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                                                                   EXHIBIT 10.23

  SPECIMEN OF STOCK OPTION GRANT IN CONNECTION WITH 2000 STOCK PLAN (EMPLOYEES)

                               STOCK OPTION GRANT

1.   GRANT OF OPTION

     Advanced Magnetics, Inc., a Delaware corporation (the "Company"), hereby
     grants to ____________ (the "Employee"), an option to purchase _____ shares
     of Common Stock, $0.01 par value per share, of the Company as hereinafter
     set forth (the "Option"), pursuant and subject to the terms and provisions
     of the Company's 2000 STOCK PLAN (the "Plan").

     All terms which are defined in the Plan shall have the same meanings
     herein.

2.   VESTING OF OPTION

     This Option shall be exercisable in cumulative installations, as follows:

<Table>
<Caption>
                              Date Exercised                         Number of Shares Exercisable
                              --------------                         ----------------------------
       <S>                                                           <C>
       On or BEFORE ____________                                     _________________________________

       AFTER ___________ and on or BEFORE ______________             _________________________________

       AFTER __________  and on or BEFORE ______________             _________________________________

       AFTER __________  and on or BEFORE ______________             _________________________________

       AFTER _________________
</Table>

3.   TERM OF OPTION

     This Option shall TERMINATE in ______________ YEARS on ________________.

4.   EXERCISE PRICE

     The EXERCISE PRICE of this Option shall be ___________________ per share.

5.   EXERCISE AND PAYMENT

     (a)  METHOD OF PAYMENT. This Option shall be exercisable by delivery to the
          Company of written notice of exercise, specifying the number of shares
          for which this Option is being exercised (subject to Section 2
          hereof), together with payment to the Company for the total exercise
          price thereof in cash, by check or by Common Stock of the Company
          owned by the Employee or by some combination thereof.

     (b)  VALUATION OF SHARES TENDERED IN PAYMENT OF PURCHASE PRICE. For the
          purposes hereof, the fair market value of any share of the Company's
          Common Stock which may be delivered to the Company in exercise of this
          Option shall be determined in good faith by the Board of Directors of

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          the Company.

     (c)  DELIVERY OF SHARES TENDERED IN PAYMENT OF PURCHASE PRICE. If the
          Company permits the Employee to exercise Options by delivery of shares
          of Common Stock of the Company, the certificate or certificates
          representing the shares of Common Stock of the Company to be delivered
          shall be duly executed in blank by the Employee or shall be
          accompanied by a stock power duly executed in blank suitable for
          purposes of transferring such shares to the Company. Fractional shares
          of Common Stock of the Company will not be accepted in payment of the
          purchase price of shares acquired upon exercise of this Option.

     (d)  USE OF STATUTORY OPTION STOCK. Notwithstanding the foregoing,
          "statutory option stock" (as defined below) may not be tendered in
          payment of the exercise price of this Option if the stock to be so
          tendered has not, at the time of tender, been held by the Employee for
          the applicable minimum statutory holding period required to receive
          the tax benefits afforded under Section 421(a) of the Code with
          respect to such stock. As used above, the term "statutory option
          stock" means stock acquired through the exercise of a qualified stock
          option, incentive stock option, restricted stock option or an option
          granted under an employee stock purchase plan. The tender of statutory
          option stock in payment of the exercise price of this Option shall be
          accompanied by written proof (in form satisfactory to the Company)
          that such stock has been held by the Employee for the applicable
          minimum statutory holding period.

6.   EFFECT OF TERMINATION OF EMPLOYMENT OR DEATH

     This Option shall not be assignable or transferable either voluntarily or
     by operation of law, except as set forth in this Section 6.

     In the event that the Employee during his or her lifetime ceases to be an
     employee of the Company or of any subsidiary for any reason, other than
     death or disability, any unexercised portion of this Option which was
     otherwise exercisable on the date of termination of employment shall expire
     unless exercised within three months of that date, but in no event after
     the expiration of the term hereof.

     In the event of the death or disability of the Employee (i) while an
     employee of the Company or any subsidiary, or (ii) during the three-month
     period following termination of his or her employment for any reason other
     than death or disability, this Option shall be exercisable for the number
     of shares otherwise exercisable on the date of death or disability, by the
     Employee or his or her personal representatives, heirs or legatees, as the
     case may be, at any time prior to the expiration of one (1) year from the
     date of the death or disability of the Employee, but in no event after the
     expiration of the term hereof.

7.   EMPLOYMENT

     Nothing contained in this Option or in the Plan shall be construed as
     giving the Employee any right to be retained in the employ of the Company
     or any of its subsidiaries.

8.   WITHHOLDING TAXES

     The Employee acknowledges and agrees that the Company has the right to
     deduct from payments of any kind otherwise due to the Employee any federal,
     state or local taxes of any kind required by law to be withheld with
     respect to exercise of this Option.

9.   PLAN PROVISIONS

Except as otherwise expressly provided herein, this Option and the rights of the
Employee hereunder shall be subject to and governed by the terms and provisions
of the Plan, including without limitation the provisions of Section 4

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thereof.

10.  EMPLOYEE REPRESENTATION; STOCK CERTIFICATE LEGEND

     The Employee hereby represents that he or she has received and read the
     Prospectus filed with the Securities and Exchange Commission as a part of
     the Registration Statement on Form S-8, which registered the shares under
     the Plan.

     If the Employee is an "affiliate" of the Company (as defined in Rule 144
     promulgated under the Securities Act of 1933), all stock certificates
     representing shares of Common Stock issued to such Employee pursuant to
     this Option shall have affixed thereto legends substantially in the
     following form:

          "The shares represented by this certificate have not been registered
          under the Securities Act of 1933, as amended (the "Act") and may not
          be sold, transferred or assigned unless such shares are registered
          under the Act or an opinion of counsel, satisfactory to the
          corporation, is obtained to the effect that such sale, transfer or
          assignment is exempt from the registration requirements of the Act."

11.  NOTICE

     Any notice required to be given under the terms of this Option shall be
     properly addressed as follows: to the Company at its principal executive
     offices, and to the Employee at his or her address set forth below, or at
     such other address as either of such parties may hereafter designate in
     writing to the other.

12.  QUALIFICATION UNDER SECTION 422A

     It is understood and intended that this Option shall qualify as an
     "incentive stock option" as defined in Section 422A of the Internal Revenue
     Code. Accordingly, the Employee understands that in order to obtain the
     benefits of an incentive stock option under Section 421 of the Code, no
     sale or other disposition may be made of any shares acquired upon exercise
     of this Option within the one (1) year period beginning on the day after
     the day of the transfer of such shares to him or her, nor within the two
     (2) year period beginning on the day after the grant of this Option. If the
     Employee intends to dispose or does dispose (whether by sale, exchange,
     gift, transfer or otherwise) of any such shares within said periods, he or
     she will notify the Company within thirty (30) days after such disposition.

13.  ENFORCEABILITY

     This Option shall be binding upon the Employee, his or her estate, and his
     or her personal representatives and beneficiaries.

14.  EFFECTIVE DATE

     The effective DATE of this Option is _________________.

     IN WITNESS WHEREOF, this Option has been executed by a duly authorized
     officer of the Company as of the effective date.

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                                        Advanced Magnetics, Inc.


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


Employee's Acceptance

The undersigned hereby accepts this Option and
agrees to the terms and provisions set forth in this
Option and in the Plan (a copy of which has been
delivered to him/her).



--------------------------------------------
(Signature of Employee)



--------------------------------------------
(Print Name of Employee)


Address:      ------------------------------

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

Date:         ------------------------------

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