Document:

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                              OFFICE BUILDING LEASE

1.       PARTIES. This Lease dated as of February 9, 2000, is made by and
         between the Midpeninsula Regional Open Space District, a special
         district formed pursuant to Section 5500, ET SEQ., of the California
         Public Resources Code ("District") and DrugAbuse Sciences Inc., a
         California Corporation ("Lessee").

2.       PREMISES. District hereby leases to Lessee, and Lessee hereby leases
         from District, that certain office space (hereinafter, "Premises"),
         the area of which is shown by outline on Exhibit "A", attached here
         to and incorporated herein by this reference. It is agreed that said
         Premises, for the purpose of this Lease, have an area of
         approximately 2,487 square feet, situated on the ground floor of
         that certain office building ("Building") known as 330 Distel
         Circle, Los Altos, California. Said Premises are more precisely
         identified as Suite 150 of said Building. The Premises exclude the
         access ways and pipes, ducts, conduits, wires and appurtenant
         fixtures serving, exclusively or in common, other parts of the
         Building. By taking possession of the Premises, Lessee accepts the
         improvements as complete except as otherwise provided herein.

3.       TERM. The term of this Lease shall be for 36 months, commencing on
         March 1, 2000 (the "Commencement" or "Commencement Date") and ending
         February 28, 2003 unless sooner terminated pursuant to this Lease.

4.       POSSESSION.

4.1      If District, for any reason whatsoever, cannot initially deliver
         possession of the Premises to Lessee at the Commencement of the term
         hereof this Lease shall not be void or voidable nor shall District be
         liable to Lessee for any loss or damage resulting therefrom, nor shall
         the expiration date of the above term be in any way extended, but, in
         that event, all rent shall be abated during the period between the
         Commencement of said term and the time when District delivers
         possession.

4.2      In the event that District shall permit Lessee to occupy the Premises
         prior to the Commencement Date of the term, such occupancy shall be
         subject to all of the provisions of this Lease, except for the payment
         of rent, and said early possession shall not advance the termination
         date herein above provided. In the event Lessee occupies the Premises
         prior to the Commencement Date of the term for the purpose of
         installation of Lessee's trade fixtures and equipment in the Premises,
         or otherwise, such use or occupancy shall be pursuant to the express
         conditions that (a) Lessee's early entry shall not interfere with
         District's work or construction or cause labor difficulty; (b) Lessees
         shall pay for and provide evidence of the insurance coverage required
         pursuant to Section 10 hereof; and (c) Lessees shall pay utility
         charges reasonably allocated to Lessee by District. Lessee shall not
         commence the operation of business prior to the Commencement Date of
         the term without express prior written consent of District.
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5.       RENT.

5.1      Lessee shall pay to District as rent for the Premises, without demand,
         deduction, abatement or set-off, except as expressly permitted herein,
         the sum of Eight Thousand Seven Hundred Four and 50/100 Dollars
         ($8,704.50) on or before the first day of each and every calendar month
         of the term of this Lease, the first monthly payment to be made
         concurrently with the execution hereof. If the Lease termination date
         is not the last day of a month, the rent payable hereunder shall be
         prorated on a daily basis at the then current rate for the fractional
         month during which this Lease terminates. Said rent shall be paid to
         District in lawful money of the United States of America, which shall
         be legal tender at the time of payment at the District office in the
         Building, or to such other person or at such other place as District
         may from time to time designate in writing.

5.2      Rent Increase.

         5.2.1    Upon the first anniversary of the Commencement Date of this
                  lease and annually on such date thereafter, the monthly
                  Rent payable under Section 5.1 of this Lease shall be
                  adjusted by the greater of four (4%) of the previous period
                  Rent, or the percentage increase, if any, in the Consumer
                  Price Index of the Bureau of Labor Statistics of the United
                  States Department of Labor for All Urban Consumers
                  (1982-84=100), "All Items," for San Francisco-Oakland-San
                  Jose Bay Area, herein referred to as "C.P.I.", since the
                  Commencement Date of this Lease or since the last annual
                  adjustment, as appropriate.

         5.2.2    The monthly Rent payable pursuant to Section 5.1 shall be
                  increased pursuant to Section 5.2.1 as follows: the Rent
                  payable for the first month of the term of this Lease, or
                  the month in which it was last adjusted, shall be
                  multiplied by a fraction, the numerator of which shall be
                  the C.P.I. of the calendar month during which the
                  adjustment is to take effect, and the denominator of which
                  shall be the C.P.I. for the calendar month in which the
                  original Lease term commenced or in which it was last
                  adjusted. The sum so calculated shall constitute the new
                  monthly Rent under Section 5 hereof, but, in no event,
                  shall such new monthly Rent be less than a four (4%)
                  increase over the previous period Rent nor greater than a
                  seven (7%) increase over the previous period Rent.

         5.2.3    In the event the compilation and/or publication of the
                  C.P.I. shall be transferred to any other governmental
                  department or bureau or agency or shall be discontinued,
                  then the index most nearly the same as the C.P.I. shall be
                  used to make such calculations. In the event that District
                  and Lessee cannot agree on such alternative index, then the
                  matter shall be submitted for decision to the American
                  Arbitration Association in the County of Santa Clara, or,
                  if such does not exist, an arbitration service
                  substantially similar thereto, in accordance with the then
                  rules of said association and the decision of the
                  arbitrators shall be binding upon the parties,
                  notwithstanding one party failing to appear after due
                  notice of the proceeding. The cost of said Arbitrators
                  shall be paid equally by District and Lessee.

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         5.2.4    Lessee shall continue to pay the rent at the rate
                  previously in effect, plus the minimum annual rent increase
                  of four percent (4%), until the amount of the C.P.I.
                  increase, if any, is determined. Within five (5) days
                  following the date on which the increase is determined,
                  Lessee shall make such payment to District as will bring
                  the increased rental current, commencing with the effective
                  date of such increase through the date of any rental
                  installments then due.  Thereafter the rent shall be paid
                  at the increased rate.

