the outstanding shares of Common Stock or the
determination of holders of Common Stock entitled to receive a dividend or other
distribution payable in additional shares of Common Stock or other securities or
rights convertible into, or entitling the holder thereof to receive directly or
indirectly, additional shares of Common Stock (hereinafter referred to as
"Common Stock Equivalents") without payment of any consideration by such holder
for the additional shares of Common Stock or the Common Stock Equivalents
(including the additional shares of Common Stock issuable upon 




                                      -4-
<PAGE>   5

conversion or exercise thereof), then, as of such record date (or the date of
such dividend distribution, split or subdivision if no record date is fixed),
the Exercise Price of this Warrant shall be appropriately decreased so that the
number of shares of Common Stock issuable upon exercise of this Warrant shall
be. increased in proportion to such increase of outstanding shares.

                  (b) If the number of shares of Common Stock outstanding at any
time after the date hereof is decreased by a combination of the outstanding
shares of Common Stock, then, following the record date of such combination, the
Exercise Price for this Warrant shall be appropriately increased so that the
number of shares of Common Stock issuable on exercise hereof shall be decreased
in proportion to such decrease in outstanding shares.

         SECTION 10. Holder's Rights. This Warrant shall not entitle the Holder
to any rights of a stockholder of the Company, except that should the Company,
during the period in which this Warrant is exercisable, declare a dividend upon
the Common Stock payable other than in cash out of earnings or surplus (computed
in accordance with generally accepted accounting principles consistently
applied) or other than in Common Stock or securities convertible into Common
Stock, then, thereafter, the Warrant Holder, upon exercise of this Warrant,
shall receive the number of shares of Common Stock purchasable upon such
exercise and, in addition and without further payment, the cash, stock or other
securities and/or other property which the Warrant Holder would have received by
way of dividends (otherwise than in cash out of earnings or earned surplus or in
Common Stock or securities convertible into Common Stock) and/or any other
distributions in respect of the Common Stock as if, continuously since the date
hereof, such Warrant Holder (a) had been the record holder of the number of
shares of Common Stock then being purchased, and (b) had retained all such cash,
stock and other securities (other than dividends in cash out of earnings or
earned surplus or in Common Stock or securities convertible into Common Stock)
and/or other property payable in respect of such Common Stock or in respect of
any stock or securities paid as dividends and originating directly or indirectly
from such Common Stock.

         SECTION 11. Notice of Adjustments. If there shall be any adjustment as
provided in Section 9, the Company shall forthwith cause written notice thereof
to be sent by facsimile, overnight or registered mail, postage prepaid, to the
registered Holder of this Warrant at the address of such Holder shown on the
books of the Company. At the request of Holder and upon surrender of this
Warrant, the Company shall reissue this Warrant in a form conforming to such
adjustments.

         SECTION 12. Cash in Lieu of Fractional Shares. The Company shall not be
required to issue fractional shares upon the exercise of this Warrant. If, by
reason of any change made pursuant to Section 9 or 10 hereof, the Holder of this
Warrant would be entitled, upon the exercise of any rights evidenced hereby, to
receive a fractional interest in a share, the Company shall, upon such exercise,
purchase such fractional interest for an 



                                      -5-
<PAGE>   6

amount in cash equal to the fair market value of such fractional interest,
determined as of the Exercise Date.

         SECTION 13. Lost, Stolen, Mutilated or Destroyed Warrants. If this
Warrant shall be mutilated, lost, stolen or destroyed, upon request by the
registered Holder of the Warrant, the Company will issue, in exchange for and
upon cancellation of the mutilated Warrant, or in substitution for the lost,
stolen or destroyed Warrant, a new Warrant, in substantially the form of this
Warrant, of like tenor and representing the right to purchase the equivalent
number of the remaining shares of Common Stock issuable upon exercise hereof,
but, in the case of loss, theft or destruction, only upon receipt of evidence
satisfactory to the Company of such loss, theft or destruction of this Warrant
and, if requested by the Company, an indemnification also satisfactory to it (it
being understood that the written agreement of the initial Holder shall be
sufficient indemnity), provided, in the case of mutilation, no indemnity shall
be required if this Warrant in identifiable form is surrendered to the Company
for cancellation.

         SECTION 14. Challenge to Good Faith Determination. Whenever the Board
shall be required to make a determination in good faith of the fair value of any
item under Section 9, such determination may be challenged in good faith by the
Holder, and any dispute shall be resolved by an investment banking firm of
recognized national standing in the United States selected by the Company and
acceptable to the Holder.

         SECTION 15. Certain Limitations. Notwithstanding anything herein to the
contrary, the Company agrees not to enter into any transaction which, by reason
of any adjustment hereunder, would cause the current Exercise Price to be less
than the par value per share of Common Stock.

         SECTION 16. Amendments. Any term of this Warrant may be amended with
the written consent of the Company and the holders of warrants representing more
than fifty percent (50%) of the outstanding warrants issued pursuant to the
Subscription Agreement, even without the consent of the Holder. Any amendment
effected in accordance with this Section 16 shall be binding upon each holder or
any the warrants issued pursuant to the Subscription Agreement, each future
holder of such warrants, and the Company; provided, however, that no special
consideration or inducement may be give to any such holder in connection with
such consent that is not given ratably to all such holders, and that such
amendment must apply to all such holders equally and ratably in accordance with
the number of shares of Common Stock issuable upon exercise of their warrants.
The Company shall promptly give notice to all holders of warrants issued
pursuant to the Subscription Agreement of any amendment effected in accordance
with this Section 16. No waivers of, or exceptions to, any term, condition, or
provision of this Warrant, in any one or more instances, shall be deemed to be,
or construed as, a further or continuing waiver of any such term, condition, or
provision.

         SECTION 17. No Impairment. The Company represents and warrants that
there are no restrictions in the Company's Certificate of Incorporation or
Bylaws which prevent 



                                      -6-
<PAGE>   7

it from satisfying its obligation to issue the shares of Common Stock issuable
upon exercise of the Warrant. The Company shall not by any action including,
without limitation, amending its Certificate of Incorporation or Bylaws, or
through any reorganization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms of this Warrant,
and will at all times in good faith assist in the carrying out of all such terms
and in the taking of all such actions as may be necessary or appropriate to
protect the rights of the Holder against impairment.

         SECTION 18. Applicable Law; Payments. The validity, interpretation and
performance of this Warrant shall be governed by the laws of the State of
Delaware. All payments shall be in U.S. Dollars by immediately available funds.

         SECTION 19. Successors and Assigns. This Warrant and the rights
evidenced hereby shall inure to the benefit of and be binding upon the
successors and assigns of the Company and the Holder.

         SECTION 20. Headings. Headings of the paragraphs in this Warrant are
for convenience and reference only and shall not, for any purpose, be deemed a
part of this Warrant.

         SECTION 21. Arbitration. All disputes arising under this Agreement
(other than claims in equity) shall be resolved by arbitration in accordance
with the Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.





                                      -7-
<PAGE>   8



         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed under seal by its duly authorized officer this 22 day of October,
1997.


                                CYTRX CORPORATION



                                By:
                                   ------------------------------
                                Name:
                                     ----------------------------
                                Title:
                                      ---------------------------

PINE STREET ASSET MANAGEMENT


By:
   --------------------------
Title:
      -----------------------



                                      -8-
<PAGE>   9


                                    EXHIBIT A

                              FORM OF SUBSCRIPTION


         The undersigned, registered holder or assignee of such registered
holder of the within Warrant, hereby (1) subscribes for _________________ shares
(subject to adjustment as provided herein) which the undersigned is entitled to
purchase under the terms of the within Warrant, (2) makes the full cash payment
called for by the within Warrant, and (3) directs that the shares issuable upon
exercise of said Warrant be issued as follows:


                                     Name:
                                          ----------------------------


                                     By:
                                        ------------------------------
                                     Title:
                                           ---------------------------



Date:
     -------------------------

- ------------------------------



NOTICE: The name and signature on this subscription form must correspond with
the name as written upon the face of the within Warrant, or upon the assignment
form on the reverse thereof, in every particular, without alteration or
enlargement and must be guaranteed by a bank or by a firm having membership on a
registered national securities exchange in the United States.






                                      -9-
<PAGE>   10



                                    EXHIBIT B

                               FORM OF ASSIGNMENT


FOR VALUE RECEIVED __________________________ hereby sells, assigns, and
transfers unto __________________, of _________________, the right to purchase
___________ shares (subject to adjustment as provided herein) evidenced by the
within Warrant, and hereby irrevocably constitutes and appoints
__________________ to transfer such right on the books of the Company, with full
power of substitution.

Date: _______________, 19____

                                      Name:
                                           ----------------------------
                                      By:
                                         ------------------------------
                                      Title:
                                            ---------------------------




Date:
     ----------------------------

- ---------------------------------




NOTICE: The name and signature on this assignment must correspond with the name
as written upon the face of the within Warrant, or upon any assignment form duly
executed pursuant to the terms of the within Warrant, in every particular,
without alteration or enlargement and must be guaranteed by a bank, or by a firm
having membership on a registered national securities exchange in the United
States.




                                      -10-

<PAGE>   1
                                                                     EXHIBIT 4.4


NEITHER THIS WARRANT, NOR THE SHARES OF COMMON STOCK FOR WHICH IT IS
EXERCISABLE, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS WARRANT HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.



                                CYTRX CORPORATION
                             STOCK PURCHASE WARRANT


         This is to certify that, the Initial Holder (as defined below) or any
successor Holder is entitled upon the due exercise hereof to purchase from CytRx
Corporation, a Delaware Corporation (the "Company") up to 500 of the authorized
but unissued shares (subject to adjustment as provided herein) of the $.001 par
value Common Stock of the Company at a price per share as specified in Section 2
of this Warrant (subject to adjustment as provided herein) and to exercise the
other rights, power and privileges hereinafter provided, all on the terms and
subject to the conditions specified herein.

         SECTION 1. Certain Definitions. Unless the context otherwise requires,
the following terms as used in this Warrant shall have the following meanings:

                  "Affiliate" shall mean any partnership or corporation
controlled by or under common control with the Initial Holder.

