Serial Number 0100
Void after 5:00 p.m., Chicago Time, on June 1, 2001 (unless extended as provided
below).

                                                             Warrant to Purchase
                                                               certain Shares of
                                                             Common Stock, dated
                                                                   June 1, 1996.

                                 CERTIFICATE OF
                        WARRANT TO PURCHASE COMMON STOCK
                                       OF
                            CHEUNG LABORATORIES, INC.

This Is To Certify That, FOR CASH AND OTHER VALUE RECEIVED, ANTHONY RIKER, LTD.,
an  Illinois   corporation  ("ARL"  or  "Riker"),   its  nominees,   or  assigns
(hereinafter,  the  "Holder(s)")  are  entitled  to  purchase,  subject  to  the
provisions of this Warrant (its successors, divisions or additions), from Cheung
Laboratories,  Inc., a corporation  duly organized,  in good standing within its
domicile,  and whose  offices as of the date hereof are at 10220-I Old  Columbia
Road, Columbia, MD 21046 (hereinafter,  the "Company"),  at any time on or after
June 1,  1996,  and not later  than 5:00 p.m.,  Chicago  Time,  on June 1, 2001,
unless  extended or renewed as provided in paragraphs 1 and 7 below,  restricted
and  legended  shares of  common  stock of the  Company  ("Common  Stock")  at a
purchase  price  equal to Forty One Cents  ($0.41  U.S.) per share  which is the
current bid price as is publicly  quoted on NASDAQ Bulletin Board as of the date
hereof (and as further adjusted by subsequent events between the preparation and
execution of this Warrant Certificate).

The number of shares of Common  Stock to be received  upon the  exercise of this
Warrant  and the  price to be paid for a share of Common  Stock may be  adjusted
from time to time as hereinafter set forth.

Supplementing, notwithstanding, and in support of the foregoing, the Company and
the original Holder hereof ("Riker"),  intend that the number of shares issuable
hereunder shall be 92,318.

The shares of Common Stock deliverable upon such exercise,  and as adjusted from
time to time, are  hereinafter  referred to as "Warrant  Stock" and the exercise
price for a share of Common  Stock in  effect at any time and as  adjusted  from
time to time is hereinafter sometimes referred to as the "Exercise Price".


                                      - 1 -









The term "Warrant" used above and throughout  this  Certificate  shall mean this
Warrant or successor  Warrants issued in exchange for it for any reason pursuant
to the terms and conditions contained herein.

         13. Exercise of Warrant.  Subject to the provisions of paragraphs 6 and
7 hereof,  this Warrant may be exercised in whole or in part at any time or from
time to time on or after  June 1, 1996 but not later  than  5:00  p.m.,  Chicago
Time,  on June  1,  2001 or if June  1,  2001  is a day on  which  U.S.  banking
institutions  are  authorized by law to close,  then on the next  succeeding day
which  shall not be such a day,  by  presentation  and  surrender  hereof to the
Company or at the office of its stock transfer agent, if any, with a copy of the
Purchase Form attached  hereto duly executed and  accompanied  by payment of the
Exercise  Price for the number of shares  specified in such form,  together with
all federal and state  taxes  applicable  upon such  exercise,  if any,  and the
Company shall  promptly issue and deliver stock  certificates  for the number of
shares purchased to the Holder hereof within two (2) business days in conformity
with  industry  practice.  The Company may  unilaterally  extend the time within
which this Warrant may be exercised but is not obligated to do so.

If this  Warrant  should be  exercised  in part  only or all or a portion  of it
renewed as provided for in paragraph 7 hereof or otherwise,  the Company  shall,
upon  surrender  of this  Warrant  for  cancellation,  execute and deliver a new
Warrant,  containing  terms and  conditions  identical to this Warrant except as
provided  for herein,  evidencing  the right of the  Holder(s)  to purchase  the
balance of the shares purchasable hereunder.

Upon receipt of this Warrant,  the executed Purchase Form and the Exercise Price
by the  Company  or,  if then  applicable,  by its  stock  transfer  agent,  the
Holder(s)  shall be deemed to be the holder(s) of record of the shares of Common
Stock issuable upon such exercise, notwithstanding that the stock transfer books
of the  Company  shall  then be closed or that  certificates  representing  such
shares of Common Stock shall not then be actually  delivered  to the  Holder(s),
their  agents or  designees.  The  Company  shall keep  detailed  records of the
disposition of this,  successor  Warrants,  and any Warrant issuable  hereunder,
each bearing a serial number, and shall make such records available to Holder(s)
or their agents upon request.

         14.  Reservation of Shares.  The Company hereby represents and warrants
that at all times subsequent  hereto there shall be reserved for issuance and/or
delivery upon exercise of this Warrant such number of shares of its Common Stock
as shall be required for issuance or delivery  upon  exercise of this Warrant or
any Warrant issuable hereunder.

         15.  Fractional  Shares.  No  fractional  shares or scrip  representing
fractional share shall be issued upon exercise of this Warrant.  With respect to
any fraction of a share called for upon any exercises hereof,  the Company shall
pay to the Holder(s) an amount in cash equal to such fraction  multiplied by the
current market value of such fractional share, determined as follows:

                                      - 2 -










                  (a) If the  Common  Stock is listed on a  national  securities
exchange or  admitted  to unlisted  trading  privileges  on such  exchange,  the
current  value shall be the last reported sale price of the Common Stock on such
exchange on the last  business day prior to the date of exercise of this Warrant
or if no such sale is made on such day on such exchange; or

                  (b) If the  Common  Stock  is not so  listed  or  admitted  to
unlisted  trading  privileges,  the current  value shall be the mean of the last
reported bid and asked prices reported by the National Association of Securities
Dealers  Automated  Quotation  System  (or,  if not so quoted on NASDAQ,  by the
National  Quotation  Bureau,  Inc.) on the last business day prior to the day of
the exercise of this Warrant; or

                  (c) If the  Common  Stock  is not so  listed  or  admitted  to
unlisted  trading  privileges and bid and asked prices are not so reported,  the
current  fair market  value shall be an amount,  not less than book value or the
last known price paid by a  purchaser  for said Common  Stock,  determined  in a
reasonable manner as may be prescribed by the Board of Directors of the Company.

