<PAGE>   1

                                                                    EXHIBIT 4.24

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "ACT"), OR UNDER THE SECURITIES LAWS OF ANY STATE.
THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON TRANSFERABILITY AND RESALE AND
MAY NOT BE TRANSFERRED OR RESOLD EXCEPT AS PERMITTED UNDER THE ACT AND THE
APPLICABLE STATE SECURITIES LAWS, PURSUANT TO REGISTRATION OR EXEMPTION
THEREFROM. THE ISSUER OF THESE SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN
FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED
TRANSFER OR RESALE IS IN COMPLIANCE WITH THE ACT AND ANY APPLICABLE STATE
SECURITIES LAWS.



                                  RIBOGENE INC.

               WARRANT FOR THE PURCHASE OF SHARES OF COMMON STOCK



_____________________, 199___                                      50,000 Shares



        For Value Received, RIBOGENE, INC., a Delaware corporation (the
"Company"), with its principal office at 26118 Research Road, Hayward,
California 94545, hereby certifies that REEDLAND CAPITAL PARTNERS ("Holder"), or
its assigns, in partial consideration for the engagement of Holder as exclusive
placement agent pursuant to that certain Letter of Engagement dated December 2,
1998, is entitled, subject to the provisions of this Warrant, to purchase from
the Company, at any time before 5:00 p.m. (Pacific Standard Time) December ___,
2003 (the "Expiration Date"), the number of fully paid and nonassessable shares
of Common Stock of the Company set forth above, subject to adjustment as
hereinafter provided.

        Holder may purchase such number of shares of Common Stock at a purchase
price per share (as appropriately adjusted pursuant to Section 7 hereof) of
Three Dollars and Eight Cents ($3.08) (the "Exercise Price"). The term "Common
Stock" shall mean the aforementioned Common Stock of the Company, together with
any other equity securities that may be issued by the Company in addition
thereto or in substitution therefor as provided herein.

        The number of shares of Common Stock to be received upon the exercise of
this Warrant and the price to be paid for a share of Common Stock are subject to
adjustment from time to time as hereinafter set forth. The shares of Common
Stock deliverable upon such exercise, as adjusted from time to time, are
hereinafter sometimes referred to as "Warrant Shares."

        SECTION 1. EXERCISE OF WARRANT. This Warrant may be exercised in whole
or in part on any business day prior to the Expiration Date by presentation and
surrender hereof to the Company at its principal office at the address set forth
in the initial paragraph hereof (or at such other address as the Company may
hereafter notify Holder in writing) with the Purchase Form annexed hereto duly
executed and accompanied by proper payment of the Exercise Price in 



                                       1.
<PAGE>   2

lawful money of the United States of America in the form of a check, subject to
collection, for the number of Warrant Shares specified in the Purchase Form. If
this Warrant should be exercised in part only, the Company shall, upon surrender
of this Warrant, execute and deliver a new Warrant evidencing the rights of
Holder thereof to purchase the balance of the Warrant Shares purchasable
hereunder. Upon receipt by the Company of this Warrant and such Purchase Form,
together with proper payment of the Exercise Price, at the principal office of
the Company, Holder shall be deemed to be the holder of record of the Warrant
Shares, notwithstanding that the stock transfer books of the Company shall then
be closed or that certificates representing such Warrant Shares shall not then
be actually delivered to Holder.

        SECTION 2. NET EXERCISE. Notwithstanding any provisions herein to the
contrary, if the fair market value of one share of the Company's Common Stock is
greater than the Exercise Price (at the date of calculation as set forth below),
in lieu of exercising this Warrant for cash, the Holder may elect to receive
shares equal to the value (as determined below) of this Warrant (or the portion
thereof being canceled) by surrender of this Warrant at the principal office of
the Company together with the properly endorsed Form of Subscription and notice
of such election in which event the Company shall issue to the Holder a number
of shares of Common Stock computed using the following formula:

                      X = Y (A-B)

                              A

        Where         X =    the number of shares of Common Stock to be issued
                             to the Holder

