Exhibit 10.6


                         PHARMACEUTICAL RESOURCES, INC.


                             Stock Option Agreement


         PHARMACEUTICAL   RESOURCES,   INC.,  a  New  Jersey   corporation  (the
"Company"),  hereby grants  Genpharm Inc., a corporation  organized and existing
under  the  laws  of  the  Province  of  Ontario,  Canada  (the  "Optionee"),  a
non-statutory  stock option (the  "Option")  to purchase  from the Company up to
351,040  shares of  common  stock,  par value  $.01 per  share,  of the  Company
("Option  Shares")  at a  price  and on the  terms  set  forth  in  this  Option
Agreement. The Option is granted by the Company to the Optionee in consideration
for Services (as such term is defined in the Services  Agreement) to be provided
by the Optionee to the Company  pursuant to the Services  Agreement,  dated June
30, 1998, between the Company and the Optionee (the "Services Agreement").


     SECTION 1. Term of Option. The Option is granted as of the date hereof (the
"Grant Date") and shall be exercisable at any time beginning three years and ten
days after the date hereof;  provided  that, to the extent not  exercised,  this
Option shall terminate on April 30, 2003.

     SECTION 2. Vesting. The Option shall vest on the following schedule:


                                                Cumulative vested
Measured from Grant Date                        portion of Option Shares
- ------------------------                        ------------------------

First anniversary                                 one-third
Second anniversary                                two-thirds
Third anniversary                                 entire amount


     SECTION 3.  Exercise  of Option.  Subject to the  provisions  hereof,  this
Option may be exercised  in whole or in part at any time,  or from time to time,
to the  extent  vested,  during its term,  as set forth in Section 1 herein,  by
presentation to the Company at its principal  office of the Option Exercise Form
attached hereto,  duly executed and accompanied by payment (either in cash or by
United  States  certified  or  official  bank check  payable to the order of the



Company) of the Exercise Price for the number of Option Shares specified in such
Form.  Upon receipt of the Option  Exercise Form and such  payment,  the Company
shall,  within five (5) business days, cause to be delivered to the Optionee one
or more  certificates  representing  the  aggregate  number  of  fully-paid  and
nonassessable Option Shares issuable upon exercise as specified in the Form.

     SECTION 4. Exercise Price. The exercise price  ("Exercise  Price") shall be
US $2.00 per share.

     SECTION 5. Reservation of Shares. The Company will reserve for issuance and
delivery upon exercise of this Option all authorized but unissued  Common Shares
or other  shares of  capital  stock of the  Company  (and other  securities  and
property) from time to time receivable upon exercise of this Option.

     SECTION 6. Restrictions on Transfer, Exercise and Registration.

          6.1  Transferability.  This  Option  may  not  be  sold,  transferred,
pledged, assigned or otherwise disposed of (collectively,  "Transferred") by the
Optionee.

          6.2 Compliance  with Securities  Legislation.  No Option Shares may be
transferred  except in full  compliance  with all  applicable  provisions of the
Securities Act of 1933 and of applicable state securities laws.

          6.3 Legend.  Each  certificate for the Option Shares shall be endorsed
with the following legend:

         "THE SECURITIES  REPRESENTED  HEREBY HAVE NOT BEEN REGISTERED UNDER THE
         SECURITIES ACT OF 1933 OR UNDER ANY STATE  SECURITIES LAWS, AND MAY NOT
         BE SOLD, TRANSFERRED, PLEDGED, ASSIGNED OR OTHERWISE DISPOSED OF IN THE
         ABSENCE OF EFFECTIVE  REGISTRATION  STATEMENTS UNDER APPLICABLE FEDERAL
         AND STATE SECURITIES LAWS OR AN OPINION OF COUNSEL  SATISFACTORY TO THE
         COMPANY THAT THE TRANSFER IS EXEMPT FROM REGISTRATION  UNDER APPLICABLE
         FEDERAL AND STATE SECURITIES LAWS."

          6.4  Registration.  The Option  Shares  shall have the  benefit of the
Registration Rights Agreement,  dated March 25, 1998, between the Company, Lipha
Americas, Inc., Merck KGaA and the Optionee.

          6.5  Restrictions on Exercise.  The Option may not be exercised if the
issuance of the Option Shares upon such exercise would constitute a violation of
any applicable federal or state securities laws or other laws or regulations. As

                                       2


a condition to the exercise of the Option,  the Company may require the Optionee
to make any representation and warranty to the Company as may be required by any
applicable law or regulation.

