<PAGE>
                                                                   EXHIBIT 10.22



                              SEPARATION AGREEMENT
                        AND GENERAL RELEASE OF ALL CLAIMS

        This Separation Agreement and General Release of All Claims
("Agreement") is made by and between Genetronics, Inc. ("Company") and Terry
Gibson ("Employee") with respect to the following facts:

        A. Employee is currently employed by Company.

        B. Company is restructuring and is eliminating Employee's position.
Employee's employment will cease effective October 26, 2001("Separation Date").
Company wishes to reach an amicable separation with Employee and assist
Employee's transition to other employment.

        C. The parties desire to settle all claims and issues that have, or
could have been raised, in relation to Employee's employment with Company and
arising out of or in any way related to the acts, transactions or occurrences
between Employee and Company to date, including, but not limited to, Employee's
employment with Company or the termination of that employment, on the terms set
forth below.

        THEREFORE, in consideration of the promises and mutual agreements
hereinafter set forth, it is agreed by and between the undersigned as follows:

        1. Severance Payment and Benefits. Company agrees to pay Employee the
equivalent of One Hundred Four Thousand, Nine Hundred Ninety-Nine Dollars and
Ninety-Six Cents ($104,999.96), less all appropriate federal and state income
and employment taxes ("Severance Payment"), a sum to which Employee is not
otherwise entitled. The Severance Payment will be made in continuing payments
every second Friday in accordance with the Company's normal payroll process
until the Severance Payment has expired. Employee acknowledges and agrees that
this Severance Payment constitutes adequate legal consideration for the promises
and representations made by Employee in this Agreement. Additionally for the
period of severance under this Agreement, Company shall pay the COBRA premium
for Employee and one dependent as well as the life insurance premium under the
Company's Group Life Insurance Policy. To the extent these payments create a
taxable event for Employee, Employee shall be solely liable for such payment of
such tax. No other benefits are offered under this Agreement.

        2. General Release.

           2.1 Employee unconditionally, irrevocably and absolutely releases and
discharges Company, and any parent and subsidiary corporations, divisions and
affiliated corporations, partnerships or other affiliated entities of Company,
past and present, as well as Company's employees, officers, directors, agents,
successors and assigns (collectively, "Released Parties"), from all claims
related in any way to the transactions or occurrences between them to date, to
the fullest extent permitted by law, including, but not limited to, Employee's
employment with Company, the termination of Employee's employment, and all other
losses, liabilities, claims, charges, demands and causes of action, known or
unknown,




<PAGE>

suspected or unsuspected, arising directly or indirectly out of or in any way
connected with Employee's employment with Company. This release is intended to
have the broadest possible application and includes, but is not limited to, any
tort, contract, common law, constitutional or other statutory claims, including,
but not limited to alleged violations of the California Labor Code or the
federal Fair Labor Standards Act, Title VII of the Civil Rights Act of 1964 and
the California Fair Employment and Housing Act, the Americans with Disabilities
Act, the Age Discrimination in Employment Act of 1967, as amended, and all
claims for attorneys' fees, costs and expenses.

           2.2 Employee acknowledges that Employee may discover facts or law
different from, or in addition to, the facts or law that Employee knows or
believes to be true with respect to the claims released in this Agreement and
agrees, nonetheless, that this Agreement and the release contained in it shall
be and remain effective in all respects notwithstanding such different or
additional facts or the discovery of them.

           2.3 Employee declares and represents that Employee intends this
Agreement to be complete and not subject to any claim of mistake, and that the
release herein expresses a full and complete release and, regardless of the
adequacy or inadequacy of the consideration, Employee intends the release herein
to be final and complete. Employee executes this release with the full knowledge
that this release covers all possible claims against the Released Parties, to
the fullest extent permitted by law.

           2.4 Employee expressly waives Employee's right to recovery of any
type, including damages or reinstatement, in any administrative or court action,
whether state or federal, and whether brought by Employee or on Employee's
behalf, related in any way to the matters released herein.