                      Y =    the number of shares of Common Stock purchasable
                             under the Warrant or, if only a portion of the
                             Warrant is being exercised, the portion of the
                             Warrant being canceled (at the date of such
                             calculation)

                      A =    the fair market value of one share of the
                             Company's Common Stock (at the date of such
                             calculation)

                      B =    Exercise Price (as adjusted to the date of such
                             calculation)

        The current fair market price of a share of Common Stock for purposes of
this Section 2 and Section 4 is the last reported sales price of the Common
Stock on the last trading day prior to the exercise date, as reported by the
American Stock Exchange, or the primary national securities exchange or market
on which the Common Stock is then quoted; provided, however, that if the Common
Stock is neither traded on the American Stock Exchange nor on a national
securities exchange or market, the price referred to above shall be the price
reflected in the over-the counter market as reported by the National Quotation
Bureau, Inc. or any organization performing a similar function.

        SECTION 3. RESERVATION OF SHARES. The Company hereby agrees that at all
times there shall be reserved for issuance and delivery upon exercise of this
Warrant all shares of its Common Stock or other shares of capital stock of the
Company from time to time issuable upon 



                                       2.
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exercise of this Warrant. All such shares shall be duly authorized and, when
issued upon such exercise in accordance with the terms of this Warrant, shall be
validly issued, fully paid and nonassessable.

        SECTION 4. FRACTIONAL INTEREST. The Company will not issue a fractional
share of Common Stock upon exercise of a Warrant. Instead, the Company will
deliver its check for the current market value of the fractional share. The
current market value of a fraction of a share is determined as follows: multiply
the current market price of a full share by the fraction of a share and round
the result to the nearest cent.

        SECTION 5.    TRANSFERS; ASSIGNMENT OR LOSS OF WARRANT.

                (a) Subject to the terms and conditions contained in Section 10
hereof, this Warrant and all rights hereunder are transferable in whole or in
part by Holder and any successor transferee; provided that prior to such
transfer Holder shall give thirty (30) days prior written notice of any such
transfer to the Company, and the Company shall have the right to acquire the
Warrant under the identical provisions contained in such notice by giving Holder
written notice within fifteen (15) days of receipt of such notice. The Company's
failure to respond to said notice within said fifteen (15) days shall be deemed
a waiver of this right of first refusal. The transfer shall be recorded on the
books of the Company upon receipt by the Company of the Transfer Notice annexed
hereto, at its principal offices and the payment to the Company of all transfer
taxes and other governmental charges imposed on such transfer.

                (b) Holder shall not, without obtaining the prior written
consent of the Company, which consent shall not be unreasonably withheld, assign
its interest in this Warrant in whole or in part to any person or persons.
Subject to the provisions of Section 10, upon surrender of this Warrant to the
Company or at the office of its stock transfer agent or warrant agent, with the
Assignment Form annexed hereto duly executed and funds sufficient to pay any
transfer tax, the Company shall, without charge, execute and deliver a new
Warrant or Warrants in the name of the assignee or assignees named in such
instrument of assignment (any such assignee will then be a "Holder" for purposes
of this Warrant) and, if Holder's entire interest is not being assigned, in the
name of Holder, and this Warrant shall promptly be canceled.

                (c) Upon receipt of evidence satisfactory to the Company of the
loss, theft, destruction or mutilation of this Warrant, and (in the case of
loss, theft or destruction) of indemnification satisfactory to the Company, and
upon surrender and cancellation of this Warrant, if mutilated, the Company shall
execute and deliver a new Warrant of like tenor and date. In the event that this
Warrant is lost, stolen, destroyed or mutilated, Holder shall pay all reasonable
attorneys' fees and expenses incurred by the Company in connection with the
replacement of this Warrant and the issuance of a new Warrant.