         16.  Exchange,  Assignment  of Loss of Warrant.  Subject to  applicable
securities laws and the terms of the legend set forth in paragraph 11(b) hereof,
this Warrant  certificate is fully exchangeable and (by definition)  assignable,
without expense, at the option of the Holder(s), upon presentation and surrender
hereof to the Company or at the office of its stock transfer  agent, if any, for
other Warrant  certificates of different  denominations  entitling the Holder(s)
thereof to purchase in the  aggregate  the same number of shares of Common Stock
purchasable hereunder.

Any assignment  hereof shall be made by surrender of this Warrant to the Company
or at the office of its stock transfer agent,  if any, with a written,  executed
assignment,  instructions  and funds  sufficient  to pay  transfer tax (if any);
whereupon the Company shall,  without charge,  execute and deliver a new Warrant
certificate  in  the  name  of the  assignee(s)  named  in  such  instrument  of
assignment and this Warrant certificate shall promptly be canceled. This Warrant
may be divided upon  presentation  hereof at the office of the Company or at the
office of its stock  transfer  agent,  if any,  together with a written  notice,
specifying the names and  denominations  in which new Warrants are to be issued,
and signed by the Holder  thereof.  The terms  "Warrant" and  "Warrants" as used
herein include any Warrants  issued in  substitution  for or replacement of this
Warrant, or into which this Warrant may be divided or exchanged.

Upon  receipt of the Company of evidence  reasonably  satisfactory  to it of the
loss,  theft,  destruction  or mutilation  of this Warrant,  and, in the case of
loss, theft or destruction, of reasonably satisfactory indemnification, and upon
surrender  and  cancellation  of this Warrant,  if  mutilated,  the Company will
execute and deliver a new Warrant of like tenure and date.  Any such new Warrant
executed and delivered shall constitute an additional  contractual obligation on
the part of the Company,  whether or not this Warrant so lost, stolen, destroyed
or mutilated

                                      - 3 -









shall be at any time enforceable by anyone. Nevertheless, neither the Company or
the Holder(s) anticipate that this Warrant or any successor Warrant shall itself
be  registered  (rather that the  underlying  shares shall be  registered),  the
Company shall not impose  unreasonable  burdens on the Holder(s) with respect to
indemnification if same becomes necessary.

         17. Rights of the Holders.  The Holder(s)  shall not, by virtue hereof,
be  entitled to any rights of a  shareholder  in the  Company,  either at law or
equity,  and the rights of the Holder(s)  are limited to those  expressed in the
Warrant and are not  enforceable  against  the Company  except to the extent set
forth herein,  PROVIDED  HOWEVER,  that the Company  shall,  in a timely manner,
provide  Holder(s)  with a copy of each and  every  press  release,  mailing  to
shareholders  and  periodic  filing  with  the  U.S.   Securities  and  Exchange
Commission  made by the Company,  and provided that the Company shall be, at all
times during the tenure of this Warrant or its  successors,  in compliance  with
all its contractual obligations to Riker and its affiliates.

         18.      Adjustments to Exercise Price and Number of Shares.

                  (a) In the case of a  dividend  or other  distribution  on any
stock of the Company or subdivision or combination of the outstanding  shares of
Common Stock,  the exercise  price and the number of shares  issuable  hereunder
shall be adjusted  as  follows:  the  Exercise  Price  shall be  proportionately
decreased in the case of each such issuance (on the day following the date fixed
for determining  shareholders entitled to receive such dividend or distribution)
or   proportionately   decreased  in  the  case  of  each  such  subdivision  or
proportionally  increased in the case of each such combination (on the date that
such  subdivision  or  combination  shall  become  effective).   Notwithstanding
anything in this  document to the  contrary,  it is the intention of the Company
and the Holder  hereof  that the number of shares of the Warrant  Stock  granted
hereunder  are based upon the  assumption  that the Company will redeem from Mr.
Gao Yu Wen  20,000,000  shares of Common Stock and retire these shares of Common
Stock from the books of the Company.  In the event that less than all 20,000,000
shares of Common  Stock are  redeemed  from Mr.  Gao,  then the number of shares
granted hereunder shall be adjusted proportionately.

                  Upon any  adjustment of the Exercise  Price,  the Holder(s) of
this Warrant shall  thereafter  (until  another such  adjustment) be entitled to
purchase,  at the new Exercise  Price,  the number of shares,  calculated to the
nearest full share, obtained by multiplying the number of shares of Common Stock
initially issuable upon exercise of this Warrant by the Exercise Price in effect
on the date hereof and  dividing  the  product so  obtained by the new  Exercise
Price.

                  (b)   Anything   in   this   paragraph   6  to  the   contrary
notwithstanding,  the  Company  shall  not be  required  to give  effect  to any
adjustment in the Exercise  Price unless and until the net effect of one or more
adjustments,  determined as above provided,  shall have required a change of the
Exercise Price by at least one cent, ($0.01 U.S.) but when the cumulative net

                                      - 4 -









effect of more than one  adjustment so determined  shall be to change the actual
Exercise  Price by at least one cent,  such change in the  Exercise  Price shall
thereupon be given effect.

                  (c)   Anything   in   this   paragraph   6  to  the   contrary
notwithstanding,  if, subsequent to the grant and sale of this Warrant and for a
period ending the day after the date that the Company's next public  offering is
completed  [a public  offering  being  defined as one in which the Company is in
receipt  of funds of not less than Five  Million  Dollars  ($5,000,000.00  U.S.)
raised by an underwriter pursuant to a Registration Statement (the Form of which
shall then be  applicable)  declared  effective by the  Securities  and Exchange
Commission (the "SEC"), and funds received in full by the Company], covering the
issuance and sale of said shares to the public,  the Company  shall issue Common
Stock or securities  convertible or exercisable into Common Stock by way of sale
for  cash  or  cash  equivalent  proceeds  or by  grant  of  options  to  retain
management,  consultants, employees, or for services or value of any kind, then;
immediately upon  consummation of such sale,  issuance,  or grant, an adjustment
shall be made in the Exercise Price and the number of shares issuable under this
Warrant such that the Holder(s)  hereof,  after such sale,  issuance,  or grant,
shall be entitled to purchase shares sufficient so that Holder(s) shall maintain
the right to acquire the same percentage of the Company's outstanding shares (on
a fully diluted basis),  for the same total investment upon complete exercise of
this  Warrant  prior to such  issuance  or  grant,  the same  percentage  of the
Company's  Common Stock as the Holder(s) were entitled to purchase prior to such
sale, issuance, or grant (the "Anti-Dilution Feature").

