<PAGE>

                                                                  EXHIBIT 4.7(B)

THE CONFIDENTIAL PORTIONS OF THIS EXHIBIT HAVE BEEN FILED SEPARATELY WITH THE
SECURITIES AND EXCHANGE COMMISSION PURSUANT TO A CONFIDENTIAL TREATMENT REQUEST
IN ACCORDANCE WITH RULE 24B-2 OF THE SECURITIES AND EXCHANGE ACT OF 1934, AS
AMENDED. REDACTED PORTIONS OF THIS EXHIBIT ARE MARKED BY AN ***.

                            SHARE PURCHASE AGREEMENT
                     (FOR THE PURCHASE OF SHARES OR OPTIONS
                            FROM COMMON SHAREHOLDERS)

          THIS AGREEMENT is made as of the 18th day of November, 2005,

BETWEEN:

               PARTEQ RESEARCH AND DEVELOPMENT INNOVATIONS, a non-share capital
               company incorporated under the laws of Ontario ("PARTEQ")

               -and-

               JAMES N. REYNOLDS, of the City of Kingston ("REYNOLDS")

               -and-

               BRIAN M. BENNETT, of the City of Kingston ("BENNETT")

               -and-

               ROLAND J. BOEGMAN, of the City of Kingston ("BOEGMAN")

               -and-

               KHEM JHAMANDAS, of the City of Kingston ("JHAMANDAS")

               -and-

               GREGORY J. THATCHER, of the City of Chicago, Illinois
               ("THATCHER")

               -and-

               JOHN LEHMANN, of the City of Wayne, Pennsylvania ("LEHMANN")

               -and-

               IAN ANDERSON, of the City of Woodbridge ("ANDERSON")

               -and-

               GRAHAM STRACHAN, of the City of Etobicoke ("STRACHAN")

<PAGE>

               -and-

               JEAN-PAUL ST. PIERRE, of the City of Mont-Royal, Quebec ("ST.
               PIERRE")

               -and-

               NEIL CUTLER, of the City of Beverly Hills, California ("CUTLER")

               -and-

               CARL COTMAN, of the City of Irvine, California ("COTMAN")

               -and-

               JUDITH BURGESS, of the City of Etobicoke ("BURGESS")

               -and-

               LIANA MEOGROSSI, of the City of Oakville ("MEOGROSSI")

               -and-

               JOY NEWSOME, of the City of Burlington ("NEWSOME")

               -and-

               PERRY MOLINOFF, of the City of Philadelphia, Pennsylvania
               ("MOLINOFF")

               -and-

               SCOTT SAMUEL, of the City of Markham ("SAMUEL")

               -and-

               JAMES RAE, of the City of Markham ("RAE")

               -and-

               PAUL SEKHRI, of the City of Boston, Massachusetts ("SEKHRI")

               -and-

               PADMINI SINGH, of the City of Brampton ("SINGH")

               -and-

               DALE ST. HILAIRE, of the Town of Caledon ("HILAIRE")

               (the above parties, being collectively referred to as the
               "VENDORS" and individually as a "VENDOR")


                                       -2-

<PAGE>

               -and-

               VERNALIS PLC, a corporation incorporated under the laws of
               England and Wales, with company number 2304992

               ("VERNALIS")

               -and-

               VERNALIS (CANADA) INC., a corporation incorporated under the laws
               of New Brunswick

               (the "PURCHASER")

RECITALS:

A.   Certain holders of warrants, conversion rights and options to acquire Class
     A Preference Shares, Class D Preference Shares and common shares (the
     "PRINCIPAL SHAREHOLDERS") in the capital of Cita Neuropharmaceuticals Inc.
     (the "CORPORATION"), the Purchaser, Vernalis and the Corporation have
     entered into a share purchase agreement (the "PRINCIPAL PURCHASE
     AGREEMENT") dated the date hereof whereby the Principal Shareholders have
     agreed to sell to the Purchaser all of their shares in the capital of the
     Corporation, including those issuable upon exercise of warrants, conversion
     rights, options and other rights to acquire shares in the capital of the
     Corporation, or to exchange certain options and other rights to acquire
     shares in the capital of the Corporation (both the shares and options
     being, collectively, the "PRINCIPAL SHAREHOLDERS' SECURITIES").

B.   Parteq, Reynolds, Bennett, Boegman, Jhamandas and Thatcher (collectively,
     the "SHAREHOLDERS") wish to sell all of their common shares in the capital
     of the Corporation and the Purchaser wishes to purchase such shares, on and
     subject to the terms and conditions of this Agreement.

C.   Lehmann, Anderson, Strachan, St. Pierre, Cutler, Cotman, Burgess,
     Meogrossi, Newsome, Molinoff, Samuel, Rae, Sekhri, Singh and St. Hilaire
     (collectively, the "OPTIONHOLDERS") wish to exchange their options to
     acquire common shares in the capital of the Corporation for options to
     acquire Class 4 Preferred Shares in the Purchaser, on and subject to the
     terms of this Agreement.

D.   The Vendors wish to appoint The VenGrowth Advanced Life Sciences Fund Inc.
     to act as their representative with respect to certain matters with respect
     to this Agreement and related documents.

E.   The Purchaser is also entering into separate agreements with other holders
     of shares in the capital of the Corporation and holders of warrants,
     conversion rights, options or rights to acquire shares in the capital of
     the Corporation to acquire all such shares and/or rights.


                                      -3-

<PAGE>

          NOW THEREFORE in consideration of the mutual covenants and agreements
contained in this Agreement and other good and valuable consideration (the
receipt and sufficiency of which are hereby acknowledged), the parties hereto
agree as follows:

                                    ARTICLE 1
                                 INTERPRETATION

1.1  DEFINITIONS

          In this Agreement,

     1.1.1 "AFFILIATE" has the meaning ascribed to such term under the Business
     Corporations Act (Ontario);

     1.1.2 "AGREED PAIN PROJECT BUDGET" means the budget for the Pain Project
     agreed between the Corporation and the Purchaser;

     1.1.3 "AGREED PARKINSON'S PROJECT BUDGET" means the budget for the
     Parkinson's Project agreed between the Corporation and the Purchaser;

     1.1.4 "AGREEMENT" means this agreement and all schedules attached to this
     agreement, in each case as they may be amended or supplemented from time to
     time, and the expressions "HEREOF", "HEREIN", "HERETO", "HEREUNDER",
     "HEREBY" and similar expressions refer to this agreement; and unless
     otherwise indicated, references to Articles and sections are to Articles
     and sections in this agreement;

     1.1.5 "ALZHEIMER'S PROJECT" means the Business which relates to CNP1061 for
     the indication of Alzheimer's disease;

     1.1.6 "API INVENTORY AMOUNT" means the aggregate purchase price of
     specified inventory acquired in respect of the Pain Project and the
     Parkinson's Project, as set out in the Principal Purchase Agreement;

     1.1.7 "BUSINESS" means the business of the Corporation of researching,
     developing and testing drug candidates related to the Pain Project, the
     Parkinson's Project and the Alzheimer's Project;

     1.1.8 "BUSINESS DAY" means any day, other than Saturday, Sunday or any
     statutory holiday in the Province of Ontario or London, England;

     1.1.9 "CANADIAN DOLLARS", "CDN. DOLLARS" or "CDN.$" means lawful currency
     of Canada;

     1.1.10 "CHARGE" means any security interest, lien, charge, pledge,
     encumbrance, mortgage, adverse claim or title retention agreement of any
     nature or kind;


                                      -4-

<PAGE>

     1.1.11 "CLASS 4 PREFERRED SHARE OPTIONS" means the options to acquire Class
     4 Preferred Shares to be granted at the Time of Closing to the
     Optionholders as set forth opposite each Optionholder's name in the Final
     Proceeds Schedule, pursuant to Purchaser Option Agreements, in exchange for
     options to acquire common shares in the capital of the Corporation, each
     Class 4 Preferred Share Option being exercisable for one Class 4 Preferred
     Share;

