REGISTRATION RIGHTS AGREEMENT

         THIS REGISTRATION  RIGHTS AGREEMENT (the "Agreement") is made by Cheung
Laboratories,  Inc., a Maryland corporation (the "Company"),  for the benefit of
the undersigned  investor  ("Investor",  collectively,  the  "Investors").  This
Agreement  shall become  effective upon acceptance and closing in respect of the
related  subscription  for  the  Senior  Secured  Convertible  Promissory  Notes
("Notes")  and  the  shares  of  common  stock  underlying  the  Notes,  and the
associated  warrants to purchase common stock of the Company  ("Warrants").  The
Notes and the Warrants are collectively  referred to herein as the "Securities."
The common  stock of the Company  into which the Notes are  convertible  and the
common stock  issuable upon exercise of the Warrants shall be referred to herein
collectively as the "Underlying Stock."

                                 R E C I T A L S

         A. The Investors  desire to purchase from the Company,  and the Company
desires to issue and sell to the Investors,  up to an aggregate of $1,200,000 in
face amount of Notes and  associated  Warrants as described in the  Confidential
Offering  Memorandum  dated July 1, 1996 and all of the  Exhibits  thereto  (the
"Offering Memorandum").

         B. As further  inducement  for the  Investors to purchase the Notes and
Warrants from the Company,  the Company  desires to undertake to register  under
the Securities Act of 1933, as amended, and the rules and regulations thereunder
(collectively,  the "Securities Act"), the Underlying Stock six months after the
Company effects a registration,  on any applicable  form, of newly issued common
stock at any time while the Investor holds the Notes, the Warrants,  some or all
of the Underlying  Stock.  This Agreement sets forth the terms and conditions of
such undertaking.

         The Company and the Investor agree as follows:

         1.       Definitions.  For purposes of this Agreement:

                  (a) The  terms  "register,"  "registered"  and  "registration"
refer  to a  registration  effected  by  preparing  and  filing  a  registration
statement or statements or similar  documents in compliance  with the Securities
Act and  pursuant to Rule 415 under the  Securities  Act or any  successor  rule
providing for offering  securities on a continuous  basis ("Rule 415"),  and the
declaration  or ordering of  effectiveness  of such  registration  statement  or
document by the Securities and Exchange Commission (the "SEC");

                  (b)  The  term   "Registerable   Securities"   means  (i)  the
Underlying  Stock,  and  (ii) any  common  stock of the  Company  issued  as (or
issuable upon the conversion or exercise of any convertible  security,  warrant,
right or other security which is issued as) a dividend or










other  distribution with respect to, or in exchange for or in replacement of any
Note, Warrant,  or any Underlying Stock,  excluding in all cases,  however,  any
Registerable  Securities sold by a holder of such  Registerable  Securities in a
transaction  in which its  registration  rights  under  this  Agreement  are not
assigned.

                  (c) The  Investors  and  assignees  with  registration  rights
assigned  to them  pursuant  to Section 8 of this  Agreement  may be referred to
herein  collectively  as "Holders" of  Registerable  Securities  and each may be
referred to herein as a "Holder" of Registerable Securities.

         2.       Registration.

                  (a)  Automatic   Registration  Right  -  (i)  Subject  to  the
provisions of Section 3(a),  below,  not earlier than six months after the final
closing date (the "Closing  Date") of a registered  offering of the common stock
of the Company to the general public covered by a registration  statement  under
the  Securities  Act,  the  Company  shall use its best  efforts  to effect  the
registration under the Securities Act of all Registerable Securities;  provided,
however,  that a Holder of  Registerable  Securities  may inform the  Company in
writing  that  it  wishes  to  exclude  all or a  portion  of  its  Registerable
Securities  from such  registration  and upon  such  notice,  such  Registerable
Securities shall be excluded from such registration.

                  (i) The holders of a majority in interest of the  Registerable
Securities shall have the right to select the managing underwriters, if any, and
to  approve  the  terms  of  the  underwriting  agreement  in  respect  of  such
registration,  subject  to the  approval  of the  Company,  which  shall  not be
unreasonably withheld.