6.       SECURITY DEPOSIT. Concurrently with the execution of this Lease, Lessee
         has deposited with District the sum of Eighteen Thousand Dollars
         ($18,000.00), in the form of an Irrevocable Letter of Credit acceptable
         to District, receipt of which is hereby acknowledged, to secure the
         faithful performance by Lessee of all of the terms, covenants and
         conditions of this Lease by Lessee to be kept and performed during the
         term hereof. Lessee agrees that if it shall fail to pay when due any
         installment of rent or any other sums provided in this Lease to be paid
         by Lessee to District, or if Lessee shall default in or breach any of
         the other terms, covenants and conditions of this Lease and District
         shall suffer any damages as a result of said default or breach, then in
         any such event District may, at its option (but District shall not be
         required to) draw upon said Irrevocable Letter of Credit for any rent
         or other sum due and unpaid by Lessee to District hereunder, for any
         damage suffered by District as a result of such default or breach to
         the extent of the amount of damage suffered by District, or for any
         reasonable attorney's fees incurred by District in connection with such
         default or breach. Should the Irrevocable Letter of Credit be drawn
         upon by District as herein provided, then Lessee, without the need for
         written demand by District, shall forthwith remit a sufficient amount
         in cash to restore said security deposit to its original amount, and
         Lessee's failure to do so within ten (10) days after such demand shall
         constitute a breach of this Lease. Should Lessee comply with all of the
         terms, covenants and conditions of this Lease and promptly pay all
         rental herein provided for as it falls due and all other sums payable
         by Lessee to District hereunder, the un-appropriated balance of said
         security deposit shall be returned to Lessee at the expiration of the
         Term of this Lease or upon any earlier termination. Should District
         sell its interest in the Premises during the term hereof and if
         District deposits with the purchaser thereof the then un-appropriated
         funds deposited by Lessee as aforesaid, thereupon District shall be
         discharged from any further liability with respect to such deposit.

7.       TAXES.

7.1      Property Taxes: The term "property taxes," as used in this Lease, is
         defined as all real estate taxes or personal property taxes levied
         with respect to the Building and the land, and any improvements,
         fixtures and equipment and other property of the District, real or
         personal, located in the Building and used in connection with the
         operation of the Building and the land, or any tax, general or
         special assessment, or other charge of any description imposed upon
         or in respect of the Building and the land, including without
         limitation, a tax upon any rent therefrom or any occupancy or use
         thereof, or a tax in lieu of or in addition to real estate or
         personal property taxes.

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7.2      Personal Property and Ad Valorem Taxes. Lessee hereby agrees to pay
         all taxes which may be levied with respect to Lessee's personal
         property located upon the Premises, including without limitation,
         the portion of the improvements to the Premises the cost of which
         was borne by Lessee, furniture, office equipment and other
         furnishings.

7.3      Possessory Interest Tax. The property interest created herein may be
         subject to property taxation and Lessee may be subject to payment of
         property taxes levied on such possessory interest. Lessee shall be
         responsible for any Possessory Interest Tax arising out of or in any
         way created by this Lease. Lessee's rent shall be reduced by the
         amount of any such Possessory Interest Tax in the month following
         actual payment by Lessee of such tax or if no rent due in cash, and
         upon submittal of a copy of the bill evidencing such obligation and
         a copy of the check evidencing such payment.

8.       USE OF PREMISES.

8.1      Use. The Premises shall be used and occupied by Lessee for general
         office purposes, including without limitation, marketing, accounting,
         tracking of regulatory control, investor relations, business
         development and related clerical functions and for no other purpose
         without the prior written consent of District.

8.2      Suitability. Lessee acknowledges that neither District nor any agent
         of District has made any representation or warranty with respect to
         the Premises or the Building or with respect to the suitability of
         either for the conduct of Lessee's business, nor has District agreed
         to undertake any modification, alteration or improvement to the
         Premises except as provided in this Lease. The taking of possession
         of the Premises by Lessee shall conclusively establish that the
         Premises and the Building were at such time in satisfactory
         condition unless within fifteen (15) days after such date Lessee
         shall give District written notice specifying in reasonable detail
         the respects in which the Premises or the Building were not in
         satisfactory condition. To District's knowledge, the Premises are in
         compliance with all rules, regulations and ordinances whether
         federal, state or local.

8.3      Uses Prohibited.

         8.3.1    Premises shall not be used for retail sales, warehousing,
                  manufacturing, or patient treatment facilities.

         8.3.2    Lessee shall not do or permit anything to be done in or
                  about the Premises nor bring or keep anything therein which
                  will in any way increase the existing rate or affect any
                  fire or other insurance upon the Building or any of its
                  contents, or cause a cancellation of any insurance policy
                  covering said Building or any part thereof or any of its
                  contents, nor shall Lessee sell or permit to be kept used
                  or sold in or about said Premises any articles or
                  substance, inflammable or otherwise, which may be
                  prohibited by a standard form policy of fire insurance.

         8.3.3    Lessee shall not do or permit anything to be done in or
                  about the Premises which will in any way obstruct or
                  interfere with the rights of other Lessees or occupants of
                  the Building or injure or annoy them or use or allow the
                  Premises to be used for any unlawful or objectionable
                  purpose, nor shall Lessee cause, maintain or

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                  permit any nuisance in or about the Premises. Lessee shall not
                  commit or suffer to be committed any waste in or upon the
                  Premises.

         8.3.4    Lessee shall not use the Premises or permit anything to be
                  done in or about the Premises which will in any way
                  conflict with any law, statute, ordinance or governmental
                  rule or regulation or requirement of duly constituted
                  public authorities now in force or which may hereafter be
                  enacted or promulgated. Lessee shall at its sole cost and
                  expense promptly comply with all laws, statutes, ordinances
                  and governmental rules, regulations or requirements now in
                  force or which may hereafter be in force and with the
                  requirements of any board of fire underwriters or other
                  similar body now or hereafter constituted relating to or
                  affecting the condition, Lessee's particular use or
                  occupancy of the Premises, excluding structural changes not
                  relating to or affecting the condition, use or occupancy of
                  the Premises, or not related or afforded by Lessee's
                  improvements or acts. The judgment of any court of
                  competent jurisdiction or the admission of Lessee in any
                  action against Lessee, whether District be a party thereto
                  or not, that Lessee has violated any law, statute,
                  ordinance or governmental rule, regulation or requirement,
                  shall be conclusive of the fact as between District and
                  Lessee.

9.       SERVICES AND UTILITIES.

9.1      District's Obligations. District agrees to furnish to the Premises
         during the hours of 8:00AM - 6:00PM, generally recognized business
         days of Monday through Friday excepting major holidays, and subject
         to the Rules and Regulations of the Building, water, gas and
         electricity suitable for the intended use of the Premises, heat and
         air conditioning required in District's judgment for the comfortable
         use and occupancy of the Premises, scavenger, janitorial and window
         washing service and security customary in similar buildings in the
         competing geographical area. District shall also maintain and keep
         lighted the common entries and toilet rooms in the Building.

9.2      Lessee's Obligation. Lessee shall pay for, prior to delinquency, all
         telephone and all other materials and services, not expressly
         required to be paid by District, which may be furnished to or used
         in, on or about the Premises during the term of this Lease.

9.3      Lessee's Additional Requirements.

         9.3.1    Lessee will not, without the prior written consent of
                  District not unreasonably withheld, and subject to any
                  conditions which District may impose, use any apparatus or
                  device in the Premises, including but without limitation
                  therefor, electronic data processing machines, punch card
                  machines and machines using current in excess of 110 volts,
                  which will in any way increase the amount of electricity or
                  water usually furnished or supplied for use of the Premises
                  as general office space. Lessee shall not connect with
                  electrical current, except through existing electrical
                  outlets in the Premises, or connect to water pipes, any
                  apparatus or device for the purposes of using electric
                  current or water.