                  "Common Stock" shall mean the Company's $.001 par value per
share Common Stock or any stock into which such stock shall have been changed or
any stock resulting from reclassification of such stock.

                  "Company" shall mean CytRx Corporation, a Delaware
corporation, and its successors and assigns.


<PAGE>   2

                  "Exercise Date" has the meaning set forth in Section 3 hereof.

                  "Exercise Price" shall mean the price specified in Section 2
hereof, as the same shall be adjusted from time to time pursuant to the
provisions of this Warrant.

                  "Fair Market Value" shall mean (i) the last sales price for a
share of Common Stock as officially reported on the principal national
securities exchange or domestic over-the-counter market on which the Common
Stock is at the time listed or traded at the time of determination of such Fair
Market Value or (ii) if such Common Stock is not at such time listed on a
national securities exchange or quoted in the domestic over-the-counter market,
the fair market value as determined by the Board of Directors of the Company in
good faith after review of all relevant factors.

                  "Holder" or "Warrant Holder" shall mean the Initial Holder and
his successors and registered assigns of this Warrant.

                  "Initial Holder" shall mean Charles N. Eckert, his successors
and affiliates.

                  "Subscription Agreement" shall mean that certain Private
Securities Subscription Agreement dated as of October 22, 1997 relating to the
purchase of certain debentures convertible into shares of Common Stock as the
same may be amended and modified from time to time, and "Debenture" shall mean
any of the debentures issued thereunder.

                  "Warrant" means this Warrant dated as of October 22, 1997
issued to Initial Holder hereby and all warrants issued upon the transfer or
division of or in substitution for such Warrant.

         SECTION 2. Exercise Price. The Exercise Price per share shall be $5.68
per share of the Common Stock. The Exercise Price shall be paid in cash.

         SECTION 3. Exercise. Prior to the later of the second anniversary of
the date hereof (the "Expiration Date"), this Warrant may be exercised by the
Holder, as to all or less than all of the shares of Common Stock covered hereby,
by surrender of this Warrant at the Company's principal office (for all purposes
of this Warrant, 154 Technology Parkway, Norcross, Georgia 30092 or such other
address as the Company may advise the registered Holder hereof by notice given
by certified or registered mail) with the form of election to subscribe attached
hereto as Exhibit A duly executed and upon tender of payment to the Company of
the Exercise Price for shares so purchased in cash or by check. Upon the date of
such receipt by the Company (herein called the "Exercise Date"), this Warrant
shall be deemed to have been exercised and the person exercising the same shall
become a holder of record of shares of Common Stock (or of the other securities
or property to which he or it is entitled upon such exercise) purchased
hereunder for all purposes, and certificates for such shares so purchased shall
be delivered to the Holder or 




                                      -2-
<PAGE>   3

its transferee within a reasonable time (not exceeding 10 days) after this
Warrant shall have been exercised as set forth hereinabove. In the event that
this Warrant is exercised in part, the Company will execute and deliver a new
Warrant of like tenor exerciseable for the number of shares for which this
Warrant may then be exercised. If this Warrant is not exercised on or prior to
the Expiration Date, this Warrant shall become void and all rights of the Holder
hereunder shall cease.

         SECTION 4. Taxes. The Company shall pay all expenses in connection
with, and all taxes and other governmental charges that may be imposed with
respect to the issue or delivery of the shares of Common Stock covered hereby
unless such tax or charge is imposed by law upon the Holder, in which case such
taxes or charges shall be paid by the Holder. The Company shall not be required,
however, to pay any tax or other charge imposed in connection with any transfer
involved in the issue of any certificate for shares of Common Stock issuable
upon exercise of this Warrant in any name other than that of the Holder, and in
such case the Company shall not be required to issue or deliver any stock
certificate until such tax or the charge has been paid or it has been
established to the satisfaction of the Company that no such tax or other charge
is due.

         SECTION 5. Warrant Register. The Company shall at all times while any
portion of this Warrant remains outstanding and exercisable keep and maintain at
its principal office a register (the "Warrant Register") in which the
registration, transfer and exchange of this Warrant shall be recorded. The
Warrant Register shall contain the names and addresses of the Holder or Holders.
Any Holder of this Warrant or any portion thereof may change his or her address
as shown on the Warrant Register by written notice to the Company requesting
such change. Any notice or written communication required or permitted to be
given to the Holder may be delivered or given by mail to such Holder as shown on
the Warrant Register and at the address shown on the Warrant Register. The
Company shall not at any time, except upon the dissolution, liquidation or
winding up of the Company, close such register so as to result in preventing or
delaying the exercise or transfer of this Warrant. If at any time, the Company
shall appoint an agent (the "Warrant Agent") to maintain such register, the
Company shall promptly give notice by certified or registered mail to the
registered Holder hereof of the name of such Warrant Agent and of the place or
places at which this Warrant may be presented for transfer, exchange or
exercise. The terms of the agreement between the Company and any Warrant Agent
at any time in effect will be in conformity with the terms of this Warrant.

         SECTION 6. Transfer. The Company shall register the transfer of any
Warrant upon records to be maintained by the Company for that purpose, upon
surrender of this Warrant, with the form of transfer authorization attached
hereto as Exhibit B duly filled in and signed, to the Company at the office
specified herein. Upon any such registration of transfer, a new Warrant, in
substantially the form of this Warrant, evidencing the Warrant rights so
transferred, shall be issued to the transferee and a new Warrant, in similar
form, evidencing the remaining Warrant rights not so transferred, if any, shall
be issued to the then registered Holder thereof. The Holder understands that
this Warrant has not been and will not be registered under the Securities Act of
1933, as amended (the "Securities 



                                      -3-
<PAGE>   4


Act") and that the Warrant and the shares of Common Stock issuable upon exercise
hereof may not be sold, assigned, transferred, pledged or otherwise encumbered
or disposed of in the absence of an effective registration statement under the
Securities Act, relating to such Warrant or shares; provided, however that this
Warrant and the shares of Common Stock issuable upon exercise hereof may be
sold, assigned, transferred, pledged or otherwise encumbered or disposed of if
the holder obtains a written opinion of counsel acceptable to the Company to the
effect that the proposed sale, assignment, transfer, pledge or other encumbrance
or disposition is exempt from registration under the Securities Act.

         SECTION 7.  Exchange. This Warrant is exchangeable, upon the surrender
hereof by the Holder at the principal offices of the Company, together with the
form of transfer authorization attached hereto duly executed, for new warrants
of like tenor and date, in such denominations as the Holder shall designate at
the time of surrender for exchange, representing in the aggregate the right to
subscribe for and purchase the number of shares which may be subscribed for and
purchased hereunder.

         SECTION 8.  Covenants of the Company.

                  (a) The Company covenants and agrees that all shares which may
be issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be fully paid and nonassessable, free from preemptive rights, and free
from all taxes, liens, encumbrances and charges with respect to the issue
thereof (other than taxes in respect of any transfer occurring contemporaneously
with such issue). The Company further covenants and agrees that during the
period within which the rights represented by this Warrant may be exercised, the
Company will at all times have authorized and reserved a sufficient number of
shares of Common Stock to provide for the exercise in full of the rights
represented by this Warrant.

                  (b) As long as the Warrant remains outstanding, the Company
shall maintain an office or agency (which may be the principal executive office
of the Company) where the Warrant may be presented for exercise, registration of
transfer, exchange, division or combination as provided in this Warrant.

         SECTION 9.  Adjustments for Stock Splits and Subdivisions.

                  (a) In the event the Company should at any time or from time
to time after the date of issuance hereof fix a record date for the effectuation
of a split or subdivision of the outstanding shares of Common Stock or the
determination of holders of Common Stock entitled to receive a dividend or other
distribution payable in additional shares of Common Stock or other securities or
rights convertible into, or entitling the holder thereof to receive directly or
indirectly, additional shares of Common Stock (hereinafter referred to as
"Common Stock Equivalents") without payment of any consideration by such holder
for the additional shares of Common Stock or the Common Stock Equivalents
(including the additional shares of Common Stock issuable upon conversion or
exercise thereof), then, as of such record date (or the date of such dividend



                                      -4-
<PAGE>   5

distribution, split or subdivision if no record date is fixed), the Exercise
Price of this Warrant shall be appropriately decreased so that the number of
shares of Common Stock issuable upon exercise of this Warrant shall be.
increased in proportion to such increase of outstanding shares.

                  (b) If the number of shares of Common Stock outstanding at any
time after the date hereof is decreased by a combination of the outstanding
shares of Common Stock, then, following the record date of such combination, the
Exercise Price for this Warrant shall be appropriately increased so that the
number of shares of Common Stock issuable on exercise hereof shall be decreased
in proportion to such decrease in outstanding shares.

         SECTION 10. Holder's Rights. This Warrant shall not entitle the Holder
to any rights of a stockholder of the Company, except that should the Company,
during the period in which this Warrant is exercisable, declare a dividend upon
the Common Stock payable other than in cash out of earnings or surplus (computed
in accordance with generally accepted accounting principles consistently
applied) or other than in Common Stock or securities convertible into Common
Stock, then, thereafter, the Warrant Holder, upon exercise of this Warrant,
shall receive the number of shares of Common Stock purchasable upon such
exercise and, in addition and without further payment, the cash, stock or other
securities and/or other property which the Warrant Holder would have received by
way of dividends (otherwise than in cash out of earnings or earned surplus or in
Common Stock or securities convertible into Common Stock) and/or any other
distributions in respect of the Common Stock as if, continuously since the date
hereof, such Warrant Holder (a) had been the record holder of the number of
shares of Common Stock then being purchased, and (b) had retained all such cash,
stock and other securities (other than dividends in cash out of earnings or
earned surplus or in Common Stock or securities convertible into Common Stock)
and/or other property payable in respect of such Common Stock or in respect of
any stock or securities paid as dividends and originating directly or indirectly
from such Common Stock.

         SECTION 11. Notice of Adjustments. If there shall be any adjustment as
provided in Section 9, the Company shall forthwith cause written notice thereof
to be sent by facsimile, overnight or registered mail, postage prepaid, to the
registered Holder of this Warrant at the address of such Holder shown on the
books of the Company. At the request of Holder and upon surrender of this
Warrant, the Company shall reissue this Warrant in a form conforming to such
adjustments.