                  (iii) The  Company  is  obligated  to use its best  efforts to
effect  only  one  such  registration  pursuant  to  this  Section  2(a) of this
Agreement.

                  (b)  Piggyback  Registration  - (i) On an unlimited  number of
occasions,  and subject to the terms of this Agreement, in the event the Company
decides to register any of its common  stock  (either for its own account or the
account  of a  security  holder or  holders,  other  than in  connection  with a
registration  being  effected  pursuant  to Section  2(a)  above) on an SEC form
(other  than S-4 or S-8) that would be  suitable  for a  registration  involving
Registerable  Securities,  the Company  will:  (x) promptly  give each Holder of
Registerable  Securities  written  notice thereof (which shall include a list of
jurisdictions  in which the Company intends to qualify such securities under the
applicable  Blue Sky or other  state  securities  laws) and (y)  include in such
registration (and in any related  qualification under the Blue Sky laws or other
state  securities  laws),  and in any  underwriting  involved  therein,  all the
Registerable  Securities specified in a written request delivered to the Company
by any Holder of Registerable  Securities  within 20 days after delivery of such
written notice from

                                      - 2 -









the Company.  Nothing  contained in this Section 2(b) shall limit the ability of
the Company to withdraw a  Registration  Statement it has filed either before or
after effectiveness.

                  (ii) If the  registration  of which the Company  gives  notice
pursuant to Section  2(b)(i) is for a registered  public  offering  involving an
underwriting, the Company shall so advise the Holders of Registerable Securities
as a part of the written notice given pursuant to Section 2(b)(i). In such event
the right of any Holder of  Registerable  Securities  to  registration  shall be
conditioned   upon  such   underwriting  and  the  inclusion  of  such  Holders'
Registerable  Securities  in such  underwriting  to the extent  provided in this
Section 2(b).  All Holders of  Registerable  Securities  proposing to distribute
their securities  through such an underwriting  shall (together with the Company
and the other holders  distributing  their securities through such underwriting)
enter into an underwriting  agreement with the Underwriter's  representative for
such offering;  provided that such holders shall have no right to participate in
the selection of the underwriters for an offering pursuant to this Section 2(b).

                  (iii) In the event the  Underwriters'  representative  advises
the Holders of  Registerable  Securities  seeking  registration  of Registerable
Securities  pursuant  to  this  Section  2(b) in  writing  that  market  factors
(including,  without limitation,  the aggregate number of shares of common stock
requested to be registered,  the general condition of the market, and the status
of the persons  proposing  to sell  securities  pursuant  to this  registration)
require  a  limitation  of  the  number  of  shares  to  be  underwritten,   the
Underwriter's  representative  may exclude some or all  Registerable  Securities
from such  registration  and  underwriting.  In such  event,  the  Underwriters'
representative  shall so advise all Holders of  Registerable  Securities  of the
number  of  shares  of  Registerable  Securities  that may be  included  in such
registration and underwriting (if any), and the number of shares of Registerable
Securities that may be included in such  registration  and underwriting (if any)
shall be allocated  among all holders  seeking  registration  in proportion,  as
nearly as  practicable,  to the number of shares  proposed to be included in the
registration by the Holder.  The number of shares of Registerable  Securities to
be  included  in  such  underwriting  shall  not be  reduced  unless  all  other
securities (other than those sold by the Company) are similarly limited from the
underwriting.  No Registerable  Securities or other securities excluded from the
underwriting  by  reason  of  this  Section  2(b)  shall  be  included  in  such
Registration Statement.

                  (iv) If any Holder of Registerable Securities,  or a holder of
other  securities  entitled (upon request) to be included in such  registration,
disapproves of the terms of any underwriting,  such Holder may elect to withdraw
therefrom by written  notice to the Company  delivered at least 20 days prior to
the effective date of the Registration Statement.