Further,  such  adjustment to the Exercise  Price and number of shares of Common
Stock issuable hereunder shall be determined by assuming that all convertible or
exercisable  securities  issued  during the  period in which this  Anti-Dilution
Feature is operative  (defined  above) have been  converted  or  exercised  upon
issuance  whether or not such  securities  shall actually have been converted or
exercised as of the date at which the adjustment is made (date of issuance).

Notwithstanding  anything else in this  paragraph  which might be interpreted to
the contrary,  should at any time subsequent to the issuance of this Warrant but
during the tenure of this Warrant and any renewals or extensions as are provided
for  herein,  any  person  or  entity  shall be  issued  an  option  or  warrant
exercisable  to purchase stock of the Company or stock of the Company is sold to
such person or entity at a price per share less than the then relevant  Exercise
Price as determined as provided herein, an immediate  adjustment in the Exercise
Price for this Warrant (and  successor  Warrants to this Warrant) shall be made.
The effect of this  adjustment  shall be to make the  Exercise  Price under this
Warrant  equal to the lesser  exercise  option or sale price  referenced  above.
However,  this adjustment  shall not have the effect of increasing the number of
shares purchasable hereunder.  Rather it shall reduce the aggregate amount paid,
assuming  full  exercise of this  Warrant,  to an amount  equal to the number of
shares  otherwise then  purchasable  hereunder  multiplied by the newly adjusted
Exercise Price pursuant to this adjustment.


                                      - 5 -









                  (d)  Whenever  reference  is made in this  paragraph  6 to the
issue or sale of shares of Common Stock,  the term "Common Stock" shall mean the
Common  Stock of the Company of the class  authorized  as of the date hereof and
any other  classes of stock  ranking on a parity with or  convertible  into such
Common  Stock  providing,  as is  contemplated,  it is the  Common  Stock of the
Company  which  is to be  offered  and  sold  at the  next  public  offering  of
registered  Common Shares of the Company.  However,  as of the date of grant and
sale of this  Warrant  and subject to the  provisions  of  paragraph  10 hereof,
shares  issuable  upon  exercise  hereof shall  include only shares of the class
designated as Common Stock of the Company as of the date hereof.

         19. Renewal of Exercise  Rights.  If, while this Warrant or any portion
of it remains in effect,  Holder(s)  wish to extend their rights to exercise all
or a portion of this Warrant which would  otherwise  expire and be lost to them,
they may do so by paying to the Company, a sum equal to five percent (5%) of the
then  relevant  Exercise  Price  pertaining to that portion of the Warrant which
would  otherwise  expire (the  "Renewal  Fee") and the Company shall extend that
portion of the Warrant  for a further  period of five (5) years from the date of
receipt of the Renewal Fee but, in no case,  beyond 5:00 p.m.,  Chicago Time, on
June 1, 2006, and shall issue a new Warrant,  identical in every respect to this
Warrant,  except that such new  Warrant  shall  reflect the fact that  Holder(s)
shall have an  additional  five (5) years to exercise  their  rights to purchase
that portion of the Warrant  Stock for which they have paid a Renewal Fee.  This
provision extends to this Warrant and all successor Warrants issuable hereunder.

This  provision is included  partially to permit  Holder(s) to coordinate  their
exercise of this  Warrant and sale of Warrant  Stock so as to minimize the Costs
and  Expenses  and  time of the  Company's  management  in  complying  with  the
provisions  of this  Warrant.  Payment of the  Renewal  Fee will  confirm no new
rights  upon the  Holder(s)  except to extend and renew the time  period  during
which Holder(s) may exercise existing rights under this Warrant.

         20.  Officer's  Certificate.  Whenever  the  Exercise  Price  shall  be
adjusted as required by the provisions of paragraph 6 hereof,  the Company shall
forthwith file in the custody of its Secretary or an Assistant  Secretary at its
principal  office,  and with its stock  transfer  agent,  if any,  an  officer's
certificate  showing the adjusted  Exercise Price  determined as herein provided
and setting forth in reasonable detail the facts requiring such adjustment. Each
such officer's  certificate  shall be made available at all reasonable times for
inspection  by the Holder(s) and the Company  shall,  forthwith  after each such
adjustment,  deliver a copy of such  certificate  to the  Holder(s)  and each of
them.  Unless  disputed in writing by the Holder hereof within thirty (30) days,
such certificate shall be conclusive as to the correctness of such adjustment.

         21.      General Notices to Warrant Holders.  So long as any portion of
this Warrant (or any successor Warrant) shall be outstanding and unexercised (a)
if the Company shall pay any dividend or make any  distribution  upon the Common
Stock or (b) if the  Company  shall  offer to the  holders  of Common  Stock for
subscription   or   purchase    by   them   any   shares   of   stock   of   any

                                      - 6 -









class or any other rights or (c) if any capital  reorganization  of the Company,
reclassification of the capital stock of the Company, consolidation or merger of
the Company with or into another corporation,  sale, lease or transfer of all or
substantially  all  of  the  property  and  assets  of the  Company  to  another
corporation  or engage in voluntary or involuntary  dissolution,  liquidation or
winding up of the company,  then the Company  shall cause to be delivered to the
Holder(s),  at least  thirty  (30) days  prior to the  relevant  date,  a notice
containing a brief  description  of the proposed  action and stating the date of
which a record is to be taken for the purpose of such dividend,  distribution of
rights,  or  such  reclassification,   reorganization,   consolidation,  merger,
conveyance,  lease, dissolution,  liquidation or winding up is to take place and
the date,  if any,  is to be fixed as of which the  holders  of Common  Stock of
record shall be entitled to exchange  their shares of Common Stock of record for
securities   or  other   property   deliverable   upon  such   reclassification,
reorganization,  consolidation,  merger, conveyance, dissolution, liquidation or
winding up.

