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                                                                    EXHIBIT 4.13

NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE
EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR
THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM
REGISTRATION UNDER SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"),
AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE
EXEMPTION FROM THE REGISTRATION REQUIREMENTS THEREUNDER AND IN COMPLIANCE WITH
APPLICABLE STATE SECURITIES OR BLUE SKY LAWS.

                              NEOTHERAPEUTICS, INC.

                                 CLOSING WARRANT

Warrant No. C-1                                       Dated: September 29, 2000

         NeoTherapeutics, Inc., a Delaware corporation (the "Company"), hereby
certifies that, for value received, Montrose Investment Ltd., or its registered
assigns ("Holder"), is entitled, subject to the terms set forth below, to
purchase from the Company up to a total of 96,853 shares of common stock, $.001
par value per share (the "Common Stock"), of the Company (each such share, a
"Warrant Share" and all such shares, the "Warrant Shares") at an exercise price
equal to $10.13 per share (as adjusted from time to time as provided in Section
9, the "Exercise Price"), at any time and from time to time from and after the
date hereof and through and including September 29, 2005 (the "Expiration
Date"), and subject to the following terms and conditions:

                  1. Registration of Warrant. The Company shall register this
Warrant, upon records to be maintained by the Company for that purpose (the
"Warrant Register"), in the name of the record Holder hereof from time to time.
The Company may deem and treat the registered Holder of this Warrant as the
absolute owner hereof for the purpose of any exercise hereof or any distribution
to the Holder, and for all other purposes, and the Company shall not be affected
by notice to the contrary.
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                  2.       Registration of Transfers and Exchanges.

                           (a) This Warrant may only be transferred pursuant to
an effective registration statement under the Securities Act, to the Company or
pursuant to an available exemption from or in a transaction not subject to the
registration requirements of the Securities Act. In connection with any transfer
of this Warrant other than pursuant to an effective registration statement or to
the Company, the Company may require the transferor thereof to provide to the
Company an opinion of counsel selected by the transferor, the form and substance
of which opinion shall be reasonably satisfactory to the Company, to the effect
that such transfer does not require registration of such Warrant under the
Securities Act. Holder agrees to the imprinting, so long as is required by this
Section 2(a), of a legend substantially similar to that first above written on
any New Warrant (as defined below). Any such transferee shall agree in writing
to be bound by the terms of this Warrant and shall have the rights of Holder
under this Warrant.

                           (b) The Company shall register the transfer of any
portion of this Warrant in the Warrant Register, upon surrender of this Warrant,
with the Form of Assignment attached hereto duly completed and signed, to the
Transfer Agent or to the Company at the office specified in or pursuant to
Section 3(b). Upon any such registration or transfer, a new warrant to purchase
Common Stock, in substantially the form of this Warrant (any such new warrant, a
"New Warrant"), evidencing the portion of this Warrant so transferred shall be
issued to the transferee and a New Warrant evidencing the remaining portion of
this Warrant not so transferred, if any, shall be issued to the transferring
Holder. The acceptance of the New Warrant by the transferee thereof shall be
deemed the acceptance of such transferee of all of the rights and obligations of
a holder of a Warrant.

                           (c) This Warrant is exchangeable, upon the surrender
hereof by the Holder to the office of the Company specified in or pursuant to
Section 3(b) for one or more New Warrants, evidencing in the aggregate the right
to purchase the number of Warrant Shares which may then be purchased hereunder.
Any such New Warrant will be dated the date of such exchange.

                  3.       Duration and Exercise of Warrants.

                           (a) This Warrant shall be exercisable by the
registered Holder on any business day before 8:00 P.M., New York City time, at
any time and from time to time on or after the date hereof to and including the
Expiration Date. At 8:00 P.M., New York City time on the Expiration Date, the
portion of this Warrant not exercised prior thereto shall be and become void and
of no value. Prior to the Expiration Date, the Company may not call or otherwise
redeem this Warrant without the prior written consent of the Holder.

                           (b) Subject to Sections 2(b), 6 and 10, upon
surrender of this Warrant, with the Form of Election to Purchase attached hereto
duly completed and signed, to the Company at its address for notice set forth in
Section 13 and upon payment of the Exercise Price multiplied by the number of
Warrant Shares that the Holder intends to purchase hereunder, in the manner
provided hereunder, all as specified by the Holder in the Form of Election to
Purchase, the Company shall promptly (but in no event later than 3 business days
after the Date of Exercise (as defined

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herein)) issue or cause to be issued and cause to be delivered to or upon the
written order of the Holder and in such name or names as the Holder may
designate, a certificate for the Warrant Shares issuable upon such exercise,
free of restrictive legends except (i) either in the event that a registration
statement covering the resale of the Warrant Shares and naming the Holder as a
selling stockholder thereunder is not then effective or the Warrant Shares are
not freely transferable without volume restrictions pursuant to Rule 144(k)
promulgated under the Securities Act of 1933, as amended (the "Securities Act"),
or (ii) if this Warrant shall have been issued pursuant to a written agreement
between the original Holder and the Company, as required by such agreement. Any
person so designated by the Holder to receive Warrant Shares shall be deemed to
have become holder of record of such Warrant Shares as of the Date of Exercise
of this Warrant.

                           A "Date of Exercise" means the date on which the
Company shall have received (i) this Warrant (or any New Warrant, as
applicable), with the Form of Election to Purchase attached hereto (or attached
to such New Warrant) appropriately completed and duly signed, and (ii) payment
of the Exercise Price for the number of Warrant Shares so indicated by the
holder hereof to be purchased.

                           (c) This Warrant shall be exercisable, either in its
entirety or, from time to time, for a portion of the number of Warrant Shares.
If less than all of the Warrant Shares which may be purchased under this Warrant
are exercised at any time, the Company shall issue or cause to be issued, at its
expense, a New Warrant evidencing the right to purchase the remaining number of
Warrant Shares for which no exercise has been evidenced by this Warrant.

                  4. Piggyback Registration Rights. During the Effectiveness
Period (as defined in the Registration Rights Agreement, of even date herewith,
between the Company and the original Holder), the Company may not file any
registration statement with the Securities and Exchange Commission (other than
registration statements of the Company filed on Form S-8 or Form S-4, each as
promulgated under the Securities Act, pursuant to which the Company is
registering securities pursuant to a Company employee benefit plan or pursuant
to a merger, acquisition or similar transaction including supplements thereto,
but not additionally filed registration statements in respect of such
securities) at any time when there is not an effective registration statement
covering the resale of the Warrant Shares and naming the Holder as a selling
stockholder thereunder, unless the Company provides the Holder with not less
than 20 days notice of its intention to file such registration statement and
provides the Holder the option to include any or all of the applicable Warrant
Shares therein. The piggyback registration rights granted to the Holder pursuant
to this Section shall continue until all of the Holder's Warrant Shares have
been sold in accordance with an effective registration statement or upon the
expiration of the Effective Period. The Company will pay all registration
expenses in connection therewith.

                  5. Demand Registration Rights. During the Effectiveness Period
if the Warrant Shares are not registered pursuant to an effective registration
statement, the Holder may make a written request for the registration under the
Securities Act (a "Demand Registration"), of all of the Warrant Shares (the
"Registrable Securities"), and the Company shall use its best efforts to effect
such Demand Registration as promptly as possible, but in any case within 90 days
thereafter. Any

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request for a Demand Registration shall specify the aggregate number of
Registrable Securities proposed to be sold and shall also specify the intended
method of disposition thereof. The right to cause a registration of the
Registrable Securities under this Section 5 shall be limited to one such
registration. In any registration initiated as a Demand Registration, the
Company will pay all of its registration expenses in connection therewith. A
Demand Registration shall not be counted as a Demand Registration hereunder
until the registration statement filed pursuant to the Demand Registration has
been declared effective by the Securities and Exchange Commission and maintained
continuously effective for a period of at least 360 days or such shorter period
when all Registrable Securities included therein have been sold in accordance
with such registration statement, provided, however that any days on which such
registration statement is not effective or on which the Holder is not permitted
by the Company or any governmental authority to sell Warrant Shares under such
registration statement shall not count towards such 360 day period.

                  6. Payment of Taxes. The Company will pay all documentary
stamp taxes attributable to the issuance of Warrant Shares upon the exercise of
this Warrant; 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
registration of any certificates for Warrant Shares or Warrants in a name other
than that of the Holder. The Holder shall be responsible for all other tax
liability that may arise as a result of holding or transferring this Warrant or
receiving Warrant Shares upon exercise hereof.

                  7. Replacement of Warrant. If this Warrant is mutilated, lost,
stolen or destroyed, the Company shall issue or cause to be issued in exchange
and substitution for and upon cancellation hereof, or in lieu of and
substitution for this Warrant, a New Warrant, but only upon receipt of evidence
reasonably satisfactory to the Company of such loss, theft or destruction and
indemnity, if requested, satisfactory to it. Applicants for a New Warrant under
such circumstances shall also comply with such other reasonable regulations and
procedures and pay such other reasonable charges as the Company may prescribe.