     1.1.12 "CLASS 2 PREFERRED SHARES" means the Class 2 non-voting,
     retractable, redeemable, preferred shares, in registered form, of the
     Purchaser having the share provisions set out in Schedule D and subject to
     the prior redemption right of the Class 1 non-voting, retractable,
     redeemable, preferred shares in registered form, of the Purchaser, with a
     stated redemption price of U.S. $1.00 per share;

     1.1.13 "CLASS 3 PREFERRED SHARES" means the Class 3 non-voting,
     retractable, redeemable, preferred shares, in registered form, of the
     Purchaser, having the share provisions set out in Schedule D and subject to
     the prior redemption right of the Class 1 non-voting, retractable,
     redeemable, preferred shares, in registered form, of the Purchaser and the
     Class 2 non-voting, retractable, redeemable, preferred shares, in
     registered form, of the Purchaser, with a stated redemption price of
     U.S.$1.00 per share and with an aggregate Redemption Price as set out in
     the Final Proceeds Schedule, plus the aggregate Redemption Price of any
     additional Class 3 Preferred Shares issued in accordance with section 2.7
     and to other Persons in respect of Net Cash, and subject to further
     reduction and set-off in accordance with section 2.3.7 and the share
     provisions attached to the Purchaser Shares;

     1.1.14 "CLASS 4 PREFERRED SHARES" means the Class 4 non-voting,
     retractable, redeemable, preferred shares, in registered form, of the
     Purchaser, having the share provisions set out in Schedule D and subject to
     the prior redemption right of the Class 1 non-voting, retractable,
     redeemable, preferred shares, in registered form, of the Purchaser and the
     Class 2 Preferred Shares, with a stated redemption price of U.S.$1.00 per
     share and with an aggregate Redemption Price as set out in the Final
     Proceeds Schedule, plus the aggregate Redemption Price of any additional
     Class 4 Preferred Shares issued in accordance with section 2.7 and to other
     Persons in respect of Net Cash, and subject to further reduction and
     set-off in accordance with section 2.3.7 and the share provisions attached
     to the Purchaser Shares;

     1.1.15 "CLOSING" means the completion of the sale and purchase and exchange
     of the Purchased Securities pursuant to this Agreement at the Time of
     Closing;

     1.1.16 "CLOSING DATE" means such date for completion of the purchase of the
     Principal Shareholders' Securities pursuant to the Principal Purchase
     Agreement as determined pursuant to the Principal Purchase Agreement;

     1.1.17 "CONVERSION RATE" means, in relation to the conversion of one
     Currency to another on a particular day, the rate of exchange quoted by the
     Bank of Canada as its spot rate of exchange for the conversion of the one
     Currency to the other at approximately noon (Toronto time) on such day;


                                      -5-

<PAGE>

     1.1.18 "CORPORATION SHAREHOLDERS AGREEMENT" means the Amended and Restated
     Shareholders Agreement dated May 4, 2004 among the shareholders of the
     Corporation and the Corporation;

     1.1.19 "CORPORATION SHARES" means the common shares in the capital of the
     Corporation;

     1.1.20 "CREST" means the relevant system, as defined in the UK
     Uncertificated Securities Regulations 1995 (SI 1995 No. 93/3272), as
     amended (in respect of which CRESTCo Limited is operator);

     1.1.21 "CURRENCY" means Canadian Dollars, Pounds Sterling or United States
     Dollars;

     1.1.22 "ESTIMATED SIGNING BALANCE SHEET" means the consolidated balance
     sheet of the Corporation and the Subsidiaries as at the date of this
     Agreement, and the calculation of Vernalis Liabilities, prepared pursuant
     to the Principal Purchase Agreement;

     1.1.23 "EXCHANGED OPTIONS" means the options to acquire common shares in
     the capital of the Corporation, as set forth opposite each Optionholder's
     name in Schedule E, to be exchanged by the Optionholders for Class 4
     Preferred Share Options pursuant to this Agreement;

     1.1.24 "FDA" means the Food and Drug Administration of the United States of
     America;

     1.1.25 "FINAL CLOSING BALANCE SHEET" means the consolidated balance sheet
     of the Corporation and the Subsidiaries as at the Closing Date, and the
     calculation of the Net Cash as at the Closing Date, prepared pursuant to
     the Principal Purchase Agreement;

     1.1.26 "FINAL PROCEEDS SCHEDULE" means the schedule setting out, as at the
     Closing Date, the allocation of Purchaser Shares, Class 4 Preferred Share
     Options, each class of shares in the capital of the Purchaser, options to
     acquire such shares, Redemption Amounts based on the occurrence of
     Milestones and other amounts set forth therein (prior to reduction and
     set-off in accordance with section 2.3.7 and excluding the allocation of
     the Redemption Amounts in respect of any additional Class 2 Preferred
     Shares, Class 3 Preferred Shares and Class 4 Preferred Shares issued
     pursuant to section 2.7 or to other Persons in respect of Net Cash), a pro
     forma of which is set out in Schedule A (the "PRO FORMA PROCEEDS
     SCHEDULE"), such schedule in final form to be agreed between Vernalis and
     the Corporation pursuant to the Principal Purchase Agreement;

     1.1.27 "FINAL SIGNING BALANCE SHEET" means the consolidated balance sheet
     of the Corporation and the Subsidiaries as at the date of this Agreement,
     and the calculation of Vernalis Liabilities, prepared pursuant to the
     Principal Purchase Agreement;


                                      -6-

<PAGE>

     1.1.28 "INTERIM EXPENDITURE" means such portion of the Interim Funding
     amount advanced by the Purchaser or Vernalis to the Corporation where the
     proposed use of such funds indicated by the Corporation pursuant to the
     Principal Purchase Agreement was to fund Permitted Costs;

     1.1.29 "INTERIM FUNDING AMOUNT" means the aggregate amount advanced by the
     Purchaser or Vernalis to the Corporation pursuant to the Principal Purchase
     Agreement to fund the Corporation's operations;

     1.1.30 "MILESTONE", in respect of the Purchaser Shares, has the meaning
     attributed to such term in section 2.3.2;

     1.1.31 "MILESTONE CONSIDERATION" means the issue of Class 3 Preferred
     Shares and Class 4 Preferred Share Options to the Vendors as set out in the
     Final Proceeds Schedule and in accordance with section 2.3.1;

     1.1.32 "MILESTONE SHARE PRICE" means, in respect of any Vernalis Shares to
     be issued on a Redemption Date, the average of the closing middle market
     prices of a Vernalis Share as shown in the Daily Official List of the
     London Stock Exchange plc on the 30 trading days up to and including the
     trading day (the "FINAL TRADING DAY") immediately prior to the occurrence
     of the relevant Milestone and converted to the relevant Currency at the
     Conversion Rate on the Final Trading Day;

     1.1.33 "MILESTONE SHARES" means, in respect of any Redemption Amount, such
     number of Vernalis Shares, if any, to be allotted and issued to satisfy
     such Redemption Amount in accordance with section 2.3.5;

     1.1.34 "NET CASH" means an amount equal to:

          (i)  the aggregate amount of cash, receivables and deposits (but not
               prepaid expenses) of the Corporation and the Subsidiaries as at
               the Closing Date plus the API Inventory Amount,

          less

          (ii) the aggregate amount of all liabilities, including any
               liabilities arising in connection with the entering into of this
               Agreement, the completion of the transactions contemplated
               hereby, any withholding tax remittances, interest and penalties
               remaining unpaid in respect of payments to Chiesi Farmaceutica
               S.p.A pursuant to the Chiesi Licence Agreements (as defined in
               the Principal Purchase Agreement)(other than U.S.$ *** to be
               withheld in connection with its right to acquire Class C
               Preference shares in the capital of the Corporation), of the
               Corporation and the Subsidiaries as at the Closing Date,

          plus

          (iii) the Vernalis Liabilities less such portion of the Interim
               Funding Amount advanced by the Purchaser or Vernalis to the
               Corporation where the proposed use of such funds indicated by the
               Corporation pursuant to the Principal Purchase Agreement was to
               fund Vernalis Liabilities,


                                      -7-

<PAGE>

          to be set out in the Final Closing Balance Sheet and calculated in the
          manner provided in Schedule 1.1.34;