     SECTION 7. Rights of the  Optionee.  The Optionee  shall not be entitled to
any rights of a  shareholder  of the Company with  respect to the Option  Shares
solely as a result of the grant of the  Option.  Such  rights  shall  exist only
after  issuance  of a stock  certificate  in  accordance  with  Section  3 above
following  the  Optionee's  exercise  of  the  Option  (or  a  portion  thereof)
hereunder. The rights of the Optionee are limited to those expressly provided in
this Option.

     SECTION 8. Termination of Services Agreement

          (a) If the Services Agreement terminates other than as a result of the
Optionee's  Breach and the Optionee  thereby  ceases to provide  Services to the
Company,  this Option may be exercised in full during the  remaining  balance of
the term of the Option  (but not in any event  before  three  years and ten days
have elapsed from the date hereof or beyond the  expiration  of the term of this
Option), notwithstanding anything to the contrary in this Option Agreement.

          (b) If the Services Agreement terminates as a result of the Optionee's
Breach and the Optionee thereby ceases to provide  Services to the Company,  the
Optionee may exercise  the Option,  to the extent  vested as of the date of such
termination,  during the remaining balance of the term of the Option (but not in
any event  before  three years and ten days have elapsed from the date hereof or
beyond the expiration of the term of the Option).

          (c) For purposes of this section,  "Breach"  means willful  refusal of
the Optionee to provide  Services to the Company in accordance with the Services
Agreement.

     SECTION 9. Anti-Dilution Provisions.

          9.1. Adjustments for Stock Dividends;  Combinations,  Etc. In case the
Company shall do any of the following (each, an "Event"):

          (a)  declare a dividend  or other  distribution  on its common  shares
payable in common shares of the Company;

          (b) effect a  subdivision  of its  outstanding  common  shares  into a
greater number of common shares (by  reclassification,  stock split or otherwise
by payment of a dividend in common shares);

                                       3


          (c) effect a  combination  of its  outstanding  common  shares  into a
lesser  number  of  common  shares  (by   reclassification,   reverse  split  or
otherwise);

          (d) issue by reclassification,  exchange or substitution of its common
shares any shares of capital stock of the Company; or

          (e) effect any other transaction having a similar effect,

then the Exercise  Price in effect at the time of the record date for such Event
shall be adjusted to a price  determined by multiplying such Exercise Price by a
fraction,  the  numerator of which shall be the number of shares of common stock
outstanding  immediately  prior to such Event and the denominator of which shall
be the number of Common Shares  outstanding  immediately  after such Event. Each
such  adjustment of the Exercise  Price shall be calculated to the nearest cent.
No such adjustment shall be made in an amount less than One Cent ($.01), but any
such amount  shall be carried  forward and shall be given  effect in  connection
with the next subsequent adjustment.  Such adjustment shall be made successively
whenever any Event shall occur.

          9.2 Adjustment in the Number of Option  Shares.  Whenever the Exercise
Price  shall be adjusted  pursuant  to Section 9.1 hereof,  the number of Option
Shares which the Optionee may purchase upon exercise of the Service Option shall
be adjusted,  to the nearest full share,  by  multiplying  such number of Option
Shares  immediately  prior to such  adjustment  by a fraction,  the numerator of
which shall be the Exercise Price  immediately  prior to such adjustment and the
denominator of which shall be the Exercise Price immediately thereafter.

          9.3  Adjustment  for   Consolidation   or  Merger.   In  case  of  any
consolidation  or merger to which the  Company  shall be a party,  other  than a
consolidation  or  merger  in  which  the  Company  shall  be the  surviving  or
continuing  corporation,  or in case of any sale or conveyance to another entity
of all or  substantially  all of the property of the Company,  or in the case of
any statutory exchange of securities with another entity (including any exchange
effected in connection with a merger of any other corporation with the Company),
the Optionee  shall have the right  thereafter  to receive from the Company upon
exercise of the Option the kind and amount of securities, cash or other property
which it would have owned or have been  entitled  to receive  immediately  after
                                       4


such  consolidation,  merger,  statutory  exchange,  sale or conveyance had this
Option  been  exercised   immediately  prior  to  the  effective  date  of  such
transaction  and,  if  necessary,  appropriate  adjustment  shall be made in the
application  of the  provisions  set forth in this Section 9 with respect to the
rights and interests  thereafter of the Optionee to the end that the  provisions
set forth in this Section 9 shall thereafter correspondingly be made applicable,
as nearly as then may reasonably be, in relation to any shares of stock or other
securities or property thereafter  deliverable upon the exercise of this Option.
Notice  of  any  such  consolidation,   merger,   statutory  exchange,  sale  or
conveyance,  and of the provisions proposed to be adjusted, shall, to the extent
reasonably practicable, be mailed to the Optionee not less than thirty (30) days
prior to such event.

     SECTION 10. Fully Paid Shares;  Taxes.  The Company  agrees that the common
shares of the Company  represented by each and every  certificate for the Option
Shares  delivered  on the exercise of this Option in  accordance  with the terms
hereof shall, at the time of such delivery,  be validly  issued,  fully-paid and
nonassessable,  free and clear of all liens, pledges,  options,  claims or other
encumbrances.  The Company  further  covenants and agrees that it will pay, when
due and payable, any and all Federal and state stamp,  original issue or similar
taxes (but  specifically not including any income taxes) which may be payable in
respect of the issue of any Option Shares or certificates therefor.

     SECTION 11. Notices. All notices hereunder shall be in writing and shall be
given: if to the Company,  at One Ram Ridge Road, Spring Valley,  New York 10977
(attention:  Kenneth I.  Sawyer),  fax number:  (914)  425-5097,  with a copy to
Hertzog,  Calamari  &  Gleason,  at 100 Park  Avenue,  New York,  New York 10017
(attention: Stephen Ollendorff, Esq., and Stephen R. Connoni, Esq.), fax number:
(212)  213-1199,  or if to the  Optionee,  at Genpharm  Inc.,  85 Advance  Road,
Etobicoke,  Ontario M8Z 2S9, Canada (attention:  [Chief Financial Officer]), fax
number: (416) 236-2940,  with a copy to Coudert Brothers,  at 1114 Avenue of the
Americas,  New York, New York 10036  (attention:  Edwin S.  Matthews,  Jr.), fax
number:  (212)  626-4120.  Any  notice  shall be deemed  to have  been  given if
personally  delivered or sent by express  commercial courier or delivery service
or by telegram,  telefax, telex or facsimile  transmission.  Any notice given in
any other manner shall be deemed given when actually received.

                                       5


     SECTION 12.  Amendments;  Waiver.  This  Option may not be amended,  and no
provision hereof may be waived,  without the prior written consent of at least a
majority of the Company  Designees (as defined in the Stock Purchase  Agreement,
dated March 25, 1998, between the Company and Lipha Americas, Inc.) on behalf of
the Company and except pursuant to a written instrument  executed by the Company
and the Optionee.

     SECTION 13. Headings. The headings of the Sections of this Option have been
inserted for  convenience of reference only and shall not be deemed to be a part
of this Option.

     SECTION  14.  Governing  Law.  This  Option is issued  under,  and shall be
governed by and construed in accordance  with, the laws of the State of New York
applicable to contracts made and to be performed wholly within such State.

     IN WITNESS WHEREOF,  the Company has caused this Option to be signed on its
behalf, in its corporate name, by its duly authorized officer, on June 30, 1998.


                                PHARMACEUTICAL RESOURCES, INC.



                                By: /s/Kenneth I. Sawyer
                                   --------------------------------
                                    Kenneth I. Sawyer
                                    President


Attest:



/s/Dennis J. O'Connor
- ------------------------------
Dennis J. O'Connor
Secretary

                                GENPHARM, INC.


 
                                By:/s/J.N. Tabatznik
                                   ---------------------------------
                                   Name: J.N. Tabatznik
                                   Title: Chief Executive Officer





                         PHARMACEUTICAL RESOURCES, INC.

                           STOCK OPTION EXERCISE FORM


         For services  performed,  the undersigned  hereby irrevocably elects to
exercise  the  attached  Option to  purchase  ______  shares of common  stock of
Pharmaceutical  Resources,  Inc. at the  Exercise  Price of $2.00 per share,  in
accordance with the Option Agreement.

         Attached  hereto is cash or a U.S.  certified  or  official  bank check
payable to the order of the  Company in the amount of the total  Exercise  Price
set forth above.


                                            -----------------------------------
                                            Name of Optionee



                                            -----------------------------------
                                            Signature of Optionee
                                            or Authorized Representative



                                            -----------------------------------
                                            Name and Title of Authorized
                                            Representative



                                            -----------------------------------
                                            Address of Optionee


                                            -----------------------------------
                                            Date