                  8. Reservation of Warrant Shares. The Company covenants that
it will at all times reserve and keep available out of the aggregate of its
authorized but unissued Common Stock, solely for the purpose of enabling it to
issue Warrant Shares upon exercise of this Warrant as herein provided, the
number of Warrant Shares which are then issuable and deliverable upon the
exercise of this entire Warrant, free from preemptive rights or any other actual
contingent purchase rights of persons other than the Holder (taking into account
the adjustments and restrictions of Section 9). The Company covenants that all
Warrant Shares that shall be so issuable and deliverable shall, upon issuance
and the payment of the applicable Exercise Price in accordance with the terms
hereof, be duly and validly authorized, issued and fully paid and nonassessable.

                  9. Certain Adjustments. The Exercise Price and number of
Warrant Shares issuable upon exercise of this Warrant are subject to adjustment
from time to time as set forth in

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this Section 9. Upon each such adjustment of the Exercise Price pursuant to this
Section 9, the Holder shall thereafter prior to the Expiration Date be entitled
to purchase, at the Exercise Price resulting from such adjustment, the number of
Warrant Shares obtained by multiplying the Exercise Price in effect immediately
prior to such adjustment by the number of Warrant Shares issuable upon exercise
of this Warrant immediately prior to such adjustment and dividing the product
thereof by the Exercise Price resulting from such adjustment. Notwithstanding
anything to the contrary set forth herein, no adjustment shall be made hereunder
to the Exercise Price due to (i) the adoption by the Company of a shareholders
rights plan, (ii) the creation of "rights" under such a plan that are evidenced
by the shares of Common Stock to which they are attached, but adjustments would
be made if such rights are ever separated from such shares of Common Stock or
otherwise become evidenced by a separate certificate or if, for any other
reason, such rights would entitle the holders thereof or of the Common Stock to
which they attach to receive shares of Common Stock , (iii) the granting of
options or warrants to employees, officers, directors, consultants and other
service providers, and the issuance of shares upon exercise of options granted,
under any stock option plan heretofore or hereinafter duly adopted by the
Company, (iv) shares of Common Stock issuable upon exercise of currently
outstanding options and warrants and upon conversion of any currently
outstanding convertible securities of the Company, in each case to the extent
disclosed in Schedule 2.1(c) to the Securities Purchase Agreement but not with
respect to any amendment or modification thereof, (v) shares of Common Stock
issuable in connection with a Strategic Transaction (as defined in Section 3.9
of the Securities Purchase Agreement), (vi) an underwritten public offering of
Common Stock resulting in net proceeds to the Company in excess of $10,000,000,
(vii) warrants issuable to Brighton Capital, Ltd. in connection with the
Securities Purchase Agreement and the issuance of shares upon exercise thereof,
(viii) warrants to be issued by the Company to Kingsbridge Capital Limited to
purchase 25,000 shares of Common Stock and the issuance of shares upon exercise
thereof, (ix) the granting of warrants to purchase up to 10,000 shares of Common
Stock in connection with equipment leasing or other debt financing transactions,
and (x) the issuance of shares of Common Stock issuable pursuant to the Private
Equity Line of Credit Agreement dated March 27, 1998 between the Company and
Kingsbridge Capital Limited.

                           (a) If the Company, at any time while this Warrant is
outstanding, (i) shall pay a stock dividend (except scheduled dividends paid on
outstanding preferred stock as of the date hereof which contain a stated
dividend rate) or otherwise make a distribution or distributions on shares of
its Common Stock or on any other class of capital stock payable in shares of
Common Stock, (ii) subdivide outstanding shares of Common Stock into a larger
number of shares, or (iii) combine outstanding shares of Common Stock into a
smaller number of shares, the Exercise Price shall be multiplied by a fraction
of which the numerator shall be the number of shares of Common Stock (excluding
treasury shares, if any) outstanding before such event and of which the
denominator shall be the number of shares of Common Stock (excluding treasury
shares, if any) outstanding after such event. Any adjustment made pursuant to
this Section shall become effective immediately after the record date for the
determination of stockholders entitled to receive such dividend or distribution
and shall become effective immediately after the effective

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date in the case of a subdivision or combination, and shall apply to successive
subdivisions and combinations.

                           (b) In case of any reclassification of the Common
Stock or any compulsory share exchange pursuant to which the Common Stock is
converted into other securities, cash or property, then the Holder shall have
the right thereafter to exercise this Warrant only into the shares of stock and
other securities and property receivable upon or deemed to be held by holders of
Common Stock following such reclassification or share exchange, and the Holder
shall be entitled upon such event to receive such amount of securities or
property equal to the amount of Warrant Shares such Holder would have been
entitled to had such Holder exercised this Warrant immediately prior to such
reclassification or share exchange. The terms of any such reclassification or
share exchange shall include such terms so as to continue to give to the Holder
the right to receive the securities or property set forth in this Section 9(b)
upon any exercise following any such reclassification or share exchange.

                           (c) If the Company, at any time while this Warrant is
outstanding, shall distribute to all holders of Common Stock (and not to holders
of this Warrant) evidences of its indebtedness or assets or rights or warrants
to subscribe for or purchase any security (excluding those referred to in
Sections 9(a), (b) and (d)), then in each such case the Exercise Price shall be
determined by multiplying the Exercise Price in effect immediately prior to the
record date fixed for determination of stockholders entitled to receive such
distribution by a fraction of which the denominator shall be the Exercise Price
determined as of the record date mentioned above, and of which the numerator
shall be such Exercise Price on such record date less the then fair market value
at such record date of the portion of such assets or evidence of indebtedness so
distributed applicable to one outstanding share of Common Stock as determined by
the Company's independent certified public accountants that regularly examines
the financial statements of the Company (an "Appraiser").

                           (d) If at any time the Company or any subsidiary
thereof, as applicable with respect to Common Stock Equivalents (as defined
below), shall issue: (x) shares of Common Stock at a price per share less than
both the market price of the Common Stock at the time of issuance of such Common
Stock and the Exercise Price then in effect, or (y) rights, warrants, options or
other securities or debt that is convertible into or exchangeable for shares of
Common Stock ("Common Stock Equivalents"), entitling any person or entity to
acquire shares of Common Stock at a price per share less than both the market
price of the Common Stock at the time of issuance of such Common Stock and the
Exercise Price then in effect (if the holder of the Common Stock Equivalent so
issued shall at any time, whether by operation of purchase price adjustments,
reset provisions, floating conversion, exercise or exchange prices or otherwise,
be entitled to receive shares of Common Stock at a price less than (i) the
Exercise Price; (ii) the market price of the Common Stock at the time of such
adjustment and (iii) the market price of the Common Stock at the time such
shares of Common Stock are acquired, such issuance shall be deemed to have
occurred for less than such Exercise Price and the market price), then,
forthwith upon such

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issue or sale, at the option of the Holder, the Exercise Price shall be reduced
to the price (calculated to the nearest cent) determined by multiplying the
Exercise Price in effect immediately prior thereto by a fraction, the numerator
of which shall be the sum of (i) the number of shares of Common Stock
outstanding immediately prior to such issuance, and (ii) the number of shares of
Common Stock which the aggregate consideration received (or to be received,
assuming exercise or conversion in full of such Common Stock Equivalents) for
the issuance of such additional shares of Common Stock would purchase at the
Exercise Price, and the denominator of which shall be the sum of the number of
shares of Common Stock outstanding immediately after the issuance of such
additional shares. For purposes hereof, all shares of Common Stock that are
issuable upon conversion, exercise or exchange of Common Stock Equivalents shall
be deemed outstanding immediately after the issuance of such Common Stock
Equivalents. Such adjustment shall be made whenever such Common Stock or Common
Stock Equivalents are issued, or, if the maximum number of shares of Common
Stock issuable upon conversion, exercise or exchange of a Common Stock
Equivalent is not determined at the time of issuance of such Common Stock
Equivalent, such adjustment shall be made at such time as the maximum number of
shares of Common Stock issuable upon conversion, exercise or exchange of such
Common Stock Equivalent becomes determinable. However, upon the expiration of
any Common Stock Equivalents the issuance of which resulted in an adjustment in
the Exercise Price pursuant to this Section, if any such Common Stock
Equivalents shall expire or be surrendered to the Company and shall not have
been exercised, converted or exchanged in full or shall have been exercised,
converted or exchanged for less than the number of shares of Common Stock used
in computing such adjustment, the Exercise Price shall immediately upon such
expiration be recomputed and effective immediately upon such expiration be
increased to the price which it would have been (but reflecting any other
adjustments in the Exercise Price made pursuant to the provisions of this
Section after the issuance of such Common Stock Equivalents) had the adjustment
of the Exercise Price made upon the issuance of such Common Stock Equivalents
been made on the basis of offering for subscription or purchase only that number
of shares of the Common Stock actually purchased upon the exercise of such
Common Stock Equivalents actually exercised. Notwithstanding anything to the
contrary contained herein, other than adjustments resulting from the expiration
of Common Stock Equivalents, no adjustment shall be made to the Exercise Price
upon: (i) the issuance of shares of Common Stock upon the exercise, conversion
or exchange of any Common Stock Equivalents outstanding as of the date of
issuance of this Warrant, or (ii) any change in the number of shares of Common
Stock issuable upon the exercise, conversion or exchange of any Common Stock
Equivalents outstanding as of the date of issuance of this Warrant, including,
without limitation, changes occurring by operation of purchase price
adjustments, reset provisions, anti-dilution provisions or floating conversion,
exercise or exchange prices.

