**Exhibit
        31.1**
 
 **CERTIFICATION
        OF CHIEF EXECUTIVE OFFICER**
 **PURSUANT
        TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 ***
 
 I,  David
        Norris, Chief Executive Officer, certify that:
 
 1.  I
        have
        reviewed this form 10-QSB for the quarter ended June 30, 2005 of Entropin,
        Inc.;
 
 2. Based
        on
        my knowledge, this report does not contain any untrue statement of a material
        fact or omit to state a material fact necessary to make the statements made,
        in
        light of the circumstances under which such statements were made, not misleading
        with respect to the period covered by this quarterly report;
 
 3.  Based
        on
        my knowledge, the financial statements, and other financial information included
        in this report, fairly present in all material respects the financial condition,
        results of operations and cash flows of the small business issuer as of,
        and
        for, the periods presented in this report;
 
 4. The
        small
        business issuer’s other certifying officer(s) and I are responsible for
        establishing and maintaining disclosure controls and procedures (as defined
        in
        Exchange Act Rules 13a-15(e) and 15d-15(c)) for the small business issuer
        and we
        have:
 
 (a)  Designed
        such disclosure controls and procedures, or caused such disclosure controls
        and
        procedures to be designed under our supervision, to ensure that material
        information relating to the small business issuer, including its consolidated
        subsidiaries, is made known to us by others within this entity, particularly
        during the period in which this report is being prepared;
 
 (b)  Omitted;
 
 (c)  Evaluated
        the effectiveness of the small business issuer’s disclosure controls and
        procedures and presented in this report our conclusions about the effectiveness
        of the disclosure controls and procedures, as of the end of the period covered
        by this report based on such evaluation; and
 
 (d)  Disclosed in this quarterly report any change in the small business issuer’s
        internal control over financial reporting that occurred during the small
        business issuer’s most recent fiscal quarter (the small business issuer’s fourth
        fiscal quarter in the case of an annual report) that has materially affected,
        or
        is reasonably likely to materially affect, the small business issuer’s internal
        control over financial reporting; and
 
 5.  The
        small
        business issuer’s other certifying officer(s) and I have disclosed, based on my
        most recent evaluation of internal control over financial reporting, to the
        small business issuer’s auditors and the audit committee of small business
        issuer’s board of directors (or persons performing the equivalent functions):
 
 (a)  All
        significant deficiencies and material weaknesses in the design or operation
        of
        internal control over financial reporting which are reasonably likely to
        adversely affect the small business issuer’s ability to record, process,
        summarize and report financial information; and
 
 (b)  Any
        fraud, whether or not material, that involves management or other employees
        who
        have a significant role in the small business issuer’s internal control over
        financial reporting.
 
 Date:
        August 9, 2005
  /s/
                  David
                  NorrisDavid
                  NorrisChief
                  Executive Officer
 
 *The
        introductory portion of paragraph 4 of the Section 302 certification that
        refers
        to the certifying offices’ responsibility for establishing and maintaining
        internal control over financial reporting for the company, as well as paragraph
        4(b), have been omitted in accordance with Release No. 33-8545 (March 2,
        2005)
        because the compliance period has been extended for small business issuers
        until
        the first fiscal year ending on or after July 15, 2006.