         22.  Reclassification,   Reorganization  or  Merger.  In  case  of  any
reclassification,  capital  reorganization or other change of outstanding shares
of Common  Stock of the Company  (other than a change in par value,  or from par
value to no par  value,  or from no par value to par value) or as a result of an
issuance  of  Common  Stock by way of  dividend  or other  distribution  or of a
subdivision or  combination,  or in case of any  consolidation  or merger of the
Company with or into another  corporation (other than a merger with a subsidiary
in which  merger the Company is the  continuing  corporation  and which does not
result  in any  reclassification,  capital  reorganization  or other  change  of
outstanding  shares of Common Stock of the class  issuable upon exercise of this
Warrant)  or in case of any sale or  conveyance  to another  corporation  of the
property  of  the  Company  as an  entirety  or  substantially  as  an  entirety
(collectively,  a "Triggering  Event"), the Company shall use good faith efforts
to cause  effective  provision to be made so that the  Holder(s)  shall have the
right  thereafter  (and  shall  have  said  right  for the same  period  of time
remaining  on any  unexercised  portion of this  Warrant),  without  immediately
exercising this Warrant,  to purchase the kind and amount of shares of stock and
other  securities and property  receivable upon such  reclassification,  capital
reorganization or other change, consolidation, merger, sale or conveyance.

Any such provision  shall include  provision for  adjustments  which shall be as
nearly equivalent as may be practicable to the adjustments  provided for in this
Warrant.  However, in the event that the Company,  using its good faith efforts,
is unable to negotiate with the acquiring  entity the assumption of the Warrants
as provided in the preceding  portion of this paragraph,  then and in such event
this Warrant shall terminate,  to the extent not previously exercised, as of the
record date for such  transaction  upon and only upon  payment of a  "Retirement
Fee" to the Holder(s) hereof.

This Retirement Fee shall consist of the same kind of property  (including cash,
if any) to be received by the Company's  stockholders pursuant to the Triggering
Event (and, at parity with holders of Common Stock,  treated in accordance  with
all the other terms and conditions,

                                      - 7 -









including  timing and manner of payment for the purchase) and the Company herein
agrees that said Retirement Fee may be arrived at by private negotiation between
the  Company and the  Holder(s)  or may be  arbitrated  in  accordance  with the
provisions herein provided.

However,  the Company now and  specifically  agrees  that,  in the event of such
private negotiation, it shall accept an amount to be paid to the Holder(s) (as a
senior  obligation of the company in any such  transaction)  in  arbitration  or
negotiation which is not less than the lowest sum per Warrant which shall result
from application of any then applicable  Warrant  Valuation  Techniques (such as
the  Black-Scholes  Model)  which may be applied  to  publicly  traded  warrants
covering  publicly traded common stock, it being intended by the Company and the
Holder(s) that the Retirement Fee should reflect: (a) the difference between the
purchase and exercise price per share plus (b) a warrant premium factor commonly
determinable by the aforementioned models. Said Retirement Fee shall be a senior
obligation of the Company and shall be paid to Holder(s)  from first proceeds of
any sale or merger in cash unless otherwise  negotiated  between the Company and
Riker (the original Holder).

All subsequent  Holders shall agree,  by acceptance of assignment of any portion
of the Warrant covered by this certificate,  to be bound by this provision.  All
costs and expenses directly  attributable to the determination of the Retirement
Fee (including but not limited to the costs of outside appraisal(s)) shall be at
the expense of the Company.

The foregoing  provisions of this section 10 shall similarly apply to successive
reclassification,  consolidations,  mergers, sales, or conveyances. In the event
that in any such  capital  reorganization  or  reclassification,  consolidation,
merger, sale or conveyance, additional shares of Common Stock shall be issued in
exchange, conversion,  substitution or payment, in whole or in part, for or of a
security of the Company other than Common Stock, any such issue shall be treated
as an issue of Common Stock covered by the  provisions of paragraphs 3, 6, and 9
hereof,  with the amount of the  consideration  received  upon the issue thereof
being  determined by the Board of Directors of the Company in consultation  with
the  Company's  auditors,  such  determination  to be final and  binding  on the
Holder(s).

         23.      Transfer to Comply with the Securities Act of 1933.

                           (a)    This Warrant or the Warrant Stock or any other
security  issued or  issuable  upon  exercise  of this  Warrant may not be sold,
transferred  or otherwise  disposed of except to a person who, in the opinion of
counsel reasonably satisfactory to the Company, is a person to whom this Warrant
or such Warrant Stock may legally be transferred  pursuant to paragraph 4 hereof
without  registration and without the delivery of a current prospectus under the
Securities  Act with  respect  thereto;  and then only  against  receipt  by the
Company of an agreement  from such person to comply with the  provisions of this
paragraph 11 with respect to any resale or other disposition of such securities.


                                      - 8 -









                           (b)     The Company may cause the following legend to
be set  forth  on each  certificate  representing  Warrant  Stock  or any  other
security  issued or  issuable  upon  exercise of this  Warrant  not  theretofore
distributed to the public  pursuant to paragraphs  12, 13, or 14 hereof,  unless
counsel for the Company is of the opinion as to any such  certificate  that such
legend is unnecessary.


                           "The  securities  represented by this certificate may
not be offered for sale,  sold or otherwise  transferred  except  pursuant to an
effective  registration  statement under the Securities Act of 1933 (the "Act"),
or pursuant to an exemption from registration under the Act."