                           (e) In case of any (1) merger or consolidation of the
Company with or into another Person, or (2) sale by the Company of more than
one-half of the assets of the Company (on a book value basis) in one or a series
of related transactions, or (3) tender or other offer or exchange (whether by
the Company or another Person) pursuant to which holders of Common Stock

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are permitted to tender or exchange their shares for other securities, stock,
cash or property of the Company or another Person; then the Holder shall have
the right thereafter to (A) exercise this Warrant for the shares of stock and
other securities, cash and property receivable upon or deemed to be held by
holders of Common Stock following such merger, consolidation or sale, and the
Holder shall be entitled upon such event or series of related events to receive
such amount of securities, cash and property as the Common Stock for which this
Warrant could have been exercised immediately prior to such merger,
consolidation or sales would have been entitled, (B) in the case of a merger or
consolidation, (x) require the surviving entity to issue to the Holder a warrant
entitling the Holder to acquire shares of such entity's common stock, which
warrant shall have terms identical (including with respect to exercise) to the
terms of this Warrant and shall be entitled to all of the rights and privileges
set forth herein and the agreements pursuant to which this Warrant was issued
(including, without limitation, as such rights relate to the acquisition,
transferability, registration and listing of such shares of stock other
securities issuable upon exercise thereof), or (C) in the event of an exchange
or tender offer or other transaction contemplated by clause (3) of this Section,
tender or exchange this Warrant for such securities, stock, cash and other
property receivable upon or deemed to be held by holders of Common Stock that
have tendered or exchanged their shares of Common Stock following such tender or
exchange, and the Holder shall be entitled upon such exchange or tender to
receive such amount of securities, cash and property as the shares of Common
Stock for which this Warrant could have been exercised immediately prior to such
tender or exchange would have been entitled as would have been issued. In the
case of clause (B), the exercise price applicable for the newly issued warrant
shall be based upon the amount of securities, cash and property that each shares
of Common Stock would receive in such transaction and the Exercise Price
immediately prior to the effectiveness or closing date for such transaction. The
terms of any such merger, sale, consolidation, tender or exchange shall include
such terms so as continue to give the Holder the right to receive the
securities, cash and property set forth in this Section upon any conversion or
redemption following such event. This provision shall similarly apply to
successive such events.

                           (f) For the purposes of this Section 9, the following
clauses shall also be applicable:

                                    (i) Record Date. In case the Company shall
take a record of the holders of its Common Stock for the purpose of entitling
them (A) to receive a dividend or other distribution payable in Common Stock or
in securities convertible or exchangeable into shares of Common Stock, or (B) to
subscribe for or purchase Common Stock or securities convertible or exchangeable
into shares of Common Stock, then such record date shall be deemed to be the
date of the issue or sale of the shares of Common Stock deemed to have been
issued or sold upon the declaration of such dividend or the making of such other
distribution or the date of the granting of such right of subscription or
purchase, as the case may be.

                                    (ii) Treasury Shares. The number of shares
of Common Stock outstanding at any given time shall not include shares owned or
held by or for the account of the Company, and the disposition of any such
shares shall be considered an issue or sale of Common Stock.

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                           (g) All calculations under this Section 9 shall be
made to the nearest cent or the nearest 1/100th of a share, as the case may be.

                           (h) Whenever the Exercise Price is adjusted pursuant
to Section 9(c) above, the Holder, after receipt of the determination by the
Appraiser, shall have the right to select an additional appraiser (which shall
be a nationally recognized accounting firm), in which case the adjustment shall
be equal to the average of the adjustments recommended by each of the Appraiser
and such appraiser. The Holder shall promptly mail or cause to be mailed to the
Company, a notice setting forth the Exercise Price after such adjustment and
setting forth a brief statement of the facts requiring such adjustment. Such
adjustment shall become effective immediately after the record date mentioned
above.

                           (i) If:

                                    (i)         the Company shall declare a
                                                dividend (or any other
                                                distribution) on its Common
                                                Stock; or

                                    (ii)        the Company shall declare a
                                                special nonrecurring cash
                                                dividend on or a redemption of
                                                its Common Stock; or

                                    (iii)       the Company shall authorize the
                                                granting to all holders of the
                                                Common Stock rights or warrants
                                                to subscribe for or purchase any
                                                shares of capital stock of any
                                                class or of any rights; or

                                    (iv)        the approval of any stockholders
                                                of the Company shall be required
                                                in connection with any
                                                reclassification of the Common
                                                Stock, any consolidation or
                                                merger to which the Company is a
                                                party, any sale or transfer of
                                                all or substantially all of the
                                                assets of the Company, or any
                                                compulsory share exchange
                                                whereby the Common Stock is
                                                converted into other securities,
                                                cash or property; or

                                    (v)         the Company shall authorize the
                                                voluntary dissolution,
                                                liquidation or winding up of the
                                                affairs of the Company,

then the Company shall cause to be mailed to each Holder at their last addresses
as they shall appear upon the Warrant Register, at least 30 calendar days prior
to the applicable record or effective date hereinafter specified, a notice
stating (x) the date on which a record is to be taken for the purpose of such
dividend, distribution, redemption, rights or warrants, or if a record is not to
be taken, the date as of which the holders of Common Stock of record to be
entitled to such dividend, distributions, redemption, rights or warrants are to
be determined or (y) the date on which such

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reclassification, consolidation, merger, sale, transfer or share exchange is
expected to become effective or close, and the date as of which it is expected
that holders of Common Stock of record shall be entitled to exchange their
shares of Common Stock for securities, cash or other property deliverable upon
such reclassification, consolidation, merger, sale, transfer, share exchange,
dissolution, liquidation or winding up; provided, however, that the failure to
mail such notice or any defect therein or in the mailing thereof shall not
affect the validity of the corporate action required to be specified in such
notice.

                  10. Payment of Exercise Price. The Holder shall pay the
Exercise Price in one of the following manners:

                           (a) Cash Exercise. The Holder may deliver immediately
available funds; or

                           (b) Cashless Exercise. The Holder may surrender this
Warrant to the Company together with a notice of cashless exercise, in which
event the Company shall issue to the Holder the number of Warrant Shares
determined as follows:

                                X = Y (A-B)/A
         where:
                                X = the number of Warrant Shares to be issued
                                to the Holder.

                                Y = the number of Warrant Shares with respect to
                                which this Warrant is being exercised.

                                A = the average of the closing sale prices of
                                the Common Stock for the five (5) trading days
                                immediately prior to (but not including) the
                                Date of Exercise.

                                B = the Exercise Price.

For purposes of Rule 144 promulgated under the Securities Act, it is intended,
understood and acknowledged that the Warrant Shares issued in a cashless
exercise transaction shall be deemed to have been acquired by the Holder, and
the holding period for the Warrant Shares shall be deemed to have been
commenced, on the issue date.

         11. Certain Exercise Restrictions. (a) A Holder may not exercise this
Warrant to the extent such exercise would result in the Holder, together with
any affiliate thereof, beneficially owning (as determined in accordance with
Section 13(d) of the Securities Exchange Act 1934, as amended and the rules
promulgated thereunder) in excess of 4.999% of the then issued and outstanding
shares of Common Stock, including shares of Common Stock issuable upon such
exercise and held by such Holder after application of this Section. Since the
Holder will not be obligated to report to the Company the number of shares of
Common Stock it may hold at the time of an exercise hereunder, unless the
exercise at issue would result in the issuance of shares of

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Common Stock in excess of 4.999% of the then outstanding shares of Common Stock
without regard to any other shares of Common Stock which may be beneficially
owned by the Holder or an affiliate thereof, the Holder shall have the authority
and obligation to determine whether the restriction contained in this Section
will limit any particular exercise hereunder and to the extent that the Holder
determines that the limitation contained in this Section applies, the
determination of which portion of this Warrant is exercisable shall be the
responsibility and obligation of the Holder. If the Holder has delivered a Form
of Election to Purchase for a number of Warrant Shares that would result in the
issuance in excess of the permitted amount hereunder, the Company shall notify
the Holder of this fact and shall honor the exercise for the maximum portion of
this Warrant permitted to be exercised on such Date of Exercise in accordance
with the periods described herein and disregard the balance of such Form of
Election to Purchase, as if never delivered The provisions of this Section may
be waived by a Holder (but only as to itself and not to any other Holder) upon
not less than 61 days prior notice to the Company. Other Holders shall be
unaffected by any such waiver.

