**Exhibit4.1**

 
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|                                                | **COLLAGENEX PHARMACEUTICALS,  INC.**

INCORPORATED UNDER THE LAWS  OF THE STATE OF DELAWARE |                                                         |
| **COMMON STOCK**

**PAR VALUE $.01 PER SHARE** |                                                                                         | CUSIP 19419B 10 0

SEE REVERSE FOR CERTAIN  DEFINITIONS |

 

THIS CERTIFIESthat

 

is the ownerof

 

**FULLY PAID AND NON-ASSESSABLE SHARES OF THECOMMON STOCK, $.01 PAR VALUE, OF** COLLAGENEXPHARMACEUTICALS, INC., (the “Corporation”) transferable on the books of theCorporation by the holder hereof in person or by duly authorized Attorney uponsurrender of this Certificate properly endorsed. This Certificate is not validuntil countersigned and registered by the Transfer Agent and Registrar.

 

WITNESS the facsimile seal of the Corporationand the facsimile signatures of its duly authorized officers.

 

Dated:

 

 
| Treasurer |   | [SEAL] |   | President  and Chief Executive Officer |
|-----------|--------|--------|--------|----------------------------------------|

 

 

Countersigned and Registered:

 
| AMERICAN  STOCK TRANSFER & TRUST COMPANY |   |
|----------------------------------------------|--------|
| (New York)                                   |   |
|                                         |   |
| Transfer  Agent  and Registrar               |   |
|                                         |   |
| By                                           |   |   |
|                                         |   |
| Authorized  Signature                        |   |
|                                              |        |  |

 

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**COLLAGENEXPHARMACEUTICALS, INC.**

 

THE CORPORATION WILL FURNISH WITHOUT CHARGE TO EACH STOCKHOLDER WHO SOREQUESTS THE POWERS, DESIGNATIONS, PREFERENCES AND RELATIVE, PARTICIPATING,OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS OF STOCK OR SERIES THEREOF ANDTHE QUALIFICATIONS, LIMITATIONS OR RESTRICTIONS OF SUCH PREFERENCES AND/ORRIGHTS ANY SUCH REQUEST SHOULD BE ADDRESSED TO THE SECRETARY OF THE CORPORATIONAT ITS PRINCIPAL PLACE OF BUSINESS.

 

The following abbreviations, when used in theinscription on the face of this certificate, shall be construed as though theywere written out in full according to applicable laws or regulations:

 
| TEN COM – as  tenants in common                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                         | UNIT GIFT MIN ACT-                           Custodian                          |
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|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                         |                                                                                                                                                                                                                                                                                                                                                | (Cust) | (Minor) |   |
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| TEN ENT   – as tenants by the entireties                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                         |                                                                                                                                                                                                                                                                                                                                                | under  Uniform Gifts to Minors Act |
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| JT TEN     – as joint tenants with right                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |                                         |                                                                                                                                                                                                                                                                                                                                                |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |    of survivorship and not as |                                                                                                                                                                                                                                                                                                                                                |   | (State) |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |    tenants  in common         |                                                                                                                                                                                                                                                                                                                                                |   |   |
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| Additional abbreviation may also be used though not in the above list                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| For value  received,                                                      hereby  sell, assign and transfer unto                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
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| PLEASE INSERT SOCIAL SECURITY OR OTHER  IDENTIFYING NUMBER OF ASSIGNEE                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |                                         |
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| (Please print or typewrite name and address including postal zip code  of assignee)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
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|                                                                                                                                                                                                             | Shares                                       |
| of  the Common Stock represented by the within Certificate, and do hereby  irrevocably constitute and appoint                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                         |                                                                                                                                                                      |
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| Attorney to  transfer the said Shares on the books of the within-named Corporation with  full power of substitution in the premises.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
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|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                         | **NOTICE:** The signature to this assignment must  correspond with the same as written upon the face of the Certificate, in  every particular, without alteration or enlargement, or any change whatever.                                                                                                                                      |
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| THE  SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION  (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH  MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO  S.E.C. RULE 17Ad-15.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |                                         |
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