     1.1.35 "PAIN PROJECT" means the Business which relates to CNP3381 for the
     indication of diabetic neuropathic pain;

     1.1.36 "PARKINSON'S PROJECT" means the Business which relates to CNP1512
     for the indication of Parkinson's disease;

     1.1.37 "PERMITTED COSTS" means any expenditure or commitment incurred or
     committed to by the Corporation and the Subsidiaries in accordance with the
     Agreed Pain Project Budget or the Agreed Parkinson's Project Budget or to
     pay salaries of employees of the Corporation and overhead costs at the same
     level as at the date of this Agreement, and approved pursuant to the
     Principal Purchase Agreement;

     1.1.38 "PERSON" means any individual, partnership, limited partnership,
     joint venture, syndicate, sole proprietorship, company or corporation with
     or without share capital, unincorporated association, trust, trustee,
     executor, administrator or other legal personal representative, regulatory
     body or agency, government or governmental agency, authority or entity
     however designated or constituted;

     1.1.39 "POUNDS STERLING" or "L" means lawful currency of the United
     Kingdom;

     1.1.40 "PRIME RATE" means the annual rate of interest which the Royal Bank
     of Canada establishes at its principal office in Toronto as the reference
     rate of interest to determine interest rates it will charge at such time
     for demand loans in Canadian dollars made to its customers in Canada and
     which it refers to as its "prime rate of interest";

     1.1.41 "PRO FORMA PROCEEDS SCHEDULE" has the meaning attributed to such
     term in section 1.1.26;

     1.1.42 "PURCHASE PRICE" has the meaning attributed to such term in section
     2.2;

     1.1.43 "PURCHASED SECURITIES" means, collectively, the Purchased Shares and
     the Exchanged Options;

     1.1.44 "PURCHASED SHARES" means the common shares in the capital of the
     Corporation to be sold by Parteq, Reynolds, Bennett, Boegman, Jhamandas and
     Thatcher to the Purchaser pursuant to this Agreement, as set forth opposite
     each Vendor's name in Schedule E;

     1.1.45 "PURCHASER OPTION AGREEMENTS" means the agreements in the form
     appended to the Purchaser Option Plan to be entered into among the
     Purchaser, the Shareholder's Representative and each Optionholder in
     respect of the grant of Class 4 Preferred Share Options;


                                      -8-

<PAGE>

     1.1.46 "PURCHASER OPTION PLAN" means the option plan to be adopted by the
     Purchaser, substantially in the form attached as Schedule B;

     1.1.47 "PURCHASER SHAREHOLDERS AGREEMENT" means the unanimous shareholders
     agreement to be entered into pursuant to the Business Corporations Act (New
     Brunswick) among all of the shareholders of the Purchaser, the Purchaser
     and Vernalis, substantially in the form attached as Schedule C;

     1.1.48 "PURCHASER SHARES" means, collectively, the Class 3 Preferred Shares
     to be issued to the Vendors and to other holders of common shares and
     rights to acquire common shares in the capital of the Corporation and the
     Class 4 Preferred Shares to be issued to the Vendors and other holders of
     rights to acquire common shares in the capital of the Corporation upon
     exercise of their Class 4 Preferred Share Options, all with rights,
     privileges, restrictions and conditions set out in the share provisions,
     substantially in the form attached as Schedule D;

     1.1.49 "REDEMPTION AMOUNT" means, in respect of any Redemption Date, the
     aggregate Redemption Price payable in cash and/or Vernalis Shares owing to
     the Vendors by the Purchaser upon the retraction or redemption of their
     Purchaser Shares (including Purchaser Shares issued upon exercise of Class
     4 Preferred Share Options) in accordance with the share provisions attached
     to such Purchaser Shares, or by Vernalis (or its designee or assignee) upon
     exercise of its call right in accordance with section 2.3.4, and, subject,
     in either case, to reduction or set-off of any Vendor's entitlement thereto
     in accordance with section 2.3.7 and the share provisions attached to the
     Purchaser Shares;

     1.1.50 "REDEMPTION DATE" means (i) in respect of any Milestone, the 45th
     day after the occurrence of that Milestone, or such other date as may be
     agreed between the Purchaser and the Vendors' Representative, and (ii) the
     Special Redemption Date;

     1.1.51 "REDEMPTION PRICE" means the stated redemption price of each
     Purchaser Share in respect of a Redemption Date of U.S.$ *** each;

     1.1.52 "REPORT" means the customary report produced for filing with the
     FDA;

     1.1.53 "SPECIAL REDEMPTION DATE" has the meaning attributed to such term in
     section 0;

     1.1.54 "SUBSIDIARIES" means 2037137 Ontario Inc. and 2060347 Ontario Inc.,
     each incorporated under the laws of the Province of Ontario and each a
     wholly-owned subsidiary of the Corporation;

     1.1.55 "TIME OF CLOSING" means such time for completion of the purchase of
     the Principal Shareholders' Securities pursuant to the Principal Purchase
     Agreement on the Closing Date;

     1.1.56 "UNITED STATES DOLLARS", "U.S. DOLLARS" or "U.S.$" means lawful
     currency of the United States of America;


                                      -9-

<PAGE>

     1.1.57 "VENDORS' REPRESENTATIVE" has the meaning attributed to such term in
     section 2.4;

     1.1.58 "VENDORS' REPRESENTATIVE AGREEMENT" has the meaning attributed to
     such term in section 2.4;

     1.1.59 "VERNALIS LIABILITIES" means the aggregate liabilities as at the
     date of this Agreement incurred or committed to by the Corporation and the
     Subsidiaries in respect of the Pain Project and the Parkinson's Project
     which are not outstanding for more than 60 days past their invoice date and
     appended to the Estimated Signing Balance Sheet, subject to adjustment in
     accordance with the Final Signing Balance Sheet; and

     1.1.60 "VERNALIS SHARES" means the ordinary shares of L*** each in
     the capital of Vernalis, adjusted for any stock split or consolidation
     effected after the date of this Agreement.

1.2  HEADINGS

          The inclusion of headings in this Agreement is for convenience of
reference only and shall not affect the construction or interpretation hereof.

1.3  GENDER AND NUMBER

          In this Agreement, unless the context otherwise requires, words
importing the singular include the plural and vice versa, words importing gender
include all genders or the neuter, and words importing the neuter include all
genders.

1.4  CURRENCY CONVERSION AND INDEMNITY

          If, in connection with any action or proceeding brought in connection
with this Agreement or any judgment or order obtained as a result thereof, it
becomes necessary to convert any amount due hereunder in one Currency (the
"OTHER CURRENCY") into Canadian Dollars, then the conversion shall be made at
the Conversion Rate on the first Business Day prior to the day on which payment
is received.

          If the conversion is not able to be made in the manner contemplated by
the preceding paragraph in the jurisdiction in which the action or proceeding is
brought, then the conversion shall be made at the Conversion Rate on the date
fixed by the court for such conversion.

          If the Conversion Rate on the date of payment is different from the
Conversion Rate on such first Business Day or on the date fixed for conversion
by the court, as the case may be, the party liable to make the payment (the
"PAYOR") shall pay such additional amount (if any) in Canadian Dollars as may be
necessary to ensure that the amount paid on such payment date is the aggregate
amount in Canadian Dollars which, when converted at the Conversion Rate on the
date of payment, is the amount due in the Other Currency, together with all
costs, charges and expenses of conversion. Any additional amount owing by the
payor to the party or parties


                                      -10-

<PAGE>

entitled to payment thereof pursuant to the provisions of this section 1.4 shall
be due as a separate debt and shall give rise to a separate cause of action and
shall not be affected by or merge into any judgment obtained for any other
amounts due under or in respect of this Agreement.