                  (b) A Holder may not exercise this Warrant to the extent such
exercise would result in the Holder, together with any affiliate thereof,
beneficially owning (as determined in accordance with Section 13(d) of the
Securities Exchange Act 1934, as amended and the rules promulgated thereunder)
in excess of 9.999% of the then issued and outstanding shares of Common Stock,
including shares of Common Stock issuable upon such exercise and held by such
Holder after application of this Section. Since the Holder will not be obligated
to report to the Company the number of shares of Common Stock it may hold at the
time of an exercise hereunder, unless the exercise at issue would result in the
issuance of shares of Common Stock in excess of 9.999% of the then outstanding
shares of Common Stock without regard to any other shares of Common Stock which
may be beneficially owned by the Holder or an affiliate thereof, the Holder
shall have the authority and obligation to determine whether the restriction
contained in this Section will limit any particular exercise hereunder and to
the extent that the Holder determines that the limitation contained in this
Section applies, the determination of which portion of this Warrant is
exercisable shall be the responsibility and obligation of the Holder. If the
Holder has delivered a Form of Election to Purchase for a number of Warrant
Shares that would result in the issuance in excess of the permitted amount
hereunder, the Company shall notify the Holder of this fact and shall honor the
exercise for the maximum portion of this Warrant permitted to be exercised on
such Date of Exercise in accordance with the periods described herein and
disregard the balance of such Form of Election to Purchase, as if never
delivered The provisions of this Section may be waived by a Holder (but only as
to itself and not to any other Holder) upon not less than 61 days prior notice
to the Company. Other Holders shall be unaffected by any such waiver.

                  12. Fractional Shares. The Company shall not be required to
issue or cause to be issued fractional Warrant Shares on the exercise of this
Warrant. The number of full Warrant Shares which shall be issuable upon the
exercise of this Warrant shall be computed on the basis of the aggregate number
of Warrant Shares purchasable on exercise of this Warrant so presented. If any
fraction of a Warrant Share would, except for the provisions of this Section, be
issuable on the exercise of this Warrant, the Company shall pay an amount in
cash equal to the Exercise Price multiplied by such fraction.

                                      -11-
<PAGE>   12
                  13. Notices. Any and all notices or other communications or
deliveries hereunder shall be in writing and shall be deemed given and effective
on the earliest of (i) the date of transmission, if such notice or communication
is delivered via facsimile at the facsimile telephone number specified in this
Section prior to 8:00 p.m. (New York City time) on a business day, (ii) the
business day after the date of transmission, if such notice or communication is
delivered via facsimile at the facsimile telephone number specified in this
Section later than 8:00 p.m. (New York City time) on any date and earlier than
11:59 p.m. (New York City time) on such date, (iii) the business day following
the date of mailing, if sent by nationally recognized overnight courier service,
or (iv) if sent other than by the methods set forth in (i)-(iii) of this
section, upon actual receipt by the party to whom such notice is required to be
given. The addresses for such communications shall be: (i) if to the Company, to
157 Technology Drive, Irvine, CA 92618, Attention: Chief Financial Officer, or
to Facsimile No. (949) 788-6706, or (ii) if to the Holder, to the Holder at the
address or facsimile number appearing on the Warrant Register or such other
address or facsimile number as the Holder may provide to the Company in
accordance with this Section.

                  14. Warrant Agent. The Company shall serve as warrant agent
under this Warrant. Upon thirty (30) days' notice to the Holder, the Company may
appoint a new warrant agent. Any corporation into which the Company or any new
warrant agent may be merged or any corporation resulting from any consolidation
to which the Company or any new warrant agent shall be a party or any
corporation to which the Company or any new warrant agent transfers
substantially all of its corporate trust or shareholders services business shall
be a successor warrant agent under this Warrant without any further act. Any
such successor warrant agent shall promptly cause notice of its succession as
warrant agent to be mailed (by first class mail, postage prepaid) to the Holder
at the Holder's last address as shown on the Warrant Register.

                  15. Miscellaneous.

                           (a) This Warrant shall be binding on and inure to the
benefit of the parties hereto and their respective successors and assigns. This
Warrant may be amended only in writing signed by the Company and the Holder and
their successors and assigns.

                           (b) Subject to Section 15(a), above, nothing in this
Warrant shall be construed to give to any person or corporation other than the
Company and the Holder any legal or equitable right, remedy or cause under this
Warrant. This Warrant shall inure to the sole and exclusive benefit of the
Company and the Holder.

                           (c) The corporate laws of the State of Delaware shall
govern all issues concerning the relative rights of the Company and its
stockholders. All other questions concerning the construction, validity,
enforcement and interpretation of this Warrant shall be governed by and
construed and enforced in accordance with the internal laws of the State of New
York, without regard to the principles of conflicts of law thereof. The Company
and the Holder hereby irrevocably submit to the exclusive jurisdiction of the
state and federal courts sitting in the City

                                      -12-
<PAGE>   13
of New York, borough of Manhattan, for the adjudication of any dispute hereunder
or in connection herewith or with any transaction contemplated hereby or
discussed herein, and hereby irrevocably waives, and agrees not to assert in any
suit, action or proceeding, any claim that it is not personally subject to the
jurisdiction of any such court, or that such suit, action or proceeding is
improper. Each of the Company and the Holder hereby irrevocably waives personal
service of process and consents to process being served in any such suit, action
or proceeding by receiving a copy thereof sent to the Company at the address in
effect for notices to it under this instrument and agrees that such service
shall constitute good and sufficient service of process and notice thereof.
Nothing contained herein shall be deemed to limit in any way any right to serve
process in any manner permitted by law.

                           (d) The headings herein are for convenience only, do
not constitute a part of this Warrant and shall not be deemed to limit or affect
any of the provisions hereof.

                           (e) In case any one or more of the provisions of this
Warrant shall be invalid or unenforceable in any respect, the validity and
enforceability of the remaining terms and provisions of this Warrant shall not
in any way be affected or impaired thereby and the parties will attempt in good
faith to agree upon a valid and enforceable provision which shall be a
commercially reasonable substitute therefor, and upon so agreeing, shall
incorporate such substitute provision in this Warrant.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                             SIGNATURE PAGE FOLLOWS]

                                      -13-
<PAGE>   14
                  IN WITNESS WHEREOF, the Company has caused this Warrant to be
duly executed by its authorized officer as of the date first indicated above.

                                    NEOTHERAPEUTICS, INC.

                                    By:  /s/ Samuel Gulko
                                         ---------------------------------------
                                    Name:  Samuel Gulko
                                         ---------------------------------------
                                    Title:  Chief Financial Officer
                                         ---------------------------------------
<PAGE>   15
                          FORM OF ELECTION TO PURCHASE

(To be executed by the Holder to exercise the right to purchase shares of Common
Stock under the foregoing Warrant)

To NeoTherapeutics, Inc.:

         In accordance with the Warrant enclosed with this Form of Election to
Purchase, the undersigned hereby irrevocably elects to purchase _____________
shares of common stock, $.001 par value per share, of NeoTherapeutics, Inc. (the
"Common Stock") and , if such Holder is not utilizing the cashless exercise
provisions set forth in this Warrant, encloses herewith $________ in cash,
certified or official bank check or checks, which sum represents the aggregate
Exercise Price (as defined in the Warrant) for the number of shares of Common
Stock to which this Form of Election to Purchase relates, together with any
applicable taxes payable by the undersigned pursuant to the Warrant.

         The undersigned requests that certificates for the shares of Common
Stock issuable upon this exercise be issued in the name of

                                                PLEASE INSERT SOCIAL SECURITY OR
                                                TAX IDENTIFICATION NUMBER

                                                ________________________________

________________________________________________________________________________
                         (Please print name and address)

         If the number of shares of Common Stock issuable upon this exercise
shall not be all of the shares of Common Stock which the undersigned is entitled
to purchase in accordance with the enclosed Warrant, the undersigned requests
that a New Warrant (as defined in the Warrant) evidencing the right to purchase
the shares of Common Stock not issuable pursuant to the exercise evidenced
hereby be issued in the name of and delivered to:

________________________________________________________________________________
                         (Please print name and address)

________________________________________________________________________________

________________________________________________________________________________

Dated:___________ ,                             Name of Holder:

                                                (Print)_________________________

                                                (By:)___________________________
                                                (Name:)
                                                (Title:)

                                                 (Signature must conform in all
                                                 respects to name of holder as
                                                 specified on the face of the
                                                 Warrant)
<PAGE>   16
                               FORM OF ASSIGNMENT

           [To be completed and signed only upon transfer of Warrant]

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers
unto ________________________________ the right represented by the within
Warrant to purchase ____________ shares of Common Stock of NeoTherapeutics, Inc.
to which the within Warrant relates and appoints ________________ attorney to
transfer said right on the books of NeoTherapeutics, Inc. with full power of
substitution in the premises.

Dated:

_____________________

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

                                           ____________________________________
                                           Address of Transferee

                                           ____________________________________

                                           ____________________________________

In the presence of:

__________________________________<PAGE>   1
                                                                    EXHIBIT 4.14

NEITHER THESE SECURITIES NOR THE SECURITIES INTO WHICH THESE SECURITIES ARE
EXERCISABLE HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR
THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM
REGISTRATION UNDER SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"),
AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE
EXEMPTION FROM THE REGISTRATION REQUIREMENTS THEREUNDER AND IN COMPLIANCE WITH
APPLICABLE STATE SECURITIES OR BLUE SKY LAWS.