         SECTION 12. Cash in Lieu of Fractional Shares. The Company shall not be
required to issue fractional shares upon the exercise of this Warrant. If, by
reason of any change made pursuant to Section 9 or 10 hereof, the Holder of this
Warrant would be entitled, upon the exercise of any rights evidenced hereby, to
receive a fractional interest in a share, the Company shall, upon such exercise,
purchase such fractional interest for an amount in cash equal to the fair market
value of such fractional interest, determined as of the Exercise Date.



                                      -5-
<PAGE>   6

         SECTION 13. Lost, Stolen, Mutilated or Destroyed Warrants. If this
Warrant shall be mutilated, lost, stolen or destroyed, upon request by the
registered Holder of the Warrant, the Company will issue, in exchange for and
upon cancellation of the mutilated Warrant, or in substitution for the lost,
stolen or destroyed Warrant, a new Warrant, in substantially the form of this
Warrant, of like tenor and representing the right to purchase the equivalent
number of the remaining shares of Common Stock issuable upon exercise hereof,
but, in the case of loss, theft or destruction, only upon receipt of evidence
satisfactory to the Company of such loss, theft or destruction of this Warrant
and, if requested by the Company, an indemnification also satisfactory to it (it
being understood that the written agreement of the initial Holder shall be
sufficient indemnity), provided, in the case of mutilation, no indemnity shall
be required if this Warrant in identifiable form is surrendered to the Company
for cancellation.

         SECTION 14. Challenge to Good Faith Determination. Whenever the Board
shall be required to make a determination in good faith of the fair value of any
item under Section 9, such determination may be challenged in good faith by the
Holder, and any dispute shall be resolved by an investment banking firm of
recognized national standing in the United States selected by the Company and
acceptable to the Holder.

         SECTION 15. Certain Limitations. Notwithstanding anything herein to the
contrary, the Company agrees not to enter into any transaction which, by reason
of any adjustment hereunder, would cause the current Exercise Price to be less
than the par value per share of Common Stock.

         SECTION 16. Amendments. Any term of this Warrant may be amended with
the written consent of the Company and the holders of warrants representing more
than fifty percent (50%) of the outstanding warrants issued pursuant to the
Subscription Agreement, even without the consent of the Holder. Any amendment
effected in accordance with this Section 16 shall be binding upon each holder or
any the warrants issued pursuant to the Subscription Agreement, each future
holder of such warrants, and the Company; provided, however, that no special
consideration or inducement may be give to any such holder in connection with
such consent that is not given ratably to all such holders, and that such
amendment must apply to all such holders equally and ratably in accordance with
the number of shares of Common Stock issuable upon exercise of their warrants.
The Company shall promptly give notice to all holders of warrants issued
pursuant to the Subscription Agreement of any amendment effected in accordance
with this Section 16. No waivers of, or exceptions to, any term, condition, or
provision of this Warrant, in any one or more instances, shall be deemed to be,
or construed as, a further or continuing waiver of any such term, condition, or
provision.

         SECTION 17. No Impairment. The Company represents and warrants that
there are no restrictions in the Company's Certificate of Incorporation or
Bylaws which prevent it from satisfying its obligation to issue the shares of
Common Stock issuable upon exercise of the Warrant. The Company shall not by any
action including, without




                                      -6-
<PAGE>   7

limitation, amending its Certificate of Incorporation or Bylaws, or through any
reorganization, transfer of assets, consolidation, merger, dissolution, issue or
sale of securities or any other voluntary action, avoid or seek to avoid the
observance or performance of any of the terms of this Warrant, and will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such actions as may be necessary or appropriate to protect the
rights of the Holder against impairment.

         SECTION 18. Applicable Law; Payments. The validity, interpretation and
performance of this Warrant shall be governed by the laws of the State of
Delaware. All payments shall be in U.S. Dollars by immediately available funds.

         SECTION 19. Successors and Assigns. This Warrant and the rights
evidenced hereby shall inure to the benefit of and be binding upon the
successors and assigns of the Company and the Holder.

         SECTION 20. Headings. Headings of the paragraphs in this Warrant are
for convenience and reference only and shall not, for any purpose, be deemed a
part of this Warrant.

         SECTION 21. Arbitration. All disputes arising under this Agreement
(other than claims in equity) shall be resolved by arbitration in accordance
with the Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.



                                      -7-
<PAGE>   8



         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed under seal by its duly authorized officer this 22 day of October,
1997.


                                CYTRX CORPORATION



                                By:
                                   --------------------------------
                                Name:
                                     ------------------------------
                                Title:
                                      -----------------------------

CHARLES N. ECKERT


- -------------------------



                                      -8-
<PAGE>   9



                                    EXHIBIT A

                              FORM OF SUBSCRIPTION


         The undersigned, registered holder or assignee of such registered
holder of the within Warrant, hereby (1) subscribes for _________________ shares
(subject to adjustment as provided herein) which the undersigned is entitled to
purchase under the terms of the within Warrant, (2) makes the full cash payment
called for by the within Warrant, and (3) directs that the shares issuable upon
exercise of said Warrant be issued as follows:


                                     Name:
                                          -------------------------------



                                     By:
                                        ---------------------------------
                                     Title:
                                           ------------------------------



Date:
     -----------------------------

- ----------------------------------



NOTICE: The name and signature on this subscription form must correspond with
the name as written upon the face of the within Warrant, or upon the assignment
form on the reverse thereof, in every particular, without alteration or
enlargement and must be guaranteed by a bank or by a firm having membership on a
registered national securities exchange in the United States.




                                      -9-
<PAGE>   10



                                    EXHIBIT B

                               FORM OF ASSIGNMENT


FOR VALUE RECEIVED __________________________ hereby sells, assigns, and
transfers unto __________________, of _________________, the right to purchase
___________ shares (subject to adjustment as provided herein) evidenced by the
within Warrant, and hereby irrevocably constitutes and appoints
__________________ to transfer such right on the books of the Company, with full
power of substitution.

Date:________________, 19___

                                  Name:
                                       ----------------------------------


                                  By:
                                     ------------------------------------
                                  Title:
                                        ---------------------------------




Date:
     -----------------------------

- ----------------------------------




NOTICE: The name and signature on this assignment must correspond with the name
as written upon the face of the within Warrant, or upon any assignment form duly
executed pursuant to the terms of the within Warrant, in every particular,
without alteration or enlargement and must be guaranteed by a bank, or by a firm
having membership on a registered national securities exchange in the United
States.




                                      -10-

<PAGE>   1
                                                                     EXHIBIT 4.5



NEITHER THIS WARRANT, NOR THE SHARES OF COMMON STOCK FOR WHICH IT IS
EXERCISABLE, HAVE BEEN REGISTERED FOR SALE UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, ANY APPLICABLE SECURITIES LAWS OF THE STATE OF DELAWARE, OR OTHER
APPLICABLE SECURITIES LAWS AND THIS WARRANT HAS BEEN ISSUED IN RELIANCE UPON
EXEMPTIONS CONTAINED IN SUCH LAWS FOR TRANSACTIONS NOT INVOLVING ANY PUBLIC
OFFERING INCLUDING, BUT NOT LIMITED TO, SECTION 7309(B)(8) OF THE DELAWARE
SECURITIES ACT. THIS WARRANT HAS BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE
SOLD, TRANSFERRED, HYPOTHECATED, PLEDGED OR DISPOSED OF IN ANY MANNER IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SUCH LAWS COVERING SUCH
TRANSACTION OR, IN THE ABSENCE THEREOF, AN OPINION OF COUNSEL SATISFACTORY TO
THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED AND ALL CONDITIONS NECESSARY
FOR THE AVAILABILITY OF ANY EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS HAVE
BEEN SATISFIED.



                                CYTRX CORPORATION
                             STOCK PURCHASE WARRANT


         This is to certify that, the Initial Holder (as defined below) or any
successor Holder is entitled upon the due exercise hereof to purchase from CytRx
Corporation, a Delaware Corporation (the "Company") up to 500 of the authorized
but unissued shares (subject to adjustment as provided herein) of the $.001 par
value Common Stock of the Company at a price per share as specified in Section 2
of this Warrant (subject to adjustment as provided herein) and to exercise the
other rights, power and privileges hereinafter provided, all on the terms and
subject to the conditions specified herein.

         SECTION 1. Certain Definitions. Unless the context otherwise requires,
the following terms as used in this Warrant shall have the following meanings:

                  "Affiliate" shall mean any partnership or corporation
controlled by or under common control with the Initial Holder.

                  "Common Stock" shall mean the Company's $.001 par value per
share Common Stock or any stock into which such stock shall have been changed or
any stock resulting from reclassification of such stock.

                  "Company" shall mean CytRx Corporation, a Delaware
corporation, and its successors and assigns.


<PAGE>   2

                  "Exercise Date" has the meaning set forth in Section 3 hereof.

                  "Exercise Price" shall mean the price specified in Section 2
hereof, as the same shall be adjusted from time to time pursuant to the
provisions of this Warrant.

                  "Fair Market Value" shall mean (i) the last sales price for a
share of Common Stock as officially reported on the principal national
securities exchange or domestic over-the-counter market on which the Common
Stock is at the time listed or traded at the time of determination of such Fair
Market Value or (ii) if such Common Stock is not at such time listed on a
national securities exchange or quoted in the domestic over-the-counter market,
the fair market value as determined by the Board of Directors of the Company in
good faith after review of all relevant factors.

                  "Holder" or "Warrant Holder" shall mean the Initial Holder and
his successors and registered assigns of this Warrant.

                  "Initial Holder" shall mean David Roskoff, his successors and
affiliates.

                  "Subscription Agreement" shall mean that certain Private
Securities Subscription Agreement dated as of October 22, 1997 relating to the
purchase of certain debentures convertible into shares of Common Stock as the
same may be amended and modified from time to time, and "Debenture" shall mean
any of the debentures issued thereunder.

                  "Warrant" means this Warrant dated as of October 22, 1997
issued to Initial Holder hereby and all warrants issued upon the transfer or
division of or in substitution for such Warrant.