1.5  ENTIRE AGREEMENT

          This Agreement constitutes the entire agreement between the parties
pertaining to the purchase or exchange of the common shares in the capital of
the Corporation. This Agreement supersedes all prior arrangements and
understandings, whether written or oral, relating to such subject matter in any
way. There are no warranties, conditions, or representations (including any that
may be implied by statute) and there are no agreements in connection with such
subject matter except as specifically set forth or referred to in this
Agreement. No reliance is placed on any warranty, representation, opinion,
advice or assertion of fact made either prior to, contemporaneous with, or after
entering into this Agreement, or any amendment or supplement thereto, by any
party to this Agreement or its directors, officers, employees or agents, to any
other party to this Agreement or its directors, officers, employees or agents,
except to the extent that the same has been reduced to writing and included as a
term of this Agreement, and none of the parties to this Agreement has been
induced to enter into this Agreement or any amendment or supplement by reason of
any such warranty, representation, opinion, advice or assertion of fact.
Accordingly, there shall be no liability, either in tort or in contract,
assessed in relation to any such warranty, representation, opinion, advice or
assertion of fact, except to the extent contemplated above. To the extent that
there is any inconsistency between the share provisions attached to the
Purchaser Shares and the terms of this Agreement, the terms of this Agreement
shall prevail.

1.6  WAIVER, AMENDMENT

          Except as expressly provided in this Agreement, no amendment or waiver
of this Agreement shall be binding unless executed in writing by the party to be
bound thereby. No waiver of any provision of this Agreement shall constitute a
waiver of any other provision nor shall any waiver of any provision of this
Agreement constitute a continuing waiver unless otherwise expressly provided.

1.7  GOVERNING LAW

          This Agreement shall be governed by and construed in accordance with
the laws of the Province of Ontario and the laws of Canada applicable therein.

1.8  ATTORNMENT

          The Vendors, Vernalis, and the Purchaser (collectively, the "ATTORNING
PARTIES" and, individually, an "ATTORNING PARTY") each agrees that any suit,
action or proceeding arising out of or relating to this Agreement against an
attorning party or any of an attorning party's assets may be brought in any
court in the Province of Ontario, and the attorning parties hereby irrevocably
and unconditionally attorn and submit to the jurisdiction of such courts. The
attorning parties irrevocably waive and agree not to raise any objection any of
them might now or hereafter have to the bringing of any such suit, action or
proceeding in any such court


                                      -11-

<PAGE>

including, without limitation, any objection that the place where such court is
located is an inconvenient forum or that there is any other suit, action or
proceeding in any other place relating in whole or in part to the same subject
matter. Each attorning party agrees that any judgment or order against that
attorning party in any such suit, action or proceeding brought in such a court
shall be conclusive and binding upon that attorning party and consents to any
such judgment or order being recognized and enforced in the courts of its
jurisdiction of incorporation.

                                    ARTICLE 2
                                PURCHASE AND SALE

2.1  AGREEMENT TO PURCHASE AND SELL

          Simultaneously with the completion of the purchase from the Principal
Shareholders of the Principal Shareholders' Securities pursuant to the Principal
Purchase Agreement and subject to the terms of this Agreement, at the Time of
Closing:

     2.1.1 the Shareholders shall sell and the Purchaser shall purchase all of
     the Purchased Shares set forth opposite their names in Schedule E for
     Milestone Consideration as set forth opposite their names in the Final
     Proceeds Schedule; and

     2.1.2 the Optionholders shall exchange the Exchanged Options set forth
     opposite their names in Schedule E for Class 4 Preferred Share Options as
     set forth opposite their names in the Final Proceeds Schedule.

The Purchaser shall not be obligated to purchase or exchange any of the
Purchased Securities in accordance with this Agreement unless the purchase or
exchange of all of the Principal Shareholders' Securities is completed
simultaneously in accordance with the Principal Purchase Agreement.

2.2  PURCHASE PRICE

          The aggregate purchase price (the "PURCHASE PRICE") to be paid by the
Purchaser to the Vendors for the Purchased Shares and the Exchanged Options
shall be equal to the Milestone Consideration, subject to adjustment on the
Special Redemption Date in accordance with section 2.7.

2.3  SATISFACTION OF MILESTONE CONSIDERATION

     2.3.1 The Milestone Consideration shall be satisfied at the Time of Closing
     by:

          2.3.1.1 the issue of such number of Class 3 Preferred Shares to each
          Shareholder as is set out opposite that Shareholder's name in the
          Final Proceeds Schedule, credited as paid in full, and delivered by
          the Purchaser to each Shareholder in certificated form; and


                                      -12-

<PAGE>

          2.3.1.2 the grant of such number of Class 4 Preferred Share Options to
          each Optionholder as is set out opposite that Optionholder's name in
          the Final Proceeds Schedule.

     The Purchaser Shares (including Purchaser Shares issued upon exercise of
     Class 4 Preferred Shares Options) shall be redeemed by the Purchaser (and
     delivered by the relevant Vendor to the Purchaser for redemption) on each
     Redemption Date for the applicable Redemption Amount in accordance with the
     share provisions attached to the Purchaser Shares and the provisions of
     this Agreement or, if Vernalis exercises its call right in accordance with
     section 2.3.4, purchased by Vernalis (and delivered by the relevant Vendor
     to Vernalis for purchase) on such Redemption Date for the applicable
     Redemption Amount in accordance with the share provisions attached to the
     Purchaser Shares and the provisions of this Agreement. Each of the Vendors,
     the Purchaser and Vernalis agrees to be bound by the share provisions
     attached to the Purchaser Shares, subject to the terms of this Agreement.

     2.3.2 The occurrence of each of the following events (each a "MILESTONE")
     shall give rise to a retraction, redemption or call right in respect of the
     Purchaser Shares up to the amounts specified below (each a "MILESTONE
     PAYMENT"), in accordance with the share provisions attached to the
     Purchaser Shares and the provisions of this Agreement, and Vernalis shall
     notify the Vendors' Representative of the occurrence of each Milestone
     within 10 Business Days of its occurrence and shall indicate the Redemption
     Date with respect to such Milestone:

          2.3.2.1 in respect of the Pain Project:

               2.3.2.1.1 U.S.$5,833,334, upon the completion of a report by
               Vernalis or its affiliates to be produced in a timely manner
               following completion of a clinical study which generates data
               sufficient to support the requirements of 21 CFR 312.21(b)
               sufficient to justify Vernalis progressing with a Phase IIb or
               a Phase III study programme, as the case may be;

               2.3.2.1.2 U.S.$5,833,333, upon the completion of a Report by
               Vernalis or its affiliates to be provided in a timely manner
               following completion of a clinical study which generates data
               sufficient tos upport the requirements of 21 CFR 312.21(c) for
               a submission for regulatory approval to the FDA to market and
               sell in the USA a product comprising CNP3381 for the treatment
               of diabetic neuropathic pain; and

               2.3.2.1.3 U.S.$5,833,333, upon the issuance by the FDA of a
               written notification to Vernalis or its affiliates pursuant to
               21 CFR3 14.105(a) that the FDA approves CNP3381 for the treatment
               of diabetic neuropathic pain, Alzheimer's disease, post-operative
               pain or mixed pain related to palliative care. For greater
               certainty, if CNP3381 is developed for more than one of the
               above-noted indications, only the first FDA approval for one of
               the indications noted above shall be a Milestone. If the
               Milestone referred to in section 2.3.2.1.2 has not occurred prior
               to the FDA approval


                                      -13-

<PAGE>

               contemplated by this section 2.3.2.1.3, that Milestone shall be
               deemed to occur concurrently with the occurrence of the Milestone
               contemplated in this section 2.3.2.1.3; and

          2.3.2.2 in respect of the Parkinson's Project:

               2.3.2.2.1 U.S.$ 5,833,334, upon the enrollment by Vernalis or its
               affiliates of the first patient into a Phase III study for the
               purpose of generating data to support the requirements of 21 CFR
               312.21(b);

               2.3.2.2.2 U.S.$ 5,833,333, upon the completion of a Report by
               Vernalis or its affiliates to be produced in a timely manner
               following completion of a trial which generates data sufficient
               to support the requirements of 21 CFR 312.21(c) for a submission
               for regulatory approval to the FDA to market and sell in the USA
               a product comprising CNP1512 for the treatment of Parkinson's
               disease;

               2.3.2.2.3 U.S.$ 5,833,333, upon the issuance by the FDA of a
               written notification to Vernalis or its affiliates pursuant to 21
               CFR 314.105(a) that the FDA approves CNP1512 for the treatment of
               Parkinson's disease; and

     provided that the Milestone Payment in respect of each of the first two
     Milestones to occur shall be reduced by an amount equal to one-half of the
     amount of the Interim Expenditure.