         24. Demand Registration. If at any time, after the next public offering
of registered  Common Shares of the Company (as  previously  covered and defined
herein) the Holder(s), or any of them, shall decide to sell or otherwise dispose
of  Warrant  Stock  then owned or to be owned  upon  intended  exercise  of this
Warrant by such Holder(s), such Holder(s) may give written notice to the Company
of the  proposed  disposition  (but,  if other than Riker,  must  simultaneously
notice  Riker),  specifying  the number of shares of Warrant Stock to be sold or
disposed  of and  requesting  that the Company  prepare and file a  registration
statement under the Securities Act of 1933, as amended (the  "Securities  Act"),
covering such Warrant Stock.

The Company  shall within 10 days  thereafter  give written  notice to the other
Holders of  Warrants  or  Warrant  Stock of such  request  and each of the other
Holders shall have the option for a period of 30 days after receipt by it (them)
of  notice  from the  Company  to  include  its  (their)  Warrant  Stock in such
registration  statement.  The  Company  shall use its best  efforts  to cause an
appropriate registration statement (the "Registration  Statement") covering such
Warrant  Stock to be filed with the  Securities  and  Exchange  Commission  (the
"Commission")  and to become effective as soon as reasonably  practicable and to
remain  effective until the completion of the  distribution of the Warrant Stock
to be offered or sold; provided,  however, that not more than once in any twelve
month period the Company  shall have the right to postpone for a period of up to
60 days any demand made  pursuant to this Warrant if the  underwriters  for such
offering  advise the  Company  in writing  that  market  conditions  make such a
postponement advisable to the Company.

The Holder(s) whose Warrant Stock is (are) included in a Registration  Statement
is (are) hereinafter referred to as the "Selling Shareholder(s)".

Each notice  delivered by a Selling  Shareholder(s)  to the Company  pursuant to
this  paragraph 12 shall  specify the Warrant  Stock  intended to be offered and
sold by such Selling Shareholder(s), express such Selling Shareholder(s) present
intent to offer such Common Shares for distribution, and contain the undertaking
of such Selling  Shareholder(s)  to provide all information and materials and to
take all action as may be required in order to permit the

                                      - 9 -









Company to comply with all applicable  requirements  of the Securities  Act, and
any rules and regulations promulgated thereunder,  and to obtain acceleration of
the effective date of such Registration Statement.

The  Company  shall  not be  obligated  to file  more  than  three  Registration
Statements  pursuant  to the  foregoing  provisions  of this  paragraph  12. The
Company  shall bear all of the Costs and  Expenses  (as  hereinafter  defined in
paragraph 20 hereof) of the first such registration.  The Selling Shareholder(s)
shall bear the costs and expenses of all further registrations  pursuant to this
paragraph 12. A demand for  registration  under this paragraph 12 will not count
as such until the Registration Statement has become effective.

         25. Shelf Registration By Original Holder. At any time and from time to
time during the term of this Warrant or its successors  (including  renewals and
extensions as provided for herein)  Anthony Riker,  Ltd. and only Anthony Riker,
Ltd. (as the original Holder hereof), may demand (and actually expects) that the
Company  will  file  a  Registration  Statement  with  the  Commission  for  the
registration of underlying  shares issuable upon exercise of this Warrant or any
part  thereof,  whether or not said Warrant has, in the interim been assigned or
re-assigned  to other parties.  In this event,  the Company shall pay all of the
Costs and Expenses of said Registration for each such demand.

Once filed, the Company shall be obligated to continue this "shelf registration"
for the maximum time allowable under the then relevant regulations,  at its sole
expense.

         26.      Procedure  for  Demand  Registration.  In  connection with the
filing of a  Registration  Statement  pursuant to  paragraph  12 hereof,  and in
supplementation  and not in limitation of the  provisions  thereof,  the Company
shall:

                  (a) Notify the Selling  Shareholder(s) as to the filing of the
Registration Statement and of all amendments or supplements thereto filed thirty
(30) days prior to the effective date of said Registration Statement;

                  (b)  Notify the  Selling  Shareholder(s),  promptly  after the
Company  shall  receive  notice  thereof,  of the time  when  said  Registration
Statement became effective or when any amendment or supplement to any prospectus
forming a part of said Registration Statement has been filed;

                  (c)      Notify  the  Selling  Shareholder(s)  promptly of any
request by the Commission for the amending or supplementing of such Registration
Statement or prospectus or for additional information;

                  (d)      Prepare  and  promptly  file with the Commission, and
promptly notify the Selling  Shareholder(s)  of the filing of, and amendments or
supplements to such Registration

                                     - 10 -









Statement  or  prospectus  as may be  necessary  to correct  any  statements  or
omissions  if, at any time when a  prospectus  relating to the Warrant  Stock is
required to be delivered under the Securities Act, any event with respect to the
Company  shall have  occurred  as a result of which any such  prospectus  or any
other  prospectus  as then in effect  would  include  an untrue  statement  of a
material  fact or  omit  to  state  any  material  fact  necessary  to make  the
statements therein not misleading; and, in prepare and file with the Commission,
promptly upon the Selling  Shareholder(s)'  written  request,  any amendments or
supplements to such Registration Statement or prospectus which may be reasonably
necessary or advisable in connection with the distribution of the Warrant Stock;

                  (e)   Prepare   promptly   upon   request   of   the   Selling
Shareholder(s) or any underwriters for the Selling Shareholder(s) such amendment
or amendments to such Registration Statement and such prospectus or prospectuses
as may be reasonably  necessary to permit  compliance  with the  requirements of
Section 10 (a) (3) of the Securities Act;

                  (f) Advise the Selling Shareholders promptly after the Company
shall  receive  notice or obtain  knowledge of the issuance of any stop order by
the Commission  suspending the effectiveness of any such Registration  Statement
or amendment  thereto or of the  initiation or threatening of any proceeding for
that  purpose,  and promptly use its best efforts to prevent the issuance of any
stop order or obtain its withdrawal promptly if such stop order would be issued;

                  (g) Use its best  efforts  to  qualify  as soon as  reasonably
practicable  the Warrant Stock for sale under the securities or blue-sky laws of
such states and  jurisdictions  within the United  States as shall be reasonably
requested by the Selling Shareholder(s);  provided that the Company shall not be
required in  connection  therewith  or as a  condition  thereto to qualify to do
business,  to become  subject  to  taxation  or to file a consent  to service of
process generally in any of the aforesaid states or jurisdiction;

                  (h) Furnish the Selling Shareholder(s),  as soon as available,
copies of any Registration  Statement and each preliminary or final  prospectus,
or supplement or amendment required to be prepared pursuant thereto, all in such
quantities  as the  Selling  Shareholder(s)  may  from  time to time  reasonably
request, and;

                  (i) If requested by the Selling Shareholder(s),  enter into an
agreement with the underwriters of the Warrant Stock being registered containing
customary provisions and reflecting the foregoing.

