CERTIFICATE OF DESIGNATION, NUMBER, POWERS,
                    PREFERENCES AND RELATIVE, PARTICIPATING,
                    OPTIONAL AND OTHER SPECIAL RIGHTS AND THE
                    QUALIFICATIONS, LIMITATIONS, RESTRICTIONS
                   AND OTHER DISTINGUISHING CHARACTERISTICS OF
                       CLASS D CONVERTIBLE PREFERRED STOCK

                                       OF

                           INNOVIR LABORATORIES, INC.

It is hereby certified that:

     1. The name of the corporation (hereinafter called the "Corporation") is
Innovir Laboratories, Inc. a Delaware corporation.

     2. The Certificate of Incorporation of the Corporation authorizes the
issuance of fifteen million (15,000,000) shares of Preferred Stock of a par
value of $.06 each and expressly vests in the Board of Directors of the
Corporation the authority provided therein to issue any or all of the remainder
of said shares in one or more classes or series and by resolution or resolutions
to establish the designation, number, full or limited voting powers, or the
denial of voting powers, preferences and relative, participating, optional and
other special rights and the qualifications, limitations, restrictions and other
distinguishing characteristics of each class or series to be issued.

     3. The Board of Directors of the Corporation, pursuant to the authority
expressly vested in it as aforesaid, has adopted the following resolutions
creating a Class D issue of Preferred Stock:

     RESOLVED, that eight million six hundred sixty-six thousand six hundred
sixty-six (8,666,666) of the fifteen million (15,000,000) authorized shares of
Preferred Stock of the Corporation shall be designated Class D Convertible
Preferred Stock, $.06 par value per share ("Class D Preferred Stock"), and shall
possess the rights and privileges set forth below:

     Section 1. DESIGNATION AND AMOUNT. The shares of such class shall be
designated as "Class D Convertible Preferred Stock" ("Class D Preferred Stock")
and the number of shares constituting the Class D Preferred Stock shall be
8,666,666. Such number of shares may be increased or decreased by resolution of
the Board of Directors; provided, that no decrease shall reduce the number of
shares of Class D Preferred Stock to a number less than the number of shares
then outstanding plus the number shares reserved for issuance upon the exercise
of outstanding options, rights


<PAGE>

or warrants or upon the conversion of any outstanding securities issued by the
Corporation convertible into Class D Preferred Stock.

     Section 2. RANK. The Class D Preferred Stock shall rank: (i) prior to all
of the Corporation's Common Stock, par value $.013 per share ("Common Stock");
(ii) prior to any class or series of capital stock of the Corporation hereafter
created specifically ranking by its terms junior to any Class D Preferred Stock
of whatever subdivision (collectively, with the Common Stock, "Junior
Securities"); (iii) on parity with the Corporation's Class B Convertible
Preferred Stock and Class C Convertible Preferred Stock and with any class or
series of capital stock of the Corporation hereafter created specifically
ranking by its terms on parity with the Class D Preferred Stock ("Parity
Securities") in each case as to distributions of assets upon liquidation,
dissolution or winding up of the Corporation, whether voluntary or involuntary
(all such distributions being referred to collectively as "Distributions").

     Section 3. DIVIDENDS. The Class D Preferred Stock will bear no dividends,
and the holders of the Class D Preferred Stock ("Holders") shall not be entitled
to receive dividends on the Class D Preferred Stock.

     Section 4. LIQUIDATION PREFERENCE.

     (a) In the event of any liquidation, dissolution or winding up of the
Corporation, either voluntary or involuntary, the Holders of shares of Class D
Preferred Stock shall be entitled to receive, immediately after any
distributions to senior securities required by the Corporation's Certificate of
Incorporation or any certificate of designation of preferences, and prior and in
preference to any distribution to Junior Securities but in parity with any
distribution of Parity Securities, an amount per share equal to $1.50 for each
outstanding share of Class D Preferred Stock. If upon the occurrence of such
event, the assets and funds thus distributed among the Holders of the Class D
Preferred Stock and Parity Securities shall be insufficient to permit the
payment to such Holders of the full preferential amounts due to the Holders of
the Class D Preferred Stock and the Parity Securities, respectively, then the
entire assets and funds of the Corporation legally available for distribution
shall be distributed among the Holders of the Class D Preferred Stock and the
Parity Securities, pro rata, based on the respective liquidation amounts to
which each such class or series of stock is entitled by the Corporation's
Certificate of Incorporation and any certificate of designation of preferences.