        SECTION 6. RIGHTS OF HOLDER. Holder shall not, by virtue hereof, be
entitled to any rights of a stockholder in the Company, either at law or equity,
and the rights of Holder are limited to those expressed in this Warrant. Nothing
contained in this Warrant shall be construed as conferring upon Holder hereof
the right to vote or to consent or to receive notice as a stockholder of the
Company on any matters or with respect to any rights whatsoever as a stockholder
of the Company. No dividends or interest shall be payable or accrued in respect
of 



                                       3.
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this Warrant or the interest represented hereby or the Warrant Shares
purchasable hereunder until, and only to the extent that, this Warrant shall
have been exercised in accordance with its terms.

        SECTION 7. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF SHARES. The number
and kind of securities purchasable upon the exercise of the Warrant and the
Exercise Price shall be subject to adjustment from time to time upon the
occurrence of certain events, as follows:

                (a) RECLASSIFICATION OF OUTSTANDING SECURITIES. In case of any
reclassification, change or conversion of securities of the class issuable upon
exercise of this Warrant (other than a change in par value, or from par value to
no par value, or from no par value to par value, or as a result of a subdivision
or combination), the Company shall execute a new Warrant (in form and substance
reasonably satisfactory to the Holder of this Warrant) providing that the Holder
of this Warrant shall have the right to exercise such new Warrant and upon such
exercise to receive, in lieu of each share of Common Stock theretofore issuable
upon exercise of this Warrant, the kind and amount of shares of stock, other
securities, money and property receivable upon such reclassification or change
by a holder of one share of Common Stock. Such new Warrant shall provide for
adjustments that shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Section 8. The provisions of this subsection
(a) shall similarly apply to successive reclassification or changes.

                (b) SUBDIVISIONS OR COMBINATION OF SHARES. If the Company at any
time while this Warrant remains outstanding and unexpired shall subdivide or
combine its Common Stock, the Exercise Price and the number of Warrant Shares
issuable upon exercise hereof shall be proportionately adjusted.

                (c) STOCK DIVIDENDS. If the Company at any time while this
Warrant is outstanding and unexpired shall pay a dividend payable in shares of
Common Stock (except any distribution specifically provided for in the foregoing
subsections (a) and (b)), then the Exercise Price shall be adjusted, from and
after the date of determination of shareholders entitled to receive such
dividend or distribution, to that price determined by multiplying the Exercise
Price in effect immediately prior to such date of determination by a fraction
(a) the numerator of which shall be the total number of shares of Common Stock
outstanding immediately prior to such dividend or distribution, and (b) the
denominator of which shall be the total number of shares of Common Stock
outstanding immediately after such dividend or distribution and the number of
Warrant Shares subject to this Warrant shall be proportionately adjusted.

                (d) NOTICE OF RECORD DATE. In the event of any taking by the
Company of a record of its shareholders for the purpose of determining
shareholders who are entitled to receive payment of any dividend (other than a
cash dividend) or other distribution, any right to subscribe for, purchase or
otherwise acquire any share of any class or any other securities or property, or
to receive any other right, or for the purpose of determining shareholders who
are entitled to vote in connection with any proposed merger or consolidation of
the Company with or into any other corporation, or any proposed sale, lease or
conveyance of all or substantially all of the assets of the Company, or any
proposed liquidation, dissolution or winding up of the Company, the Company
shall mail to the Holder of this Warrant, at least ten days prior to the date
specified 



                                       4.
<PAGE>   5

therein, a notice specifying 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.

                (e) NO ADJUSTMENT UPON EXERCISE OF WARRANTS. No adjustments
shall be made under any Section herein in connection with the issuance of
Warrant Shares upon exercise of the Warrants.

        SECTION 8. OFFICER'S CERTIFICATE. Whenever the Exercise Price shall be
adjusted as required by the provisions of Section 8, the Company shall deliver
an officer's certificate showing the adjusted Exercise Price determined as
herein provided, setting forth in reasonable detail the facts requiring such
adjustment and the manner of computing such adjustment. Each such officer's
certificate shall be signed by the chairman, president or chief financial
officer of the Company.