                              NEOTHERAPEUTICS, INC.

                                 CLOSING WARRANT

Warrant No. C-2                                        Dated: September 29, 2000

         NeoTherapeutics, Inc., a Delaware corporation (the "Company"), hereby
certifies that, for value received, Strong River Investments, Inc., or its
registered assigns ("Holder"), is entitled, subject to the terms set forth
below, to purchase from the Company up to a total of 96,853 shares of common
stock, $.001 par value per share (the "Common Stock"), of the Company (each such
share, a "Warrant Share" and all such shares, the "Warrant Shares") at an
exercise price equal to $10.13 per share (as adjusted from time to time as
provided in Section 9, the "Exercise Price"), at any time and from time to time
from and after the date hereof and through and including September 29, 2005 (the
"Expiration Date"), and subject to the following terms and conditions:

                  1. Registration of Warrant. The Company shall register this
Warrant, upon records to be maintained by the Company for that purpose (the
"Warrant Register"), in the name of the record Holder hereof from time to time.
The Company may deem and treat the registered Holder of this Warrant as the
absolute owner hereof for the purpose of any exercise hereof or any distribution
to the Holder, and for all other purposes, and the Company shall not be affected
by notice to the contrary.
<PAGE>   2
                  2.       Registration of Transfers and Exchanges.

                           (a) This Warrant may only be transferred pursuant to
an effective registration statement under the Securities Act, to the Company or
pursuant to an available exemption from or in a transaction not subject to the
registration requirements of the Securities Act. In connection with any transfer
of this Warrant other than pursuant to an effective registration statement or to
the Company, the Company may require the transferor thereof to provide to the
Company an opinion of counsel selected by the transferor, the form and substance
of which opinion shall be reasonably satisfactory to the Company, to the effect
that such transfer does not require registration of such Warrant under the
Securities Act. Holder agrees to the imprinting, so long as is required by this
Section 2(a), of a legend substantially similar to that first above written on
any New Warrant (as defined below). Any such transferee shall agree in writing
to be bound by the terms of this Warrant and shall have the rights of Holder
under this Warrant.

                           (b) The Company shall register the transfer of any
portion of this Warrant in the Warrant Register, upon surrender of this Warrant,
with the Form of Assignment attached hereto duly completed and signed, to the
Transfer Agent or to the Company at the office specified in or pursuant to
Section 3(b). Upon any such registration or transfer, a new warrant to purchase
Common Stock, in substantially the form of this Warrant (any such new warrant, a
"New Warrant"), evidencing the portion of this Warrant so transferred shall be
issued to the transferee and a New Warrant evidencing the remaining portion of
this Warrant not so transferred, if any, shall be issued to the transferring
Holder. The acceptance of the New Warrant by the transferee thereof shall be
deemed the acceptance of such transferee of all of the rights and obligations of
a holder of a Warrant.

                           (c) This Warrant is exchangeable, upon the surrender
hereof by the Holder to the office of the Company specified in or pursuant to
Section 3(b) for one or more New Warrants, evidencing in the aggregate the right
to purchase the number of Warrant Shares which may then be purchased hereunder.
Any such New Warrant will be dated the date of such exchange.

                  3.       Duration and Exercise of Warrants.

                           (a) This Warrant shall be exercisable by the
registered Holder on any business day before 8:00 P.M., New York City time, at
any time and from time to time on or after the date hereof to and including the
Expiration Date. At 8:00 P.M., New York City time on the Expiration Date, the
portion of this Warrant not exercised prior thereto shall be and become void and
of no value. Prior to the Expiration Date, the Company may not call or otherwise
redeem this Warrant without the prior written consent of the Holder.

                           (b) Subject to Sections 2(b), 6 and 10, upon
surrender of this Warrant, with the Form of Election to Purchase attached hereto
duly completed and signed, to the Company at its address for notice set forth in
Section 13 and upon payment of the Exercise Price multiplied by the number of
Warrant Shares that the Holder intends to purchase hereunder, in the manner
provided hereunder, all as specified by the Holder in the Form of Election to
Purchase, the Company shall promptly (but in no event later than 3 business days
after the Date of Exercise (as defined

                                      -2-
<PAGE>   3
herein)) issue or cause to be issued and cause to be delivered to or upon the
written order of the Holder and in such name or names as the Holder may
designate, a certificate for the Warrant Shares issuable upon such exercise,
free of restrictive legends except (i) either in the event that a registration
statement covering the resale of the Warrant Shares and naming the Holder as a
selling stockholder thereunder is not then effective or the Warrant Shares are
not freely transferable without volume restrictions pursuant to Rule 144(k)
promulgated under the Securities Act of 1933, as amended (the "Securities Act"),
or (ii) if this Warrant shall have been issued pursuant to a written agreement
between the original Holder and the Company, as required by such agreement. Any
person so designated by the Holder to receive Warrant Shares shall be deemed to
have become holder of record of such Warrant Shares as of the Date of Exercise
of this Warrant.

                           A "Date of Exercise" means the date on which the
Company shall have received (i) this Warrant (or any New Warrant, as
applicable), with the Form of Election to Purchase attached hereto (or attached
to such New Warrant) appropriately completed and duly signed, and (ii) payment
of the Exercise Price for the number of Warrant Shares so indicated by the
holder hereof to be purchased.

                           (c) This Warrant shall be exercisable, either in its
entirety or, from time to time, for a portion of the number of Warrant Shares.
If less than all of the Warrant Shares which may be purchased under this Warrant
are exercised at any time, the Company shall issue or cause to be issued, at its
expense, a New Warrant evidencing the right to purchase the remaining number of
Warrant Shares for which no exercise has been evidenced by this Warrant.

                  4. Piggyback Registration Rights. During the Effectiveness
Period (as defined in the Registration Rights Agreement, of even date herewith,
between the Company and the original Holder), the Company may not file any
registration statement with the Securities and Exchange Commission (other than
registration statements of the Company filed on Form S-8 or Form S-4, each as
promulgated under the Securities Act, pursuant to which the Company is
registering securities pursuant to a Company employee benefit plan or pursuant
to a merger, acquisition or similar transaction including supplements thereto,
but not additionally filed registration statements in respect of such
securities) at any time when there is not an effective registration statement
covering the resale of the Warrant Shares and naming the Holder as a selling
stockholder thereunder, unless the Company provides the Holder with not less
than 20 days notice of its intention to file such registration statement and
provides the Holder the option to include any or all of the applicable Warrant
Shares therein. The piggyback registration rights granted to the Holder pursuant
to this Section shall continue until all of the Holder's Warrant Shares have
been sold in accordance with an effective registration statement or upon the
expiration of the Effective Period. The Company will pay all registration
expenses in connection therewith.

                  5. Demand Registration Rights. During the Effectiveness Period
if the Warrant Shares are not registered pursuant to an effective registration
statement, the Holder may make a written request for the registration under the
Securities Act (a "Demand Registration"), of all of the Warrant Shares (the
"Registrable Securities"), and the Company shall use its best efforts to effect
such Demand Registration as promptly as possible, but in any case within 90 days
thereafter. Any

                                      -3-
<PAGE>   4
request for a Demand Registration shall specify the aggregate number of
Registrable Securities proposed to be sold and shall also specify the intended
method of disposition thereof. The right to cause a registration of the
Registrable Securities under this Section 5 shall be limited to one such
registration. In any registration initiated as a Demand Registration, the
Company will pay all of its registration expenses in connection therewith. A
Demand Registration shall not be counted as a Demand Registration hereunder
until the registration statement filed pursuant to the Demand Registration has
been declared effective by the Securities and Exchange Commission and maintained
continuously effective for a period of at least 360 days or such shorter period
when all Registrable Securities included therein have been sold in accordance
with such registration statement, provided, however that any days on which such
registration statement is not effective or on which the Holder is not permitted
by the Company or any governmental authority to sell Warrant Shares under such
registration statement shall not count towards such 360 day period.

                  6. Payment of Taxes. The Company will pay all documentary
stamp taxes attributable to the issuance of Warrant Shares upon the exercise of
this Warrant; 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
registration of any certificates for Warrant Shares or Warrants in a name other
than that of the Holder. The Holder shall be responsible for all other tax
liability that may arise as a result of holding or transferring this Warrant or
receiving Warrant Shares upon exercise hereof.

                  7. Replacement of Warrant. If this Warrant is mutilated, lost,
stolen or destroyed, the Company shall issue or cause to be issued in exchange
and substitution for and upon cancellation hereof, or in lieu of and
substitution for this Warrant, a New Warrant, but only upon receipt of evidence
reasonably satisfactory to the Company of such loss, theft or destruction and
indemnity, if requested, satisfactory to it. Applicants for a New Warrant under
such circumstances shall also comply with such other reasonable regulations and
procedures and pay such other reasonable charges as the Company may prescribe.