         3.      Obligations of the Company.  When required under this Agreement
to effect the registration of the Registerable Securities, the Company shall, as
expeditiously as reasonably possible, use its best efforts to:


                                      - 3 -









                  (a) Prepare and file with the SEC a registration  statement or
statements or similar documents (the  "Registration  Statement") with respect to
all Registerable Securities,  other than any Registerable Securities excluded by
Holders  of  Registerable   Securities  pursuant  to  Section  2(a),  cause  the
Registration  Statement to become  effective not later than six months after the
closing date of the Company's Next Public  Offering of common stock and keep the
Registration  Statement  effective  pursuant  to Rule 415 at all times until the
earlier of (i) the third  anniversary of the final closing date of the Company's
offering of Notes and Warrants to the  Investors,  or (ii) the date on which all
Investors can sell any of the  Registerable  Securities  pursuant to Rule 144 of
the  Securities Act without  restriction  under Rule 144(e)  thereof;  provided,
however, that if a public offering of common stock by the Company is closed on a
date that is more  than two  years  following  the  first  date  each  Holder of
Registerable  Securities held such  Registerable  Securities,  the Company shall
have  no  obligation  to  file a  Registration  Statement  in  respect  of  such
registerable  securities pursuant to this Agreement,  except pursuant to Section
2(b).

                  (b) Prepare and file with the SEC such  amendments  (including
post-effective amendments) and supplements to the Registration Statement and the
Prospectus  used  in  connection  with  the  Registration  Statement  as  may be
necessary to keep the  Registration  Statement  effective at all times until the
earlier of (i) the third  anniversary of the final closing date of the Company's
offering of the Notes and Warrants,  or (ii) the date on which all Investors can
sell their respective shares of Registerable  Securities pursuant to Rule 144 of
the Securities Act without restriction under Rule 144(e) thereof,  and to comply
with the provisions of the Securities Act with respect to the disposition of all
securities covered by the Registration Statement.

                  (c) Furnish promptly to the Holders of Registerable Securities
such numbers of copies of a prospectus,  including a preliminary prospectus, and
all amendments and supplements  thereto,  in conformity with the requirements of
the  Securities  Act, and such other  documents  as the Holders of  Registerable
Securities  may  reasonably  request in order to facilitate  the  disposition of
Registerable Securities.

                  (d)  Register  and  qualify  the  securities  covered  by  the
Registration  Statement  under  such other  securities  or Blue Sky laws of such
jurisdictions as shall be reasonably  requested by the Investors and prepare and
file  in  those   jurisdictions   such  amendments   (including   post-effective
amendments)  and  supplements and to take such other actions as may be necessary
to maintain such registration and qualification in effect at all times until the
earlier of (i) the third  anniversary  of the final  closing date of the Company
offering of the Notes and Warrants,  or (ii) the date on which all Investors can
sell their respective shares of Registerable  Securities pursuant to Rule 144 of
the Securities Act with out restriction  under Rule 144(e) thereof,  and to take
all other  actions  necessary  or advisable  to enable the  disposition  of such
securities  in such  jurisdictions,  provided  that  the  Company  shall  not be
required in connection therewith or as a condition thereto to qualify to do

                                      - 4 -









business  or to file a general  consent to service of process in any such states
or jurisdictions or to provide any undertaking or make any change in its charter
or bylaws  which the Board of  Directors  determines  to be contrary to the best
interest of the Company and its stockholders.

                  (e) In the event the  holders of a majority in interest of the
Registerable  Securities  select  underwriters for the offering,  enter into and
perform its obligations under an underwriting  agreement, in usual and customary
form, including, without limitation,  customary indemnification and contribution
obligations, with the managing underwriter of such offering. The Investors shall
also enter into and perform their customary obligations under any such agreement
including,  without  limitation,   customary  indemnification  and  contribution
obligations.

                  (f) Notify the Holders of Registerable Securities, at any time
when  a  prospectus   relating  to  Registerable   Securities   covered  by  the
Registration  Statement is required to be delivered under the Securities Act, of
the happening of any event as a result of which the  prospectus  included in the
Registration  Statement,  as then in effect,  includes an untrue  statement of a
material fact or omits to state a material fact required to be stated therein or
necessary  to make  the  statements  therein  not  misleading  in  light  of the
circumstances then existing.  The Company shall promptly amend or supplement the
Registration Statement to correct any such untrue statement or omission.