         SECTION 2. Exercise Price. The Exercise Price per share shall be $5.68
per share of the Common Stock. The Exercise Price shall be paid in cash.

         SECTION 3. Exercise. Prior to the later of the second anniversary of
the date hereof (the "Expiration Date"), this Warrant may be exercised by the
Holder, as to all or less than all of the shares of Common Stock covered hereby,
by surrender of this Warrant at the Company's principal office (for all purposes
of this Warrant, 154 Technology Parkway, Norcross, Georgia 30092 or such other
address as the Company may advise the registered Holder hereof by notice given
by certified or registered mail) with the form of election to subscribe attached
hereto as Exhibit A duly executed and upon tender of payment to the Company of
the Exercise Price for shares so purchased in cash or by check. Upon the date of
such receipt by the Company (herein called the "Exercise Date"), this Warrant
shall be deemed to have been exercised and the person exercising the same shall
become a holder of record of shares of Common Stock (or of the other securities
or property to which he or it is entitled upon such exercise) purchased
hereunder for all purposes, and certificates for such shares so purchased shall
be delivered to the Holder or 



                                      -2-
<PAGE>   3


its transferee within a reasonable time (not exceeding 10 days) after this
Warrant shall have been exercised as set forth hereinabove. In the event that
this Warrant is exercised in part, the Company will execute and deliver a new
Warrant of like tenor exerciseable for the number of shares for which this
Warrant may then be exercised. If this Warrant is not exercised on or prior to
the Expiration Date, this Warrant shall become void and all rights of the Holder
hereunder shall cease.

         SECTION 4. Taxes. The Company shall pay all expenses in connection
with, and all taxes and other governmental charges that may be imposed with
respect to the issue or delivery of the shares of Common Stock covered hereby
unless such tax or charge is imposed by law upon the Holder, in which case such
taxes or charges shall be paid by the Holder. The Company shall not be required,
however, to pay any tax or other charge imposed in connection with any transfer
involved in the issue of any certificate for shares of Common Stock issuable
upon exercise of this Warrant in any name other than that of the Holder, and in
such case the Company shall not be required to issue or deliver any stock
certificate until such tax or the charge has been paid or it has been
established to the satisfaction of the Company that no such tax or other charge
is due.

         SECTION 5. Warrant Register. The Company shall at all times while any
portion of this Warrant remains outstanding and exercisable keep and maintain at
its principal office a register (the "Warrant Register") in which the
registration, transfer and exchange of this Warrant shall be recorded. The
Warrant Register shall contain the names and addresses of the Holder or Holders.
Any Holder of this Warrant or any portion thereof may change his or her address
as shown on the Warrant Register by written notice to the Company requesting
such change. Any notice or written communication required or permitted to be
given to the Holder may be delivered or given by mail to such Holder as shown on
the Warrant Register and at the address shown on the Warrant Register. The
Company shall not at any time, except upon the dissolution, liquidation or
winding up of the Company, close such register so as to result in preventing or
delaying the exercise or transfer of this Warrant. If at any time, the Company
shall appoint an agent (the "Warrant Agent") to maintain such register, the
Company shall promptly give notice by certified or registered mail to the
registered Holder hereof of the name of such Warrant Agent and of the place or
places at which this Warrant may be presented for transfer, exchange or
exercise. The terms of the agreement between the Company and any Warrant Agent
at any time in effect will be in conformity with the terms of this Warrant.

         SECTION 6. Transfer. The Company shall register the transfer of any
Warrant upon records to be maintained by the Company for that purpose, upon
surrender of this Warrant, with the form of transfer authorization attached
hereto as Exhibit B duly filled in and signed, to the Company at the office
specified herein. Upon any such registration of transfer, a new Warrant, in
substantially the form of this Warrant, evidencing the Warrant rights so
transferred, shall be issued to the transferee and a new Warrant, in similar
form, evidencing the remaining Warrant rights not so transferred, if any, shall
be issued to the then registered Holder thereof. The Holder understands that
this Warrant has not been and will not be registered under the Securities Act of
1933, as amended (the "Securities 



                                      -3-
<PAGE>   4

Act") and that the Warrant and the shares of Common Stock issuable upon exercise
hereof may not be sold, assigned, transferred, pledged or otherwise encumbered
or disposed of in the absence of an effective registration statement under the
Securities Act, relating to such Warrant or shares; provided, however that this
Warrant and the shares of Common Stock issuable upon exercise hereof may be
sold, assigned, transferred, pledged or otherwise encumbered or disposed of if
the holder obtains a written opinion of counsel acceptable to the Company to the
effect that the proposed sale, assignment, transfer, pledge or other encumbrance
or disposition is exempt from registration under the Securities Act.

         SECTION 7.  Exchange. This Warrant is exchangeable, upon the surrender
hereof by the Holder at the principal offices of the Company, together with the
form of transfer authorization attached hereto duly executed, for new warrants
of like tenor and date, in such denominations as the Holder shall designate at
the time of surrender for exchange, representing in the aggregate the right to
subscribe for and purchase the number of shares which may be subscribed for and
purchased hereunder.

         SECTION 8.  Covenants of the Company.

                  (a) The Company covenants and agrees that all shares which may
be issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be fully paid and nonassessable, free from preemptive rights, and free
from all taxes, liens, encumbrances and charges with respect to the issue
thereof (other than taxes in respect of any transfer occurring contemporaneously
with such issue). The Company further covenants and agrees that during the
period within which the rights represented by this Warrant may be exercised, the
Company will at all times have authorized and reserved a sufficient number of
shares of Common Stock to provide for the exercise in full of the rights
represented by this Warrant.

                  (b) As long as the Warrant remains outstanding, the Company
shall maintain an office or agency (which may be the principal executive office
of the Company) where the Warrant may be presented for exercise, registration of
transfer, exchange, division or combination as provided in this Warrant.

         SECTION 9.  Adjustments for Stock Splits and Subdivisions.

                  (a) In the event the Company should at any time or from time
to time after the date of issuance hereof fix a record date for the effectuation
of a split or subdivision of the outstanding shares of Common Stock or the
determination of holders of Common Stock entitled to receive a dividend or other
distribution payable in additional shares of Common Stock or other securities or
rights convertible into, or entitling the holder thereof to receive directly or
indirectly, additional shares of Common Stock (hereinafter referred to as
"Common Stock Equivalents") without payment of any consideration by such holder
for the additional shares of Common Stock or the Common Stock Equivalents
(including the additional shares of Common Stock issuable upon conversion or
exercise thereof), then, as of such record date (or the date of such dividend




                                      -4-
<PAGE>   5

distribution, split or subdivision if no record date is fixed), the Exercise
Price of this Warrant shall be appropriately decreased so that the number of
shares of Common Stock issuable upon exercise of this Warrant shall be.
increased in proportion to such increase of outstanding shares.

                  (b) If the number of shares of Common Stock outstanding at any
time after the date hereof is decreased by a combination of the outstanding
shares of Common Stock, then, following the record date of such combination, the
Exercise Price for this Warrant shall be appropriately increased so that the
number of shares of Common Stock issuable on exercise hereof shall be decreased
in proportion to such decrease in outstanding shares.

         SECTION 10. Holder's Rights. This Warrant shall not entitle the Holder
to any rights of a stockholder of the Company, except that should the Company,
during the period in which this Warrant is exercisable, declare a dividend upon
the Common Stock payable other than in cash out of earnings or surplus (computed
in accordance with generally accepted accounting principles consistently
applied) or other than in Common Stock or securities convertible into Common
Stock, then, thereafter, the Warrant Holder, upon exercise of this Warrant,
shall receive the number of shares of Common Stock purchasable upon such
exercise and, in addition and without further payment, the cash, stock or other
securities and/or other property which the Warrant Holder would have received by
way of dividends (otherwise than in cash out of earnings or earned surplus or in
Common Stock or securities convertible into Common Stock) and/or any other
distributions in respect of the Common Stock as if, continuously since the date
hereof, such Warrant Holder (a) had been the record holder of the number of
shares of Common Stock then being purchased, and (b) had retained all such cash,
stock and other securities (other than dividends in cash out of earnings or
earned surplus or in Common Stock or securities convertible into Common Stock)
and/or other property payable in respect of such Common Stock or in respect of
any stock or securities paid as dividends and originating directly or indirectly
from such Common Stock.

         SECTION 11. Notice of Adjustments. If there shall be any adjustment as
provided in Section 9, the Company shall forthwith cause written notice thereof
to be sent by facsimile, overnight or registered mail, postage prepaid, to the
registered Holder of this Warrant at the address of such Holder shown on the
books of the Company. At the request of Holder and upon surrender of this
Warrant, the Company shall reissue this Warrant in a form conforming to such
adjustments.

         SECTION 12. Cash in Lieu of Fractional Shares. The Company shall not be
required to issue fractional shares upon the exercise of this Warrant. If, by
reason of any change made pursuant to Section 9 or 10 hereof, the Holder of this
Warrant would be entitled, upon the exercise of any rights evidenced hereby, to
receive a fractional interest in a share, the Company shall, upon such exercise,
purchase such fractional interest for an amount in cash equal to the fair market
value of such fractional interest, determined as of the Exercise Date.



                                      -5-
<PAGE>   6

         SECTION 13. Lost, Stolen, Mutilated or Destroyed Warrants. If this
Warrant shall be mutilated, lost, stolen or destroyed, upon request by the
registered Holder of the Warrant, the Company will issue, in exchange for and
upon cancellation of the mutilated Warrant, or in substitution for the lost,
stolen or destroyed Warrant, a new Warrant, in substantially the form of this
Warrant, of like tenor and representing the right to purchase the equivalent
number of the remaining shares of Common Stock issuable upon exercise hereof,
but, in the case of loss, theft or destruction, only upon receipt of evidence
satisfactory to the Company of such loss, theft or destruction of this Warrant
and, if requested by the Company, an indemnification also satisfactory to it (it
being understood that the written agreement of the initial Holder shall be
sufficient indemnity), provided, in the case of mutilation, no indemnity shall
be required if this Warrant in identifiable form is surrendered to the Company
for cancellation.