                  8. Reservation of Warrant Shares. The Company covenants that
it will at all times reserve and keep available out of the aggregate of its
authorized but unissued Common Stock, solely for the purpose of enabling it to
issue Warrant Shares upon exercise of this Warrant as herein provided, the
number of Warrant Shares which are then issuable and deliverable upon the
exercise of this entire Warrant, free from preemptive rights or any other actual
contingent purchase rights of persons other than the Holder (taking into account
the adjustments and restrictions of Section 9). The Company covenants that all
Warrant Shares that shall be so issuable and deliverable shall, upon issuance
and the payment of the applicable Exercise Price in accordance with the terms
hereof, be duly and validly authorized, issued and fully paid and nonassessable.

                  9. Certain Adjustments. The Exercise Price and number of
Warrant Shares issuable upon exercise of this Warrant are subject to adjustment
from time to time as set forth in

                                      -4-
<PAGE>   5
this Section 9. Upon each such adjustment of the Exercise Price pursuant to this
Section 9, the Holder shall thereafter prior to the Expiration Date be entitled
to purchase, at the Exercise Price resulting from such adjustment, the number of
Warrant Shares obtained by multiplying the Exercise Price in effect immediately
prior to such adjustment by the number of Warrant Shares issuable upon exercise
of this Warrant immediately prior to such adjustment and dividing the product
thereof by the Exercise Price resulting from such adjustment. Notwithstanding
anything to the contrary set forth herein, no adjustment shall be made hereunder
to the Exercise Price due to (i) the adoption by the Company of a shareholders
rights plan, (ii) the creation of "rights" under such a plan that are evidenced
by the shares of Common Stock to which they are attached, but adjustments would
be made if such rights are ever separated from such shares of Common Stock or
otherwise become evidenced by a separate certificate or if, for any other
reason, such rights would entitle the holders thereof or of the Common Stock to
which they attach to receive shares of Common Stock , (iii) the granting of
options or warrants to employees, officers, directors, consultants and other
service providers, and the issuance of shares upon exercise of options granted,
under any stock option plan heretofore or hereinafter duly adopted by the
Company, (iv) shares of Common Stock issuable upon exercise of currently
outstanding options and warrants and upon conversion of any currently
outstanding convertible securities of the Company, in each case to the extent
disclosed in Schedule 2.1(c) to the Securities Purchase Agreement but not with
respect to any amendment or modification thereof, (v) shares of Common Stock
issuable in connection with a Strategic Transaction (as defined in Section 3.9
of the Securities Purchase Agreement), (vi) an underwritten public offering of
Common Stock resulting in net proceeds to the Company in excess of $10,000,000,
(vii) warrants issuable to Brighton Capital, Ltd. in connection with the
Securities Purchase Agreement and the issuance of shares upon exercise thereof,
(viii) warrants to be issued by the Company to Kingsbridge Capital Limited to
purchase 25,000 shares of Common Stock and the issuance of shares upon exercise
thereof, (ix) the granting of warrants to purchase up to 10,000 shares of Common
Stock in connection with equipment leasing or other debt financing transactions,
and (x) the issuance of shares of Common Stock issuable pursuant to the Private
Equity Line of Credit Agreement dated March 27, 1998 between the Company and
Kingsbridge Capital Limited.

                           (a) If the Company, at any time while this Warrant is
outstanding, (i) shall pay a stock dividend (except scheduled dividends paid on
outstanding preferred stock as of the date hereof which contain a stated
dividend rate) or otherwise make a distribution or distributions on shares of
its Common Stock or on any other class of capital stock payable in shares of
Common Stock, (ii) subdivide outstanding shares of Common Stock into a larger
number of shares, or (iii) combine outstanding shares of Common Stock into a
smaller number of shares, the Exercise Price shall be multiplied by a fraction
of which the numerator shall be the number of shares of Common Stock (excluding
treasury shares, if any) outstanding before such event and of which the
denominator shall be the number of shares of Common Stock (excluding treasury
shares, if any) outstanding after such event. Any adjustment made pursuant to
this Section shall become effective immediately after the record date for the
determination of stockholders entitled to receive such dividend or distribution
and shall become effective immediately after the effective

                                      -5-
<PAGE>   6
date in the case of a subdivision or combination, and shall apply to successive
subdivisions and combinations.

                           (b) In case of any reclassification of the Common
Stock or any compulsory share exchange pursuant to which the Common Stock is
converted into other securities, cash or property, then the Holder shall have
the right thereafter to exercise this Warrant only into the shares of stock and
other securities and property receivable upon or deemed to be held by holders of
Common Stock following such reclassification or share exchange, and the Holder
shall be entitled upon such event to receive such amount of securities or
property equal to the amount of Warrant Shares such Holder would have been
entitled to had such Holder exercised this Warrant immediately prior to such
reclassification or share exchange. The terms of any such reclassification or
share exchange shall include such terms so as to continue to give to the Holder
the right to receive the securities or property set forth in this Section 9(b)
upon any exercise following any such reclassification or share exchange.

                           (c) If the Company, at any time while this Warrant is
outstanding, shall distribute to all holders of Common Stock (and not to holders
of this Warrant) evidences of its indebtedness or assets or rights or warrants
to subscribe for or purchase any security (excluding those referred to in
Sections 9(a), (b) and (d)), then in each such case the Exercise Price shall be
determined by multiplying the Exercise Price in effect immediately prior to the
record date fixed for determination of stockholders entitled to receive such
distribution by a fraction of which the denominator shall be the Exercise Price
determined as of the record date mentioned above, and of which the numerator
shall be such Exercise Price on such record date less the then fair market value
at such record date of the portion of such assets or evidence of indebtedness so
distributed applicable to one outstanding share of Common Stock as determined by
the Company's independent certified public accountants that regularly examines
the financial statements of the Company (an "Appraiser").

                           (d) If at any time the Company or any subsidiary
thereof, as applicable with respect to Common Stock Equivalents (as defined
below), shall issue: (x) shares of Common Stock at a price per share less than
both the market price of the Common Stock at the time of issuance of such Common
Stock and the Exercise Price then in effect, or (y) rights, warrants, options or
other securities or debt that is convertible into or exchangeable for shares of
Common Stock ("Common Stock Equivalents"), entitling any person or entity to
acquire shares of Common Stock at a price per share less than both the market
price of the Common Stock at the time of issuance of such Common Stock and the
Exercise Price then in effect (if the holder of the Common Stock Equivalent so
issued shall at any time, whether by operation of purchase price adjustments,
reset provisions, floating conversion, exercise or exchange prices or otherwise,
be entitled to receive shares of Common Stock at a price less than (i) the
Exercise Price; (ii) the market price of the Common Stock at the time of such
adjustment and (iii) the market price of the Common Stock at the time such
shares of Common Stock are acquired, such issuance shall be deemed to have
occurred for less than such Exercise Price and the market price), then,
forthwith upon such

                                      -6-
<PAGE>   7
issue or sale, at the option of the Holder, the Exercise Price shall be reduced
to the price (calculated to the nearest cent) determined by multiplying the
Exercise Price in effect immediately prior thereto by a fraction, the numerator
of which shall be the sum of (i) the number of shares of Common Stock
outstanding immediately prior to such issuance, and (ii) the number of shares of
Common Stock which the aggregate consideration received (or to be received,
assuming exercise or conversion in full of such Common Stock Equivalents) for
the issuance of such additional shares of Common Stock would purchase at the
Exercise Price, and the denominator of which shall be the sum of the number of
shares of Common Stock outstanding immediately after the issuance of such
additional shares. For purposes hereof, all shares of Common Stock that are
issuable upon conversion, exercise or exchange of Common Stock Equivalents shall
be deemed outstanding immediately after the issuance of such Common Stock
Equivalents. Such adjustment shall be made whenever such Common Stock or Common
Stock Equivalents are issued, or, if the maximum number of shares of Common
Stock issuable upon conversion, exercise or exchange of a Common Stock
Equivalent is not determined at the time of issuance of such Common Stock
Equivalent, such adjustment shall be made at such time as the maximum number of
shares of Common Stock issuable upon conversion, exercise or exchange of such
Common Stock Equivalent becomes determinable. However, upon the expiration of
any Common Stock Equivalents the issuance of which resulted in an adjustment in
the Exercise Price pursuant to this Section, if any such Common Stock
Equivalents shall expire or be surrendered to the Company and shall not have
been exercised, converted or exchanged in full or shall have been exercised,
converted or exchanged for less than the number of shares of Common Stock used
in computing such adjustment, the Exercise Price shall immediately upon such
expiration be recomputed and effective immediately upon such expiration be
increased to the price which it would have been (but reflecting any other
adjustments in the Exercise Price made pursuant to the provisions of this
Section after the issuance of such Common Stock Equivalents) had the adjustment
of the Exercise Price made upon the issuance of such Common Stock Equivalents
been made on the basis of offering for subscription or purchase only that number
of shares of the Common Stock actually purchased upon the exercise of such
Common Stock Equivalents actually exercised. Notwithstanding anything to the
contrary contained herein, other than adjustments resulting from the expiration
of Common Stock Equivalents, no adjustment shall be made to the Exercise Price
upon: (i) the issuance of shares of Common Stock upon the exercise, conversion
or exchange of any Common Stock Equivalents outstanding as of the date of
issuance of this Warrant, or (ii) any change in the number of shares of Common
Stock issuable upon the exercise, conversion or exchange of any Common Stock
Equivalents outstanding as of the date of issuance of this Warrant, including,
without limitation, changes occurring by operation of purchase price
adjustments, reset provisions, anti-dilution provisions or floating conversion,
exercise or exchange prices.