     2.3.3 Subject to section 2.3.4, the Redemption Amount in respect of a
     Redemption Date shall be satisfied by the allotment and issue of Vernalis
     Shares or, at the option of the Purchaser, by payment in cash or by a
     combination of cash and Vernalis Shares (such combination of cash and
     Milestone Shares to be at the discretion of the Purchaser) on the
     Redemption Date. Notwithstanding the foregoing, the Redemption Amount in
     respect of the Special Redemption Date, if applicable, may only be
     satisfied in cash.

     2.3.4 Vernalis (or its designee or assignee) may, at its option, elect, by
     notice to the Vendors' Representative at any time after the occurrence of a
     Milestone and on or before the relevant Redemption Date, to purchase, on
     the relevant Redemption Date, such Purchaser Shares which may be redeemed
     on such Redemption Date for the applicable Redemption Amount,
     notwithstanding that any Vendor or the Purchaser has exercised its
     retraction or redemption right, respectively, pursuant to the share
     provisions attached to the Purchaser Shares. If Vernalis exercises its call
     right in accordance with this section 2.3.4 and the share provisions
     attached to the Purchaser Shares in respect of a Redemption Date, the
     Redemption Amount payable on that Redemption Date shall be satisfied by the
     allotment and issue of Vernalis Shares or, at the option of Vernalis, by
     payment in cash or by a combination of cash and Vernalis Shares (such
     combination of cash and Vernalis Shares to be at the discretion of
     Vernalis) on that Redemption Date and in accordance with the share
     provisions attached to the Purchaser Shares. Upon exercise by Vernalis of
     its call right in


                                      -14-

<PAGE>

     accordance with this section 2.3.4, the retraction and redemption right of
     the Vendor or the Purchaser, respectively, pursuant to the share provisions
     attached to the Purchaser Shares in respect of the Redemption Date shall be
     cancelled. Notwithstanding the foregoing, the Redemption Amount in respect
     of the Special Redemption Date, if applicable, may only be satisfied in
     cash.

     2.3.5 To the extent the Purchaser or Vernalis, as applicable, elects not to
     satisfy any Redemption Amount in cash, Vernalis shall allot and issue
     Vernalis Shares, credited as paid in full, and deliver on the relevant
     Redemption Date to each Vendor (or its nominee), in uncertificated form to
     an account in CREST designated by that Vendor, such number of Vernalis
     Shares as at the Milestone Share Price shall be equal to that Vendor's
     entitlement to a Redemption Amount divided by the Milestone Share Price
     (rounded up to the nearest whole share), subject to any reduction as
     provided in section 2.3.7.

     2.3.6 Any Redemption Amount to be satisfied in cash, subject to any further
     reduction as provided in section 2.3.7, shall be paid on the relevant
     Redemption Date to the Vendors' Representative, on behalf of the Vendors,
     and the Vendors' Representative shall pay such Redemption Amount to the
     Vendors in accordance with their entitlement on the Redemption Date and
     neither the Purchaser nor Vernalis, as applicable, shall have any
     responsibility for such distribution. The Vendors' Representative may, not
     less than five Business Days prior to the relevant Redemption Date, direct
     the Purchaser or Vernalis, as applicable, to pay to any Vendor directly any
     amounts contemplated by this section 2.3.6.

     2.3.7 A Vendor's entitlement to a Redemption Amount on a Redemption Date
     may be further reduced and set-off by the Purchaser or Vernalis by and
     against the amount of any claim against that Vendor in respect of any loss,
     damages or deficiencies suffered by the Purchaser or Vernalis as a result
     of any breach by that Vendor of a representation or covenant contained in
     this Agreement, being either the approximate and reasonable estimate of the
     likely amount of any such claim as determined by the Purchaser or Vernalis,
     as applicable, or, if such claim has been settled or finally determined,
     the amount of such claim, to the extent not satisfied in full on the fifth
     Business Day preceding the Redemption Date (using the Milestone Share Price
     as the value of the Milestone Shares when calculating the number of
     Milestone Shares to be reduced).

     2.3.8 In the event any Vendor's entitlement to a Redemption Amount is
     reduced by the amount of an estimated claim (the "ESTIMATED CLAIM") as
     provided in section 2.3.7, upon such claim becoming settled or finally
     determined (the "DETERMINED CLAIM") the Purchaser or Vernalis, as
     applicable, shall, if and to the extent the amount of the Determined Claim
     for which such Vendor is responsible, is less than the Estimated Claim for
     which such Vendor is responsible, satisfy the difference (up to the amount
     of the reduction made pursuant to section 2.3.7) in cash or Vernalis Shares
     or a combination of the two (depending upon and proportionately to whether
     the relevant Redemption Amount was satisfied in cash or Vernalis Shares or
     a combination of the two) and the provisions of this section 2.3 shall
     apply mutatis


                                      -15-

<PAGE>

     mutandis, with the Milestone Share Price, when calculating the number of
     Vernalis Shares to be issued pursuant to this section 2.3.8, being that
     used in respect of the relevant Redemption Date.

     2.3.9 Notwithstanding that the Purchaser or Vernalis, as applicable, elects
     to pay a Redemption Amount, in whole or in part, in Vernalis Shares, the
     Purchaser or Vernalis, as applicable, may elect to pay to any Vendor who is
     located or resident in a jurisdiction on the Redemption Date or date for
     payment pursuant to section 2.3.8 where the issuance of such shares would
     be in contravention of applicable securities laws (with no obligation to
     qualify or register the shares or rely upon an exemption from such
     requirement), its entitlement to a Redemption Amount in cash only.

     2.3.10 Each of Molinoff, Sekhri, Thatcher, Lehmann, Cutler and Cotman
     severally, and not jointly, covenants in respect of itself only to deliver
     to the Purchaser, at the Time of Closing, a certificate issued pursuant to
     section 116 of the Income Tax Act (Canada) of such Vendor's disposition of
     its Purchased Shares. In the event that a Vendor is a non-resident of
     Canada under the Income Tax Act (Canada) on any Redemption Date or date for
     payment pursuant to section 2.3.8, it shall deliver to the Purchaser or
     Vernalis, as applicable, a certificate issued pursuant to section 116 of
     the Income Tax Act (Canada) on account of the Vendor's entitlement to a
     Redemption Amount on such Redemption Date or date for payment pursuant to
     section 2.3.8. Notwithstanding the foregoing, neither the Purchaser nor
     Vernalis, as applicable, shall be required to issue any Purchaser Shares or
     Vernalis Shares to any Vendor until the delivery of such certificate, as
     applicable. The Purchaser or Vernalis, as applicable, shall be entitled to
     deduct or withhold from any Redemption Amount payable in cash to a Vendor
     any amount required to be deducted or withheld under applicable law.

     2.3.11 Vernalis (or its designee or assignee) may, at its option, elect by
     notice to the Vendors' Representative at any time after the earlier of (i)
     the tenth anniversary of the Closing or (ii) the Redemption Date in respect
     of the last Milestone to occur, provided that any Redemption Amount owing
     in respect of such Redemption Date has been satisfied in full, to purchase,
     on the date specified in such notice, all of the outstanding Purchaser
     Shares for a purchase price of U.S.$ *** per share, payable in cash to the
     Vendors' Representative on behalf of the Vendors.

2.4  APPOINTMENT OF VENDORS' REPRESENTATIVE

          Each of the Vendors hereby appoints The VenGrowth Advanced Life
Sciences Fund Inc. to act as its representative (the "VENDORS' REPRESENTATIVE")
to carry out such duties and responsibilities and to exercise such rights and
powers on its behalf as are provided in this Agreement and in related documents
in accordance with an agreement (the "VENDORS' REPRESENTATIVE AGREEMENT") to be
entered into among the Vendors' Representative, the Vendors, and certain other
Persons to become shareholders or optionholders of the Purchaser (other than
Vernalis).