         SECTION 14. Challenge to Good Faith Determination. Whenever the Board
shall be required to make a determination in good faith of the fair value of any
item under Section 9, such determination may be challenged in good faith by the
Holder, and any dispute shall be resolved by an investment banking firm of
recognized national standing in the United States selected by the Company and
acceptable to the Holder.

         SECTION 15. Certain Limitations. Notwithstanding anything herein to the
contrary, the Company agrees not to enter into any transaction which, by reason
of any adjustment hereunder, would cause the current Exercise Price to be less
than the par value per share of Common Stock.

         SECTION 16. Amendments. Any term of this Warrant may be amended with
the written consent of the Company and the holders of warrants representing more
than fifty percent (50%) of the outstanding warrants issued pursuant to the
Subscription Agreement, even without the consent of the Holder. Any amendment
effected in accordance with this Section 16 shall be binding upon each holder or
any the warrants issued pursuant to the Subscription Agreement, each future
holder of such warrants, and the Company; provided, however, that no special
consideration or inducement may be give to any such holder in connection with
such consent that is not given ratably to all such holders, and that such
amendment must apply to all such holders equally and ratably in accordance with
the number of shares of Common Stock issuable upon exercise of their warrants.
The Company shall promptly give notice to all holders of warrants issued
pursuant to the Subscription Agreement of any amendment effected in accordance
with this Section 16. No waivers of, or exceptions to, any term, condition, or
provision of this Warrant, in any one or more instances, shall be deemed to be,
or construed as, a further or continuing waiver of any such term, condition, or
provision.

         SECTION 17. No Impairment. The Company represents and warrants that
there are no restrictions in the Company's Certificate of Incorporation or
Bylaws which prevent it from satisfying its obligation to issue the shares of
Common Stock issuable upon exercise of the Warrant. The Company shall not by any
action including, without 




                                      -6-
<PAGE>   7

limitation, amending its Certificate of Incorporation or Bylaws, or through any
reorganization, transfer of assets, consolidation, merger, dissolution, issue or
sale of securities or any other voluntary action, avoid or seek to avoid the
observance or performance of any of the terms of this Warrant, and will at all
times in good faith assist in the carrying out of all such terms and in the
taking of all such actions as may be necessary or appropriate to protect the
rights of the Holder against impairment.

         SECTION 18. Applicable Law; Payments. The validity, interpretation and
performance of this Warrant shall be governed by the laws of the State of
Delaware. All payments shall be in U.S. Dollars by immediately available funds.

         SECTION 19. Successors and Assigns. This Warrant and the rights
evidenced hereby shall inure to the benefit of and be binding upon the
successors and assigns of the Company and the Holder.

         SECTION 20. Headings. Headings of the paragraphs in this Warrant are
for convenience and reference only and shall not, for any purpose, be deemed a
part of this Warrant.

         SECTION 21. Arbitration. All disputes arising under this Agreement
(other than claims in equity) shall be resolved by arbitration in accordance
with the Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Holder in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Holder and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Holder in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Holder as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.



                                      -7-
<PAGE>   8


         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed under seal by its duly authorized officer this 22 day of October,
1997.


                                CYTRX CORPORATION



                                By:
                                   ----------------------------------
                                Name:
                                     --------------------------------
                                Title:
                                      -------------------------------

DAVID KOSLOFF


- -----------------------



                                      -8-
<PAGE>   9


                                    EXHIBIT A

                              FORM OF SUBSCRIPTION


         The undersigned, registered holder or assignee of such registered
holder of the within Warrant, hereby (1) subscribes for _________________ shares
(subject to adjustment as provided herein) which the undersigned is entitled to
purchase under the terms of the within Warrant, (2) makes the full cash payment
called for by the within Warrant, and (3) directs that the shares issuable upon
exercise of said Warrant be issued as follows:


                                       Name:
                                            ---------------------------------


                                       By:
                                          -----------------------------------
                                       Title:
                                             --------------------------------



Date:
     ---------------------------

- --------------------------------



NOTICE: The name and signature on this subscription form must correspond with
the name as written upon the face of the within Warrant, or upon the assignment
form on the reverse thereof, in every particular, without alteration or
enlargement and must be guaranteed by a bank or by a firm having membership on a
registered national securities exchange in the United States.




                                      -9-
<PAGE>   10


                                    EXHIBIT B

                               FORM OF ASSIGNMENT


FOR VALUE RECEIVED __________________________ hereby sells, assigns, and
transfers unto __________________, of _________________, the right to purchase
___________ shares (subject to adjustment as provided herein) evidenced by the
within Warrant, and hereby irrevocably constitutes and appoints
__________________ to transfer such right on the books of the Company, with full
power of substitution.

Date:________________, 19___

                                       Name:
                                            ---------------------------------

                                       By:
                                          -----------------------------------
                                       Title:
                                            ---------------------------------




Date:
     -----------------------------

- ----------------------------------




NOTICE: The name and signature on this assignment must correspond with the name
as written upon the face of the within Warrant, or upon any assignment form duly
executed pursuant to the terms of the within Warrant, in every particular,
without alteration or enlargement and must be guaranteed by a bank, or by a firm
having membership on a registered national securities exchange in the United
States.




                                      -10-

<PAGE>   1
                                                                     EXHIBIT 5.1


                          REGISTRATION RIGHTS AGREEMENT


       THIS REGISTRATION RIGHTS AGREEMENT (this "Agreement") is made and entered
into as of October 22, 1997, by and among CytRx Corporation, a Delaware
corporation (the "Company"), and GUNDYCO in trust for R.R.S.P. 550-98866-19,
Excalibur Limited Partnership, Pine Street Asset Management, Charles N. Eckert
and David Kosloff (each, an "Investor" and collectively, the "Investors").

                                   BACKGROUND

       A. Pursuant to the terms of a Private Securities Subscription Agreement,
dated as of October 22, 1997 (as the same may be amended, the "Subscription
Agreement"), by and among the Company and the Investors, the Investors shall
purchase the $2,000,000 aggregate principal amount of 6% Convertible Debentures
Due _____________ of the Company (together with up to $2,000,000 additional
principal amount of such Debentures, if and to the extent the Company exercises
its option to issue such additional amounts of such Convertible Debentures, the
"Debentures"), which may be converted into shares of the $.001 par value per
share common stock of the Company (the "Common Stock").

       B. Pursuant to the Subscription Agreement, the Investors shall acquire
warrants to purchase up to _________ shares of the Common Stock (the
"Warrants").

       C. The Company has agreed to issue to Shipley, Raidy Capital Partners,
L.P. (the "Placement Agent") 3,000 shares of the Common Stock as a placement fee
in accordance with the engagement letter dated September 30, 1997, between the
Company and the Placement Agent (the "Engagement Letter").

       D. The Company has agreed, as a condition precedent to Investor's
obligations under the Subscription Agreement, to grant the Investors certain
registration rights.

       E. The Company and the Investors desire to define such registration
rights on the terms and subject to the conditions herein set forth.

                                    AGREEMENT

       In consideration of the foregoing premises and for other good and
valuable consideration, the parties hereby agree as follows:

       1.     DEFINITIONS

       As used in this Agreement, the following terms have the respective
meanings set forth below:


<PAGE>   2

       Commission: shall mean the Securities and Exchange Commission or any
other federal agency at the time administering the Securities Act;

       Effective Date: shall mean the Closing Date, as defined by the
Subscription Agreement;

       Exchange Act:  shall mean the Securities Exchange Act of 1934, as 
amended;

       Holder:  shall mean any holder of Registrable Securities;

       Initiating Holder: shall mean any Holder or Holders who in the aggregate
are Holders of more than 50% of the then outstanding Registrable Securities;

       Person: shall mean an individual, partnership, joint stock company,
corporation, trust or unincorporated organization, and a government or agency or
political subdivision thereof;

       register, registered and registration: shall mean a registration effected
by preparing and filing a registration statement in compliance with the
Securities Act (and any post-effective amendments filed or required to be filed)
and the declaration or ordering of effectiveness of such registration statement;

       Registrable Securities: shall mean (A) the shares of Common Stock into
which the Debentures are convertible, or for which the Warrants are exercisable,
(B) any securities of the Company issued as a dividend or other distribution
with respect to, or in exchange for or in replacement of, the shares of Common
Stock referred to in clause (A), and (C) the shares of Common Stock issued to
the Placement Agent pursuant to the Engagement Letter; provided, that
Registrable Securities shall not include (i) securities with respect to which a
registration statement with respect to the sale of such securities has become
effective under the Securities Act and all such securities have been disposed of
in accordance with such registration statement, (ii) such securities as may be
sold pursuant to Rule 144 (or any successor provision thereto) under the
Securities Act ("Rule 144"), (iii) such securities as are acquired by the
Company or any of its subsidiaries or (iv) Common Stock into which Debentures
are convertible or for which Warrants are exercisable, if such Debentures have
not been converted or such Warrants exercised, and such Debentures or Warrants
cease to be outstanding;

       Registration Expenses: shall mean all expenses incurred by the Company in
compliance with Sections 3(a), (b) and (c) hereof, including, without
limitation, all registration and filing fees, printing expenses, fees and
disbursements of counsel for the Company, fees and expenses of one counsel for
all the Holders, blue sky fees and expenses and the expense of any special
audits incident to or required by any such registration (but excluding the
compensation of regular employees of the Company, which shall be paid in any
event by the Company);

       Security, Securities: shall have the meaning set forth in Section 2(1) of
the Securities Act;

       Securities Act: shall mean the Securities Act of 1933, as amended; and




                                      -2-
<PAGE>   3

       Selling Expenses: shall mean all underwriting discounts and selling
commissions applicable to the sale of Registrable Securities and all fees and
disbursements of counsel for each of the Holders other than fees and expenses of
one counsel for all the Holders.

