<PAGE>

                                                                   Exhibit 10(p)


                               Pharmos Corporation
                         99 Wood Avenue South, Suite 301
                                Iselin, NJ 08830



                                          As of April 23, 2001


Dr. Gad Riesenfeld
30 South Adelaide Street
Highland Park, NJ 08904-1606

      Re:   Amendment of Employment Agreement

Dear Gadi:

            I am writing to confirm our agreement about the following amendments
to the Employment  Agreement (the "Employment  Agreement")  dated as of April 2,
2001 between Pharmos  Corporation  (the  "Company") and Gad  Riesenfeld.  Unless
otherwise  indicated,  capitalized terms used in this letter shall have the same
meaning  as when  used  in the  Employment  Agreement.  Except  for the  changes
provided herein, the Employment Agreement remains in full force and effect.

            We have agreed as follows:

1. In recognition  of the additional  work you will have to perform in assisting
   with the transition of a new Chief Executive Officer,  the Company has agreed
   to grant to you, upon the commencement date of a new Chief Executive Officer,
   that number of incentive stock options, equal to the highest annual grant you
   received during the three years immediately prior thereto. Such stock options
   will provide for vesting 25% per year on the first,  second, third and fourth
   anniversaries   of  the  date  of  grant  and  will  be  exercisable  at  the
   then-current  market price of the Company's  Common  Stock.  The stock option
   grant will be in addition to any compensation  otherwise due to you under the
   Employment Agreement or otherwise authorized by the Board of Directors or its
   Compensation  Committee and will  immediately  vest in all  circumstances  in
   which all other  outstanding  stock  options of yours will  immediately  vest
   under the terms of the Employment Agreement.

2. The Employment  Agreement is amended to provide that upon the commencement of
   employment by the Company of a new Chief Executive  Officer,  any termination
   by the Company within 12 months after such  commencement  of employment  will
   require  180 days'  prior  written  notice to you and will  entitle you to 12
   months of base salary and the benefits  otherwise  payable under Section 6(d)
   of the  Employment  Agreement.  Similarly,  any  resignation by you within 12
   months  thereafter,  other than for Good Reason (as defined in the Employment
   Agreement) will require 90 days' prior written notice by you and will entitle
   you to 12 months of base  salary and the  benefits  otherwise  payable  under
   Section 6(d) of the Employment Agreement. In either event, you will act as an
   unpaid consultant to the Corporation for a one year period following any such
   termination. To reflect such changes, new sections 6(g) and 6(h) are added to
   the Employment Agreement, as follows:

                        "(g)  Termination  by the  Corporation  or by RIESENFELD
            upon  the  commencement  of  employment  of a  new  Chief  Executive
            Officer.  In the

<PAGE>

            event the Corporation hires a new Chief Executive Officer other than
            Dr. Haim Aviv,  and within 12 months after the  commencement  of his
            employment by the  Corporation  either the Corporation or RIESENFELD
            terminates his relationship  with the Corporation,  RIESENFELD shall
            receive the following:

                  (i) an amount  equal to twelve  (12) months of base salary for
                  the then  current year (in addition to the base salary paid to
                  RIESENFELD  after the delivery by either party of the required
                  notice of termination  as provided  herein and the actual date
                  of  termination);  (ii)  Other  Compensation  (as  defined  in
                  Section 9); and (iii) the full vesting of  RIESENFELD's  stock
                  options and  warrants,  and  extended  exercisability  thereof
                  until their respective expiration dates.

            Any  termination  by the  Corporation  within  12  months  after the
            commencement of employment of a new Chief Executive  Officer,  other
            than upon a Change in Control, Death, Disability or for Cause, shall
            require the  Corporation  to give to  RIESENFELD  written  notice of
            termination  no less than 180 days  prior to the  effective  date of
            termination.   Any   termination   by   RIESENFELD   following   the
            commencement  of  employment  by such new Chief  Executive  Officer,
            other than by RIESENFELD for Good Reason,  shall require  RIESENFELD
            to deliver  written notice of termination to the Corporation no less
            than 90 days prior to the effective date of termination.  RIESENFELD
            shall  be  entitled  to  the  foregoing   benefits  once  notice  of
            termination  is given by either party,  regardless of his subsequent
            Death, Disability or termination for Cause.

                        (h) Consulting by RIESENFELD following termination under
            Section 6(g). If RIESENFELD's employment is terminated either by the
            Corporation  or by RIESENFELD in accordance  with the  provisions of
            Section  6(g),  RIESENFELD  agrees  that he shall  act as an  unpaid
            consultant  to the  Corporation  on  operations  matters  and  other
            matters  requested of him by the Chief  Executive  Officer or by the
            Board of  Directors  for a twelve (12) month  period  following  the
            effective date of termination. As a consultant,  RIESENFELD shall be
            available by  telephone,  and,  upon  reasonable  prior  notice,  in
            person. If RIESENFELD is required to appear in person at meetings or
            the  like,  the  Corporation  will  reimburse  him for his time at a
            mutually agreed upon level of  compensation,  and in any event shall
            reimburse him for all documented  out-of-pocket expenses incurred in
            the performance of his duties as a consultant hereunder."

            We  have  indicated  to  you,  and  by  your  signature  below,  you
acknowledge that the provisions of this letter and the changes in the Employment
Agreement set forth herein are subject to the approval by the Company's Board of
Directors or its Compensation Committee.



                                       2
<PAGE>



            Please  acknowledge  your acceptance of the foregoing by signing and
returning a copy of this letter to us.

                                          PHARMOS CORPORATION

                                          By: /s/ Haim Aviv
                                              ---------------------------
                                                Haim Aviv,
                                                Chairman of the Board and
                                                Chief Executive Officer


AGREED AND ACCEPTED:

/s/ Gad Riesenfeld
-------------------------
Gad Riesenfeld





                                       3