        3. California Civil Code Section 1542 Waiver. Employee expressly
acknowledges and agrees that all rights under Section 1542 of the California
Civil Code are expressly waived. That section provides:

           A GENERAL RELEASE DOES NOT EXTEND TO CLAIMS WHICH THE CREDITOR DOES
           NOT KNOW OR SUSPECT TO EXIST IN HIS FAVOR AT THE TIME OF EXECUTING
           THE RELEASE, WHICH IF KNOWN BY HIM MUST HAVE MATERIALLY AFFECTED HIS
           SETTLEMENT WITH THE DEBTOR.

        4. Representation Concerning Filing of Legal Actions. Employee
represents that, as of the date of this Agreement, Employee has not filed any
lawsuits, charges, complaints, petitions, claims or other accusatory pleadings
against Company or any of the other Released Parties in any court or with any
governmental agency. Employee further agrees that, to the fullest extent
permitted by law, Employee will not prosecute, nor allow to be prosecuted on
Employee's behalf, in any administrative agency, whether state or federal, or in
any court, whether state or federal, any claim or demand of any type related to
the matters released above, it being the intention of the parties that with the
execution of this release, the Released Parties will be absolutely,
unconditionally and forever discharged of and from all obligations to or on
behalf of Employee related in any way to the matters discharged herein.




                                       2
<PAGE>

        5. No Admissions. By entering into this Agreement, the Released Parties
make no admission that they have engaged, or are now engaging, in any unlawful
conduct. The parties understand and acknowledge that this Agreement is not an
admission of liability and shall not be used or construed as such in any legal
or administrative proceeding.

        6. Older Workers' Benefit Protection Act.

           6.1 This Agreement is intended to satisfy the requirements of the
Older Workers' Benefit Protection Act, 29 U.S.C. Section 626(f). Accordingly,
Employee acknowledges and agrees that Employee has read and understands the
terms of this Agreement; that this Agreement advises Employee in writing that
Employee may consult with an attorney before executing this Agreement, if
desired; that Employee has obtained and considered such legal counsel as
Employee deems necessary; that Employee has been given forty-five (45) days to
consider whether or not to enter into this Agreement (although Employee may
elect not to use the full 45-day period at Employee's option); and that by
signing this Agreement, Employee acknowledges that Employee does so freely,
knowingly, and voluntarily. The Agreement shall not become effective or
enforceable until the eighth day after Employee signs the Agreement ("Effective
Date"). In other words, the Employee may revoke acceptance of this Agreement
within seven (7) days after signing it. The Employee's revocation must be in
writing and received by Ken Dix, Vice President, Legal Affairs, by 5:00 p.m.
Pacific Standard Time on the seventh day in order to be effective. The Severance
Payment will become due and payable after the Effective Date in accordance with
Paragraph 1, provided the Agreement has not been revoked. This Agreement does
not waive or release any rights or claims that Employee may have under the Age
Discrimination in Employment Act that arise after the execution of this
Agreement.

           6.2 Employee further acknowledges that Employee has been advised of
the following information:

                      (i) All Employees whose positions are being eliminated
pursuant to the reduction in force on October 26, 2001 are eligible for
severance pay;

                      (ii) All such Employees age 40 or over will have
forty-five (45) days within which to consider whether to accept the Separation
Agreement;

                      (iii) All Employees under age 40 will have seven (7) days
within which to consider whether to accept the Separation Agreement;

                      (iv) The job titles and ages of all Employees eligible for
this program are listed in part A to Exhibit 1 of this Agreement;

                      (v) Employees in the same job classification or
organizational unit as Employee who are not eligible for this program are listed
in part B to Exhibit 1 of this Agreement.

        7. Severability. In the event any provision of this Agreement shall be
found unenforceable by an arbitrator or a court of competent jurisdiction, the
provision shall be deemed modified to the extent necessary to allow
enforceability of the provision as so limited, it being intended that Company
shall receive the benefits contemplated herein to the fullest extent permitted
by law. If a deemed modification is not satisfactory in the judgment of such
arbitrator




                                       3
<PAGE>

or court, the unenforceable provision shall be deemed deleted, and the validity
and enforceability of the remaining provisions shall not be affected thereby.

        8. Applicable Law. The validity, interpretation and performance of this
Agreement shall be construed and interpreted according to the laws of the United
States of America and the State of California.

        9. Binding on Successors. The parties agree that this Agreement shall be
binding on, and inure to the benefit of, Employee or its successors, heirs
and/or assigns.

        10. Full Defense. This Agreement may be pled as a full and complete
defense to, and may be used as a basis for an injunction against, any action,
suit or other proceeding that may be prosecuted, instituted or attempted by
Employee in breach hereof. Employee agrees that in the event an action or
proceeding is instituted by the Released Parties in order to enforce the terms
or provisions of this Agreement, the Released Parties shall be entitled to an
award of reasonable costs and attorneys' fees incurred in connection with
enforcing this Agreement.

        11. Good Faith. The parties agree to do all things necessary and to
execute all further documents necessary and appropriate to carry out and
effectuate the terms and purposes of this Agreement.

        12. Entire Agreement; Modification. This Agreement is intended to be the
entire agreement between the parties and supersedes and cancels any and all
other and prior agreements, written or oral, between the parties regarding this
subject matter. It is agreed that there are no collateral agreements or
representations, written or oral, regarding the terms and conditions of
Employee's separation of employment with Company and settlement of all claims
between the parties other than those set forth in this Agreement. This Agreement
may be amended only by a written instrument executed by all parties hereto.

THE PARTIES TO THIS AGREEMENT HAVE READ THE FOREGOING AGREEMENT AND FULLY
UNDERSTAND EACH AND EVERY PROVISION CONTAINED HEREIN. WHEREFORE, THE PARTIES
HAVE EXECUTED THIS AGREEMENT ON THE DATES SHOWN BELOW.



Dated:    November 1, 2001                By:  /s/ Terry Gibson
       ---------------------                  ----------------------------------
                                               Terry Gibson

                                          Genetronics, Inc.



Dated:  November 7, 2001                  By:  /s/ Avtar H. Dillon
       ---------------------                  ----------------------------------
                                               Avtar H. Dhillon, M.D.
                                               President & CEO




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<PAGE>

                                    EXHIBIT 1

The Older Workers' Benefit Protection Act requires that Genetronics, Inc.,
provide the following information to you:

    A.     Individuals Selected for the October 26, 2001 Reduction in Force by
           Job Title and Age:

<TABLE>
<CAPTION>
    JOB TITLE                                             AGE
    ---------                                             ---
    <S>                                                   <C>
    COO                                                   60
    CFO                                                   57
    Director, HR                                          40
    Director, Marketing                                   49
    Network Administrator                                 34
    Receptionist                                          59
    Mechanical Engineer                                   30
    Principal Manuf. Engineer                             49
    Creative Art Designer                                 50
    Technical Services Engineer                           60
    Safety Officer                                        31
    QA Administrator                                      33
    Marketing Admin Specialist                            33
    Customer Service Rep                                  39
    Admin Sales Assist                                    27
    Document Control Coord                                47
</TABLE>

    B.     Individuals Not Selected for the October 26, 2001 Reduction in Force
           (Within Same Job Classification or Organizational Units) by Job Title
           and Age:

<TABLE>
<CAPTION>
    JOB TITLE                                             AGE
    ---------                                             ---
    <S>                                                   <C>
    CEO                                                   40
    Controller                                            38
    Dept. Assist. HR                                      42
    IT Manager                                            27
    Mechanical Engineer                                   26
    QA Tech                                               44
    QA Tech                                               44
    Admin Assist                                          55
</TABLE>




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