     (b) Upon the completion of the distribution required by subsection 4(a), if
assets remain in this Corporation, they shall be distributed to holders of
Parity Securities and Junior Securities in accordance with the Corporation's
Certificate of Incorporation including any duly adopted certificate(s) of
designation of preferences.

     (c) A consolidation or merger of the Corporation with or into any other
corporation or corporations, or a sale, conveyance or disposition of all or
substantially all of the assets of the Corporation or the effectuation by the
Corporation of a

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transaction or series of related transactions in which more than 50% of the
voting power of the Corporation is disposed of, shall not be deemed to be a
liquidation, dissolution or winding up within the meaning of this Section 4.

     Section 5. CONVERSION.

     The record Holders of this Class D Preferred Stock shall have conversion
rights as follows (the "Conversion Rights"):

     (a) Right to Convert. Each record Holder of Class D Preferred Stock shall
be entitled, at the option of the Holder, at the office of the Company or any
transfer agent for the Class D Preferred Stock, to convert each share of Class D
Preferred Stock held by such Holder into one share of restricted, fully-paid and
nonassessable share of the $.013 par value common stock of the Company (the
"Common Stock"); provided, however, that there are sufficient shares of Common
Stock into which such Class D Preferred Stock may be converted. If, by June 30,
1997, the number of authorized but unissued shares of Common Stock are not
sufficient to effect the conversion of all the then outstanding shares of Class
D Preferred Stock, each share of Class D Preferred Stock for which there is not
sufficient number of authorized but unissued shares at such date shall, as of
such date, be convertible into one and one-half shares of restricted, fully-paid
and nonassessable shares of Common Stock.

     (b) Mechanics of Conversion. In order to convert Class D Preferred Stock
into full shares of Common Stock, the Holder shall (i) fax a copy of the fully
executed notice of conversion in the form attached as Exhibit A hereto ("Notice
of Conversion") to the Company or its designated transfer agent at such office
indicating that he elects to convert the same, which notice shall specify the
number of shares of Class D Preferred Stock to be converted (together with a
copy of the first page of each certificate to be converted), prior to midnight,
New York City time (the "Conversion Notice Deadline") on the date of conversion
specified on the Notice of Conversion and (ii) surrender the original
certificate or certificates therefor, duly endorsed, and the original Notice of
Conversion by either overnight courier or two-day courier, to the office of the
Company or of any transfer agent for the Class D Preferred Stock; provided,
however, that the Company shall not be obligated to issue certificates
evidencing the shares of Common Stock issuable upon such conversion unless
either the certificates evidencing such Class D Preferred Stock are delivered to
the Company or its transfer agent as provided above, or the Holder notifies the
Company or its transfer agent that such certificates have been lost, stolen or
destroyed. Upon receipt by the Company of evidence of the loss, theft,
destruction or mutilation of the certificate or certificates ("Stock
Certificates") representing shares of Class D Preferred Stock and (in the case
of loss, theft or destruction) of indemnity or security reasonably satisfactory
to the Company, and upon surrender and cancellation of the Stock Certificate(s),
if mutilated, the Company shall execute and deliver new Stock Certificate(s) of
like tenor and date representing, at the Holder's option, either shares of Class
D Preferred Stock or the shares of Common Stock into which such Class D
Preferred Stock may be

                                       -3-


<PAGE>

converted. No fractional shares of Common Stock shall be issued upon conversion
of this Class D Preferred Stock.

