Exhibit 10.3

                              MACROCHEM CORPORATION
                               110 Hartwell Avenue
                       Lexington, Massachusetts 02421-3134

                                                      September 12, 2005


BY HAND DELIVERY

Mr. Thomas C. K. Chan, Ph.D
Vice President of Research and Development,
  Chief Technology Officer
c/o MacroChem Corporation
110 Hartwell Avenue
Lexington, Massachusetts 02421-3134

Dear Thomas:

    The purpose of this letter is to confirm the agreement between you and
MacroChem Corporation ("MACROCHEM" or the "COMPANY") concerning your remaining
employment, your separation from the Company, and your severance arrangements,
as follows:

1.  TRANSITION PERIOD. From the date of this Agreement until November 30, 2005
(the "SEPARATION DATE"), you will continue to be employed by the Company in your
current position (the "TRANSITION PERIOD"). You agree not to resign from your
employment prior to November 30, 2005, without the prior written consent of the
Company, which consent will not be unreasonably withheld.

2.  SALARY. Within five (5) business days of the effective date of this
Agreement, as defined below, you will receive a lump sum payment equal to
$35,351.92, which amount consists of (i) $29,436.92 representing pay, at your
rate of pay in effect on August 31, 2005, for the vacation days you have earned
but not used as of the date hereof, PLUS (ii) $5,915.00 representing base
salary, which as of September 1, 2005 shall be $455 per week, for the period
beginning September 1, 2005 and ending November 30, 2005 (the "SALARY PAYMENT").

3.  DUTIES DURING THE TRANSITION PERIOD. During the Transition Period, you agree
to cooperate fully with the Company and to devote to the Company your best
efforts, professional judgment, skill and knowledge, and such professional time
as is necessary to assist the Company in winding down and selling its business
and assets. The Company acknowledges that you will be actively seeking new
employment during the Transition Period and agrees that you may arrange
reasonable time off to pursue such new employment, provided that it does not
interfere with your obligations to the Company under this Agreement .

4.  SEVERANCE. In consideration of your acceptance of this Agreement, the
Company will provide you, within five business days of the effective date of

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this Agreement, as defined below, with a lump sum severance payment equivalent
to nine (9) months of your base salary in effect on August 31, 2005, LESS an
amount equal to the Salary Payment.

5.  HEALTH AND DENTAL BENEFIT. Subject to your meeting in full your obligations
under this Agreement and executing in a timely manner (and without revocation)
the release of claims attached hereto as EXHIBIT A following, but within
forty-five days of, the Separation Date (or following, but within 45 days of,
such earlier date as may be specified by the Company), the Company will pay you
a lump sum payment on the Separation Date equal to $14,781.60 (the "BENEFIT
PAYMENT"). The Benefit Payment shall be made to you within 5 days of the later
of (i) the effective date of said release of claims (that is, the day after the
expiration of the seven day revocation period provided for in the release) and
(ii) the Company's receipt of a signed release of claims.

6.  DEDUCTIONS. All payments by the Company under this Agreement will be reduced
by all taxes and other amounts that the Company is required to withhold under
applicable law and all other deductions authorized by you.

7.  ACKNOWLEDGMENT OF FULL PAYMENT, STATUS OF BENEFITS AND OTHER MATTERS.

    (a) You agree that except as provided under this Agreement, no further
    compensation is owed to you, whether for services provided to the Company or
    otherwise. Without limiting the generality of the preceding sentence, you
    also acknowledge that you will not be eligible to receive any further bonus
    or other incentive compensation. The parties expressly agree that the Key
    Employee Agreement between you and the Company dated as of September 24,
    2001 (the "EMPLOYMENT AGREEMENT"), and the Severance Agreement between you
    and the Company dated as of October 25, 2002 (the "SEVERANCE AGREEMENT) are
    terminated and of no further force or effect as of September 1, 2005, and
    that payment by the Company in accordance with the terms of this Agreement
    shall be in full and complete satisfaction of any and all compensation that
    may be due to you in the nature of severance or separation pay, whether
    pursuant to the Employment Agreement, the Severance Agreement or otherwise,
    and that you shall have no claim to compensation or benefits under the
    Employment Agreement, Severance Agreement or any other agreement or
    arrangement with, or plan, policy program or practice of, the Company
    providing compensation or benefits in the event of termination of employment
    except as expressly set forth in this Agreement.

    (b) You will not continue to earn vacation or other paid time off after the
    date hereof. If you were participating immediately prior to the Transition
    Period then, during the Transition Period, the Company will contribute the
    full amount of the premium cost of participation for you and your eligible
    dependents in the Company's group health and dental plans. Except as
    expressly provided herein or by federal or state law, your participation in
    all employee benefit plans and programs of the Company will end as of the
    Separation Date, in accordance with the terms of those plans and programs.

8.  STOCK OPTIONS. Your rights and obligations with respect to any stock options
granted to you by the Company that are exercisable on the Separation Date shall
be governed by the applicable stock option grants, agreements and plans and


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other restrictions or provisions generally applicable to options granted to
Company employees, as these may be amended from time to time by the Company. All
stock options, if any, granted to you by the Company which are not exercisable
on the Separation Date will be forfeited and cancelled as of that date.

9.  CONFIDENTIAL INFORMATION. Notwithstanding anything to the contrary herein,
you and the Company hereby agree the Confidential Information, Inventions and
Noncompetition Agreement, dated as of September 24, 2001, by and between you and
the Company (the "NON-COMPETITION AGREEMENT"), shall remain in full force and
effect following the execution of this Agreement.

10. NON-DISPARAGEMENT AND CONFIDENTIALITY. You agree that you will not disparage
or criticize the Company or its business, product candidates, officers,
directors or employees, and that you will not otherwise do or say anything that
could harm the interests or reputation of the Company or its employees.

11. RETURN OF DOCUMENTS. In signing this Agreement, you give the Company
assurance that you will return to it, no later than the Separation Date, any and
all documents, materials and information related to the business, whether
present or otherwise, of the Company and all keys and other property of the
Company in your possession or control. Further, you agree that after the
Separation Date, you will not, for any purpose, attempt to access or use any
computer or computer network or system of the Company, including without
limitation their electronic mail systems. Further, you acknowledge that you have
disclosed to the Company all passwords necessary or desirable to enable the
Company to access all information which you have password-protected on its
computer network or system.

12. ENTIRE AGREEMENT. This Agreement and the Noncompetition Agreement contain
the entire agreement between you and the Company and replace all prior and
contemporaneous agreements, communications and understandings, whether written
or oral, with respect to your employment and its termination and all related
matters, including, without limitation, the Employment Agreement and the
Severance Agreement.

13. RELEASE OF CLAIMS.

    (a) In order to be certain that this Agreement will resolve any and all
    concerns that you might have, the Company requests that you carefully
    consider its terms, including the release of claims set forth below, and, in
    that regard encourages you to seek the advice of an attorney before signing
    this Agreement.

    (b) For and in consideration of the special pay and benefits to be provided
    to you under this Agreement, and as a condition of your receipt of such
    benefits, to which you would not otherwise be entitled, you, on your own
    behalf and on behalf of your heirs, beneficiaries, executors,
    administrators, representatives and assigns, and all others connected with
    or claiming through you, hereby release and forever discharge the Company
    and all of its past, present and future officers, directors, shareholders,
    general and limited partners, joint venturers, members, managers, employees,
    agents, predecessors, successors and assigns, and all others connected with
    any of them, and any and all benefit plans maintained by the Company and all


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    past, present and future representatives, agents, trustees, fiduciaries and
    administrators of such plans, both individually and in their official
    capacities, from any and all causes of action, rights or claims of any name
    or nature whatsoever (all, collectively, "Claims"), whether known or
    unknown, which you had in the past, now have, or might now have, through the
    date on which you sign this Agreement, including without limitation Claims
    in any way resulting from, arising out of or connected with your employment
    or its termination or pursuant to any federal, state or local law,
    regulation or other requirement, including without limitation Title VII of
    the Civil Rights Act of 1964, the Age Discrimination in Employment Act, the
    Americans with Disabilities Act and the fair employment practices statutes
    of the state or states in which you have provided services to the Company.

    (c) This Agreement, including the release of claims set forth the paragraph
    immediately above, creates legally binding obligations and the Company
    therefore encourages and advises you to consult an attorney before signing
    this Agreement. In signing this Agreement, you give the Company assurance
    that you have signed it voluntarily and with a full understanding of its
    terms; that you have had sufficient opportunity, before signing this
    Agreement, to consider its terms and to consult with an attorney, if you
    wished to do so, or to consult with any other legal or tax advisors or
    members of your immediate family; and that, in signing this Agreement, you
    have not relied on any promises or representations, express or implied, that
    are not set forth expressly in this Agreement. You acknowledge that in
    accordance with the requirements of the Older Workers Benefit Protection
    Act, the Company is providing you, in EXHIBIT B, a list of the job
    titles and ages of all employees who have been selected for layoff at this
    time and therefore are eligible for severance benefits, together with the
    job classifications and ages of all individuals who have not been selected
    for layoff and therefore are not eligible for severance benefits.


    If the terms of this Agreement are acceptable to you, please sign, date
and return it to me within 45 days of the date you receive it. You may revoke
this Agreement at any time during the seven-day period immediately following the
date of your signing by sending written revocation to the Company's Board of
Directors. If you do not do so, then, at the expiration of that seven-day
period, this letter will take effect as a legally-binding agreement between you
and the Company on the basis set forth above. The enclosed copy of this letter,
which you should also sign and date, is for your records.


                                                 Sincerely,

                                                 MACROCHEM CORPORATION

                                                 By:  /s/ Robert J. DeLuccia


Accepted and agreed:

Signature:  /s/ T. Chan

Date:  9/13/05


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                                                                       EXHIBIT A

                                RELEASE OF CLAIMS


        For and in consideration of the Benefit Payment, as defined in the
    Agreement between me and MacroChem Corporation (the "COMPANY") dated
    September ___, 2005, and as a condition of my receipt of such benefits, to
    which I would not otherwise be entitled, I, on my own behalf and on behalf
    of my heirs, beneficiaries, executors, administrators, representatives and
    assigns, and all others connected with or claiming through me, hereby
    release and forever discharge the Company and all of its past, present and
    future officers, directors, shareholders, general and limited partners,
    joint venturers, members, managers, employees, agents, predecessors,
    successors and assigns, and all others connected with any of them, and any
    and all benefit plans maintained by the Company and all past, present and
    future representatives, agents, trustees, fiduciaries and administrators of
    such plans, both individually and in their official capacities, from any and
    all causes of action, rights or claims of any name or nature whatsoever
    (all, collectively, "CLAIMS"), whether known or unknown, which I had in the
    past, now have, or might now have, through the date on which I sign this
    Release of Claims, including without limitation Claims in any way resulting
    from, arising out of or connected with my employment or its termination or
    pursuant to any federal, state or local law, regulation or other
    requirement, including without limitation Title VII of the Civil Rights Act
    of 1964, the Age Discrimination in Employment Act, the Americans with
    Disabilities Act and the fair employment practices statutes of the state or
    states in which I have provided services to the Company .

        In signing this Release of Claims, I acknowledge that I have had at
    least forty five (45) days from the later of the date I received it or the
    date I gave or received notice of termination of my employment to consider
    the terms of this Release of Claims; that I have signed it following my last
    day of employment with the Company; that I am advised and encouraged by the
    Company to seek the advice of an attorney prior to signing this Release of
    Claims; and that I am signing this Release of Claims voluntarily and with a
    full understanding of its terms. I also acknowledge receipt of the list of
    the job titles and ages of all employees selected for layoff and therefore
    eligible for severance benefits, together with the job titles and ages of
    those not so selected, appended as EXHIBIT B. I understand that I may revoke
    this Release of Claims at any time within seven (7) days of the date of my
    signing by written notice to the Board of Directors of the Company and that
    this Release of Claims will take effect only upon the expiration of such
    seven-day revocation period and only if I have not timely revoked it.

        Intending to be legally bound, I have signed this Release of Claims
    under seal as of the date written below.

Signature: ________________________________________

Date Signed: ______________________________________



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                                                                       EXHIBIT B

       INFORMATION PROVIDED UNDER THE OLDER WORKER BENEFITS PROTECTION ACT

 The following information is being provided to you by MacroChem Corporation
 (the "COMPANY") in accordance with the Older Workers Benefit Protection Act
 (the "OWBPA") and in conjunction with the termination of your employment and
 the Company's offer to you of severance benefits under the Agreement between
 you and the Company dated September__ 2005 (the "AGREEMENT"), which benefits
 are conditioned on your signing (both as of the effective date of the Agreement
 and again as of the termination of your employment with the Company) effective
 waivers of claims in favor of the Company (as defined in the Agreement).

 All employees of the Company other than its Chief Executive Officer are
 eligible for severance benefits if their employment with the Company is
 permanently terminated and they otherwise meet the eligibility requirements set
 by the Company, which include a requirement that the employee signs a release
 of claims such as that contained in your Agreement with the Company.

 The OWBPA requires that the Company to inform you of the "decisional unit" used
 in determining who would be laid off at this time and to provide you a listing
 of the job titles and ages of all persons in that decisional unit selected for
 separation and those who were not. In this case, the decisional unit is the
 Company in its entirety.

 Following is a listing of the job titles and ages of all employees in the
 decisional unit who were selected for termination at this time and the job
 titles and ages of all employees in that unit who were not so selected:

- --------------------------------------------------------------------------------
             JOB TITLE                AGE    # SELECTED    # NOT SELECTED
- --------------------------------------------------------------------------------
Vice President of Research and        49         1               0
Development, Chief Technology
Officer
- --------------------------------------------------------------------------------
Vice President and General Counsel    38         1               0
- --------------------------------------------------------------------------------
Vice President, Chief Financial       61         1               0
Officer and Treasurer
- --------------------------------------------------------------------------------
Vice President, Market Development    62         1               0
- --------------------------------------------------------------------------------


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