                  (g)  Notify  the  Holders of  Registerable  Securities  of the
issuance  by the SEC of any  stop  order  suspending  the  effectiveness  of the
Registration  Statement or the initiation of any  proceedings  for the purposes.
The Company  will make every  reasonable  effort to prevent the  issuance of any
stop order and, if any stop order is issued,  to obtain the  lifting  thereof at
the earliest possible time.

                  (h)  Permit a single  firm of  counsel  designated  as selling
stockholders'  counsel  by  the  holders  of  a  majority  in  interest  of  the
Registerable Securities commencing at a reasonable period of time prior to their
filing, to review the Registration  Statement and all amendments and supplements
thereto  and  shall  not  file any  document  in a form to  which  such  counsel
reasonably objects.

                  (i) Make generally  available to its security  holders as soon
as practicable, but not later than 90 days after the close of the period covered
thereby,  an earnings  statement (in form  complying with the provisions of Rule
158 under the  Securities  Act) covering a 12- month period  beginning not later
than the first day of the Company's  fiscal quarter next following the effective
date of the Registration Statement.

                  (j)  At the request of the Holders of Registerable Securities,
furnish  to the  underwriters  on the  date  that  Registerable  Securities  are
delivered to the underwriters for sale

                                      - 5 -









in connection  with a  registration  pursuant to this  Agreement (i) an opinion,
dated such date,  of the counsel  representing  the Company for the  purposes of
such registration, in form and substance as is customarily given to underwriters
in an underwritten  public offering,  addressed to the underwriters,  and (ii) a
letter dated such date, from the independent certified public accountants of the
Company, in form and substance as is customarily given by independent  certified
public accountants to underwriters in an underwritten public offering, addressed
to the underwriters.

                  (k)  Make   available   for   inspection  by  the  Holders  of
Registerable Securities, any underwriters participating in the offering pursuant
to the registration and the counsel, accountants or other agents retained by the
Investors,  all pertinent  financial and other records,  corporate documents and
properties  of the Company,  and cause the  Company's  officers,  directors  and
employees to supply all  information  reasonably  requested by the  Investors in
connection with the registration.

                  (l)  If  the  Common  Stock  is  then  listed  on  a  national
securities  exchange,  cause the  Registerable  Securities  to be listed on such
exchange.  If the  Common  Stock is not then  listed  on a  national  securities
exchange, facilitate the reporting of the Common Stock on NASDAQ.

                  (m)  Provide a transfer  agent and  registrar,  which may be a
single entity, for the Registerable Securities not later than the effective date
of the Registration Statement.

                  (n)  Take all  actions  necessary  to  facilitate  the  timely
preparation  and delivery of certificates  (not bearing any restrictive  legend)
representing the Registerable Securities to be sold pursuant to the Registration
Statement  and to  enable  such  certificates  to be in such  denominations  and
registered in such names as the Holders of such  Registerable  Securities or any
underwriters may reasonably request.

                  (o) Take all other  reasonable  actions  necessary to expedite
and  facilitate  disposition  by the  Investors of the  Registerable  Securities
pursuant to the Registration Statement.

         4.  Furnish  Information.  It shall  be a  condition  precedent  to the
obligations  of the Company to take any action  pursuant to this  Agreement with
respect to each Investor  that such  Investor  shall furnish to the Company such
information  regarding itself,  the Registerable  Securities held by it, and the
intended  method  of  disposition  of such  securities  as shall  be  reasonably
required to effect the  registration  of the  Registerable  Securities and shall
execute such documents in connection  with such  registration as the Company may
reasonably request.

         5.       Expenses of Registration.  All expenses incurred in connection
with  registration,  filings or  qualifications  pursuant  to  Sections 2 and 3,
including without

                                      - 6 -









limitation,  all registration,  listing, filing and qualification fees, printers
and accounting  fees, the fees and  disbursements of counsel for the Company and
the reasonable fees and  disbursements  of one form of counsel for the Investors
shall be borne by the Company (except in the case of the automatic  registration
pursuant to Section 2(a) for which  underwriter  discounts and commissions shall
not be borne by the Company).