       2.     SHELF REGISTRATION


              (a) Within 15 days after the Effective Date, the Company shall
file a "shelf" registration statement pursuant to Rule 415 under the Securities
Act (the "Shelf Registration") with respect to the Registrable Securities to be
issued under the Subscription Agreement. The Shelf Registrations shall be on
Form S-3 under the Securities Act or such other appropriate form selected by the
Company which allows resales of Registrable Securities. The Company shall,
subject to Section 2(h) hereof, use its reasonable best efforts to cause the
Shelf Registration to become effective as soon as practicable after the filing
thereof, and shall use its reasonable best efforts to keep the Shelf
Registration continuously effective from the date such Shelf Registration is
effective until the earlier to occur of (i) the second anniversary of the
Effective Date, or (ii) the date on which all Registrable Securities may be sold
pursuant to Rule 144(k), in order to permit the prospectus forming a part
thereof to be usable by Holders during such period. The Shelf Registration may
include securities of the Company other than Registrable Securities. If the
Shelf Registration is not declared effective by the Commission on or before the
90th day after the Effective Date, then the Company shall accrue to each
Investor, as liquidated damages, an amount equal to one percent (1%) of the
principal amount of the Debentures then held by such Investor for each thirty
(30) days thereafter until the Shelf Registration is declared effective by the
Commission. The Company shall pay the liquidated damages on the first day after
they accrue (i.e., the ninety-first (91st) day and the thirty-first (31st) day
thereafter).

              (b) Subject to Section 2(i) hereof, the Company shall supplement
or amend the Shelf Registration, (i) as required by the registration form
utilized by the Company or by the instructions applicable to such registration
form or by the Securities Act or the rules and regulations promulgated
thereunder, (ii) to include in such Shelf Registration any additional securities
that become Registrable Securities by operation of the definition thereof, and
(iii) following the written request of an Initiating Holder pursuant to Section
2(c) below, to cover offers and sales of all or a part of the Registrable
Securities by means of an underwriting including the incorporation of any
information required pursuant to Section 2(e)(ix) below. The Company shall
furnish to the Holders of the Registrable Securities to which the Shelf
Registration relates copies of any such supplement or amendment sufficiently in
advance (but in no event less than five business days in advance) of its use
and/or filing with the Commission to allow the Holders a meaningful opportunity
to comment thereon.

              (c) The Holders may, at their election and upon written notice by
the Initiating Holders to the Company, effect offers and sales under the Shelf
Registration by means of one or more underwritten offerings. If the Holders
intend to distribute the Registrable Securities by means of an underwriting,
they shall so advise the Company. An underwritten registration under this
Section 2(c) may include other Securities of the Company held by Persons who, by
virtue of agreements with the Company, are entitled to include their Securities
in any such registration 




                                      -3-
<PAGE>   4

("Other Stockholders"). If Other Stockholders request inclusion in any such
registration, the Holders shall offer to include the Securities of such Other
Stockholders in the underwriting and may condition such offer on their
acceptance of the further applicable provisions of this Section 2. The Holders
whose shares are to be included in such registration and the Company shall
(together with all Other Stockholders proposing to distribute their securities
through such underwriting) enter into underwriting and related agreements in
customary form with the representative of the underwriter or underwriters
selected for such underwriting by the Company and reasonably acceptable to the
Initiating Holders. Such underwriting agreement will contain such
representations and warranties by the Company and such other terms and
provisions as are customarily contained in underwriting agreements with respect
to secondary distributions, including, without limitation, indemnities and
contribution to the effect and to the extent provided in Section 2(f) hereof and
the provision of opinions of counsel and accountants' letters to the effect and
to the extent provided in Section 2(e) hereof, and the representations and
warranties by, and the other agreements on the part of, the Company to and for
the benefit of such underwriters shall also be made to and for the benefit of
the Holders. The Company shall cooperate fully with the Holders and the
underwriters in connection with any underwritten offering. Notwithstanding any
other provision of this Section 2(c), if the representative advises the Holders
in writing that marketing factors require a limitation on the number of shares
to be underwritten, the Securities of the Company held by Other Stockholders
shall be excluded from such registration to the extend so required by such
limitation. If, after the exclusion of such shares, still further reductions are
required, the number of shares included in the registration by each Holder shall
be reduced on a pro rata basis (based on the number of shares held by such
Holder), by such minimum number of shares as is necessary to comply with such
request. No Registrable Securities or any other securities excluded from the
underwriting by reason of the underwriter's marketing limitation shall be
included in such registration. If any Other Stockholder who has requested
inclusion in such registration as provided above disapproves of the terms of the
underwriting, such person may elect to withdraw therefrom by written notice to
the Company, the underwriter and the Initiating Holders. The securities so
withdrawn shall also be withdrawn from registration. If the underwriter has not
limited the number of Registrable Securities or other securities to be
underwritten, the Company and officers and directors of the Company may include
its or their securities for its or their own account in such registration if the
representative so agrees and if the number of Registrable Securities and other
securities which would otherwise have been included in such registration and
underwriting will not thereby be limited.

              (d) Expenses of Registration. All Registration Expenses incurred
in connection with any registration, qualification or compliance pursuant to
this Section 2 shall be borne by the Company, and all Selling Expenses shall be
borne by the Holders of the securities so registered pro rata on the basis of
the number of their shares so registered.

              (e) Registration Procedures. In the case of each registration
effected by the Company pursuant to this Section 2, the Company will keep the
Holders, as applicable, advised in writing as to the initiation of each
registration and as to the completion thereof. At its expense, the Company will:




                                      -4-
<PAGE>   5

                  (i)   furnish to each Holder, and to any underwriter before
       filing with the Commission, copies of any registration statement
       (including all exhibits) and any prospectus forming a part thereof and
       any amendments and supplements thereto (including all documents
       incorporated or deemed incorporated by reference therein prior to the
       effectiveness of such registration statement and including each
       preliminary prospectus, any summary prospectus or any term sheet (as such
       term is used in Rule 434 under the Securities Act)) and any other
       prospectus filed under Rule 424 under the Securities Act, which
       documents, other than documents incorporated or deemed incorporated by
       reference, will be subject to the review of the Holders and any such
       underwriter for a period of at least five business days, and the Company
       shall not file any such registration statement or such prospectus or any
       amendment or supplement to such registration statement or prospectus to
       which any Holder or any such underwriter shall reasonably object within
       five business days after the receipt thereof; a Holder or such
       underwriters, if any, shall be deemed to have reasonably objected to such
       filing only if the registration statement, amendment, prospectus or
       supplement, as applicable, as proposed to be filed, contains a material
       misstatement or omission;

                  (ii)  furnish to each Holder and to any underwriter, such
       number of conformed copies of the applicable registration statement and
       of each amendment and supplement thereto (in each case including all
       exhibits) and such number of copies of the prospectus forming a part of
       such registration statement (including each preliminary prospectus, any
       summary prospectus or any term sheet (as such term is used in Rule 434
       under the Securities Act)) and any other prospectus filed under Rule 424
       under the Securities Act, in conformity with the requirements of the
       Securities Act, and such other documents, including without limitation
       documents incorporated or deemed to be incorporated by reference prior to
       the effectiveness of such registration, as each of the Holders or any
       such underwriter, from time to time may reasonably request;

                  (iii) to the extent practicable, promptly prior to the filing
       of any document that is to be incorporated by reference into any
       registration statement or prospectus forming a part thereof subsequent to
       the effectiveness thereof, and in any event no later than the date such
       document is filed with the Commission, provide copies of such document to
       the Holders, if requested, and to any underwriter, and make
       representatives of the Company available for discussion of such document
       and other customary due diligence matters, and include in such document
       prior to the filing thereof such information as any Holder or any such
       underwriter reasonably may request;

                  (iv)  make available at reasonable times for inspection by the
       Holders, any underwriter participating in any disposition pursuant to
       such registration and any attorney or accountant retained by the Holders
       or any such underwriter, all financial and other records, pertinent
       corporate documents and properties of the Company and cause the officers,
       directors and employees of the Company to supply all information
       reasonably requested by the Holders and any such underwriters, attorneys
       or accountants in connection with such registration subsequent to the
       filing of the applicable registration statement and prior to the
       effectiveness of the applicable registration statement;



                                      -5-
<PAGE>   6

                  (v)    use its reasonable best efforts (x) to register or 
       qualify all Registrable Securities and other securities covered by such
       registration under such other securities or blue sky laws of such States
       of the United States of America where an exemption is not available and
       as the sellers of Registrable Securities covered by such registration
       shall reasonably request, (y) to keep such registration or qualification
       in effect for so long as the applicable registration statement remains in
       effect, and (z) to take any other action which may be reasonably
       necessary or advisable to enable such sellers to consummate the
       disposition in such jurisdictions of the securities to be sold by such
       sellers, except that the Company shall not for any such purpose be
       required to qualify generally to do business as a foreign corporation in
       any jurisdiction where it is not so qualified, or to subject itself to
       taxation in any such jurisdiction, or to execute a general consent to
       service of process in effecting such registration, qualification or
       compliance, unless the Company is already subject to service in such
       jurisdiction and except as may be required by the Securities Act or
       applicable rules or regulations thereunder;

                  (vi)   use its reasonable best efforts to cause all 
       Registrable Securities covered by such registration statement to be
       registered with or approved by such other federal or state governmental
       agencies or authorities as may be necessary in the opinion of counsel to
       the Company and counsel to the Holders of Registrable Securities to
       enable the Holders thereof to consummate the disposition of such
       Registrable Securities;

                  (vii)  subject to Section 2(h) hereof, promptly notify each
       Holder of Registrable Securities covered by a registration statement (A)
       upon discovery that, or upon the happening of any event as a result of
       which, the prospectus forming a part of such registration statement, as
       then in effect, includes an untrue statement of a material fact or omits
       to state any material fact required to be stated therein or necessary to
       make the statements therein, in the light of the circumstances under
       which they were made, not misleading, (B) of the issuance by the
       Commission of any stop order suspending the effectiveness of such
       registration statement or the initiation of proceedings for that purpose,
       (C) of any request by the Commission for (1) amendments to such
       registration statement or any document incorporated or deemed to be
       incorporated by reference in any such registration statement, (2)
       supplements to the prospectus forming a part of such registration
       statement or (3) additional information, or (D) of the receipt by the
       Company of any notification with respect to the suspension of the
       qualification or exemption from qualification of any of the Registrable
       Securities for sale in any jurisdiction or the initiation of any
       proceeding for such purpose, and at the request of any such Holder
       promptly prepare and furnish to it a reasonable number of copies of a
       supplement to or an amendment of such prospectus as may be necessary so
       that, as thereafter delivered to the purchasers of such securities, such
       prospectus shall not include an untrue statement of a material fact or
       omit to state a material fact required to be stated therein or necessary
       to make the statements therein, in the light of the circumstances under
       which they were made, not misleading;