         27.  Incidental  Registration.  Other than as covering in  paragraph 13
hereof,  if at any time the Company  subsequent  to the next public  offering of
registered  Common  Shares  of  the  Company,  shall  propose  the  filing  of a
Registration  Statement on an appropriate  form under the Securities Act for the
registration  of  any  securities  of the  Company,  other  than a  registration
statement on Form S-4 or S-8 or any equivalent  form of  registration  statement
then in effect,

                                     - 11 -









then the Company shall give the Holder(s)  notice of such proposed  registration
and shall include in any Registration  Statement relating to such securities all
or a portion of the Warrant  Stock then owned or to be owned by such  Holder(s),
which such  Holder(s)  shall request (such  Holder(s) to be considered  "Selling
Shareholder(s)"),  by notice given by such Selling Shareholder(s) to the Company
within 15 business  days after the giving of such notice by the Company,  within
15  business  days  after the  giving of such  notice by the  Company,  to be so
included.  In the event of the  inclusion  of  Warrant  Stock  pursuant  to this
paragraph   15,  the  Company   shall  bear  the  Costs  and  Expenses  of  such
registration;  provided,  however that the Selling  Shareholder(s) shall pay the
fees and  disbursements of their own counsel and, pro-rata based upon the number
of shares of Warrant Stock included  therein as these relate to the total number
of Common Shares to be offered or sold, the Securities Act registration fees and
underwriters  discounts and  compensation  attributable to the inclusion of such
Warrant Stock; and, provided further,  however, that amounts to which any person
or entity  shall become  entitled  pursuant to this  sentence  shall not include
amounts which may become payable pursuant to paragraphs 16 or 17 hereof. Nothing
in this  paragraph  15 shall  require  the  registration  of Warrant  Stock in a
Registration  Statement  relating  solely to (a)  securities to be issued by the
Company in connection with the acquisition of the stock or the assets of another
corporation,  or the merger or consolidation of any other corporation by or with
the  Company  or  any  of  its  subsidiaries,  or an  exchange  offer  with  any
corporation,  (b) securities to be offered to the then existing security holders
of the Company,  or (c) securities to be offered to employees of the Company. In
the  event  the   distribution  of  securities  of  the  Company  covered  by  a
Registration  Statement  referred to in this paragraph 15 is to be underwritten,
then the Company's  obligation to include  Warrant Stock in such a  Registration
Statement  shall be  subject,  at the option of the  Company,  to the  following
further conditions:

                  (a)  The   distribution   for  the   account  of  the  Selling
Shareholders shall be underwritten by the same underwriters who are underwriting
the  distribution  of the  securities  for the account of the Company and/or any
other persons whose  securities are covered by such  Registration  Statement and
the Selling  Shareholder(s) shall enter into an agreement with such underwriters
containing customary provisions.

                  (b)  If  the  Selling   Shareholders   are   included  in  the
Registration  Statement and if the underwriting  agreement entered into with the
aforesaid  underwriters contains restrictions upon the sale of securities of the
Company,  other than the  securities  which are to be included  in the  proposed
distribution,  for a period not exceeding 90 days from the effective date of the
Registration Statement, then such restrictions shall be binding upon the Selling
Shareholder(s) with respect to any Warrant Stock not covered by the Registration
Statement and, if requested by the underwriter, the Selling Shareholder(s) shall
enter into a written agreement to that effect.

                  (c) If the  underwriters  shall state in writing that they are
unwilling to include any or all of the Selling  Shareholder(s)  Warrant Stock in
the proposed underwriting because such inclusion would materially interfere with
the orderly sale and distribution of the securities being

                                     - 12 -









offered by the Company, then the number of the Selling Shareholder(s)' shares of
Warrant  Stock to be  included  shall be  reduced  pro rata on the  basis of the
number of shares of Warrant  Stock  originally  requested to be included by such
Selling  Shareholder(s),  or there  shall be no  inclusion  of the shares of the
Selling  Shareholder(s) in the Registration Statement not proposed distribution,
in accordance with such statement by the underwriters.

                  However,  if in such an event,  the Holder(s) hereof shall not
be able to include at least fifty percent (50%) of the Warrant Stock  originally
requested to be included,  then the Company  shall agree to pay all of the Costs
and Expenses of a Shelf Registration to be filed at a later date.

         28.  Indemnification  by the Company.  The Company shall  indemnify and
hold  harmless  each Selling  Shareholder,  any  underwriter  (as defined in the
Securities  Act) for the  Selling  Shareholder,  and each  person,  if any,  who
controls the Selling  Shareholder or such underwriter  within the meaning of the
Securities Act (but, in the case of an underwriter or a controlling person, only
if such under writer or controlling  person indemnifies the persons mentioned in
paragraph  17(b)  hereof in the manner set forth  therein)  against  any losses,
claims,  damages  or  liabilities,  joint  or  several,  to  which  the  Selling
Shareholder or any such underwriter or controlling person becomes subject, under
the  Securities  Act or otherwise,  insofar as such losses,  claims,  damages or
liabilities (or actions in respect  thereof) are caused by any untrue  statement
or alleged untrue  statement of any material fact  contained in any  preliminary
prospectus (if used prior to the effective date of the Registration  Statement),
or contained, on the effective date thereof, in any Registration Statement under
which the Selling  Shareholder(s)' shares of Warrant Stock were registered under
the  Securities  Act, the  prospectus  contained  therein,  or any  amendment or
supplement  thereto,  arising  out of or based  upon  the  omission  or  alleged
omission  to state  therein a material  fact  required  to be stated  therein or
necessary  to make the  statements  therein not  misleading;  the Company  shall
reimburse  the  Selling  Shareholder,  or any such  underwriter  or  controlling
person,  in connection  with  investigating  or defending any such loss,  claim,
damage,  liability or action;  provided,  however, that the Company shall not be
liable to any such  person in any such case to the  extent  that any such  loss,
claim,  damage,  liability  or action  arises out of or is based upon any untrue
statement or alleged  untrue  statement or omission or alleged  omission made in
reliance upon and in  conformity  with  information  furnished in writing to the
Company  by  such  person  expressly  for  inclusion  in any  of  the  foregoing
documents.