        SECTION 9. TRANSFER TO COMPLY WITH THE SECURITIES ACT OF 1933. This
Warrant may not be exercised and neither this Warrant nor any of the Warrant
Shares, nor any interest in either, may be offered, sold, assigned, pledged,
hypothecated, encumbered or in any other manner transferred or disposed of, in
whole or in part, except in compliance with applicable United States federal and
state securities or blue sky laws and the terms and conditions hereof. Each
Warrant shall bear a legend in substantially the same form as the legend set
forth on the first page of this Warrant. Each certificate for Warrant Shares
issued upon exercise of this Warrant, unless at the time of exercise such
Warrant Shares are acquired pursuant to a registration statement that has been
declared effective under the Securities Act of 1933, as amended (the "Securities
Act"), and applicable blue sky laws, shall bear a legend substantially in the
following form:

        THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
        SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR UNDER THE SECURITIES
        LAWS OF ANY STATE. THESE SECURITIES ARE SUBJECT TO RESTRICTIONS ON
        TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT
        AS PERMITTED UNDER THE ACT AND THE APPLICABLE STATE SECURITIES LAWS,
        PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM. THE ISSUER OF THESE
        SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN FORM AND SUBSTANCE
        SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED TRANSFER OR
        RESALE IS IN COMPLIANCE WITH THE ACT AND ANY APPLICABLE STATE SECURITIES
        LAWS.

Any certificate for any Warrant Shares issued at any time in exchange or
substitution for any certificate for any Warrant Shares bearing such legend
(except a new certificate for any Warrant Shares issued after the acquisition of
such Warrant Shares pursuant to a registration statement that has been declared
effective under the Securities Act) shall also bear such legend unless, in the
opinion of counsel for the Company, the Warrant Shares represented thereby need
no longer be subject to the restriction contained herein. The provisions of this
Section 10 shall be binding 



                                       5.
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upon all subsequent holders of certificates for Warrant Shares bearing the above
legend and all subsequent holders of this Warrant, if any.

        SECTION 10. REPRESENTATIONS AND COVENANTS OF HOLDER. This Warrant has
been entered into by the Company in reliance upon the following representations
and covenants of Holder, which by its execution hereof Holder hereby confirms:

                (a) Investment Purpose. The right to acquire Common Stock, and
any Common Stock issued upon exercise of Holder's rights contained herein, will
be acquired for investment and not with a view to the sale or distribution of
any part thereof, and Holder has no present intention of selling or engaging in
any public distribution of the same except pursuant to a registration or
exemption.

                (b) Private Issue. Holder understands (i) that the Common Stock
issuable upon exercise of Holder's rights contained herein is not registered
under the Securities Act or qualified under applicable state securities laws on
the ground that the issuance contemplated by this Warrant will be exempt from
the registration and qualification requirements thereof, and (ii) that the
Company's reliance on such exemption is predicated on the representations set
forth in this Section 11.

                (c) Disposition of Holder's Rights. In no event will Holder make
a disposition of any of its rights to acquire Common Stock, or of any Common
Stock issued upon exercise of such rights, unless and until (i) it shall have
notified the Company of the proposed disposition, and (ii) if requested by the
Company, it shall have furnished the Company with an opinion of counsel (which
counsel may either be inside or outside counsel to Holder) satisfactory to the
Company and its counsel to the effect that (A) appropriate action necessary for
compliance with the Securities Act has been taken, or (B) an exemption from the
registration requirements of the Securities Act is available. Notwithstanding
the foregoing, the restrictions imposed upon the transferability of any of its
rights to acquire Common Stock, or of any Common Stock issued on the exercise of
such rights do not apply to transfers from the beneficial owner of any of the
aforementioned securities to its nominee or from such nominee to its beneficial
owner, and shall terminate as to any particular share of Common Stock when (1)
such security shall have been effectively registered under the Act and sold by
the holder thereof in accordance with such registration, (2) such security shall
have been sold without registration in compliance with Rule 144 under the
Securities Act, or (3) a letter shall have been issued to Holder at its request
by the staff of the Securities and Exchange Commission or a ruling shall have
been issued to Holder at its request by such Commission stating that no action
shall be recommended by such staff or taken by such Commission, as the case may
be, if such security is transferred without registration under the Securities
Act in accordance with the conditions set forth in such letter or ruling, and
such letter or ruling specifies that no subsequent restrictions on transfer are
required. Whenever the restrictions imposed hereunder shall terminate, as
hereinabove provided, Holder or a holder of a share of Common Stock then
outstanding as to which such restrictions have terminated shall be entitled to
receive from the Company, without expense to such holder, one or more new
certificates for the Warrant or for such shares of Common Stock not bearing any
restrictive legend.



                                       6.
<PAGE>   7

                (d) Financial Risk. Holder has such knowledge and experience in
financial and business matters as to be capable of evaluating the merits and
risks of its investment and has the ability to bear the economic risks of its
investment.

                (e) Risk of No Registration. Holder understands that if the
Company does not register with the Securities and Exchange Commission pursuant
to Section 12 of the Securities Act, or file reports pursuant to Section 15(d)
of the Securities Exchange Act of 1934, as amended (the "Exchange Act), or if a
registration statement covering the securities under the Securities Act is not
in effect when it desires to sell (i) the rights to purchase Common Stock
pursuant to this Warrant, or (ii) the Common Stock issued upon exercise of the
right to purchase, it may be required to hold such securities for an indefinite
period. Holder also understands that any sale of its rights of Holder to
purchase Common Stock, or of any Common Stock, which might be made by it in
reliance upon Rule 144 under the Securities Act may be made only in accordance
with the terms and conditions of that Rule.

                (f) Accredited Investor. Holder is an "accredited investor"
within the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

        SECTION 11. REGISTRATION RIGHTS.

                (a) If, within one year of the date of this Warrant, the Company
shall file any registration statement under the Securities Act for purposes of a
public offering of the securities of the Company (including, but not limited to,
registration statements relating to secondary offerings of securities of the
Company, but excluding registration statements relating to employee benefit
plans and corporate reorganizations), then the Company will:

                        (A) Promptly give to Holder a written notice thereof
prior to such filing; and

                        (B) use its best efforts to include in such registration
(and any related qualification under blue sky laws or other compliance), except
as set forth in Section 12(b) below, and in any underwriting involved therein,
all of the Warrant Shares specified in a written request or requests made by
Holder and received by the Company within ten (10) days after the written notice
from the Company described in clause (A) above is mailed or delivered by the
Company. Such written request may specify all or a part of the Warrant Shares.

                (b) If the registration of which the Company gives notice to
Holder is for a registered public offering involving an underwriting, the
Company shall so advise Holder as a part of the written notice given pursuant to
Section 12(a)(A). In such event, the right of Holder to registration pursuant to
Section 12(a) shall be conditioned upon Holder's participation in such
underwriting and the inclusion of all or any part of the Warrant Shares
specified in Holder's notice in the underwriting to the extent provided herein.
Holder shall (together with the Company and the other holders of securities of
the Company with registration rights to participate therein distributing their
securities through such underwriting) enter into an underwriting agreement in
customary form with the representative of the underwriter or underwriters
selected by the Company.



                                       7.
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        Notwithstanding any other provision of Sections 12(a) or (b), if the
representative of the underwriters advises the Company in writing that marketing
factors require a limitation on the number of shares to be underwritten, the
representative may (subject to the limitations set forth below) exclude all of
the Warrant Shares from, or limit the number of Warrant Shares to be included
in, the registration and underwriting. The Company shall so advise Holder and
other holders of securities requesting registration, and the number of shares
that are entitled to be included in the registration and underwriting shall be
allocated first to the Company for securities being sold for its own account and
thereafter the number of shares that are entitled to be included in the
registration shall be allocated among Holder and other holders requesting
inclusion of shares on a pro rata basis, subject to any prior agreements among
the Company and its other stockholders, but only to the extent that such other
agreements provide for additional limitations on the number of shares such other
stockholders or the Company will be entitled to include in the registration,
which agreements are in effect as of the date hereof. If Holder or any other
person does not agree to the terms of any such underwriting, Holder and any
other such person shall be excluded therefrom by written notice from the Company
or the underwriter. Any Warrant Shares or other securities excluded or withdrawn
from such underwriting shall also be withdrawn from such registration.