          In the event of any disagreement between any Vendor and/or the
Vendors' Representative resulting in adverse claims or demands with respect to
the amounts delivered


                                      -16-

<PAGE>

under this Agreement to the Vendors' Representative on behalf of the Vendors,
the Vendors' Representative shall be entitled, at its option, to refuse to
comply with any claims or demands on it with respect thereto so long as such
disagreement shall continue, and in so refusing, the Vendors' Representative may
elect to make no delivery of such amounts. In doing so, the Vendors'
Representative shall not be or become liable in any way to the Vendors, Vernalis
or the Purchaser for its failure or refusal to comply with such claims or
demands.

          The Vendors' Representative may resign from such position at any time
by written notice to the parties to the Vendors' Representative Agreement, the
Purchaser and Vernalis provided that the Vendors' Representative shall have
appointed a successor to the Vendors' Representative satisfactory to the
Purchaser, acting reasonably, which appointment will be binding on the parties
to the Vendors' Representative Agreement, and provided that such successor shall
have consented to act in such capacity.

2.5  DELIVERY OF SHARE CERTIFICATES

          At the Time of Closing, the Shareholders shall deliver to the
Purchaser share certificates representing the Purchased Shares duly endorsed in
blank for transfer or accompanied by duly signed powers of attorney for transfer
in blank.

2.6  DELIVERY OF OPTION AGREEMENTS

          At the Time of Closing, the Optionholders, the Purchaser and the
Vendors' Representative shall enter into Purchaser Option Agreements in respect
of the grant of the Class 4 Preferred Share Options, as provided in this
Agreement.

2.7  NET CASH PAYMENT

          On the 15th Business Day after the final determination of the Final
Closing Balance Sheet in accordance with the Principal Purchase Agreement, if
the Net Cash as set out in the Final Closing Balance Sheet is a positive number,
the Purchaser shall issue to the Vendors on such date (the "SPECIAL REDEMPTION
DATE") such number of Class 3 Preferred Shares (in the case of Shareholders) and
Class 4 Preferred Shares (in the case of Optionholders) with an aggregate
Redemption Price equal to the amount of such Net Cash, converted to U.S. Dollars
at the Conversion Rate as at the Closing Date, multiplied by a fraction, (i) the
numerator of which is the aggregate of the number of Class 3 Preferred Shares
owned by the Vendors on the Special Redemption Date and the number of Class 4
Preferred Share Options held by the Vendors on the Special Redemption Date and
(ii) the denominator of which is the aggregate number of all Class 3 Preferred
Shares outstanding on the Special Redemption Date and the number of all Class 4
Preferred Share Options outstanding on the Special Redemption Date. Such Class 3
Preferred Shares and Class 4 Preferred Shares issuable to such Vendors shall be
credited as paid in full, and delivered by the Purchaser to the Vendors'
Representative, on behalf of the Vendors, in certificated form, each Vendor
being entitled to such number of such Class 3 Preferred Shares or Class 4
Preferred Shares, as the case may be (rounded upwards to the nearest whole
share), based on its pro rata holding of Class 3 Preferred Shares or Class 4
Preferred Share Options, relative to all Shareholders or Optionholders,
respectively.


                                      -17-
<PAGE>

2.8  FINAL PROCEEDS SCHEDULE

          The Final Proceeds Schedule shall be based on the Pro Forma Proceeds
Schedule and calculated in accordance with, and in a manner consistent with, the
spreadsheet contained within the CD-Rom delivered by the Corporation to Vernalis
on the date of this Agreement, updated to reflect the final resolution as at the
Closing Date of the variable factors noted in the Pro Forma Proceeds Schedule
(other than those variables to be reflected in the Final Closing Balance Sheet).
The Final Proceeds Schedule as agreed between Vernalis and the Corporation shall
be binding upon the parties to this Agreement, and neither the Purchaser nor
Vernalis shall have any responsibility or liability for any dispute or claim
arising as to the allocation, in accordance with the Final Proceeds Schedule, of
Purchaser Shares, Class 4 Preferred Share Options, each class of shares in the
capital of the Purchaser, options to acquire such shares, Redemption Amounts and
the other amounts set forth therein. The Vendors acknowledge and agree that the
Pro Forma Proceeds Schedule and the Final Proceeds Schedule are intended only to
set out the allocation of Purchaser Shares, Class 4 Preferred Share Options,
each class of shares in the capital of the Purchaser, options to acquire such
shares, Redemption Amounts and the other amounts set forth therein (prior to
reduction and set-off in accordance with section 2.3.7 and excluding the issue
of any additional Class 2 Preferred Shares, Class 3 Preferred Shares and Class 4
Preferred Shares pursuant to section 2.7 or to other Persons in respect of Net
Cash), and, subject to section 2.7, nothing in this section 2.8 shall oblige the
Purchaser or Vernalis to pay, issue or allot (or procure the payment, issue or
allotment of) additional consideration to the Vendors. In the event that
additional Class 2 Preferred Shares, Class 3 Preferred Shares or Class 4
Preferred Shares are issued in accordance with section 2.7 or to other Persons
in respect of Net Cash, the Final Proceeds Schedule shall be updated by the
Purchaser and the Vendors' Representative accordingly.

                                    ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

3.1  VENDORS' REPRESENTATIONS AND WARRANTIES

          Each Vendor hereby severally, and not jointly, represents and warrants
to each of the Purchaser and Vernalis as follows with respect to itself only and
each Vendor acknowledges that each of the Purchaser and Vernalis is relying upon
the following representations and warranties in connection with the purchase of
the Purchased Securities (and such representations and warranties shall be
deemed to be repeated on the Closing Date and, in the case of the representation
and warranty contained in section 3.1.10, unless the Purchaser and Vernalis have
been notified otherwise in writing at least 10 Business Days prior thereto, on
each Redemption Date or date of payment under section 2.3.8):

     3.1.1 INCORPORATION. In the case of Parteq, it is duly incorporated and
     validly existing under the laws of its jurisdiction of incorporation.

     3.1.2 CAPACITY AND DUE AUTHORIZATION. In the case of Parteq, it has the
     corporate power and capacity to enter into, and to perform its obligations
     under, this Agreement.


                                      -18-

<PAGE>

     In the case of the Vendors other than Parteq, it has the capacity to enter
     into, and to perform its obligations under, this Agreement.

     3.1.3 ENFORCEABILITY. This Agreement has been duly authorized (in the case
     of Parteq), executed and delivered by it and is its valid and binding
     obligation, enforceable against it in accordance with its terms, subject to
     the usual exceptions as to bankruptcy and the availability of equitable
     remedies.

     3.1.4 TITLE TO, AND RIGHT TO, SELL PURCHASED SECURITIES. It is the sole
     registered and beneficial owner of the Purchased Securities set forth in
     Schedule E with good and marketable title thereto, free of all Charges. Set
     forth opposite its name in Schedule E are all of the agreements, options,
     warrants, conversion rights or other rights to acquire Corporation Shares
     or other shares or securities of the Corporation. Except for the
     Corporation Shareholders Agreement, there are no agreements or restrictions
     which in any way limit or restrict the transfer to the Purchaser of its
     Purchased Securities nor are there any shareholders agreements, pooling
     agreements, voting trusts or other agreements or understandings with
     respect to the voting of its Purchased Shares or shares issuable upon
     exercise of its Exchanged Options or any of them. It waives all of its
     rights under the Corporation Shareholders Agreement in respect of the
     transactions contemplated in this Agreement and, at the Time of Closing,
     the Corporation Shareholders Agreement shall be deemed to be terminated by
     it without further action. At the Time of Closing it will have full legal
     right, power and authority to sell the Purchased Shares to the Purchaser,
     or exchange the Exchanged Options with the Purchaser, free of all Charges.
     A correct and complete copy of the Corporation Shareholders Agreement has
     been provided to Vernalis.