         29.    Indemnification by Selling Shareholders. Each individual Selling
Shareholder shall:

                  (a)  Furnish  to  the  Company  in  writing  all   information
concerning  it and  it's  holdings  of  securities  of the  Company  as shall be
required  in  connection  with the  preparation  and filing of any  Registration
Statement covering any Shares of Warrant Stock.


                                     - 13 -









                  (b)  Indemnify  and hold  harmless  the  Company,  each of its
directors,  each of its officers who has signed a Registration  Statement,  each
person,  if any, who controls the Company  within the meaning of the  Securities
Act and any  underwriter  (as defined in the  Securities  Act) for the  Company,
against any losses,  claims,  damages or liabilities to which any such director,
officer,  controlling  person  or  underwriter  may  become  subject  under  the
Securities  Act or  otherwise,  insofar  as such  losses,  claims,  damages,  or
liabilities (or actions in respect  therefor) are caused by any untrue statement
of any material fact contained in any  preliminary  prospectus (if used prior to
the effective date of the Registration Statement) or contained, on the effective
date  thereof,   in  any   Registration   Statement   under  which  the  Selling
Shareholder's   securities  were  registered   under  the  Securities  Act,  the
prospectus contained therein, or any amendment or supplement thereto, or arising
out of or based upon the omission to state  therein a material  fact required to
be stated therein or necessary to make the statement therein not misleading;  in
each case to the extent,  but only to the extent,  that such untrue statement or
omission was made in reliance upon and in conformity with information  furnished
to the Company in writing by the Selling Shareholder  expressly for inclusion in
any of the foregoing documents,  and the Selling Shareholder shall reimburse the
Company and any such director,  officer,  controlling  person or underwriter for
any legal or other  expenses  reasonably  incurred  by the  Company  or any such
director,  officer,   controlling  person  or  underwriter  in  connection  with
investigating or defending any such loss, claim, damage, liability or action.

         30. Notification by Selling  Shareholders.  The Selling  Shareholder(s)
and each other person indemnified  pursuant to paragraph 16 hereof shall, in the
event it receives  notice of the  commencement of any action against it which is
based upon an alleged  act or omission  which,  if proven,  would  result in the
Company having to indemnify it pursuant to paragraph 16 hereof,  promptly notify
the  Company,  in  writing,  of the  commencement  of such action and permit the
Company,  if the Company so notifies the Selling  Shareholder(s)  within 10 days
after  receipt by the Company of notice of the  commencement  of the action,  to
participate in and to assume the defense of such action with counsel  reasonably
satisfactory to the Selling  Shareholder(s) or such other indemnified person, as
the case may be. The omission to notify the Company promptly of the commencement
of any such action  shall not relieve the Company of any  liability to indemnify
the Selling Shareholder(s) or such other indemnified person, as the case may be,
under  paragraph 16 hereof,  except to the extent that the Company  shall suffer
any loss by reason of such failure to give notice which it may have  pursuant to
the rights conveyed to the Holders) in this Warrant.

         31.  Notification by the Company to Selling  Shareholders.  The Company
agrees that, in the event it receives  notice of the  commencement of any action
against it which is based  upon an alleged  act or  omission  which,  if proven,
would result in a Selling  Shareholder  having to indemnify the Company pursuant
to  paragraph  17(b)  hereof,  the  Company  will  promptly  notify the  Selling
Shareholder in writing of the commencement of such action and permit the Selling
Shareholder,  if the Selling  Shareholder so notifies the Company within 10 days
after receipt by the Selling  Shareholder of notice of the  commencement  of the
action, to participate

                                     - 14 -









in and assume the defense of such action with counsel reasonably satisfactory to
the  Company.  The  omission to notify the Selling  Shareholder  promptly of the
commencement  of any such action  shall not relieve the Selling  Shareholder  of
liability to indemnify the Company under paragraph  17(b) hereof,  except to the
extent  that the  Selling  Shareholder  shall  suffer any loss by reason of such
failure to give  notice,  and shall not relieve the Selling  Shareholder  of any
other  liabilities  which it may have under this or any other  agreement then in
effect between the Company and the Selling Shareholder.

         32. Costs and Expenses.  As used in this Warrant,  "Costs and Expenses"
shall  include  all  of the  costs  and  expenses  relating  to  the  respective
Registration  Statement(s) involved,  including but not limited to, registration
fees, filing and qualification  fees,  blue-sky  expenses,  printing and mailing
expenses, fees and expenses of Company's counsel and, if/when appropriate,  fees
and  expenses of counsel  designated  by the Selling  Shareholder(s)  (provided,
however, that no more than one such counsel for the Selling Shareholder(s) shall
be designated on any occasion).

         33.      Addresses.  All  notices,   certificates,   waiver  and  other
communications required or permitted to be given hereunder to any of the parties
by any other party shall be in writing and shall be delivered personally or sent
by next day delivery  service or registered or certified mail,  postage prepaid,
as follows:

                       (a)      If to the Company, addressed to:

                                        Cheung Laboratories, Inc.
                                        10220-I Old Columbia Road
                                        Columbia, MD 21046-1705
                                        Attention: Mr. John Mon, General Manager

                       (b)      If to a Holder,  addressed to the address of
                                each  such  Holder  as  shall,  from time to
                                time,  appear on the  records of the Company
                                or those of the Company's  transfer agent as
                                may be the case.