                (c) As used herein, "Registration Expenses" shall mean all
expenses incurred by the Company in complying with this Section 12, including,
without limitation, all registration, qualification and filing fees; printing
expenses; fees and disbursements of counsel for the Company (and the fees and
disbursements of counsel for the Company in its capacity as counsel to Holder
and other holders hereunder; if Company counsel does not make itself available
for this purpose, the Company will pay the reasonable fees and disbursements of
one counsel for Holder and other holders as mutually agreed upon by all such
holders) and of the Company's independent accounting firm; 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). All Registration
Expenses in connection with any registration pursuant to Section 12(a) hereof
shall be borne by the Company; provided, however, that (A) any incremental
filing fees or other expenses incurred by the Company solely by reason of
Holder's exercise of registration rights pursuant to Section 12(a), and (B) any
underwriting discounts and commissions payable in connection with Holder's
exercise of registration rights pursuant to Section 12(a) shall be borne by
Holder.

                (d) The rights conferred upon Holder under this Section 12 may
be assigned by Holder to any permitted transferee of the Warrant Shares;
provided that such transfer complies with Section 10 hereof.

                (e) In the event any Warrant Shares are included in a
registration statement under Section 12(a):

                        (A) To the extent permitted by law, the Company will
indemnify and hold harmless Holder, the partners, officers, directors and legal
counsel of Holder, any underwriter (as defined in the Securities Act) for Holder
and each person, if any, who controls Holder or such underwriter within the
meaning of the Securities Act or the Exchange Act, against any losses, claims,
damages, or liabilities (joint or several) to which they may become 



                                       8.
<PAGE>   9

subject under the Securities Act, the Exchange Act or other federal or state
law, insofar as such losses, claims, damages or liabilities (or actions in
respect thereof) arise out of or are based upon any of the following statements,
omissions or violations (collectively a "Violation") by the Company: (i) any
untrue statement or alleged untrue statement of a material fact contained in
such registration statement, including any preliminary prospectus or final
prospectus contained therein or any amendments or supplements thereto, (ii) the
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
(iii) any violation or alleged violation by the Company of the Securities Act,
the Exchange Act, any state securities law or any rule or regulation promulgated
under the Securities Act, the Exchange Act or any state securities law in
connection with the offering covered by such registration statement; and the
Company will reimburse Holder and each partner, officer or director, underwriter
or controlling person for any legal or other expenses reasonably incurred by
them in connection with investigating or defending any such loss, claim, damage,
liability or action; provided, however, that the indemnity agreement contained
in this Section 12(e)(A) shall not apply to amounts paid in settlement of any
such loss, claim, damage, liability or action if such settlement is effected
without the consent of the Company, which consent shall not be unreasonably
withheld, nor shall the Company be liable in any such case for any such loss,
claim, damage, liability or action to the extent that it arises out of or is
based upon a Violation which occurs in reliance upon and in conformity with
written information furnished expressly for use in connection with such
registration by Holder or such partner, officer, director, underwriter or
controlling person of Holder.

                        (B) To the extent permitted by law, Holder will
indemnify and hold harmless the Company, each of its directors, its officers and
legal counsel and each person, if any, who controls the Company within the
meaning of the Securities Act, any underwriter and any other person selling
securities under such registration statement or any of such other person's
partners, directors or officers or any person who controls such person, against
any losses, claims, damages or liabilities (joint or several) to which the
Company or any such director, officer, controlling person, underwriter or other
such person, or partner, director, officer or controlling person of such person
may become subject under the Securities Act, the Exchange Act or other federal
or state law, insofar as such losses, claims, damages or liabilities (or actions
in respect thereto) arise out of or are based upon any Violation, in each case
to the extent (and only to the extent) that such Violation occurs in reliance
upon and in conformity with written information furnished by Holder under an
instrument duly executed by Holder and stated to be specifically for use in
connection with such registration; and Holder will reimburse any legal or other
expenses reasonably incurred by the Company or any such director, officer,
controlling person, underwriter or other person, or partner, officer, director
or controlling person of such other person in connection with investigating or
defending any such loss, claim, damage, liability or action if it is judicially
determined that there was such a Violation; provided, however, that the
indemnity agreement contained in this Section 12(e)(B) shall not apply to
amounts paid in settlement of any such loss, claim, damage, liability or action
if such settlement is effected without the consent of Holder, which consent
shall not be unreasonably withheld; provided further, that in no event shall any
indemnity under this Section 12(e)(B) exceed the net proceeds from the offering
received by such Holder. 



                                       9.
<PAGE>   10

                        (C) Promptly after receipt by an indemnified party under
this Section 12(e) of notice of the commencement of any action (including any
governmental action), such indemnified party will, if a claim in respect thereof
is to be made against any indemnifying party under this Section 12(e), deliver
to the indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an indemnified party shall
have the right to retain its own counsel, with the fees and expenses to be paid
by the indemnifying party, if representation of such indemnified party by the
counsel retained by the indemnifying party would be inappropriate due to actual
or potential differing interests between such indemnified party and any other
party represented by such counsel in such proceeding. The failure to deliver
written notice to the indemnifying party within a reasonable time of the
commencement of any such action, if materially prejudicial to its ability to
defend such action, shall relieve such indemnifying party of any liability to
the indemnified party under this Section 12(e), but the omission so to deliver
written notice to the indemnifying party will not relieve it of any liability
that it may have to any indemnified party otherwise than under this Section
12(e).

                        (D) If the indemnification provided for in this Section
12(e) is held by a court of competent jurisdiction to be unavailable to an
indemnified party with respect to any losses, claims, damages or liabilities
referred to herein, the indemnifying party, in lieu of indemnifying such
indemnified party thereunder, shall to the extent permitted by applicable law
contribute to the amount paid or payable by such indemnified party as a result
of such loss, claim, damage or liability 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 Violation(s) that resulted
in such loss, claim, damage or liability, as well as any other relevant
equitable considerations. The relative fault of the indemnifying party and of
the indemnified party shall be determined by a court of law by reference to,
among other things, whether the untrue or alleged untrue statement of a material
fact or the 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; provided, that in no event shall any contribution by
Holder hereunder exceed the proceeds from the offering received by Holder.

                        (E) The obligations of the Company and Holder under this
Section 12(e) shall survive completion of any offering of securities in a
registration statement pursuant to Section 12. No indemnifying party, in the
defense of any such claim or litigation, shall, except with the consent of each
indemnified party, 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.

        SECTION 12. SATURDAYS, SUNDAYS AND HOLIDAYS. If the last or appointed
day for the taking of any action or the expiration of any right required or
granted herein shall be a Saturday or a Sunday or shall be a legal holiday in
the State of California, then such action may 



                                      10.
<PAGE>   11

be taken or such right may be exercised on the next succeeding day not a
Saturday, Sunday or legal holiday in the State of California.

        SECTION 13. ISSUE TAX. The issuance of certificates for Common Stock
upon the exercise of the Warrant shall be made without charge to the holder of
the Warrant for any issue tax (other than any applicable income taxes) in
respect thereof; provided, however, that the Company shall not be required to
pay any tax which may be payable in respect of any transfer involved in the
issuance and delivery of any certificates in a name other than that of the then
Holder of the Warrant being exercised.

        SECTION 14. MODIFICATION AND WAIVER. Neither this Warrant nor any term
hereof may be changed, waived, discharged or terminated other than by an
instrument in writing signed by the Company and by Holder.

        SECTION 15. NOTICES. Unless otherwise specified herein, any notice,
request or other document required or permitted to be given or delivered to
Holder or the Company shall be given in writing and shall be deemed effectively
given (i) upon personal delivery to the party to be notified, (ii) three (3)
days after deposit in the United States mail if sent by registered or certified
mail, postage prepaid, or (iii) one (1) day after deposit with an overnight
courier, specifying next day delivery, with written verification of receipt. All
communications shall be sent to Holder at its address as shown on the books of
the Company, or to the Company at the address indicated therefor in the first
paragraph of this Warrant.

        SECTION 16. DESCRIPTIVE HEADINGS AND GOVERNING LAW. The description
headings of the several sections and paragraphs of this Warrant are inserted for
convenience only and do not constitute a part of this Warrant. This Warrant
shall be construed and enforced in accordance with, and the rights of the
parties shall be governed by, the laws of the State of California, without
regard to its conflicts of laws principles.

        SECTION 17. ATTORNEYS' FEES. In any litigation, arbitration or court
proceeding between the Company and Holder relating hereto, the prevailing party
shall be entitled to attorneys' fees and expenses and all costs of proceedings
incurred in enforcing this Warrant.

        SECTION 18. SURVIVAL. The representations, warranties, covenants and
conditions of the respective parties contained herein or made pursuant to this
Warrant shall survive the execution and delivery of this Warrant.

        SECTION 19. SEVERABILITY. In the event any one or more of the provisions
of this Warrant shall for any reason be held invalid, illegal or unenforceable,
the remaining provisions of this Warrant shall be unimpaired, and the invalid,
illegal or unenforceable provision shall be replaced by a mutually acceptable
valid, legal and enforceable provision, which comes closest to the intention of
the parties underlying the invalid, illegal or unenforceable provision.



                                      11.
<PAGE>   12

        IN WITNESS WHEREOF, the Company has duly caused this Warrant to be
signed by its duly authorized officer and to be dated as of the date first above
written.


                                            COMPANY:

                                            RIBOGENE, INC.


                                            By:
                                               ---------------------------------
                                               Charles J. Casamento
                                               Chief Executive Officer



                                      12.
<PAGE>   13

                                  PURCHASE FORM



                                                         Dated ___________, ____



        The undersigned hereby irrevocably elects to exercise the within Warrant
to purchase ______ shares of Common Stock and hereby makes payment of
$_____________ in payment of the exercise price thereof, together with all
applicable transfer taxes, if any.

        In exercising its rights to purchase the Common Stock of RiboGene, Inc.,
the undersigned hereby confirms and acknowledges the investment representations
and warranties made in Section 11 of the Warrant.

        Please issue a certificate or certificates representing said shares of
Common Stock in the name of the undersigned or in such other name as is
specified below.


                                            ------------------------------------
                                            (Name)


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




                                            HOLDER:

                                            REEDLAND CAPITAL PARTNERS



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

                                            Print Name:
                                                       -------------------------
                                            Title:
                                                  ------------------------------



                                      13.
<PAGE>   14

                                 ASSIGNMENT FORM

                                                          Dated _________, _____



        FOR VALUE RECEIVED, REEDLAND CAPITAL PARTNERS hereby sells, assigns and
transfers unto_________________________________________________________________ 
(the "Assignee"),             (please type or print in block letters)
________________________________________________________________________________
                                (insert address)
its right to purchase up to _______ shares of Common Stock represented by this
Warrant and does hereby irrevocably constitute and appoint
____________________________ attorney, to transfer the same on the books of the
Company, with full power of substitution in the premises.


                                            REEDLAND CAPITAL PARTNERS




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

                                            Print Name:
                                                       -------------------------

                                            Title:
                                                  ------------------------------



                                      14.
<PAGE>   15

                                 TRANSFER NOTICE



      (To transfer or assign the foregoing Warrant, execute this form and supply
      required information. Do not use this form to purchase shares.)

        FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced
thereby are hereby transferred and assigned to:

________________________________________________________________________________
                                 (Please Print)

whose address is _______________________________________________________________

________________________________________________________________________________




                                            Dated
                                                 -------------------------------

                                            Holder's Signature
                                                              ------------------

                                            Holder's Address
                                                              ------------------





Note:     The signature to this Transfer Notice must correspond with the name as
          it appears on the face of the Warrant, without alteration or
          enlargement or any change whatever. Officers of corporations and those
          acting in a fiduciary or other representative capacity should file
          proper evidence of authority to assign the foregoing Warrant.



                                      15.