         6.       Indemnification.  In the event any Registerable Securities are
included in a Registration Statement:

                  (a) To the extent permitted by law, the Company will indemnify
and hold  harmless  each  Investor,  the  directors,  employees,  agents and the
officers of the Company, each person who signs the Registration  Statement,  and
each person,  if any, who controls any of them, any  underwriter  (as defined in
the Securities Act) for such Holders of Registerable Securities and each person,
if any, who controls any such  underwriter  within the meaning of the Securities
Act or the Securities Exchange Act of 1934, as amended (the "1934 Act"), against
any losses, claims, damages, expenses or liabilities (or actions or proceedings,
whether  commenced or threatened,  in respect  thereof)  arising out of or based
upon any of the following statements,  omissions or violations (collectively,  a
"Violation"): (i) any untrue statement or alleged untrue statement of a material
fact  contained  in  the  Registration  Statement,   including  any  preliminary
prospectus  or  final  prospectus   contained   therein  or  any  amendments  or
supplements  thereto,  (ii) the omission or alleged  omission to state therein a
material fact required to be stated therein, or necessary to make the statements
therein,  in light of the circumstances in which they were made, not misleading,
or (iii) any  violation or alleged  violation  by the Company of the  Securities
Act,  the  1934  Act,  any  state  securities  laws or any  rule  or  regulation
promulgated under the Securities Act, the 1934 Act or any state securities laws;
and the Company  will  reimburse  the  Investors  and each such  underwriter  or
controlling  person,  promptly as such expenses are  incurred,  for any legal or
other expenses  reasonably  incurred by them in connection with investigating or
defending  any such  loss,  claim,  damage,  liability,  action  or  proceeding;
provided,  however,  that the indemnity agreement contained in this Section 6(a)
shall not apply to amounts paid in settlement of any such loss,  claim,  damage,
liability or action if such  settlement  is effected  without the consent of the
Company, which consent shall not be unreasonably withheld, nor shall the Company
be liable in any such  case for any such  loss,  claim,  damage,  liability,  or
action to the extent  that it arises out of or is based upon a  Violation  which
occurs in reliance upon and in  conformity  with written  information  furnished
expressly for use in connection  with such  registration by the Investors or any
such underwriter or controlling person, as the case may be. Such indemnity shall
remain in full force and effect  regardless of any  investigation  made by or on
behalf of the Investors or any such underwriter or controlling  person and shall
survive  the  transfer  of  the  Registerable   Securities  by  the  Holders  of
Registerable Securities.


                                      - 7 -









                  (b)  To  the  extent   permitted   by  law,   each  Holder  of
Registerable  Securities,  severally  and not jointly,  will  indemnify and hold
harmless  the  Company,  each of its  directors,  each of its  officers who have
signed the Registration Statement, each person, if any, who controls the Company
within the meaning of the  Securities Act or the 1934 Act, any  underwriter  and
any other stockholder selling securities pursuant to the Registration  Statement
of any of its  directors or officers or any person who  controls  such holder or
underwriter,  against  any  losses,  claims,  damages of  liabilities  (joint or
several) to which any of them may become subject,  under the Securities Act, the
1934 Act of other federal or state law, insofar as such losses,  claims, damages
or  liabilities  (or actions in respect  thereof) arise out of or are based upon
any  Violation,  in each case to the extent (and only to the  extent)  that such
Violation  occurs in reliance  upon and in conformity  with written  information
furnished  by  such  Holder  of  Registerable  Securities  expressly  for use in
connection with such  registration;  and such Holder of Registerable  Securities
will reimburse any legal or other expenses reasonably incurred by any of them in
connection  with  investigating  or  defending  any such  loss,  claim,  damage,
liability or action;  provided,  however, that the indemnity agreement contained
in this Section 6(b) shall not apply to amounts paid in  settlement  of any such
loss, claim, damage,  liability or action if such settlement is effected without
the consent of such Holder of Registerable  Securities,  which consent shall not
be  unreasonably  withheld;  and provided,  further,  that the Investor shall be
liable under this paragraph for only that amount of losses,  claims, damages and
liabilities  as does not exceed the proceeds to such Investor as a result of the
sale of Registerable Securities pursuant to such registration.