Any notice  delivered  personally or sent by next day delivery  service shall be
deemed to have been given on the date so delivered,  and any notice delivered by
registered  or certified  mail shall be deemed to have been given on the date it
is received.  Any party may change the address to which notices hereunder are to
be sent by  giving  written  notice  of such  change of  address  in the  manner
provided for giving notice.

         34.  Waiver.  No waiver by a Holder  of any  right  hereunder  shall be
effective  unless it is in writing  which  specifically  refers to the provision
hereof under which such right  arises,  and no such waiver  shall  operate or be
construed  as a  waiver  of any  subsequent  breach,  whether  of a  similar  or
dissimilar nature.

                                     - 15 -










         35.  Entire  Warrant.  This  Warrant  may be amended,  supplemented  or
modified only by a written instrument executed by the Company and the Holder(s).
While separate executed letters proposing and/or accepting  amendment(s) sent to
the Company by the Holder(s) or to the Holder(s) by the Company  shall,  for the
purposes  of  this  paragraph  23,  constitute  a  valid  agreement  as  to  the
relationship  then created by and between the Company and the individual  Holder
in question, only Anthony Riker, Ltd. (as the original Holder) may, by agreement
with the Company,  bind all subsequent  Holders to one single written instrument
which  shall  serve to amend the terms and  conditions  hereof,  and to which by
their  acceptance  of an  assignment  of  any  portion  of  this  Warrant,  they
implicitly agree to be bound by.

         36.  Applicable  Law.  This Warrant and the legal  relations  among the
parties  hereto  shall be  governed  by and  construed  in  accordance  with the
substantive laws of the State of Illinois applicable to contracts made and to be
performed  therein  without  giving effect to the principles of conflict of laws
thereof.

         37.  Appraisal  Rights.  In the  event  that  the  Company's  board  of
directors  has not  approved  and the Company has not  executed  the next public
offering of the Company's  Common Stock prior to the second  anniversary  of the
issuance of this Warrant,  a majority in interest of the Holder(s) may, in their
sole discretion and at any time thereafter, give notice to the Company that they
wish to avail  themselves of Appraisal Rights rather than force the Company into
filing a  Registration  Statement  against  its will by  demanding  registration
hereunder.

Should this event occur,  the Company and the  Holder(s)  shall meet together to
appraise  the value of the  Warrant(s)  and shall  proceed  to do so in the same
fashion  and  spirit as is  provided  for in the first  paragraph  of section 10
hereof in determining a Retirement  Fee to be paid the Holders upon  termination
of the Warrant(s).

         38. Binding Effect.  The provisions  contained in this Warrant shall be
binding  upon and inure to the  benefit of the Company and the Holders and their
respective successors,  permitted assigns, heirs and legal representatives.  Any
person to whom all or a part of a Holder's rights and obligations  hereunder are
assigned shall fulfill such of the assigning Holder's  obligations  hereunder as
have been  assigned,  and shall be  entitled  to all of the rights and  benefits
hereunder to the extent that such person has assumed such Holder's  obligations.
The rights and powers of each  successive  Holder  hereunder are granted to such
Holder  as an owner  of  Warrants  or  Warrant  Stock  as the  case may be.  Any
subsequent  Holder whether becoming such by transfer,  assignment,  operation of
law or  otherwise,  shall have the same rights and powers which a Holder  owning
the same number of Warrants  and/or  Warrant Stock has  hereunder,  and shall be
entitled to  exercise  such  rights and powers  until such Holder or  subsequent
Holder no longer owns any Warrants or Warrant Stock.  Except as provided in this
paragraph  26, this  Warrant  does not  create,  and shall not be  construed  as
creating, any rights enforceable by any person not a Holder.


                                     - 16 -









         39. Validity. If any term,  provision,  covenant or restriction of this
Warrant is held by a court of  competent  jurisdiction  to be  invalid,  void or
unenforceable,  the  Company  agrees  that such  term,  provision,  covenant  or
restriction  shall be  reformed  to the  extent  possible  consistent  with such
judicial holding to reflect the intent of the Company and the original Holder as
stated  herein  and  the  remainder  of the  terms,  provisions,  covenants  and
restrictions  of this Warrant shall remain in full force and effect and shall in
no way be  affected,  impaired  or  invalidated.  It is  hereby  stipulated  and
declared to be the  intention  of the Company that it would have  executed  this
Warrant  including the remaining terms,  provisions,  covenants and restrictions
without including any of such provision of term which may be hereafter  declared
invalid,  void or unenforceable.  This Warrant (Serial Number:  0100) is granted
and sold on this 1st day of June, 1996.

                                             Cheung Laboratories, Inc.

                                             By:______________________________
                                              Augustine Cheung, President
                                  PURCHASE FORM

                                                               Dated: __________

Cheung Laboratories, Inc.
10220-1 Old Columbia Road
Columbia, MD  21046-1705

Attention: Mr. John Mon, General Manager


Attached herewith is Cheung Laboratories,  Inc.'s Common Stock Purchase Warrant,
Serial Number:  __________,  giving the Holder the right to purchase  __________
shares.

I/We  hereby  notify  you that  I/we are  exercising  my/our  right to  purchase
__________  shares  and have  enclosed  herewith  my/our  check in the amount of
$__________,  representing  the  aggregate  exercise  price of said  shares.  If
transfer  taxes  (federal or state) are  applicable  to this  transaction,  I/we
understand that you will be billing me/us for said taxes,  which I/we agree will
be  promptly  remitted  to you  within  ten  (10)  days  of  my/our  receipt  of
notification.

I/We hereby  state that the shares being  purchased  are to be held by me/us for
investment purposes and not with a view to sale, except pursuant to an effective
registration statement or an exemption therefrom.


                                     - 17 -








Please cancel the enclosed Warrant and, if applicable,  send me/us a Warrant, in
partial  substitution  on identical  terms,  for the remaining  shares not being
purchased pursuant to this notification.



Yours very truly,


Holder of Warrant, Serial Number __________


_______________________
_______________________
_______________________
_______________________



                                     - 18 -