     The Company shall use all reasonable efforts to issue and deliver within
three (3) business days after delivery to the Company of such Stock
Certificate(s), or after such agreement and indemnification, to such Holder of
Class D Preferred Stock at the address of the Holder on the books of the
Company, a certificate or certificates for the number of shares of Common Stock
to which the Holder shall be entitled as aforesaid. The date on which conversion
occurs (the "Date of Conversion") shall be deemed to be the date set forth in
such Notice of Conversion, provided (i) that the advance copy of the Notice of
Conversion is faxed to the Company before midnight, New York City time, on the
Date of Conversion, and (ii) that the original Stock Certificates representing
the shares of Class D Preferred Stock to be converted are received by the
transfer agent or the Company within five business days thereafter. The person
or persons entitled to receive the 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 on such date. If the original Stock Certificates
representing the Class D Preferred Stock to be converted are not received by the
transfer agent or the Company within five business days after the Date of
Conversion or if the facsimile of the Notice of Conversion is not received by
the Company or its designated transfer agent prior to the Conversion Notice
Deadline, the Notice of Conversion, at the Company's option, may be declared
null and void.

     Following conversion of shares of Class D Preferred Stock, such shares of
Class D Preferred Stock will no longer be outstanding.

     (c) Reservation of Stock Issuable Upon Conversion. Subject to the amendment
of the Company's Certificate of Incorporation to increase the number of shares
of Common Stock authorized thereunder, 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 Class D Preferred
Stock, such number of its shares of Common Stock as shall from time to time be
sufficient to effect the conversion of all then outstanding Class D Preferred
Stock; and if at any time the number of authorized but unissued shares of Common
Stock shall not be sufficient to effect the conversion of all the then
outstanding shares of Class D Preferred Stock, the Company will take such
corporate action as may be necessary to increase its authorized but unissued
shares of Common Stock to such number of shares as shall be sufficient for such
purpose.

     (d) Automatic Conversion. Each share of Class D Preferred Stock outstanding
on June 30, 1997 automatically shall be converted into Common Stock on such
date, and June 30, 1997 shall be deemed the Date of Conversion with respect to
such Conversion.

                                       -4-


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     Section 6. CORPORATE CHANGE.

     The number of shares of Common Stock into which each share of Class D
Preferred Stock shall convert shall be appropriately adjusted to reflect, as
deemed equitable and appropriate by the Corporation, any stock dividend, stock
split or share combination of the Common Stock. In the event of a merger,
reorganization, recapitalization or similar event of or with respect to the
Company (a "Corporate Change") (other than a Corporate Change in which all or
substantially all of the consideration received by the holders of the Company's
equity securities upon such Corporate Change consists of cash or assets other
than securities issued by the acquiring entity or any affiliate thereof), this
Class D Preferred Stock shall be assumed by the acquiring entity and thereafter
this Class D Preferred Stock shall be convertible into such class and type of
securities as the Holder would have received had the Holder converted this Class
D Preferred Stock immediately prior to such Corporate Change.

     Section 7. VOTING RIGHTS. Except as otherwise provided by the Delaware
General Corporation Law, each holder of Class D Preferred Stock shall be
entitled to vote, in respect of each share of Class D Preferred Stock registered
in such holder's name, the number of votes as such holder would have had if such
share of Class D Preferred Stock were converted into Common Stock immediately
prior to the record date for determining which stockholders are entitled to
vote. In addition, each holder of Class D Preferred Stock shall otherwise
participate in any proceeding in which actions shall be taken by the
stockholders of the Corporation and shall be entitled to notification as to any
meeting of the stockholders. Except to the extent that Delaware law requires the
vote of the holders of the Class D Preferred Stock, voting separately as a
class, to authorize a given action of the Corporation, the holders of the Class
D Preferred Stock shall not be entitled to such a vote. To the extent such a
vote is required, however, the affirmative vote or consent of the holders of at
least a majority of the outstanding shares of the Class D Preferred Stock shall
constitute the approval of such action by the class. Holders of the Class D
Preferred Stock shall be entitled to participate in all stockholder meetings,
written consents or other stockholder actions with respect to which they would
be entitled to vote or participate, including receipt of notice thereof pursuant
to the Corporation's by-laws and applicable statutes.