                  (viii) use its reasonable best efforts to obtain the
       withdrawal of any order suspending the effectiveness of any such
       registration, or the lifting of any suspension of the 



                                      -6-
<PAGE>   7

       qualification (or exemption from qualification) of any of the Registrable
       Securities for sale in any jurisdiction;

                  (ix)    if requested by the Initiating Holders, or any
       underwriter, promptly incorporate in such registration statement or
       prospectus, pursuant to a supplement or post effective amendment if
       necessary, such information as the Initiating Holders and any underwriter
       may reasonably request to have included therein, including, without
       limitation, information relating to the "plan of distribution" of the
       Registrable Securities, information with respect to the principal amount
       or number of shares of Registrable Securities being sold to such
       underwriter, the purchase price being paid therefor and any other terms
       of the offering of the Registrable Securities to be sold in such offering
       and make all required filings of any such prospectus supplement or
       post-effective amendment as soon as practicable after the Company is
       notified of the matters to be incorporated in such prospectus supplement
       or post effective amendment;

                  (x)     furnish to the Holders, addressed to them, an opinion
       of counsel for the Company, dated the date of the closing under the
       underwriting agreement, if any, or the date of effectiveness of the
       registration statement if such registration is not an underwritten
       offering, and use its reasonable best efforts to furnish to the Holders,
       addressed to them, a "cold comfort" letter signed by the independent
       certified public accountants who have certified the Company's financial
       statements included in such registration, covering substantially the same
       matters with respect to such registration (and the prospectus included
       therein) and, in the case of such accountants' letter, with respect to
       events subsequent to the date of such financial statements, as are
       customarily covered in opinions of issuer's counsel and in accountants'
       letters delivered to underwriters in underwritten public offerings of
       securities and such other matters as the Holders may reasonably request;

                  (xi)    otherwise use its reasonable best efforts to comply
       with all applicable rules and regulations of the Commission, and make
       available to its security holders, as soon as reasonably practicable, an
       earnings statement covering the period of at least 12 months, but not
       more than 18 months, beginning with the first full calendar month after
       the effective date of such registration statement, which earnings
       statement shall satisfy the provisions of Section 11(a) of the Securities
       Act and Rule 158 promulgated thereunder;

                  (xii)   provide promptly to the Holders upon request any
       document filed by the Company with the Commission pursuant to the
       requirements of Section 13 and Section 15 of the Exchange Act; and

                  (xiii)  use its reasonable best efforts to cause all
       Registrable Securities included in any registration pursuant hereto to be
       listed on each securities exchange on which securities of the same class
       are then listed, or, if not then listed on any securities exchange, to be
       eligible for trading in any over-the-counter market or trading system in
       which securities of the same class are then traded.


                                      -7-
<PAGE>   8

              (f)   Indemnification.

                    (i)  The Company will indemnify each of the Holders, as
applicable, each of its officers, directors, members and partners, and each
person controlling each of the Holders, with respect to each registration which
has been effected pursuant to this Section 2, and each underwriter, if any, and
each person who controls any underwriter, against all claims, losses, damages
and liabilities (or actions in respect thereof) arising out of or based on any
untrue statement (or alleged untrue statement) of a material fact contained in
any prospectus, offering circular or other document (including any related
registration statement, notification or the like) incident to any such
registration, qualification or compliance, or based on any omission (or alleged
omission) to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, or any violation by the
Company of the Securities Act or the Exchange Act or any rule or regulation
thereunder applicable to the Company and relating to action or inaction required
of the Company in connection with any such registration, qualification or
compliance, and will reimburse each of the Holders, each of its officers,
directors, members and partners, and each person controlling each of the
Holders, each such underwriter and each person who controls any such
underwriter, for any legal and any other expenses reasonably incurred in
connection with investigating and defending any such claim, loss, damage,
liability or action, provided that the Company will not be liable in any such
case to the extent that any such claim, loss, damage, liability or expense
arises out of or is based on any untrue statement or omission based upon written
information furnished to the Company by the Holders or underwriter and stated to
be specifically for use therein.

                    (ii) Each of the Holders will, if Registrable Securities
held by it are included in the securities as to which such registration,
qualification or compliance is being effected, indemnify the Company, each of
its directors and officers and each underwriter, if any, of the Company's
securities covered by such a registration statement and each person who controls
the Company or such underwriter, each Other Stockholder and each of their
officers, directors, members and partners, and each person controlling such
Other Stockholder against all claims, losses, damages and liabilities (or
actions in respect thereof) arising out of or based on any untrue statement (or
alleged untrue statement) of a material fact contained in any such registration
statement, prospectus, offering circular or other document made by such Holder,
or any omission (or alleged omission) to state therein a material fact required
to be stated therein or necessary to make the statements by such Holder therein
not misleading, and will reimburse the Company and such Other Stockholders,
directors, officers, partners, members, persons, underwriters or control persons
for any legal or any other expenses reasonably incurred in connection with
investigating or defending any such claim, loss, damage, liability or action, in
each case to the extent, but only to the extent, that such untrue statement (or
alleged untrue statement) or omission (or alleged omission) is made in such
registration statement, prospectus, offering circular or other document in
reliance upon and in conformity with written information furnished to the
Company by such Holder and stated to be specifically for use therein; provided,
however, that the obligations of each of the Holders hereunder and under clause
(vi) below shall be limited to an amount equal to the net proceeds to such
Holder of securities sold as contemplated herein.



                                      -8-
<PAGE>   9

                    (iii) Each party entitled to indemnification under this
Section 2(f) (the "Indemnified Party") shall give notice to the party required
to provide indemnification (the "Indemnifying Party") promptly after such
Indemnified Party has actual knowledge of any claim as to which indemnity may be
sought, and shall permit the Indemnifying Party to assume the defense of any
such claim or any litigation resulting therefrom; provided that counsel for the
Indemnifying Party, who shall conduct the defense of such claim or any
litigation resulting therefrom, shall be approved by the Indemnified Party
(whose approval shall not unreasonably be withheld) and the Indemnified Party
may participate in such defense at such party's expense (unless the Indemnified
Party shall have reasonably concluded that there may be a conflict of interest
between the Indemnifying Party and the Indemnified Party in such action, in
which case the fees and expenses of one such counsel for all Indemnified Parties
shall be at the expense of the Indemnifying Party), and provided further that
the failure of any Indemnified Party to give notice as provided herein shall not
relieve the Indemnifying Party of its obligations under this Section 2 unless
the Indemnifying Party is materially prejudiced thereby. No Indemnifying Party,
in the defense of any such claim or litigation shall, except with the consent of
each Indemnified Party (which consent shall not be unreasonably withheld or
delayed), consent to entry of any judgment or enter into any settlement which
does not include as an unconditional term thereof the giving by the claimant or
plaintiff to such Indemnified Party of a release from all liability in respect
to such claim or litigation. Each Indemnified Party shall furnish such
information regarding itself or the claim in question as an Indemnifying Party
may reasonably request in writing and as shall be reasonably required in
connection with the defense of such claim and litigation resulting therefrom.

                    (iv)  If the indemnification provided for in this Section
2(f) is held by a court of competent jurisdiction to be unavailable to an
Indemnified Party with respect to any loss, liability, claim, damage or expense
referred to herein, then the Indemnifying Party, in lieu of indemnifying such
Indemnified Party hereunder, shall contribute to the amount paid or payable by
such Indemnified Party as a result of such loss, liability, claim, damage or
expense in such proportion as is appropriate to reflect the relative fault of
the Indemnifying Party on the one hand and of the Indemnified Party on the other
in connection with the statements or omissions which resulted in such loss,
liability, claim, damage or expense, as well as any other relevant equitable
considerations. The relative fault of the Indemnifying Party and of the
Indemnified Party shall be determined by reference to, among other things,
whether the untrue (or alleged untrue) statement of a material fact or the
omission (or alleged omission) to state a material fact relates to information
supplied by the Indemnifying Party or by the Indemnified Party and the parties'
relative intent, knowledge, access to information and opportunity to correct or
prevent such statement or omission.

                    (v)   Notwithstanding the foregoing, to the extent that the
provisions on indemnification and contribution contained in the underwriting
agreement entered into in connection with any underwritten public offering
contemplated by this Agreement are in conflict with the foregoing provisions,
the provisions in such underwriting agreement shall be controlling.

                    (vi)  The foregoing indemnity agreement of the Company and
Holders is subject to the condition that, insofar as they relate to any loss,
claim, liability or damage made in a preliminary prospectus but eliminated or
remedied in the amended prospectus on file with the 




                                      -9-
<PAGE>   10

Commission at the time the registration statement in question becomes effective
or the amended prospectus filed with the Commission pursuant to Commission Rule
424(b) (the "Final Prospectus"), such indemnity or contribution agreement shall
not inure to the benefit of any underwriter or Holder (but only if such Holder
was required to deliver such Final Prospectus) if a copy of the Final Prospectus
was furnished to the underwriter and was not furnished to the person asserting
the loss, liability, claim or damage at or prior to the time such action is
required by the Securities Act.

              (g) Information by the Holders. Each of the Holders holding
securities included in any registration shall furnish to the Company such
information regarding such Holder and the distribution proposed by such Holder
as the Company may reasonably request in writing and as shall be reasonably
required in connection with any registration, qualification or compliance
referred to in this Section 2.

              (h) Holdback Agreement; Postponement. Notwithstanding the
provisions of Sections 3(a), (b) and (c), if the Board of Directors of the
Company determines in good faith that it is in the best interests of the Company
(A) not to disclose the existence of facts surrounding any proposed or pending
acquisition, disposition, strategic alliance or financing transaction involving
the Company or (B) to avoid a material mistatement or omission in the Shelf
Registration, to suspend the registration rights set forth herein, the Company
may, by notice to the Holders in accordance with Section 5(a), suspend the
rights of the Holders to make sales pursuant to the Shelf Registration; provided
that (x) such periods of suspension may not exceed sixty (60) days in the
aggregate during any period of 12 consecutive months and (y) the Company may not
impose such a suspension or a postponement following the printing and
distribution of a preliminary prospectus in any underwritten public offering of
Registrable Securities pursuant to Section 2(c) (except such suspension, not to
exceed ten days, which results from an event that is not within the reasonable
control of the Company). The Company shall use reasonable commerical efforts to
minimize the period of any suspension of sales under this Section 2(h).