                           (e) In case of any (1) merger or consolidation of the
Company with or into another Person, or (2) sale by the Company of more than
one-half of the assets of the Company (on a book value basis) in one or a series
of related transactions, or (3) tender or other offer or exchange (whether by
the Company or another Person) pursuant to which holders of Common Stock

                                      -7-
<PAGE>   8
are permitted to tender or exchange their shares for other securities, stock,
cash or property of the Company or another Person; then the Holder shall have
the right thereafter to (A) exercise this Warrant for the shares of stock and
other securities, cash and property receivable upon or deemed to be held by
holders of Common Stock following such merger, consolidation or sale, and the
Holder shall be entitled upon such event or series of related events to receive
such amount of securities, cash and property as the Common Stock for which this
Warrant could have been exercised immediately prior to such merger,
consolidation or sales would have been entitled, (B) in the case of a merger or
consolidation, (x) require the surviving entity to issue to the Holder a warrant
entitling the Holder to acquire shares of such entity's common stock, which
warrant shall have terms identical (including with respect to exercise) to the
terms of this Warrant and shall be entitled to all of the rights and privileges
set forth herein and the agreements pursuant to which this Warrant was issued
(including, without limitation, as such rights relate to the acquisition,
transferability, registration and listing of such shares of stock other
securities issuable upon exercise thereof), or (C) in the event of an exchange
or tender offer or other transaction contemplated by clause (3) of this Section,
tender or exchange this Warrant for such securities, stock, cash and other
property receivable upon or deemed to be held by holders of Common Stock that
have tendered or exchanged their shares of Common Stock following such tender or
exchange, and the Holder shall be entitled upon such exchange or tender to
receive such amount of securities, cash and property as the shares of Common
Stock for which this Warrant could have been exercised immediately prior to such
tender or exchange would have been entitled as would have been issued. In the
case of clause (B), the exercise price applicable for the newly issued warrant
shall be based upon the amount of securities, cash and property that each shares
of Common Stock would receive in such transaction and the Exercise Price
immediately prior to the effectiveness or closing date for such transaction. The
terms of any such merger, sale, consolidation, tender or exchange shall include
such terms so as continue to give the Holder the right to receive the
securities, cash and property set forth in this Section upon any conversion or
redemption following such event. This provision shall similarly apply to
successive such events.

                           (f) For the purposes of this Section 9, the following
clauses shall also be applicable:

                                    (i) Record Date. In case the Company shall
take a record of the holders of its Common Stock for the purpose of entitling
them (A) to receive a dividend or other distribution payable in Common Stock or
in securities convertible or exchangeable into shares of Common Stock, or (B) to
subscribe for or purchase Common Stock or securities convertible or exchangeable
into shares of Common Stock, then such record date shall be deemed to be the
date of the issue or sale of the shares of Common Stock deemed to have been
issued or sold upon the declaration of such dividend or the making of such other
distribution or the date of the granting of such right of subscription or
purchase, as the case may be.

                                    (ii) Treasury Shares. The number of shares
of Common Stock outstanding at any given time shall not include shares owned or
held by or for the account of the Company, and the disposition of any such
shares shall be considered an issue or sale of Common Stock.

                                      -8-
<PAGE>   9
                           (g) All calculations under this Section 9 shall be
made to the nearest cent or the nearest 1/100th of a share, as the case may be.

                           (h) Whenever the Exercise Price is adjusted pursuant
to Section 9(c) above, the Holder, after receipt of the determination by the
Appraiser, shall have the right to select an additional appraiser (which shall
be a nationally recognized accounting firm), in which case the adjustment shall
be equal to the average of the adjustments recommended by each of the Appraiser
and such appraiser. The Holder shall promptly mail or cause to be mailed to the
Company, a notice setting forth the Exercise Price after such adjustment and
setting forth a brief statement of the facts requiring such adjustment. Such
adjustment shall become effective immediately after the record date mentioned
above.

                                (i) If:

                                    (i)         the Company shall declare a
                                                dividend (or any other
                                                distribution) on its Common
                                                Stock; or

                                    (ii)        the Company shall declare a
                                                special nonrecurring cash
                                                dividend on or a redemption of
                                                its Common Stock; or

                                    (iii)       the Company shall authorize the
                                                granting to all holders of the
                                                Common Stock rights or warrants
                                                to subscribe for or purchase any
                                                shares of capital stock of any
                                                class or of any rights; or

                                    (iv)        the approval of any stockholders
                                                of the Company shall be required
                                                in connection with any
                                                reclassification of the Common
                                                Stock, any consolidation or
                                                merger to which the Company is a
                                                party, any sale or transfer of
                                                all or substantially all of the
                                                assets of the Company, or any
                                                compulsory share exchange
                                                whereby the Common Stock is
                                                converted into other securities,
                                                cash or property; or

                                    (v)         the Company shall authorize the
                                                voluntary dissolution,
                                                liquidation or winding up of the
                                                affairs of the Company,

then the Company shall cause to be mailed to each Holder at their last addresses
as they shall appear upon the Warrant Register, at least 30 calendar days prior
to the applicable record or effective date hereinafter specified, a notice
stating (x) the date on which a record is to be taken for the purpose of such
dividend, distribution, redemption, rights or warrants, or if a record is not to
be taken, the date as of which the holders of Common Stock of record to be
entitled to such dividend, distributions, redemption, rights or warrants are to
be determined or (y) the date on which such

                                      -9-
<PAGE>   10
reclassification, consolidation, merger, sale, transfer or share exchange is
expected to become effective or close, and the date as of which it is expected
that holders of Common Stock of record shall be entitled to exchange their
shares of Common Stock for securities, cash or other property deliverable upon
such reclassification, consolidation, merger, sale, transfer, share exchange,
dissolution, liquidation or winding up; provided, however, that the failure to
mail such notice or any defect therein or in the mailing thereof shall not
affect the validity of the corporate action required to be specified in such
notice.

                  10. Payment of Exercise Price. The Holder shall pay the
Exercise Price in one of the following manners:

                           (a) Cash Exercise. The Holder may deliver immediately
available funds; or

                           (b) Cashless Exercise. The Holder may surrender this
Warrant to the Company together with a notice of cashless exercise, in which
event the Company shall issue to the Holder the number of Warrant Shares
determined as follows:

                                  X = Y (A-B)/A
         where:
                                  X = the number of Warrant Shares to be issued
                                  to the Holder.

                                  Y = the number of Warrant Shares with
                                  respect to which this Warrant is being
                                  exercised.

                                  A = the average of the closing sale prices
                                  of the Common Stock for the five (5) trading
                                  days immediately prior to (but not
                                  including) the Date of Exercise.

                                  B = the Exercise Price.

For purposes of Rule 144 promulgated under the Securities Act, it is intended,
understood and acknowledged that the Warrant Shares issued in a cashless
exercise transaction shall be deemed to have been acquired by the Holder, and
the holding period for the Warrant Shares shall be deemed to have been
commenced, on the issue date.

         11. Certain Exercise Restrictions. (a) A Holder may not exercise this
Warrant to the extent such exercise would result in the Holder, together with
any affiliate thereof, beneficially owning (as determined in accordance with
Section 13(d) of the Securities Exchange Act 1934, as amended and the rules
promulgated thereunder) in excess of 4.999% of the then issued and outstanding
shares of Common Stock, including shares of Common Stock issuable upon such
exercise and held by such Holder after application of this Section. Since the
Holder will not be obligated to report to the Company the number of shares of
Common Stock it may hold at the time of an exercise hereunder, unless the
exercise at issue would result in the issuance of shares of

                                      -10-
<PAGE>   11
Common Stock in excess of 4.999% of the then outstanding shares of Common Stock
without regard to any other shares of Common Stock which may be beneficially
owned by the Holder or an affiliate thereof, the Holder shall have the authority
and obligation to determine whether the restriction contained in this Section
will limit any particular exercise hereunder and to the extent that the Holder
determines that the limitation contained in this Section applies, the
determination of which portion of this Warrant is exercisable shall be the
responsibility and obligation of the Holder. If the Holder has delivered a Form
of Election to Purchase for a number of Warrant Shares that would result in the
issuance in excess of the permitted amount hereunder, the Company shall notify
the Holder of this fact and shall honor the exercise for the maximum portion of
this Warrant permitted to be exercised on such Date of Exercise in accordance
with the periods described herein and disregard the balance of such Form of
Election to Purchase, as if never delivered The provisions of this Section may
be waived by a Holder (but only as to itself and not to any other Holder) upon
not less than 61 days prior notice to the Company. Other Holders shall be
unaffected by any such waiver.