                  (c) Promptly after receipt by an indemnified  party under this
Section  6  of  notice  of  the  commencement  of  any  action   (including  any
governmental action), such indemnified party will, if a claim in respect thereof
is to be made  against any  indemnifying  party under this Section 6, deliver to
the  indemnifying  party a written  notice of the  commencement  thereof and the
indemnifying  party shall have the right to  participate  in, and, to the extent
the indemnifying  party so desires,  jointly with any other  indemnifying  party
similarly  noticed,  to assume  control  of the  defense  thereof  with  counsel
mutually  satisfactory to the parties;  provided,  however,  than an indemnified
party shall have the right to retain its own counsel, with the fees and expenses
to be paid by the indemnifying  party, if, in the reasonable  opinion of counsel
for the indemnifying  party,  representation  of such  indemnified  party by the
counsel retained by the indemnifying party, would be inappropriate due to actual
or potential  differing  interests  between such indemnified party and any other
party  represented  by such counsel in such  proceeding.  The failure to deliver
written  notice  to the  indemnifying  party  within  a  reasonable  time of the
commencement  of any such action shall  relieve such  indemnifying  party of any
liability  to the  indemnified  party  under  this  Section 6 only to the extent
prejudicial to its ability to defend such action, but the omission so to deliver
written  notice to the  indemnifying  party will not relieve it of any liability
that it may have to any  indemnified  party otherwise than under this Section 6.
The  indemnification  required  by  this  Section  6 shall  be made by  periodic
payments of the amount thereof during

                                      - 8 -









the course of the  investigation  or defense,  promptly as such  expense,  loss,
damage or liability is incurred.

                  (d) To the extent any indemnification by an indemnifying party
is  prohibited  or limited by law,  the  indemnifying  party  agrees to make the
maximum contribution with respect to any amounts for which it would otherwise be
liable under this Section 6 to the extent permitted by law, provided that (i) no
contribution  shall be made under  circumstances  where the maker would not have
been  liable for  indemnification  under the fault  standards  set forth in this
Section  6, (ii) no  seller  of  Registerable  Securities  guilty of  fraudulent
misrepresentation  (within the meaning of Section 11(f) of the  Securities  Act)
shall be entitled to contribution from any seller of Registerable Securities who
was not guilty of such fraudulent  misrepresentation,  and (iii) contribution by
any  seller of  Registerable  Securities  shall be  limited in amount to the net
amount of proceeds  received  by such seller from the sale of such  Registerable
Securities.

         7. Reports Under Securities Exchange Act of 1934. With a view to making
available to the Holders of Registerable Securities the benefits of SEC Rule 144
promulgated under the Securities Act and any other rule or regulation of the SEC
that may at any time permit the  Investors to sell  securities of the Company to
the public without registration, the Company agrees to:

                  (a)      make and keep public information available,  as those
terms are understood and defined in SEC Rule 144, at all times;

                  (b)      file with the SEC in a timely  manner all reports and
other  documents  required of the Company under the  Securities Act and the 1934
Act; and

                  (c) furnish to each Holder of Registerable Securities, so long
as such Holder of  Registerable  Securities  owns any  Registerable  Securities,
forthwith  upon  request  (i) a written  statement  by the  Company  that it has
complied with the reporting requirements of SEC Rule 144, the Securities Act and
the 1934 Act, (ii) a copy of the most recent  annual or quarterly  report of the
Company and such other reports and documents so filed by the Company,  and )iii)
such other information as may be reasonably  requested in availing the Investors
of any rule or  regulation  of the SEC which  permits  the  selling  of any such
securities without registration.

         8.  Assignment of Registration  Rights.  The rights to have the Company
register  Registerable  Securities pursuant to this Agreement may be assigned by
the  Holders  of  Registerable  Securities,  subject  to  the  Holders  of  such
Registerable  Securities and such assignment  being in compliance with the terms
of this Agreement and any agreements  incorporated  herein,  and subject to such
assignment  being in conformity with federal and state securities law, rules and
regulations, unless exempt therefrom; to transferees or

                                      - 9 -









assignees,  of such  securities  provided such  transferee or assignee  within a
reasonable time after such transfer, furnishes the Company written notice of the
name and address of such  transferee or assignee and the securities with respect
to which such registration rights are being assigned;  provided,  further,  that
such assignment  shall be effective only if immediately  following such transfer
the further  disposition  of such  securities  by the  transferee or assignee is
restricted  under  the  Securities  Act.  The  term  "Investor"  as used in this
Agreement shall include permitted assignees.

