Exhibit 3.1

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

OF

DURECT CORPORATION

FIRST. The name of the corporation is DURECT Corporation (the “Corporation”).

SECOND. The address of the Corporation’s registered office in the State of Delaware is 1521 Concord Pike, Suite 201, Wilmington, New Castle County, DE 19803. The name of its registered agent at such address is United Agent Group Inc.

THIRD. The purpose of the Corporation is to engage in any lawful act or activity for which corporations may be organized under the General Corporation Law of the State of Delaware, as amended.

FOURTH. The total number of shares that the Corporation shall have authority to issue is 100 shares of Common Stock, and the par value of each such share is $0.01.

FIFTH. The board of directors of the Corporation is expressly authorized to adopt, amend or repeal bylaws of the Corporation.

SIXTH. Elections of directors need not be by written ballot except and to the extent provided in the bylaws of the Corporation.

SEVENTH. To the fullest extent permitted by law, no director of the Corporation shall be personally liable to the Corporation or its stockholders for monetary damages for breach of fiduciary duty as a director. No amendment to, modification of or repeal of this Article SEVENTH shall apply to or have any effect on the liability or alleged liability of any director of the Corporation for or with respect to any acts or omissions of such director occurring prior to any such amendment, modification or repeal.