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         9.3.2    If Lessee shall require water or electric current in excess
                  of that usually furnished or supplied for use of the
                  Premises as general office space, Lessee shall first
                  procure the consent of District for the use thereof, which
                  consent District may not unreasonably withhold. District
                  may cause a water meter or electric current meter to be
                  installed in the Premises, so as to measure the amount of
                  water and electric current consumed for any such other use.
                  The costs of such meters and of installation, maintenance
                  and repair thereof shall be paid for by Lessee and Lessee
                  agrees to pay District promptly upon demand by District for
                  all such water and electric current consumed as shown by
                  said meters, at the rate charged for such services by the
                  city in which the Building is located or the local public
                  utility as the case may be, furnishing the same, pays any
                  additional expense incurred in keeping account of the water
                  and electric current to consumed.

         9.3.3    Wherever heat generating machines or equipment are used in
                  the Premises which affect the temperature otherwise
                  maintained by the air conditioning system, District
                  reserves the right to install supplementary air
                  conditioning units in the Premises and the cost thereof
                  including the cost of installation, operation and
                  maintenance thereof, shall be paid by Lessee to District
                  upon demand by District.

9.4      Nonliability for Failure to Provide Services or Utilities. District
         shall not be liable for, and Lessee shall not be entitled to, any
         abatement or reduction of rent by reason of District's failure to
         furnish any of the foregoing when such failure is caused by
         accidents, breakage, repairs, strikes, lockouts or other labor
         disturbances or labor disputes of any character, or by any other
         cause similar or dissimilar, beyond the reasonable control of
         District. District shall not be liable under any circumstances for
         loss of or injury to property, however occurring, through or in
         connection with or incidental to failure to furnish any of the
         foregoing, except for loss arising due to District's or District's
         agents, employees or contractors active negligence or willful
         misconduct.

10.      INSURANCE.

10.1     Coverage. Lessee shall assume the risk of damage to any fixtures,
         goods, inventory, merchandise, equipment, furniture and leasehold
         improvements, and District shall not be liable for injury to
         Lessee's business or any loss of income therefrom relative to such
         damage. Lessee shall, at all times during the term of this Lease,
         and at its own cost and expense, procure and continue in force the
         following insurance coverage:

         10.1.1   Comprehensive general liability insurance, insuring
                  District and Lessee against any liability arising out of
                  the ownership, use, occupancy or maintenance of the
                  Premises and all areas appurtenant thereto in an amount of
                  not less than Two Million Dollars ($2,000,000.00) per
                  occurrence.

         10.1.2   Fire and extended coverage insurance including vandalism
                  and malicious mischief coverage, in an amount equal to the
                  full replacement value of all fixtures, furniture and
                  improvements installed by or at the expense of Lessee.

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10.2     Insurance Policies. The limits of said insurance policies shall not,
         however, limit the liability of the Lessee hereunder. Lessee may
         carry said Insurance under blanket policies; providing, however,
         said Insurance by Lessee shall have a District's protective
         liability endorsement attached thereto. If Lessee shall fail to
         procure and maintain said insurance District may, but shall not be
         required to, procure and maintain same, but at the expense of
         Lessee. Insurance required hereunder shall be in companies rated A-
         or better in "Best's Insurance Guide." Lessee shall deliver to
         District prior to occupancy of the Premises copies of policies of
         insurance required herein or certificates evidencing the existence
         and amounts of such insurance with loss payable clauses, all such
         policies subject to District's approval which shall not be
         unreasonably withheld. No policy shall be cancelable or subject to
         reduction of coverage except after thirty (30) days prior written
         notice to District.

10.3     Waiver of Subrogation. As long as their respective insurers so
         permit, District and Lessee each hereby waive any and all rights of
         recovery against the other for any loss or damage occasioned to such
         waiving party or its property or the property of others under its
         control to the extent that such loss or damage is insured against
         under any fire or extended coverage insurance policy which either
         may have in force at the time of such loss or damage. Each party
         shall obtain any special endorsement, if required by their insurer,
         to evidence compliance with the aforementioned waiver.

11.      MAINTENANCE AND REPAIRS.

11.1     District's Obligations. District shall maintain in good order,
         condition and repair the Building and all other portions of the
         Premises not the obligation of Lessee or any other Lessee in the
         Building, including the basic plumbing, air conditioning, heating
         and electrical systems installed or furnished by District, unless
         such maintenance and repairs are caused in part or in whole by the
         act, neglect, fault or omission of any duty by the Lessee, it
         agents, servants, employees or invitees, in which case Lessee shall
         pay to District the reasonable cost of such maintenance and repairs.
         District shall not be liable for any failure to make any such
         repairs or to perform any maintenance unless such failure shall
         persist for five (5) business days after written notice of the need
         of such repairs or maintenance is given to District by Lessee,
         provided such repairs or maintenance can be reasonably performed
         within five (5) business days. Except as provided in Section 18
         hereof there shall be no abatement of rent and no liability of
         District by reason of any injury to or interference with Lessee's
         business arising from the making of any repairs, alterations or
         improvements in or to any portion of the Building or the Premises or
         in or to fixtures, appurtenances and equipment therein. Lessee
         waives the right to make repair at District's expense under any law,
         statute or ordinance now or hereafter in effect.

11.2     Lessee's Obligations. By taking possession of the Premises, Lessee
         shall be deemed to have accepted the Premises as being in good,
         sanitary order, condition and repair, and Lessee's obligations to
         preserve the Premises are as follows:

         11.2.1   Lessee at Lessee's sole cost and expense, except for
                  services furnished by District pursuant to Section 9
                  hereof, shall maintain the non-structural portion of the

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                  Premises in good order, condition and repair including the
                  interior surfaces of the ceilings, walls and floors, all
                  doors, interior windows, exterior windows at or below
                  street level, all plumbing pipes, electrical wiring,
                  switches, fixtures and special items in excess of building
                  standard furnishings, and equipment installed by or at the
                  expense of Lessee. Lessee expressly waives the benefits of
                  any statute now or hereafter in effect which would
                  otherwise afford Lessee the right to make repairs at
                  District's expense or to terminate this Lease because of
                  District's failure to keep the Premises in good order,
                  condition and repair.

          11.2.2  Upon the expiration or earlier termination of this Lease,
                  Lessee shall surrender the Premises in the same condition
                  as received, ordinary wear and tear and condemnation or
                  damage by fire, earthquake, act of God or the elements
                  alone excepted, and shall promptly remove or cause to be
                  removed from the Premises and the Building, at Lessee's
                  expense, any signs, notices and displays placed by Lessee.

          11.2.3  Lessee agrees to repair any damage to the Premises or the
                  Building caused by or in connection with the removal of any
                  articles of personal property, business or trade fixtures,
                  machinery, equipment, furniture, movable partitions,
                  including without limitation thereto, repairing the floor
                  and patching and painting the walls where required by
                  District to District's reasonable satisfaction, all at
                  Lessee's sole cost and expense. Lessee shall indemnify the
                  District against any loss or liability resulting from delay
                  by Lessee in so surrendering the Premises, including
                  without limitation any claims made by any succeeding Lessee
                  founded on such delay.

          11.2.4  In the event Lessee fails to maintain the Premises in good
                  order, condition and repair, District shall give Lessee
                  notice to do such acts as are reasonably required to so
                  maintain the Premises. In the event Lessee fails to
                  promptly commence such work and diligently prosecute it to
                  completion, then District shall have the right to do such
                  acts and expend such funds at the expense of Lessee as are
                  reasonably required to perform such work. Any amount so
                  expended by District shall be paid by Lessee promptly after
                  demand with interest at ten percent (10%) per annum from
                  the date of such work. District shall have no liability to
                  Lessee for any damage, inconvenience or interference with
                  the use of the Premises by Lessee as a result of performing
                  any such work.

12.      ALTERATIONS AND ADDITIONS.

12.1     Lessee shall at Lessee's sole cost and expense, replace the existing
         carpet and paint the interior walls of the Premises. The colors of
         the carpet and paint shall be approved by District, which approval
         shall not be unreasonably withheld. Lessee shall be allowed to
         credit up to $7,200 of the carpet and paint costs against the rent
         payment due in the second month of the Lease Term.

12.2     Lessee shall make no other alterations, additions or improvements to
         the Premises or any part thereof without obtaining the prior written
         consent of District.

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12.3     District may impose as a condition to the aforesaid consent such
         requirements as District may deem necessary in its reasonable
         discretion, including with limitation thereto, the manner in which
         the work is done, a right of approval of the contractor by whom the
         work is to be performed, the times during which it is to be
         accomplished, and the requirement that upon written request of
         District prior to the expiration or earlier termination of the
         Lease, Lessee will remove any and all movable partitions, counters,
         personal property, equipment, fixtures and furniture, unless upon
         granting consent District agrees otherwise.

12.4     All such alterations, additions or improvements shall at the
         expiration or earlier termination of the Lease, become the property
         of District and remain upon and be surrendered with the Premises,
         unless specified pursuant to Section 11.2 above, or if upon granting
         consent, District agrees otherwise.

12.5     All articles of personal property and all business and trade
         fixtures machinery and equipment, furniture and movable partitions
         owned by Lessee or installed by Lessee at its expense in the
         Premises shall be and remain the property of Lessee and may be
         removed by Lessee at any time during the Lease term when Lessee is
         not in default hereunder.

13.      INDEMNIFICATION. Lessee shall indemnify and hold harmless District
         from and against any and all claims arising from Lessee's use of the
         Premises, or from the conduct of Lessee's business or from any
         activity, work or things done, permitted or suffered by Lessee in or
         about the Premises or elsewhere and shall further indemnify and hold
         harmless District from and against any and all claims arising from
         any breach or default in the performance of any obligation on
         Lessee's part to be performed under the terms of this Lease, or
         arising from any negligence of the Lessee, or any of Lessee's
         customers, directors, officers, invitees, licensees, agents,
         contractors or employees, and from and against all costs, attorney's
         fees, expenses and liabilities incurred in the defense of any such
         claim or any action or proceeding brought thereby; and in case any
         action or proceeding be brought against District by reason of any
         such claim. Lessee upon notice from District shall defend the same
         at Lessee's expense by counsel satisfactory to District. Lessee, as
         a material part of the consideration to District, hereby assumes all
         risk of damage to property or injury to persons, in, upon or about
         the Premises arising from any cause, and Lessee hereby waives all
         claims in respect thereof against District except claims solely
         arising from willful or active negligent acts or omissions by
         District or its agents or employees. Lessee hereby agrees that
         District shall not be liable for injury to (a) Lessee's business or
         for any loss of income therefrom or damage to the goods, wares,
         merchandise or other property of Lessee, (b) Lessee's customers,
         directors, officers, invitees, licensees or any other persons in or
         about the Premises, (c) Lessee's employees, agents or contractors,
         whether such damage or injury is caused by or results from fire,
         steam, electricity, gas, water or rain, or from the breakage,
         leakage, obstruction or other defects of pipes, sprinklers, wires,
         appliances, plumbing, air conditioning or lighting fixtures, or from
         any other cause, whether the said damage or injury results from
         conditions arising upon the Premises or upon other portions of the
         Building, or from other sources or places, and regardless of whether
         the cause of such damage or injury or the means of repairing the
         same is inaccessible to Lessee. District shall not be liable for any
         damages arising from any act or neglect of any other Lessee of the
         Building.

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14.      LIENS. Lessee shall not permit to be enforced against the Premises,
         any mechanics', materialmen's, contractors' or other liens arising
         from, or any claims for damages growing out of any work of repair or
         alteration as herein authorized or otherwise arising (except from
         the actions of District), and Lessee shall pay or cause to be paid
         all of said liens and claims before any action is brought to enforce
         the same against District or the Premises; and Lessee agrees to
         indemnify and hold District and the Premises free and harmless from
         all liability for any and all such liens and claims and all costs
         and expenses in connection therewith. Lessee shall give District no
         less than ten (10) days prior notice in writing before commencing
         construction of any kind on the Premises so that District may post
         notices of nonresponsibility.

15.      ASSIGNMENT AND SUBLETTING.

15.1     District's Consent Required. Lessee shall not assign, transfer,
         mortgage, pledge, hypothecate or encumber this Lease or any interest
         therein, and shall not sublet the Premises or any part thereof
         without the prior written consent of District, such consent not to
         be unreasonably withheld and any attempt to do so without such
         consent being first had and obtained shall be wholly void and shall
         constitute a breach of this Lease.

15.2     Subletting Submission. Should Lessee desire to assign or sublet the
         Premises, Lessee shall submit in writing to District (a) the name
         and legal composition of the proposed sublessee or assignee; (b) the
         nature of the business proposed to be carried on in the Premises;
         (c) the terms and provisions of the proposed sublease for District's
         review and approval; and (d) such reasonable financial information
         for District's review and approval as District may request
         concerning the proposed sub-lessee or assignee. In determining the
         approval of an assignee or sub-lessee, the compatibility and
         suitability of the proposed assignee or sub-lessee with the
         District's government operations, statutory purposes and open space
         mission shall be of prime importance.

15.3     No Release of Lessee. No consent by District to any assignment of
         subletting by Lessee shall relieve Lessee of any obligation to be
         performed by Lessee under this Lease, whether occurring before or
         after such consent, assignment or subletting. The consent by
         District to any assignment of subletting shall not relieve Lessee
         from the obligation to obtain District's express prior written
         consent to any other assignment or subletting. The acceptance of
         rent by District from any other person shall not be deemed to be a
         waiver by District of any provision of this Lease or to be a consent
         to any assignment, subletting or other transfer. Consent to one
         assignment, subletting or other transfer shall not be deemed to
         constitute consent to any subsequent assignment, subletting or other
         transfer.

16.      ENTRY BY DISTRICT. District reserves and shall at any and all times
         have the right to enter the Premises to inspect the same, to supply
         janitor service and any other service to be provided by District to
         Lessee hereunder, to submit said Premises to prospective purchasers
         or Lessees, to post notices of nonresponsibility and "for lease"
         signs, and to alter, improve or repair the Premises and any portion
         of the Building without abatement of rent, and may for that purpose
         erect scaffolding and other necessary structures where reasonably
         required by the character of the work to be performed, always
         providing the entrance to the Premises shall not be blocked thereby,
         and further providing that the

                                       10
<PAGE>

         business of Lessee shall not be interfered with unreasonably. Lessee
         hereby waives any claim for damages for any injury or inconvenience
         to or interference with Lessee's business, any loss of occupancy and
         any other loss occasioned thereby. For each of the aforesaid
         purposes, District shall at all times have and retain a key with
         which to unlock all of the doors in, upon and about the Premises,
         excluding Lessee's vaults and safes, and District shall have the
         right to use any and all means which District may deem proper to
         open said doors in an emergency, in order to obtain entry to the
         Premises, and any entry to the Premises obtained by District by any
         of said means, or otherwise, shall not under any circumstances be
         construed or deemed to be a forcible or unlawful entry into, or a
         detainer of the Premises, or an eviction of Lessee from the Premises
         or any portion thereof.

17.      HOLDING OVER. This lease shall terminate and become null and void
         without further notice upon the expiration of the term herein
         specified and any holding over by Lessee after such expiration shall
         not constitute a renewal hereof or give Lessee any rights under this
         Lease, except as otherwise herein provided, it being understood and
         agreed that this Lease cannot be renewed, extended or in any manner
         modified except in writing signed by both parties hereto. If Lessee
         shall hold over for any period after the expiration of said term,
         District may, at its option, exercised by written notice to Lessee,
         treat Lessee as a Lessee from month-to-month commencing on the first
         day following the expiration of this Lease and subject to the terms
         and conditions herein contained, at a rental in the amount of one
         hundred twenty-five percent (125%) of the last monthly rental, plus
         all other charges payable hereunder. If Lessee fails to surrender
         the Premises upon the expiration of this Lease despite demand to do
         so by District, Lessee shall indemnify and hold District harmless
         form all loss or liability, including without limitation, any claim
         made by an succeeding Lessee founded on or resulting from such
         failure to surrender.

18.      DAMAGE OR DESTRUCT10N.

18.1     Partial Damage - Insured. In the event the Premises or the Building
         are damaged by any casualty which is covered under fire and extended
         coverage insurance carried by District, then District shall restore
         such damage provided insurance proceeds are available to pay ninety
         percent (90%) or more of the cost of restoration and provided such
         restoration can be completed within sixty (60) days after the
         Commencement of the work in the opinion of a registered architect or
         engineer appointed by District. In such event this Lease shall
         continue in full force and effect, except that Lessee shall be
         entitled to proportionate reduction of rent as determined by
         District while such restoration takes place, such proportionate
         reduction to be based upon the extent to which the restoration
         efforts interfere with Lessee's business in the Premises. Lessee
         shall not be entitled to any compensation or damages for loss of the
         use of the whole or any part of the Premises and/or any
         inconvenience or annoyance occasioned by any such damage, repair,
         reconstruction or restoration.

18.2     Partial Damage - Uninsured. In the event the Premises or the
         Building are damaged by a risk not covered by District's insurance
         or the proceeds of available insurance are less than ninety percent
         (90%) of the cost of restoration, or if the restoration cannot be
         completed within sixty (60) days after the Commencement of work in
         the opinion of the

                                       11

<PAGE>

         registered architect or engineer appointed by District, then District
         shall have the option either to (a) repair or restore such damage,
         this Lease continuing full force and effect, but the rent to be
         proportionately abated as hereinabove provided, or (b) give notice
         to Lessee (at any time within thirty (30) days after such damage)
         terminating this Lease as of a date to be specified in such notice,
         which date shall not be less than thirty (30) nor more than sixty
         (60) days after giving such notice. In the event of the giving of
         such notice, this Lease shall expire and all interest of Lessee in
         the Premises shall terminate on such date so specified in such
         notice and the rent, reduced by any proportionate reduction based
         upon the extent, if any, to which said damage interfered with the
         use and occupancy of Lessee as determined hereinabove shall be paid
         to the date of such termination. District agrees to refund to the
         Lessee any rent therefore paid in advance for any period of time
         subsequent to such date of termination as provided herein.

18.3     Total Destruction. In the event the Premises are total destroyed or
         the Premises cannot be restored as required herein under applicable
         laws and regulations, notwithstanding the availability of insurance
         proceeds, this Lease shall be terminated effective as of the date of
         the damage.

18.4     Damage Near End of the Term. Notwithstanding anything to the
         contrary contained in this Section 18, District shall not have any
         obligation whatsoever to repair, reconstruct or restore the Premises
         when the damage resulting from any casualty covered under this
         Section 18 occurs during the last twelve (12) months of the term of
         this Lease or any extension thereof.

18.5     District's Obligations. The District shall not be required to repair
         any injury or damage by fire or other cause, or to make any
         restoration or replacement of any panelings, decorations,
         partitions, railings, floor covering, office fixtures or any other
         improvements or property installed in the Premises by Lessee or at
         the direct or indirect expense of Lessee. Lessee shall be required
         to restore or replace same in the event of damage. Except for
         abatement of rent, if any, Lessee shall have no claim against
         District for any damages suffered by reason of any such damage,
         destruction repair or restoration, nor shall Lessee have the right
         to terminate this Lease as the result of any statutory provision now
         or hereafter in effect pertaining the damage and destruction of the
         Premises or the Building, except as expressly provided herein.

18.6     Lessee's Right to Terminate. If at anytime a portion of the Premise
         is damaged or destroyed by any cause thereby rendering the Premises
         unusable, even if such damage is required to be insured against
         pursuant to Article 10, District shall notify Lessee in writing as
         to the estimated time for repairing the damage within ten (10) days
         of the date on which District learns of the damage. If District
         reasonably estimates that the time required for repair exceeds three
         (3) months, from the date of damage, or the damage occurs within the
         last twelve months of the Lease term, then Lessee, at Lessee's sole
         election; may terminate this Lease by delivering written notice of
         termination to District within ten (10) days after receipt of the
         estimation. Regardless of the total repair time, if this Lease is
         not terminated, rent will abate during the period until the Premises
         are repaired and ready for Lessee's full use and occupancy.

                                       12

<PAGE>

19.      DEFAULT; REMEDIES.

19.1     Default. The occurrence of any of the following shall constitute a
         material default and breach of this Lease by Lessee:

         19.1.1   Any failure by Lessee to pay the rent or any other monetary
                  sums required to be paid hereunder (where such failure
                  continues for three (3) business days after written notice
                  by District to Lessee; or

         19.1.2   The abandonment of the Premises by Lessee; or

         19.1.3   A failure by Lessee to observe and perform any other
                  provision of this Lease to be observed or performed by
                  Lessee, where such failure continues for thirty (30) days
                  after written notice thereof by District to Lessee:
                  provided, however, that if the nature of the default is
                  such that the same cannot reasonably be cured within said
                  thirty (30) day period, Lessee shall not be deemed to be in
                  default if Lessee shall within such period commence such
                  cure and thereafter diligently prosecute the same to
                  completion; or

          19.1.4  The making by Lessee of any general assignment or general
                  arrangement for the benefit of creditors; the filing by or
                  against Lessee of a petition to have Lessee adjudged a
                  bankrupt or of a petition for reorganization or arrangement
                  under any law relating to bankruptcy [unless, in the case of
                  a petition filed against Lessee, same is dismissed within
                  sixty (60) days]; the appointment of trustee or receiver to
                  take possession of substantially all of Lessee's assets
                  located at the Premises or of Lessee's interest in this
                  Lease, where possession is not restored to Lessee within
                  thirty (30) days, or the attachment, execution or other
                  judicial seizure of substantially all of Lessee's assets
                  located at the Premises or of Lessee's interest in this
                  Lease, where such seizure is not discharged within thirty
                  (30) days. Lessee agrees that in the event of the above,
                  then this Lease or any interest in or to the Premises shall
                  not become an asset in any of such proceedings.

19.2     Remedies. In the event of any such material default or breach by
         Lessee, District may, at any time thereafter, without limiting
         District in the exercise of any right or remedy at law or in equity
         which District may have by reason of such default or breach:

         19.2.1   Maintain this Lease in full force and effect and recover
                  the rent and other monetary charges as they become due,
                  without terminating Lessee's right to possession
                  irrespective of whether Lessee shall have abandoned the
                  Premises. In the event District elects not to terminate the
                  Lease, District shall have the right to attempt to re-let
                  the Premises at such rent and upon such conditions and for
                  such a term, and to do all acts necessary to maintain or
                  preserve the Premises as District deems reasonable and
                  necessary without being deemed to have elected to terminate
                  the Lease, including removal of all persons and property
                  from the Premises. Such property may be removed and stored
                  in a public warehouse or elsewhere at the cost of and for
                  the account of Lessee. In the event any such reletting
                  occurs, this Lease shall terminate automatically upon the
                  new Lessee

                                       13

<PAGE>

                  taking possession of the Premises, notwithstanding failure by
                  District to elect to terminate the Lease initially.
                  District at any time during the term of this Lease may
                  elect to terminate this Lease by virtue of such previous
                  default of Lessee.

         19.2.2   Terminate Lessee's right to possession by any lawful means,
                  in which case this Lease shall terminate and Lessee shall
                  immediately surrender possession of the Premises to
                  District. In such event District shall be entitled to
                  recover from Lessee all damages incurred by District by
                  reason of Lessee's default, including without limitation
                  thereto, the following: (a) the worth at the time of award
                  of any unpaid rent which has been earned at the time of
                  such termination; plus (b) the worth at the time of award
                  of the amount by which the unpaid rent which would have
                  been earned after termination until the time of award
                  exceeds the amount of such rental loss that is proved could
                  have been reasonably avoided; plus (c) any other amount
                  necessary to compensate District for all the detriment
                  proximately caused by Lessee's failure to perform any
                  obligations under this Lease or which in the ordinary
                  course of events would be likely to result therefrom; plus
                  (d) at District's election, such other amounts in addition
                  to or in lieu of the foregoing as may be permitted from
                  time to time by applicable State law. Upon any such
                  re-entry District shall have the right to make any
                  reasonable repairs, alterations or modifications to the
                  Premises, which District in its sole discretion deems
                  reasonable and necessary. As used in (a) above, the "worth
                  at the time of award" is computed by allowing interest at
                  the rate of ten percent (10%) per annum from the date of
                  default. As used in (b), the "worth at the time of award"
                  is computed by discounting such amount at the discount rate
                  of the U.S. Federal Reserve Bank at the time of award plus
                  one percent (1%). The term "rent," as used in this Section
                  18, shall be deemed to be and to mean the rent to be paid
                  pursuant to Section 5 and all other monetary sums required
                  to be paid by Lessee pursuant to the terms of this Lease.

                  All rights, options and remedies of District contained in
                  this Lease shall be construed and held to be cumulative,
                  and no one of them shall be exclusive of the other, and
                  District shall have the right to pursue any one or all of
                  such remedies or any other remedy or relief which may be
                  provided by law, whether or not stated in this Lease. No
                  waiver of any default of Lessee hereunder shall be implied
                  from any acceptance by District or any rent or other
                  payments due hereunder or any omission by District to take
                  any action on account of such default if such default
                  persists or is repeated, and no express waiver shall affect
                  defaults other than as specified in said waiver. The
                  consent or approval of District to or of any act by Lessee
                  requiring District's consent or approval shall not be
                  deemed to waive or render unnecessary District's consent or
                  approval to or of any subsequent similar acts by Lessee.

20.      CONDEMNATION. If all or any part of the Premises shall be taken or
         appropriated for public or quasi-public use by right of eminent
         domain with or without litigation or transferred by agreement in
         connection with such public or quasi-public use, either party hereto
         shall have the right at its option exercisable within thirty (30)
         days of receipt of notice of such taking to terminate this Lease as
         of the date possession is taken by the

                                       14
<PAGE>

         condemning authority; provided, however, that before Lessee may
         terminate this Lease by reason of taking or appropriation as
         provided hereinabove, such taking or appropriation shall be of such
         an extent and nature as to substantially handicap, impede or impair
         Lessee's use of the Premises. If any part of the Building other than
         the Premises shall be so taken or appropriated, District shall have
         the right at its option to terminate this Lease. No award for any
         partial or entire taking shall be apportioned, and Lessee hereby
         assigns to District any award which may be made in such taking or
         condemnation, together with any and all rights of Lessee now or
         hereafter arising in or to the same or any part thereof, provided,
         however, that nothing contained herein shall be deemed to give
         District any interest in or to require Lessee to assign to District
         any award made to Lessee for the taking of personal property and
         fixtures belonging to Lessee and/or the interruption of or damage to
         Lessee's business and/or for Lessee's unamortized cost of leasehold
         improvements and/or for Lessee's loss of goodwill and/or moving
         expenses. In the event of a partial taking which does not result in
         a termination of this Lease, rent shall be abated in the proportion
         which the part of the Premises so made unusable bears to the rented
         area of the Premises immediately prior to the taking District, at
         District's sole cost, will make Premises suitable for Lessee's use.
         No temporary taking of the Premises and/or of Lessee's rights herein
         or under this Lease shall terminate this Lease or give Lessee any
         right to any abatement of rent thereunder, and any award made to
         Lessee by reason of any such temporary taking shall belong entirely
         to Lessee and District shall not be entitled to share therein.

21.      LATE CHARGES.

21.1     Lessee hereby acknowledges that late payment by Lessee to District
         of rent and other sums due hereunder not paid within five (5)
         calendar days of the due date of such payment will cause District to
         incur costs not contemplated by this Lease, the exact amount of
         which will be extremely difficult to ascertain. Such costs include
         but are not limited to, processing and accounting charges, and late
         charges which may be imposed on District by the terms of any
         mortgage or trust deed covering the Premises. Accordingly, in the
         event that Lessee shall fail to pay to District within five (5) days
         of the date when due any payment owing to District pursuant to the
         terms of this Lease, said late payment shall bear interest at the
         rate of ten percent (10%) per annum from the date due and payable
         until the same shall have been fully paid and, in addition:

         21.1.1   Service Charge. For each such payment to District not paid
                  within five (5) days following the date of said payment
                  Lessee shall pay to District a service change in the amount
                  of Five Hundred Dollars ($500.00); and

         21.1.2   District's Option. Following each second consecutive late
                  payment of rent, District shall have the option (a) to
                  require that beginning with the first payment of rent due
                  following the date such late payment was due, rent shall no
                  longer be paid in monthly installments but shall be payable
                  three (3) months in advance until twelve (12) months have
                  elapsed with no late payment, at which time the rent will
                  revert to payment in monthly amounts.

                                       15

<PAGE>

22.      DISTRICT'S PERFORMANCE OF LESSEE'S OBLIGATIONS. Should Lessee fail
         to pay and discharge, when due and payable, any tax or assessment,
         or any premium or other charge in connection with any insurance
         policy or policies which Lessee is obligated to pay, or any lien or
         claim for labor or material employed or used in, or any claim for
         damages arising out of the repair, alternation, maintenance and use
         of the Premises, as provided in this Lease, after ten (10) days
         written notice from District, then District may, at its option, and
         without waiving or releasing Lessee from any of Lessee's obligations
         hereunder, pay any such tax, assessment, lien, claim, insurance
         premium or charge, or settle or discharge any action therefore or
         satisfy any judgment thereon. All costs, expenses and other sums,
         incurred or paid by District in connection therewith, together with
         interest at the rate of ten percent (10%) per annum on such costs,
         expenses and sums from the date incurred or paid by District, shall
         be deemed to be an additional charge hereunder and shall be paid by
         Lessee with and at the same time as the next installment of rent
         hereunder, and any default therein shall constitute a breach of the
         covenants and conditions of this Lease.

23.      COST OF SUIT. In the event that any action shall be instituted by
         either of the parties hereto for the endorsement of any of its
         rights or remedies in and under this Lease, or any facts based upon
         or involving same, the prevailing party, whether in court or by way
         of out-of-court settlement, shall be entitled to recover from the
         nonprevailing party or parties such prevailing party's attorney
         fees, court costs, expert witness fees and/or other expenses
         relating to such controversy, including attorney's fees, court costs
         and/or expenses on appeal, if any.

24.      ESTOPPEL STATEMENT. Lessee shall at any time and from time to time
         upon not less than ten (10) days prior written notice from District
         execute, acknowledge and deliver to District a statement in writing,
         (a) certifying that this Lease is unmodified and in full force and
         effect (or, if modified, stating the nature of such modification and
         certifying that this Lease as so modified, is in full force and
         effect), and the date to which the rental and other charges are paid
         in advance, if any, and (b) acknowledging that there are not, to
         Lessee's knowledge, any uncured defaults on the part of the District
         hereunder, or specifying such defaults if any are claimed. Any such
         statement may be relied upon by any prospective purchaser or
         encumbrancer of all or any portion of the real property of which the
         Premises are a part.

25.      PARKING. Lessee shall have the right to use, in common with District
         and other Lessees or occupants of the Building, their pro-rata
         portion of the parking facilities of the Building, at no additional
         cost, which is hereby agreed to be nine (9) unassigned parking
         spaces and includes use of spaces designated for handicapped parking
         as necessary. Such parking spaces shall be subject to the rules and
         regulations of District, which may be established or altered by
         District at any time or from time to time during the term hereof and
         shall be effective upon written notice to Lessee.

26.      AUTHORITY OF PARTIES.

26.1     Lessee represents that it is a corporation duly authorized to
         conduct business in California. Each individual executing this Lease
         on behalf of said corporation represents

                                       16

<PAGE>

         and warrants that such individual is duly authorized to execute and
         deliver this Lease on behalf of said corporation, in accordance with
         a duly adopted resolution of the Board of Directors of said
         corporation or in accordance with the bylaws of said corporation,
         and that this Lease is binding upon said corporation in accordance
         with its terms.

26.2     District represents that it is a special district formed pursuant to
         Article 3 of Chapter 3 of Division 5 of the California Public
         Resources Code and is authorized by Section 5540 therein to, INTER
         ALIA., lease real property in furtherance of District purposes. The
         individual executing this Lease on behalf of District is duly
         authorized to execute and deliver this Lease and to do such other
         acts as are necessary or convenient to accomplish such matter.

27.      NOTICES. All notices and demands which may or are to be required or
         permitted to be given by either party to the other hereunder shall
         be in writing. All notices and demands by the District to the Lessee
         shall be sent by United States Mail, postage prepaid, addressed to
         the Lessee at the Premises, or to such other place as Lessee may
         from time to time designate in a notice to the District. All notices
         and demands by the Lessee to the District shall be sent by United
         States Mail, postage prepaid, addressed to the District at the
         Building, or to such other person or place as the District may from
         time to time designate by notice to Lessee.

28.      SUBORDINATION. Lessee covenants and agrees that it will execute,
         without further consideration, any and all instruments desired by
         District or District's mortgagee, creditor, or Lessor, subordinating
         this Lease in the manner requested by District to all ground or
         underlying leases and the lien of any mortgage and/or any deed of
         trust or other encumbrance which may hereafter affect the Premises
         together with all renewals, modifications, consolidations,
         replacements or extensions thereof, provided that any lien or
         encumbrancer relying on such subordination or such additional
         agreements will covenant with Lessee that this Lease shall remain in
         full force and effect and Lessee shall not be disturbed in the event
         of sale or foreclosure so long as Lessee is not in default
         hereunder. Lessee agrees to attorn to the successor in interest of
         District following any transfer of such interest either voluntarily
         or by operation of Law and to recognize such successor as the
         District under this Lease. However, if District or any such ground
         District or mortgagee so elects, this Lease shall be deemed prior in
         lien to any ground lease, mortgage, deed of trust or other
         encumbrance upon or including the Premises regardless of date of
         recording and Lessee will execute a statement in writing to such
         effect at District's request. District is hereby irrevocably
         appointed and authorized as agent and attorney-in-fact of Lessee to
         execute all subordination instruments in the event Lessee fails to
         execute said instruments within ten (10) days after notice from
         District demanding the execution thereof.