         9.       Miscellaneous.

                  (a) Notices  required or permitted to be given hereunder shall
be in  writing  and shall be deemed to be  sufficiently  given  when  personally
delivered or sent by registered mail,  return-receipt request,  addressed (i) if
to the Company at Cheung Laboratories, Inc. c/o Augustine Cheung, PhD., Chairman
of the Board and Chief Executive Office at 10220-I Old Columbia Road,  Columbia,
Maryland 21046-1705,  and (ii) if to an Investor, at the address set forth under
his name in the  Subscription  Agreement,  or at such other address as each such
party shall furnish by notice given in accordance with this Section 9(a).

                  (b) Failure of any party to exercise any right or remedy under
this  Agreement or otherwise,  or delay by a party in  exercising  such right to
remedy, will not operate as a waiver thereof. No waiver will be effective unless
and until it is in writing and signed by the party giving the waiver.

                  (c) The Agreement shall be enforced, governed and construed in
all respects in accordance with the laws of the State of Maryland,  as such laws
are applied by Maryland courts to agreements entered into and to be performed in
Maryland by and between  residents of Maryland.  In the event that any provision
of this Agreement is invalid or  unenforceable  under any applicable  statute or
rule of law, then such provision shall be deemed  inoperative to the extent that
it may  conflict  therewith  and shall be deemed  modified to conform  with such
statute  or rule of law.  Any  provision  hereof  which  may  prove  invalid  or
unenforceable  under any law shall not affect the validity or  enforceability of
any other provision hereof.

                  (d) The Company  will not,  after the date of this  Agreement,
enter into any agreement  with respect to its securities  which is  inconsistent
with the  rights  granted  to the  Holders of  Registerable  Securities  in this
Agreement or otherwise conflicts with the provisions hereof.

                  (e) The provisions of this Agreement, including the provisions
of this sentence, may not be amended,  modified or supplemented,  and waivers or
consents to departures  from the  provisions  hereof may not be given unless the
Company has  obtained  the written  consent of holders of at least a majority of
shares of the Registerable Securities.

                                     - 10 -









Notwithstanding  the  foregoing,  a waiver  or  consent  to  departure  from the
provisions  hereof with respect to a matter  which  relates  exclusively  to the
rights of Holders of  Registerable  Securities  whose  securities are being sold
pursuant to a  Registration  Statement and which does not directly or indirectly
affect the rights of other Holders of  Registerable  Securities  may be given by
the holders of a majority  of the shares of the  Registerable  Securities  being
sold by such holders,  provided that the  provisions of this sentence may not be
amended,  modified,  or supplemented except in accordance with the provisions of
the immediately preceding sentence.

                  (f) Subject to Section 8 hereof, this Agreement shall inure to
the benefit of and be binding upon the successors and permitted  assigns of each
of the parties, including without limitation and without the need for an express
assignment, subsequent holders of Registerable Securities.

                  (g)  This   Agreement   may  be  executed  in  any  number  of
counterparts and by the parties hereto in separate counterparts and by facsimile
signatures, each of which when so executed shall be deemed to be an original and
all of which taken together shall constitute one and the same agreement.

                  (h) This  Agreement  is  intended  by the  parties  as a final
expression  of their  agreement  and  intended  to be a complete  and  exclusive
statement of the agreement and understanding of the parties hereto in respect of
the  subject  matter  contained  herein.  There are no  restrictions,  promises,
warranties  or  undertakings,  other than those set forth or  referred to herein
with respect to the  registration  rights granted by the Company with respect to
the securities sold in connection with the Offering.  This Agreement  supersedes
all prior agreements and understanding  between the parties with respect to such
subject matters.

Dated this ____ day of July, 1996.

INVESTOR:                                          CHEUNG LABORATORIES, INC.



______________________________       By:  ____________________________
Signature

______________________________    Title:  ____________________________
Printed Name



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