              (i) Assignment. The registration rights set forth in Section 2
hereof may be assigned, in whole or in part, to any transferee of Registrable
Securities (who shall be considered thereafter to be a Holder (provided that any
transferee who is not an affiliate of Investor shall be a Holder only with
respect to such Registrable Securities so acquired and any stock of the Company
issued as a dividend or other distribution with respect to, or in exchange for
or in replacement of, such Registrable Securities) and shall be bound by all
obligations and limitations of this Agreement).

       3.     RULE 144 REPORTING

       With a view to making available the benefits of certain rules and
regulations of the Commission which may permit the sale of restricted securities
to the public without registration, the Company agrees to:

       (i)    make and keep public information available (as those terms are
              understood and defined in Rule 144) at all times;



                                      -10-
<PAGE>   11

       (ii)   use its reasonable best efforts to file with the Commission in a
              timely manner all reports and other documents required of the
              Company under the Securities Act and the Exchange Act; and

       (iii)  so long as there are outstanding any Registrable Securities,
              furnish to each Holder, upon request, a written statement by the
              Company as to its compliance with the reporting requirements of
              Rule 144 and of the Securities Act and the Exchange Act, a copy of
              the most recent annual or quarterly report of the Company, and
              such other reports and documents so filed as such Holder may
              reasonably request in availing itself of any rule or regulation of
              the Commission allowing such Holder to sell any such securities
              without registration.

       4.     INTERPRETATION OF THIS AGREEMENT

              (a) Directly or Indirectly. Where any provision in this Agreement
refers to action to be taken by any Person, or which such Person is prohibited
from taking, such provision shall be applicable whether such action is taken
directly or indirectly by such Person.

              (b) Governing Law. This Agreement shall be governed by and
construed in accordance with the laws of the State of Delaware.

              (c) Section Headings. The headings of the sections and subsections
of this Agreement are inserted for convenience only and shall not be deemed to
constitute a part thereof.

              (d) Arbitration. All disputes arising under this Agreement (other
than claims in equity) shall be resolved by arbitration in accordance with the
Commercial Arbitration Rules of the American Arbitration Association.
Arbitration shall be by a single arbitrator experienced in the matters at issue
and selected by the Company and the Investor in accordance with the Commercial
Arbitration Rules of the American Arbitration Association. The arbitration shall
be held in such place in New York, New York, as may be specified by the
arbitrator (or any place agreed to by the Company, the Investor and the
arbitrator). The decision of the arbitrator shall be final and binding as to any
matters submitted under this Agreement; provided, however, if necessary, such
decision and satisfaction procedure may be enforced by either the Company or the
Investor in any court of record having jurisdiction over the subject matter or
over any of the parties to this Agreement. All costs and expenses incurred in
connection with any such arbitration proceeding (including reasonable attorneys
fees) shall be borne by the party against which the decision is rendered, or, if
no decision is rendered, such costs and expenses shall be home equally by the
Company as one party and the Investor as the other party. If the arbitrator's
decision is a compromise, the determination of which party or parties bears the
costs and expenses incurred in connection with any such arbitration proceeding
shall be made by the arbitrator on the basis of the arbitrator's assessment of
the relative merits of the parties' positions.




                                      -11-
<PAGE>   12

       5.     MISCELLANEOUS

              (a) Notices.

                    (i) All communications under this Agreement shall be in
writing and shall be delivered by facsimile or by hand or mailed by overnight
courier or by registered or certified mail, postage prepaid: .

                        (A) if to the Company, to CytRx Corporation, 154
Technology Parkway, Technology Park/Atlanta, Norcross, Georgia 30092 (770)
368-9500, Attention: Chief Executive Officer, or at such other address as it may
have furnished in writing to the Investors;

                        (B) if to the Investors, at the addresses listed on
Schedule I hereto, or at such other addresses as may have been furnished the
Company in writing.

                    (ii) Any notice so addressed shall be deemed to be given: if
delivered by hand, on the date of such delivery; if mailed by courier, on the
first business day following the date of such mailing; and if mailed by
registered or certified mail, on the third business day after the date of such
mailing.

              (b) Reproduction of Documents. This Agreement and all documents
relating thereto, including, without limitation, any consents, waivers and
modifications which may hereafter be executed may be reproduced by the Investor
by any photographic, photostatic, microfilm, microcard, miniature photographic
or other similar process and the Investors may destroy any original document so
reproduced. The parties hereto agree and stipulate that any such reproduction
shall be admissible in evidence as the original itself in any judicial or
administrative proceeding (whether or not the original is in existence and
whether or not such reproduction was made by the Investors in the regular course
of business) and that any enlargement, facsimile or further reproduction of such
reproduction shall likewise be admissible in evidence.

              (c) Successors and Assigns. This Agreement shall inure to the
benefit of and be binding upon the successors and assigns of each of the
parties.

              (d) Entire Agreement; Amendment and Waiver. This Agreement
constitutes the entire understanding of the parties hereto and supersedes all
prior understanding among such parties. This Agreement may be amended, and the
observance of any term of this Agreement may be waived, with (and only with) the
written consent of the Company and the Holders of a majority of the then
outstanding Registrable Securities.

              (e) Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall be deemed an original and all of which
together shall be considered one and the same agreement.



                                      -12-
<PAGE>   13

              (f) No Inconsistent Agreements. The Company will not hereafter
enter into any agreement with respect to its securities which is inconsistent
with the rights granted to the Holders of Registrable Securities in this
Agreement.

              (g) Remedies. Each Holder of Registrable Securities, in addition
to being entitled to exercise all rights granted by law, including recovery of
damages, will be entitled to specific performance of its rights under this
Agreement. The Company agrees that monetary damages would not be adequate
compensation for any loss incurred by reason of a breach by it of the provisions
of this Agreement and hereby agrees to waive the defense in any action for
specific performance that a remedy at law would be adequate.

              (h) Severability. In the event that any one or more of the
provisions contained herein, or the application thereof in any circumstances, is
held invalid, illegal or unenforceable in any respect for any reason, the
validity, legality and enforceability of any such provision in every other
respect and of the remaining provisions contained herein shall not be in any way
impaired thereby, it being intended and understood that all of the rights and
privileges of each of the Holders shall be enforceable to the fullest extent
permitted by law.





                                      -13-
<PAGE>   14


       IN WITNESS WHEREOF, the undersigned have executed this Agreement as of
the date first set forth above.

                                   CYTRX CORPORATION


                                   By:
                                      -----------------------------------------
                                      Name:
                                           ------------------------------------
                                      Title:
                                            -----------------------------------


                                   INVESTORS:


                                   GUNDYCO, in trust for R.R.S.P. 550-98866-19


                                   By:
                                      -----------------------------------------
                                      Name:
                                           ------------------------------------
                                      Title:
                                            -----------------------------------


                                   EXCALIBUR LIMITED PARTNERSHIP


                                   By:
                                      -----------------------------------------
                                      Excalibur Capital Management Inc.

                                   By:
                                      -----------------------------------------
                                      Name:  William S. Hechter
                                           ------------------------------------
                                      Title: President
                                            -----------------------------------


                                   PINE STREET ASSET MANAGEMENT

                                   By:
                                      -----------------------------------------
                                      Its:
                                          -------------------------------------


                                   --------------------------------------------
                                   Name: Charles N. Eckert


                                   --------------------------------------------
                                   Name: David Kosloff




                                      -14-

<PAGE>   1
                                                                     EXHIBIT 5.2




CytRx Announces Private Placement of $2 Million in Convertible Debentures

       ATLANTA, Oct. 22 /PRNewswire/ -- CytRx Corporation (Nasdaq: CYTR)
announced the private placement of $2.0 million of convertible notes. The
debentures, which will not be convertible into CytRx common stock for 60 days
from the closing date, may at the option of the shareholder thereafter be
converted at the lesser of 85% of the average closing bid price for the 10 days
preceding the conversion, or $5.68 per share. The debentures will be sold at par
and bear interest at a rate of 6% per annum. The investors will also be issued
two year warrants to purchase 40,000 shares of CytRx common stock with a strike
price equal to $5.68. CytRx has certain rights to redeem the notes at 110% of
par including if the conversion price is below $4. CytRx also has an option to
sell another $2 million of debentures to the same investors subject to certain
conditions. CytRx has agreed to file a registration statement for the resale of
the shares associated with this placement. CytRx was advised by Shipley Raidy
Capital Partners, L.P. in this transaction.

       "While allowing us to proceed at full speed with our Phase III program
for FLOCOR(TM) this offering will mitigate the cash demands this trial will have
on the other CytRx operations," reported Jack Luchese, President and Chief
Executive Officer.

       CytRx's business strategy is to build shareholder value through the
development and commercialization of high value human therapeutic products and
the successful development and rollout of its promising subsidiary companies.
CytRx's FLOCOR(TM) is being developed to treat acute sickle call crisis and
other vascular diseases. Protox is being developed to treat bacterial and viral
infections. Vaxcel, Inc. is developing Optivax(R) to improve the effectiveness
of vaccines. VetLife, Inc. markets and distributes products to enhance food
animal growth. Proceutics, Inc. provides high quality preclinical development
services to the pharmaceutical industry.

       This press release contains forward-looking statements that involve risks
and uncertainties. Actual results may differ materially from those discussed
herein, due to, among other things, the research, development and market risks
which could adversely affect the Company's time line for clinical trials,
regulatory approval, marketing and licensing.

SOURCE   CytRx    Corporation
         -0-                                       10/22/97
         /CONTACT:         Joe Medlin, CytRx Corporation, 770-368-9500/
         (CYTR)


   454 Technology Parkway *Technology Park /Atlanta *Norcross, Georgia 30092
                Telephone: (404) 368-9500 * FAX: (404) 368-0622




© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission