278178.001(B&F)

                                    AMENDMENT


         This  Amendment  ("Amendment")  dated October 23, 1996 by and among Mr.
Sun Shou Yi ("Sun"), Mr. Ou Yang An ("Ou"), Mr. Gao Yu Wen ("Gao") (collectively
the "Gao Group") and Cheung Laboratories,  Inc., a Maryland corporation ("CLI"),
amends that certain Redemption Agreement dated June 6, 1996 between Sun as Gao's
representative  and CLI (the  "Redemption  Agreement");  that certain  Letter of
Intent  dated May 27,  1996  between  Sun as Gao's  representative  and CLI (the
"Letter);  that certain Escrow Agreement dated June __, 1996 by and among Sun as
Gao's representative, CLI and Ms. Leung To Kwan, Solicitor, S.H. Leung & Company
("Leung") (the "Escrow");  that certain Agreement to Settle  Investment  Account
dated  June 8,  1996  between  Ou and CLI  ("Agreement  to  Settle");  and  that
Irrevocable  Proxy  dated  June 6,  1996  from  Gao  ("Proxy").  The  Redemption
Agreement,  the Letter,  the Escrow,  the  Agreement to Settle and the Proxy are
collectively referred to as the "Settlement Agreements."

                                   Witnesseth:

         Whereas,  various  members of the Gao Group entered into the Settlement
Agreements with CLI; and

         Whereas,  CLI and the Gao Group  desire to clarify  that all parties in
the Gao Group agree to the terms and conditions of the Settlement Agreements and
this Amendment; and

         Whereas,  the parties desire to amend the Settlement  Agreements as set
forth below.

         Now  Therefore,  in exchange  for ten dollars  ($10) and other good and
valuable   consideration   the  receipt  and  sufficiency  of  which  is  hereby
acknowledged the Gao Group and CLI agree as follows:

                  1. Contemporaneous with the execution of this Amendment, Leung
as the  Escrow  Agent  pursuant  to this  Amendment  is  instructed  to  deliver
certificates  representing  16,000,000 shares of CLI ("Amended Shares") to Verle
Blaha, President of CLI without any restrictions, liens or encumbrances. The Gao
Group  represents and warrants to CLI that the Amended Shares are free and clear
of all encumbrances and restrictions.

                  2. The Proxy is amended to cover only the 4,000,000  shares of
CLI  remaining  in  escrow  ("Common  Shares")  and the  period  of the Proxy is
extended to the time at which the Common Shares are released to CLI or March 31,
1997 whichever event occurs first.

                  3. The  amount  payable to the Gao Group for the Common Shares
is reduced from $2,200,000 to $2,160,000 which reflects the agreed on credit for









funds remaining in the Agreement to Settle ("Cash Amount").  Notwithstanding the
Settlement Agreements,  the period of time to pay the Cash Amount is extended to
December 31, 1996 and may be extended for an  additional 3 month period upon the
payment of 3/4% per month  interest for the period January 1, 1997 through March
31, 1997.

                  4. The Cash Amount shall be wired or hand delivered to Leung's
trust account.  The Escrow Agent shall release such Cash Amount to Ou as the Gao
Group's representative  contemporaneous with sending the Common Shares to CLI by
hand delivery or DHL as follows:

                                   Verle Blaha
                            Cheung Laboratories, Inc.
                            10220-I Old Columbia Road
                          Columbia, Maryland 21046-1705

                  5. Other than the  Settlement  Agreements  as modified by this
Amendment,  all  agreements  (whether  written  or  oral),   understandings  and
covenants  between the parties are null and void. Other than as modified in this
Amendment all of the terms and  conditions of the  Settlement  Agreements  shall
remain in full force and effect.

                  6. This Amendment is not and shall not in any way be construed
as  an  admission  by  any  party,  or  any  of  their  respective   affiliates,
subsidiaries,  shareholders,  directors,  partners, agents, officers, employees,
representatives,  or attorneys of any illegal acts  whatsoever,  but constitutes
the good faith settlement of all potential claims against the parties,  or their
respective  affiliates,  subsidiaries,   successors,  shareholders,   directors,
partners, agents, officers, employees, representatives or attorneys. The parties
have entered into this Amendment in order to bring the relationship  between CLI
and the Gao Group to a final  conclusion,  to resolve all potential claims which
might be brought by any of the respective affiliates, subsidiaries,  successors,
shareholders,  directors, partners, agents, officers, employees, representatives
or  attorneys,   and  in  order  to  avoid  the  burden,   expense,  delay,  and
uncertainties of litigation.

                  7. The Gao  Group  irrevocably  and  unconditionally  remises,
releases and forever  discharges CLI and each of its past,  present,  and future
affiliates,  subsidiaries,  shareholders, partners, agents, directors, officers,
employees,    representatives,    attorneys,   successors,   heirs,   executors,
administrators,  and assigns,  and all persons acting by,  through,  under or in
concert with any of them (collectively  "Assigns"),  or any of them, of and from
any and all actions,  causes of actions,  suits,  charges,  complaints,  claims,
liabilities, obligations, promises, agreements, controversies, demands, damages,
judgments,  and expenses (including attorney's fees and costs actually incurred)
and all other  liabilities  of any nature  whatsoever,  in law or equity,  which
either  party  ever  had,  now  has  or  their  respective   heirs,   executors,



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administrators, successors, or assigns hereafter may have, particularly, against
each or any of the  Assigns,  arising from or related in any way to any dealings
the  parties  have had through  the date of this  Amendment  and each party does
hereby covenant not to file a lawsuit to assert any such claims.

                  8. CLI irrevocably and unconditionally remises,  releases, and
forever  discharges the Gao Group and each of their respective heirs,  executors
and administrators (collectively "Assigns"), or any of them, of and from any and
all actions, causes of actions, suits, charges, complaints, claims, liabilities,
obligations, promises, agreements,  controversies,  demands, damages, judgments,
and expenses  (including  attorney's  fees and costs actually  incurred) and all
other liabilities of any nature whatsoever, in law or equity, which either party
ever  had,  now  has  or  their  respective  heirs,  executors,  administrators,
successors, or assigns hereafter may have, particularly,  against each or any of
the Assigns, arising from or related in any way to any dealings the parties have
had through the date of this  Amendment and each party does hereby  covenant not
to file a lawsuit to assert any such claims.

                  9. The parties  expressly  acknowledge  that this Amendment is
intended to include in its effect,  without  limitation,  all claims  which have
arisen and of which the parties  know or do not know,  should  have  known,  had
reason  to know or  suspect  to exist in their  respective  favor at the time of
execution hereof, and that this Amendment contemplates the extinguishment of any
such claim or claims.

                  10. The parties represent and certify that each is voluntarily
entering  into this  Amendment;  that the  other  parties  and their  respective
agents,  representatives,  and attorneys have made no representations concerning
the terms or effects of this Amendment  other than those contained  herein;  and
they have reviewed the Amendment with legal counsel of choice.

                  11.  The  parties  represent  and  certify  that they have not
assigned  or  otherwise  conveyed  any rights or  obligations  that they have in
connection  with  transactions  contemplated  by or  within  the  scope  of  the
Settlement Agreements or this Amendment.

                  12.  Notwithstanding  the releases set forth above, each party
agrees that it will cooperate  fully with all  reasonable  requests by the other
party, or any of their  respective  successors,  subsidiaries or affiliates,  to
participate in the preparation  for,  responses to, or prosecution or defense of
any pending or threatened litigation or governmental proceeding or investigation
by or against or involving  CLI, or any of their  successors,  subsidiaries,  or
affiliates,  relating to any events which occurred  during or as a result of the
relationship  of the parties.  Furthermore,  in the event  governmental or third
parties assert claims against CLI which involve any relationship between CLI and
the Gao Group,  CLI may assert  cross  claims and other  claims  against the Gao
Group.  In the  event  such  claims  are  successful,  the Gao  Group  agrees to
indemnify and hold harmless CLI and its affiliates.


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                  13. This  Amendment  is made and entered  into in the State of
Maryland, and shall in all respects be interpreted,  enforced and governed under
the laws of said State. The federal district court of Baltimore,  Maryland shall
have jurisdiction over the parties.  The language of all parts of this Amendment
shall in all cases be construed as a whole, according to its fair meaning.

                  14. The parties  acknowledge  the  termination of all previous
agreements other than the Settlement  Agreements and this Amendment between them
by their mutual consent.

                  15.  Should any  provision  of this  Amendment  be declared or
determined by a court of competent  jurisdiction  to be illegal or invalid,  the
validity of the  remaining  parts,  terms and  provisions  shall not be affected
thereby,  and said illegal or invalid part,  term, or provision  shall be deemed
not to be a part of the Settlement Agreements and this Amendment.

                  16. The Settlement Agreements and this Amendment set forth the
entire  agreement  between the parties hereto,  and fully supersedes any and all
prior agreements or understandings  between the parties hereto pertaining to the
subject matter hereof.

                  17.  CLI  shall  file  its  Form  10-K  for the  period  ended
September 30, 1996 with the United  States  Securities  and Exchange  Commission
disclosing this Amendment and the release of any interest in the Aestar shares.

                  18. CLI covenants  that it will utilize a portion of theuse of
proceeds  on a first  priority  basis  from a public or private  offering  to be
conducted for the purpose of purchasing the Common Shares or in the  alternative
will assign its right to repurchase  the Common  Shares to private  investors to
purchase such shares directly from the Gao Group.

                  IN WITNESS WHEREOF,  and intending to be legally bound hereby,
the Gao Group and CLI have executed the foregoing Amendment.


                                            CHEUNG LABORATORIES, INC.


                                            By:________________________________
                                               Name:
                                               Title:




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                                       ________________________________________
                                       Gao Yu Wen, by and through his attorney
                                       in fact, Ou Yang An

                                       ________________________________________
                                       Sun   Shou   Yi,   in   his
                                       individual  capacity and as
                                       representative  of  Gao  Yu
                                       Wen  by  and   through  his
                                       attorney  in fact,  Ou Yang
                                       An

                                       ________________________________________
                                       Ou Yang An, in his individual capacity
                                       and as representative of Gao Yu Wen




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