     3.1.5 NO CONTRAVENTION. None of the entering into of this Agreement nor the
     performance by it of any of its obligations under this Agreement will
     contravene, breach or result in any default under its articles, by-laws,
     constating documents or other organizational documents, if applicable, or
     under any mortgage, lease, agreement, other legally binding instrument,
     licence, permit, statute, regulation, order, judgment, decree or law to
     which it is a party or by which it may be bound.

     3.1.6 CONSENTS AND APPROVALS. No authorization, consent or approval of, or
     filing with or notice to, any governmental agency, regulatory body, court
     or other Person is required in connection with the execution, delivery or
     performance by it of this Agreement or the sale or exchange by it of any of
     the Purchased Securities hereunder.

     3.1.7 COMPLIANCE WITH CONFIDENTIALITY OBLIGATIONS. It has complied with all
     applicable confidentiality or proprietary obligations in favour of the
     Corporation and has not, directly of indirectly, used for its own purposes
     or disclosed to any Person any confidential or proprietary information of
     the Corporation or the Subsidiaries, including know-how and data, technical
     or non-technical, relating to the Business.

     3.1.8 PRINCIPAL PURCHASE AGREEMENT. It acknowledges that it is aware of the
     terms of the Principal Purchase Agreement and that, if requested, it
     received a copy of the Principal Purchase Agreement.


                                      -19-

<PAGE>

     3.1.9 TAX RESIDENCY. Except for Molinoff, Sekhri, Thatcher, Lehmann, Cutler
     and Cotman, it is not a non-resident of Canada under the Income Tax Act
     (Canada).

     3.1.10 U.S. SECURITIES LAWS. Except for Molinoff, Sekhri, Thatcher,
     Lehmann, Cutler and Cotman, it is not located or resident in the United
     States of America for securities laws purposes. In the case of Molinoff,
     Sekhri, Thatcher, Lehmann, Cutler and Cotman:

          3.1.10.1 except for Lehmann, Cutlter and Cotman, it is an "Accredited
          Investor" within the meaning of paragraphs (4), (5) or (6) of Rule
          501(a) of Regulation D under the U.S. Securities Act of 1933, as
          amended;

          3.1.10.2 it has, either alone or together with its investment
          advisors, if any, such knowledge and experience in financial and
          business matters to be capable of evaluation the merits and risks
          involved in entering into this Agreement;

          3.1.10.3 it acknowledges that the information provided by the
          Purchaser and Vernalis in connection with the Agreement is solely for
          its own use in deciding whether to enter into this Agreement and does
          not constitute an offer to any third party or to the public generally
          to purchase any securities of the Purchaser or Vernalis;

          3.1.10.4 it has received a copy of Vernalis' Annual Report on Form
          20-F for the fiscal year ended December 31, 2004, has had an
          opportunity to ask questions of, and receive answers from, appropriate
          representatives of the Purchaser or Vernalis concerning the terms and
          conditions of the Agreement and has had access to such financial and
          other information concerning the Purchaser or Vernalis as it has
          deemed necessary in connection with making its decision to enter into
          this Agreement. It acknowledges that neither the Purchaser nor
          Vernalis, nor any person representing the Purchaser or Vernalis, has
          made any representation to it with respect to the Purchaser or
          Vernalis or their respective securities;

          3.1.10.5 it has such knowledge and experience in financial and
          business matters that it is capable of evaluating the merits and risks
          of entering into this Agreement;

          3.1.10.6 it acknowledges and agrees that any Redemption Amounts which
          may be payable to it may be paid to it in the form of cash only;

          3.1.10.7 it understands that the representations and undertakings
          herein are required in connection with securities laws of the United
          States of America and that the Purchaser and Vernalis will rely
          thereon and it irrevocably authorizes the Purchaser and Vernalis to
          produce this Agreement to any interested party in any administrative
          or legal proceedings or official enquiry with respect to the matters
          covered herein;


                                      -20-

<PAGE>

          3.1.10.8 it is entering into this Agreement to acquire the Purchaser
          Shares (and any Vernalis Shares that may be received in redemption or
          retraction thereof) for its own account, as principal, for investment
          and not with a view to resale or distribution and that it will not
          sell or otherwise transfer the Purchaser Shares; and

          3.1.10.9 it understands that no federal or state agency has approved
          or disapproved the issuance of the Purchaser Shares, passed upon the
          merits of this Agreement or made any finding or determination
          regarding the fairness of the terms of this Agreement.

3.2  PURCHASER'S AND VERNALIS' REPRESENTATIONS AND WARRANTIES

          The Purchaser and Vernalis each jointly and severally represents and
warrants to the Vendors as follows and acknowledges that the Vendors are relying
upon the following representations and warranties in connection with their sale
or exchange of the Purchased Securities (and such representations and warranties
shall be deemed to be repeated on the Closing Date:

     3.2.1 INCORPORATION. The Purchaser is duly incorporated and validly
     existing under the laws of New Brunswick. Vernalis is duly incorporated and
     validly existing under the laws of England and Wales.

     3.2.2 CORPORATE POWER AND DUE AUTHORIZATION. The Purchaser and Vernalis
     each have the corporate power and capacity to enter into, and to perform
     its obligations under, this Agreement, subject to shareholder and
     regulatory approvals and requirements and filings in connection with the
     issue of securities of the Purchaser and Vernalis as contemplated herein.
     This Agreement has been duly authorized by the board of directors of each
     of the Purchaser and Vernalis. This Agreement has been duly executed and
     delivered by the Purchaser and Vernalis.

     3.2.3 ENFORCEABILITY. This Agreement is a valid and binding obligation of
     each of the Purchaser and Vernalis, enforceable in accordance with its
     terms, subject to the usual exceptions as to bankruptcy and the
     availability of equitable remedies.

     3.2.4 NO CONTRAVENTION. None of the entering into of this Agreement nor the
     performance by the Purchaser nor Vernalis of any of its obligations under
     this Agreement will contravene, breach or result in any default under its
     articles, by-laws, constating documents or other organizational documents
     or under any mortgage, lease, agreement, other legally binding instrument,
     licence, permit, statute, regulation, order, judgment, decree or law to
     which it is a party or by which it may be bound.

     3.2.5 CONSENTS AND APPROVALS. No authorization, consent or approval of, or
     filing with or notice to, any governmental agency, regulatory body, court
     or other Person is required in connection with the execution, delivery or
     performance by the Purchaser nor Vernalis of this Agreement nor the
     performance by it of any of its obligations, subject to shareholder and
     regulatory approvals and requirements and filings in connection with the
     issue of securities of the Purchaser and Vernalis as contemplated herein.


                                      -21-

<PAGE>

     3.2.6 ISSUE OF PURCHASER SHARES AND VERNALIS SHARES. At the time of issue
     of the Purchaser Shares or Vernalis Shares in accordance with the share
     provisions attached to the Purchaser Shares and the provisions of this
     Agreement and the Purchaser Option Agreements, as applicable, such
     Purchaser Shares and Vernalis Shares, as the case may be, shall be validly
     issued and fully paid.

                                    ARTICLE 4
                                    COVENANTS

4.1  VENDORS' COVENANTS

          Each Vendor severally, and not jointly, covenants in respect of itself
only in favour of the Purchaser and Vernalis as follows:

     4.1.1 EXERCISE OF RIGHTS. To exercise, prior to the Time of Closing, all
     warrants, conversion rights, options and other rights to acquire, directly
     or indirectly, Corporation Shares prior to the Time of Closing.

     4.1.2 PURCHASER SHAREHOLDERS AGREEMENT. To enter into, at the Time of
     Closing, the Purchaser Shareholders Agreement and hereby authorizes the
     Vendors' Representative to execute the Purchaser Shareholders Agreement on
     its behalf.

     4.1.3 PURCHASER OPTION AGREEMENTS. To enter into, in the case of the
     Optionholders, along with the Purchaser and the Vendors' Representative, at
     the Time of Closing, the Purchaser Option Agreements.

     4.1.4 VENDORS' REPRESENTATIVE AGREEMENT. To enter into, at the Time of
     Closing, the Vendors' Representative Agreement.