                  (b) A Holder may not exercise this Warrant to the extent such
exercise would result in the Holder, together with any affiliate thereof,
beneficially owning (as determined in accordance with Section 13(d) of the
Securities Exchange Act 1934, as amended and the rules promulgated thereunder)
in excess of 9.999% of the then issued and outstanding shares of Common Stock,
including shares of Common Stock issuable upon such exercise and held by such
Holder after application of this Section. Since the Holder will not be obligated
to report to the Company the number of shares of Common Stock it may hold at the
time of an exercise hereunder, unless the exercise at issue would result in the
issuance of shares of Common Stock in excess of 9.999% of the then outstanding
shares of Common Stock without regard to any other shares of Common Stock which
may be beneficially owned by the Holder or an affiliate thereof, the Holder
shall have the authority and obligation to determine whether the restriction
contained in this Section will limit any particular exercise hereunder and to
the extent that the Holder determines that the limitation contained in this
Section applies, the determination of which portion of this Warrant is
exercisable shall be the responsibility and obligation of the Holder. If the
Holder has delivered a Form of Election to Purchase for a number of Warrant
Shares that would result in the issuance in excess of the permitted amount
hereunder, the Company shall notify the Holder of this fact and shall honor the
exercise for the maximum portion of this Warrant permitted to be exercised on
such Date of Exercise in accordance with the periods described herein and
disregard the balance of such Form of Election to Purchase, as if never
delivered The provisions of this Section may be waived by a Holder (but only as
to itself and not to any other Holder) upon not less than 61 days prior notice
to the Company. Other Holders shall be unaffected by any such waiver.

                  12. Fractional Shares. The Company shall not be required to
issue or cause to be issued fractional Warrant Shares on the exercise of this
Warrant. The number of full Warrant Shares which shall be issuable upon the
exercise of this Warrant shall be computed on the basis of the aggregate number
of Warrant Shares purchasable on exercise of this Warrant so presented. If any
fraction of a Warrant Share would, except for the provisions of this Section, be
issuable on the exercise of this Warrant, the Company shall pay an amount in
cash equal to the Exercise Price multiplied by such fraction.

                                      -11-
<PAGE>   12
                  13. Notices. Any and all notices or other communications or
deliveries hereunder shall be in writing and shall be deemed given and effective
on the earliest of (i) the date of transmission, if such notice or communication
is delivered via facsimile at the facsimile telephone number specified in this
Section prior to 8:00 p.m. (New York City time) on a business day, (ii) the
business day after the date of transmission, if such notice or communication is
delivered via facsimile at the facsimile telephone number specified in this
Section later than 8:00 p.m. (New York City time) on any date and earlier than
11:59 p.m. (New York City time) on such date, (iii) the business day following
the date of mailing, if sent by nationally recognized overnight courier service,
or (iv) if sent other than by the methods set forth in (i)-(iii) of this
section, upon actual receipt by the party to whom such notice is required to be
given. The addresses for such communications shall be: (i) if to the Company, to
157 Technology Drive, Irvine, CA 92618, Attention: Chief Financial Officer, or
to Facsimile No. (949) 788-6706, or (ii) if to the Holder, to the Holder at the
address or facsimile number appearing on the Warrant Register or such other
address or facsimile number as the Holder may provide to the Company in
accordance with this Section.

                  14. Warrant Agent. The Company shall serve as warrant agent
under this Warrant. Upon thirty (30) days' notice to the Holder, the Company may
appoint a new warrant agent. Any corporation into which the Company or any new
warrant agent may be merged or any corporation resulting from any consolidation
to which the Company or any new warrant agent shall be a party or any
corporation to which the Company or any new warrant agent transfers
substantially all of its corporate trust or shareholders services business shall
be a successor warrant agent under this Warrant without any further act. Any
such successor warrant agent shall promptly cause notice of its succession as
warrant agent to be mailed (by first class mail, postage prepaid) to the Holder
at the Holder's last address as shown on the Warrant Register.

                  15.      Miscellaneous.

                           (a) This Warrant shall be binding on and inure to the
benefit of the parties hereto and their respective successors and assigns. This
Warrant may be amended only in writing signed by the Company and the Holder and
their successors and assigns.

                           (b) Subject to Section 15(a), above, nothing in this
Warrant shall be construed to give to any person or corporation other than the
Company and the Holder any legal or equitable right, remedy or cause under this
Warrant. This Warrant shall inure to the sole and exclusive benefit of the
Company and the Holder.

                           (c) The corporate laws of the State of Delaware shall
govern all issues concerning the relative rights of the Company and its
stockholders. All other questions concerning the construction, validity,
enforcement and interpretation of this Warrant shall be governed by and
construed and enforced in accordance with the internal laws of the State of New
York, without regard to the principles of conflicts of law thereof. The Company
and the Holder hereby irrevocably submit to the exclusive jurisdiction of the
state and federal courts sitting in the City

                                      -12-
<PAGE>   13
of New York, borough of Manhattan, for the adjudication of any dispute hereunder
or in connection herewith or with any transaction contemplated hereby or
discussed herein, and hereby irrevocably waives, and agrees not to assert in any
suit, action or proceeding, any claim that it is not personally subject to the
jurisdiction of any such court, or that such suit, action or proceeding is
improper. Each of the Company and the Holder hereby irrevocably waives personal
service of process and consents to process being served in any such suit, action
or proceeding by receiving a copy thereof sent to the Company at the address in
effect for notices to it under this instrument and agrees that such service
shall constitute good and sufficient service of process and notice thereof.
Nothing contained herein shall be deemed to limit in any way any right to serve
process in any manner permitted by law.

                           (d) The headings herein are for convenience only, do
not constitute a part of this Warrant and shall not be deemed to limit or affect
any of the provisions hereof.

                           (e) In case any one or more of the provisions of this
Warrant shall be invalid or unenforceable in any respect, the validity and
enforceability of the remaining terms and provisions of this Warrant shall not
in any way be affected or impaired thereby and the parties will attempt in good
faith to agree upon a valid and enforceable provision which shall be a
commercially reasonable substitute therefor, and upon so agreeing, shall
incorporate such substitute provision in this Warrant.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                             SIGNATURE PAGE FOLLOWS]

                                      -13-
<PAGE>   14
                  IN WITNESS WHEREOF, the Company has caused this Warrant to be
duly executed by its authorized officer as of the date first indicated above.

                                    NEOTHERAPEUTICS, INC.

                                    By:  /s/ Samuel Gulko
                                         ---------------------------------------
                                    Name:  Samuel Gulko
                                         ---------------------------------------
                                    Title:  Chief Financial Officer
                                         ---------------------------------------
<PAGE>   15
                          FORM OF ELECTION TO PURCHASE

(To be executed by the Holder to exercise the right to purchase shares of Common
Stock under the foregoing Warrant)

To NeoTherapeutics, Inc.:

         In accordance with the Warrant enclosed with this Form of Election to
Purchase, the undersigned hereby irrevocably elects to purchase _____________
shares of common stock, $.001 par value per share, of NeoTherapeutics, Inc. (the
"Common Stock") and , if such Holder is not utilizing the cashless exercise
provisions set forth in this Warrant, encloses herewith $________ in cash,
certified or official bank check or checks, which sum represents the aggregate
Exercise Price (as defined in the Warrant) for the number of shares of Common
Stock to which this Form of Election to Purchase relates, together with any
applicable taxes payable by the undersigned pursuant to the Warrant.

         The undersigned requests that certificates for the shares of Common
Stock issuable upon this exercise be issued in the name of

                                           PLEASE INSERT SOCIAL SECURITY OR
                                           TAX IDENTIFICATION NUMBER

                                           _____________________________________

________________________________________________________________________________
                         (Please print name and address)

         If the number of shares of Common Stock issuable upon this exercise
shall not be all of the shares of Common Stock which the undersigned is entitled
to purchase in accordance with the enclosed Warrant, the undersigned requests
that a New Warrant (as defined in the Warrant) evidencing the right to purchase
the shares of Common Stock not issuable pursuant to the exercise evidenced
hereby be issued in the name of and delivered to:

________________________________________________________________________________
                         (Please print name and address)

________________________________________________________________________________

________________________________________________________________________________

Dated:            ,                 Name of Holder:

                                    (Print)_____________________________________

                                    (By:)_______________________________________
                                    (Name:)
                                    (Title:)

                                     (Signature must conform in all respects to
                                     name of holder as specified on the face of
                                     the Warrant)
<PAGE>   16
                               FORM OF ASSIGNMENT

           [To be completed and signed only upon transfer of Warrant]

         FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers
unto ________________________________ the right represented by the within
Warrant to purchase ____________ shares of Common Stock of NeoTherapeutics, Inc.
to which the within Warrant relates and appoints ________________ attorney to
transfer said right on the books of NeoTherapeutics, Inc. with full power of
substitution in the premises.

Dated:

_______________, ____

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

                                    ___________________________________________
                                    Address of Transferee

                                    ___________________________________________

                                    ___________________________________________

In the presence of:

__________________________

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