     Section 8. PROTECTIVE PROVISIONS. So long as shares of Class D Preferred
Stock are outstanding, the Corporation shall not without first obtaining the
approval (by vote or written consent, as provided by law) of the holders of at
least a majority of the then outstanding shares of Class D Preferred Stock:

     (a) alter or change the rights, preferences or privileges of the shares of
Class D Preferred Stock so as to affect adversely the Class D Preferred Stock;

     (b) create any new class or series of stock having a preference over the
Class D Preferred Stock with respect to Distributions (as defined in Section 2
above); or

                                       -5-


<PAGE>

     (c) do any act or thing not authorized or contemplated by this Designation
which would result in taxation of the holders of shares of the Class D Preferred
Stock under Section 305 of the Internal Revenue Code of 1986, as amended (or any
comparable provision of the Internal Revenue Code as hereafter from time to time
amended).

     Section 9. STATUS OF REDEEMED OR CONVERTED STOCK. In the event any shares
of Class D Preferred Stock shall be converted pursuant to Section 5 hereof, the
shares so converted shall be canceled, shall return to the status of authorized
but unissued Preferred Stock of no designated class or series and shall not be
issuable by the Corporation as Class D Preferred Stock.

     Section 10. PREFERENCE RIGHTS. Nothing contained herein shall be construed
to prevent the Board of Directors of the Corporation from issuing one or more
classes or series of preferred stock with liquidation preferences equal to the
liquidation preferences of the Class D Preferred Stock.

     FURTHER RESOLVED, that the statements contained in the foregoing resolution
creating and designating the said Class D Preferred Stock and fixing the number,
powers, preferences and relative, optional, participating and other special
rights and the qualifications, limitations, restrictions and other
distinguishing characteristics thereof shall, upon the effective date of said
Class, be deemed to be included in and be a part of the certificate of
incorporation of the Corporation pursuant to the provisions of the Delaware
General Corporation Law.

     FURTHER RESOLVED, that the officers of the Company be, and hereby are,
authorized and directed to file this Certificate of Designation pursuant to the
provisions of Section 151 of the General Corporation Law of the State of
Delaware, with respect to the Class D Preferred Stock provided for by the
foregoing resolutions.

Signed on the 9th day of December, 1996.

                                        /s/ GARY POKRASSA
                                        --------------------------------
                                        Name:   Gary Pokrassa
                                        Title:  Vice President--Finance

Attest: /S/ KATHLEEN E. PICKERING
        -------------------------
Name:   Kathleen E. Pickering
Title:  Assistant Secretary

                                       -6-


<PAGE>

                                                                       EXHIBIT A
                                                                       ---------
                              NOTICE OF CONVERSION

                    (To be Executed by the Registered Holder
                    in order to Convert the Preferred Stock)

As of the date written below, the undersigned hereby irrevocably elects to
convert shares of Class D Convertible Preferred Stock, represented by stock
certificate No(s). (the "Preferred Stock Certificates") into shares of common
stock ("Common Stock") of Innovir Laboratories, Inc. (the "Company") according
to the conditions of the Certificate of Designation of Class D Convertible
Preferred Stock. If shares are to be issued in the name of a person other than
undersigned, the undersigned will pay all transfer taxes payable with respect
thereto and is delivering herewith such certificates. No fee will be charged to
the Holder for any conversion, except for transfer taxes, if any.

The undersigned represents and warrants that all offers and sales by the
undersigned of the shares of Common Stock issuable to the undersigned upon
conversion of the Class D Preferred Stock shall be made in accordance with the
Securities Act of 1933, as amended (the "Act"), pursuant to registration of the
Common Stock under the Act or pursuant to an exemption from registration under
the Act.

                                          ------------------------------------
                                          Date of Conversion
                                
                                          ------------------------------------
                                          Signature
                                
                                          ------------------------------------
                                          Name
                                
                                          Address:
                                
                                          ------------------------------------
                                
                                          ------------------------------------
                            
* No shares of common Stock will be issued until the original preferred Stock
Certificate(s) to be converted and the Notice of Conversion are received by the
Company's Attorney or Transfer Agent. The original Stock Certificate(s)
representing the Class D Preferred Stock to be converted and the Notice of
Conversion must be received by the Company's Attorney or Transfer Agent by the
fifth business day following the Date of Conversion or the Notice of Conversion,
at the Company's option, may be declared null and void.

                                      -7-