     4.1.5 WITHDRAWAL RIGHT. To not exercise, or attempt to exercise, any right
     or entitlement which may be applicable to, or enforceable by, it under
     section 87(Q) of the Financial Services and Markets Act 2000 (United
     Kingdom) (as amended). Each of the Vendors acknowledges that the issue of
     Vernalis Shares to it under this Agreement will be by way of a bilateral
     contract and as such section 87(Q) will not entitle it to withdraw in the
     event that Vernalis publishes a supplementary prospectus. Each Vendor
     further severally, and not jointly, covenants in respect of itself only, in
     favour of Vernalis that, in the event it is so entitled to withdraw, by
     signing this Agreement, it is confirming its acceptance of the offer of
     Vernalis Shares contained in this Agreement on the same terms immediately
     after such withdrawal.


                                      -22-

<PAGE>

                                    ARTICLE 5
                                 GENERAL MATTERS

5.1  CONFIDENTIALITY

     5.1.1 No Vendor shall directly or indirectly use for its own purposes or
     disclose to any other Person any confidential or proprietary information,
     including know-how and data, technical or non-technical, relating to the
     business of Vernalis which becomes known to the Vendor or its accountants,
     legal advisers or representatives as a result of Vernalis making the same
     available in connection with the transaction contemplated hereby.

     5.1.2 No Vendor shall directly or indirectly use for its own purposes or
     disclose to any Person any confidential or proprietary information of the
     Corporation or the Subsidiaries, including know-how and data, technical or
     non-technical, relating to the Business.

5.2  PUBLIC NOTICES

          No press release or other public announcement concerning the
transaction contemplated by this Agreement shall be made by the Vendors without
the prior written consent of Vernalis.

5.3  EXPENSES

          Each of the Vendors, the Purchaser and Vernalis shall be responsible
for the expenses (including fees and expenses of legal advisers, accountants and
other professional advisers) incurred by it in connection with the negotiation
and settlement of this Agreement and the completion of the transaction
contemplated hereby.

5.4  TERMINATION

          This Agreement shall terminate and the obligations and covenants of
the parties hereunder, other than those set out in sections 5.1 and 5.2, shall
terminate upon the termination of the Principal Purchase Agreement but shall not
terminate prior thereto in any circumstances.

5.5  ASSIGNMENT

          Except as provided in this section, no party may assign its rights or
benefits under this Agreement, nor may a Vendor transfer its Purchaser Shares
except (i) to Vernalis or an affiliate of Vernalis, or (ii) by will or the laws
of descent and distribution. The Purchaser or Vernalis may, at any time after
the Time of Closing and from time to time, assign its rights and benefits under
this Agreement, in whole or in part, to any affiliate or to any Person who
acquires all or substantially all of the assets or shares of the Corporation.


                                      -23-

<PAGE>

5.6  NOTICES

          Any notice or other communication required or permitted to be given
hereunder shall be in writing and shall be given by prepaid mail, by facsimile
or other means of electronic communication or by hand-delivery as hereinafter
provided. Any such notice or other communication, if mailed by prepaid mail at
any time other than during a general discontinuance of postal service due to
strike, lockout or otherwise, shall be deemed to have been received on the
seventh Business Day after the post-marked date thereof, or if sent by facsimile
or other means of electronic communication, shall be deemed to have been
received on the Business Day following the sending, or if delivered by hand
shall be deemed to have been received at the time it is delivered to the
applicable address noted below either to the individual designated below or to
an individual at such address having apparent authority to accept deliveries on
behalf of the addressee. Notice of change of address shall also be governed by
this section 5.6. In the event of a general discontinuance of postal service due
to strike, lock-out or otherwise, notices or other communications shall be
delivered by hand or sent by facsimile or other means of electronic
communication and shall be deemed to have been received in accordance with this
section 5.6. Notices and other communications shall be addressed as follows:

     (a)  if to the Vendors:

          c/o The VenGrowth Advanced Life Sciences Fund Inc. (as Vendors'
          Representative)
          105 Adelaide Street West, Suite 1000
          Toronto, Ontario
          M5H 1P9

          Attention:         Dr. Luc Marengere/Phil Kurtz
          Telecopier number: 416-971-6519

          with a copy to the Vendors' counsel at:

          Borden Ladner Gervais LLP
          40 King Street West, Suite 4200
          Toronto, Ontario,
          M5H 3Y4

          Attention:         Jeffrey Graham
          Telecopier number: 416-361-7377


                                      -24-

<PAGE>

     (b)  if to the Purchaser or Vernalis:

          Vernalis plc
          Oakdene Court
          613 Reading Road
          Winnersh, Berkshire
          RG 41 5UA

          Attention:         John Slater
          Telecopier number: + 44 118 989 9300

          with a copy to the Purchaser's counsel at:

          Torys LLP
          Suite 3000, 79 Wellington Street West
          Box 270, TD Centre
          Toronto, Ontario M5K 1N2

          Attention:         Kathleen L. Keller-Hobson
          Telecopier number: (416) 865-7380

          and to:

          Allen & Overy LLP
          One New Change
          London EC4M 9QQ
          United Kingdom

          Attention:         Anna Buscall
          Telecopier number: + 44 20 7330 9999

          The failure to send or deliver a copy of a notice to the Purchaser's
Counsel or the Vendors' Counsel, as the case may be, shall not invalidate any
notice given under this section 5.6.

5.7  TIME OF ESSENCE

          Time is of the essence of this Agreement.

5.8  FURTHER ASSURANCES

          Each of the parties shall promptly do, make, execute, deliver, or
cause to be done, made, executed or delivered, all such further acts, documents
and things as the other party hereto may reasonably require from time to time
for the purpose of giving effect to this Agreement and shall use reasonable
efforts and take all such steps as may be reasonably within its power to
implement to their full extent the provisions of this Agreement.


                                      -25-

<PAGE>

5.9  COUNTERPARTS

          This Agreement may be signed in counterparts and each such counterpart
shall constitute an original document and such counterparts, taken together,
shall constitute one and the same instrument.


                                      -26-

<PAGE>

          IN WITNESS WHEREOF the parties hereto have executed this Agreement.

                                        PARTEQ RESEARCH AND DEVELOPMENT
                                        INNOVATIONS


                                        by:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------


                                        by:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------


                                        ----------------------------------------
                                        JOHN MOLLOY on behalf of the following
                                        parties pursuant to powers of attorney
                                        executed on the date set forth opposite
                                        each party's name:

                                        James N. Reynolds      Oct 24, 2005
                                        Brian M. Bennett       Oct 24, 2005
                                        Roland J. Boegman      Nov 1, 2005
                                        Khem Jhamandas         Nov 3, 2005
                                        Gregory J. Thatcher    Oct 26, 2005
                                        John Lehmann           Nov 10, 2005
                                        Graham Strachan        Nov 3, 2005
                                        Jean-Paul St. Pierre   Oct 24, 2005
                                        Neil Cutler            Nov 8, 2005
                                        Carl Cotman            Oct 28, 2005
                                        Judith Burgess         Nov 3, 2005
                                        Liana Meogrossi        Nov 3, 2005
                                        Joy Newsome            Nov 3, 2005
                                        Perry Molinoff         Oct 31, 2005
                                        James Rae              Nov 2, 2005
                                        Paul Sekhri            Nov 3, 2005
                                        Padmini Singh          Nov 3, 2005
                                        Dale St. Hilaire       Nov 3, 2005
                                        Scott Samuel           Nov 3, 2005


                                        ----------------------------------------
                                        IAN ANDERSON

                              Signature Page for Common Share Purchase Agreement

<PAGE>

                                        VERNALIS PLC


                                        by:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------


                                        VERNALIS (CANADA) INC.


                                        by:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------

          The undersigned hereby agrees to act as the Vendors' Representative
and to carry out such duties and responsibilities on behalf of the Vendors as
provided in this Agreement.

                                        THE VENGROWTH ADVANCED LIFE SCIENCES
                                        FUND INC., as Vendors' Representative


                                        by:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------


                                        by:
                                            ------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------

                              Signature Page for Common Share Purchase Agreement