**Exhibit4.1**

INCORPORATED UNDERTHE LAWS OF THE STATE OF DELAWARE

| NUMBER |   | **TorreyPines  Therapeutics, Inc.** |   | SHARES |
|--------|--------|-------------------------------------|--------|--------|

 

| **AUTHORIZED COMMON STOCK:  150,000,000 SHARES  PAR VALUE: $.001** |   | CUSIP 89235K 10  5 |
|--------------------------------------------------------------------|--------|--------------------|

 

**ThisCertifies that**

*Is TheRecord Holder Of*

*Shares of***TorreyPines Therapeutics, Inc.***CommonStock                                     transferableon the books of the Corporation by the holder hereof, in person or by dulyauthorized attorney upon surrender of this Certificate properly endorsed. ThisCertificate is not valid until countersigned by the Transfer Agent andregistered by the Registrar.*

*Witnessthe facsimile seal of the Corporation and the facsimile signatures of its dulyauthorized officers.*

*Dated:*

| /s/ Craig Johnson |   |   |   | /s/ Neil Kurtz |
|-------------------|--------|--------|--------|----------------|
| SECRETARY         |   | [SEAL] |   | PRESIDENT      |

 

COUNTERSIGNED AND REGISTERED:

**AMERICAN STOCK TRANSFER &TRUST COMPANY**

(New York, NY)
| BY:    | TRANSFER AGENT AND  REGISTRAR |   |
|--------|-------------------------------|--------|
|   |                          |   |
|   |                          |   |
|   | AUTHORIZED SIGNATURE          |   |

 

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The followingabbreviations, when used in the inscription on the face of this certificate,shall be construed as though they were written out in full according toapplicable laws or regulations:

 
| TEN COM | – | as tenants in common            | UNIF GIFT MIN ACT – |               Custodian                    |
|---------|--------|---------------------------------|--------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| TEN ENT | – | as tenants by the entireties    |                     | (Cust)                                                                                                                                                                                                          |   | (Minor) |
| JT TEN  | – | as joint tenants with right of  |                     | under Uniform Gifts to Minors                                                                                                                                                                                   |
|    |   | survivorship and not as tenants |                     | Act                                                                                                                                                                                                             |
|    |   | in common                       |                     | (State)                                                                                                                                                                                                         |

 

Additional abbreviationsmay also be used though not in the above list.

 

For Value Received                                                     hereby sell, assign and transfer unto

 

PLEASE INSERT SOCIALSECURITY OR OTHERIDENTIFYING NUMBER OF ASSIGNEE

 

 

 

(PLEASE PRINT ORTYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

 

 

 

                                                                Sharesof the capital stock represented by the within certificate, and do herebyirrevocably constitute and appoint

 

                                                   Attorney to transfer thesaid stock on the books of the within named Corporation with full power ofsubstitution in the premises.

 
| Dated  |    |                                                                                                                                                                                        |
|--------|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |
|   |    |
|   |    |                                                                                                                                                                                        |
|   | NOTICE: | THE SIGNATURE TO THIS  ASSIGNMENT MUST CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE OF THE  CERTIFICATE IN EVERY PARTICULAR WITHOUT ALTERATION OR ENLARGEMENT OR ANY  CHANGE WHATEVER. |
|        |         |                                                                                                                                                                                             |  |  |

 

 

·**NOTICE SIGNATURE GUARANTEED:**

 

SIGNATURE(S) MUST BE GUARANTEED BY A FIRM WHICH IS AMEMBER OF A REGISTERED NATIONAL STOCK EXCHANGE OR BY A BANK (OTHER THAN ASAVINGS BANK), OR A TRUST COMPANY. THE GUARANTEEING FIRM MUST BE A MEMBER OFTHE *MEDALLION GUARANTEE PROGRAM.*

 

TRANSFER FEE WILL APPLY

 

THIS CERTIFICATE ALSO EVIDENCES AND ENTITLES THE HOLDER HEREOF TOCERTAIN RIGHTS AS SET FORTH IN A RIGHTS AGREEMENT BETWEEN TORREYPINESTHERAPEUTICS, INC. (THE “COMPANY”) AND THE AMERICAN STOCK TRANSFER & TRUSTCOMPANY DATED AS OF MAY 13, 2005, AS AMENDED (THE “RIGHTS AGREEMENT”), THETERMS OF WHICH ARE HEREBY INCORPORATED HEREIN BY REFERENCE AND A COPY OF WHICHIS ON FILE AT THE PRINCIPAL OFFICES OF THE COMPANY UNDER CERTAIN CIRCUMSTANCES,AS SET FORTH IN THE RIGHTS AGREEMENT, SUCH RIGHTS MAY BE REDEEMED, MAY EXPIREOR MAY BE EVIDENCED BY SEPARATE CERTIFICATES AND WILL NO LONGER BE EVIDENCED BYTHIS CERTIFICATE. THE COMPANY WILL MAIL TO THE HOLDER OF THIS CERTIFICATE ACOPY OF THE RIGHTS AGREEMENT WITHOUT CHARGE WITHIN FIVE DAYS AFTER RECEIPT OF AWRITTEN REQUEST THEREFOR. UNDER CERTAIN CIRCUMSTANCES, RIGHTS ISSUED TOACQUIRING PERSONS (AS DEFINED IN THE RIGHTS AGREEMENT) OR CERTAIN RELATEDPERSONS AND ANY SUBSEQUENT HOLDER OF SUCH RIGHTS MAY BECOME NULL AND VOID.

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