29.      TRANSFER BY DISTRICT. The term "District" as used in this Lease, so
         far as covenants or obligations on the part of District are
         concerned, shall mean and include only the owner or owners at the
         time in question of the Premises, and in the event of any transfer
         or transfers of the title to the Premises, District herein named
         (and in case of any subsequent transfers or conveyances, the then
         grantor), except as hereinafter provided, shall be automatically
         freed and relieved from and after the date of such transfer or

                                       17
<PAGE>

         conveyance, of all personal liability as respects the performance of
         any covenants or obligations on the part of District contained in
         the Lease thereafter to be performed; provided that any funds in
         which Lessee has an interest which are in the hands of such District
         or the then grantor at the time of such transfer shall be turned
         over to the grantee, and any amount then due and payable to Lessee
         by District or the then grantor under any provisions of this Lease
         shall be paid to Lessee. It is intended hereby that the covenants
         and obligations contained in this Lease on the part of District
         shall, subject to the foregoing, be binding on District, its
         successors and assigns, only during and in respect of their
         respective successive periods of ownership.

30.      INABILITY TO PERFORM. This Lease and the obligation of Lessee to pay
         rent hereunder and to keep, observe and perform all of the other
         terms, covenants, conditions, provisions and agreement of this Lease
         on the part of Lessee to be kept, observed or performed shall in
         nowise be affected, impaired or excused because District is unable
         to fulfill any of its obligations under this Lease or to supply or
         is delayed in supplying any service expressly or impliedly to be
         supplied or is unable to supply or is delayed in supplying any
         equipment or fixtures, if District is prevented or delayed from
         doing so by reason of strike or labor troubles, unavailability of
         materials, riots, rebellion, insurrection, invasion, war, action or
         interference of governmental authorities, acts of God or any other
         cause whether similar or dissimilar of the foregoing which is beyond
         the control of District.

31.      SURRENDER OF PREMISES. The voluntary or other surrender of this
         Lease by Lessee, or a mutual cancellation thereof shall not work a
         merger, and shall, at the option of the District, terminate all or
         any existing subleases, or subtenancies, or may, at the option of
         District, operate as an assignment to it of any or all such
         subleases or subtenancies.

32.      RULES AND REGULATIONS. Lessee and Lessee's agents, servants,
         employees, visitors and licensees shall observe and comply fully and
         faithfully with all reasonable and nondiscriminatory rules and
         regulations adopted by District for the care, protection,
         cleanliness and operation of the Building and its Lessees, including
         those rules and regulations attached to this Lease as Exhibit "B"
         and incorporated herein by this reference, and any modification or
         addition thereto adopted by District, provided District shall give
         written notice thereof to Lessee. District shall not be responsible
         to Lessee for the nonperformance by any other Lessee or occupant of
         the Building of any of said rules and regulations.

33.      SCOPE AND AMENDMENTS. This Lease is and shall be considered to be
         the only agreement between the parties hereto. All negotiations and
         oral agreements acceptable to both parties are included herein. No
         amendment or other modification of this Lease shall be effective
         unless in a writing signed by District and by Lessee.

34.      GENERAL PROVISIONS.

34.1     Waiver. No waiver of any default or breach of any covenant by either
         party hereunder shall be implied from any omission by either party
         to take action on account of such

                                       18

<PAGE>

         default if such default persists or is repeated, and no express waiver
         shall affect any default other than the default specified in the
         waiver, and then said waiver shall be operative only for the time and
         to the extent therein stated. Waivers of any covenant, term or
         condition contained herein by either party shall not be construed as a
         waiver of any subsequent breach of the same covenant, term or
         condition. The consent or approval by either party to or of any act by
         either party requiring further consent or approval shall not be deemed
         to waiver or render unnecessary their consent or approval to or of any
         subsequent similar acts.

34.2     Accord and Satisfaction. No payment by Lessee or receipt by District
         of a lesser amount than the rent payment herein stipulated shall be
         deemed to be other than on account of the rent, nor shall any
         endorsement or statement on any check or any letter accompanying any
         check or payment as rent be deemed an accord and satisfaction, and
         District may accept such check or payment without prejudice to
         District's right to recover the balance of such rent or pursue any
         other remedy provided in this Lease.

34.3     Individual Liability. The obligations of District under this Lease
         do not constitute personal obligations of the employees, officers or
         directors of the District, and Lessee shall look solely to the real
         estate that is the subject of this Lease and to no other assets of
         District for satisfaction of any liability in respect of this Lease
         and will not seek recourse against the employees, officers or
         directors of the District or any of their personal assets for such
         satisfaction.

34.4     Time.  Time is of the essence hereof.

34.5     Captions; Attachments; Defined Terms.

         34.5.1   The captions of the Sections of this Lease are for
                  convenience only and shall not be deemed to be relevant in
                  resolving any question of interpretation or construction of
                  any Section of this Lease.

         34.5.2   Exhibits attached hereto, and addendum and schedules
                  initialed by the parties, are deemed by attachment to
                  constitute part of this Lease and are incorporated herein.

         34.5.3   The words "District" and "Lessee", as used herein shall
                  include the plural as well as the singular. Words used in
                  neuter gender include the masculine and feminine and words
                  in the masculine or feminine gender include the neuter. If
                  there be more than one District or Lessee, the obligations
                  hereunder upon District or Lessee shall be joint and
                  several; as to a Lessee which consists of husband and wife,
                  the obligations shall extend individually to their sole and
                  separate property as well as community property. The term
                  "District" shall mean only the owner or owners at the time
                  in question of the fee title or a Lessee's interest in a
                  ground lease of the land underlying the Building. The
                  obligations contained in this Lease to be performed by the
                  District shall be binding on District successors and
                  assigns only during their respective period of ownership.

34.6     Severability. If any term, covenant, condition or provision of this
         Lease, or the application thereof to any person or circumstance, shall
         to any extent be held by a court

                                       19

<PAGE>

         of competent jurisdiction to be invalid, void, or unenforceable, the
         remainder of the terms, covenants, conditions, or provisions of this
         Lease, or the application thereof to any person or circumstance,
         shall remain in full force and effect and shall in no way be
         affected, impaired or invalidated thereby.

34.7     Applicable Law. This Lease, and the rights and obligations of the
         parties hereto, shall be construed and enforced in accordance with the
         laws of the State in which the Premises are located.

34.8     Examination of Lease. Submission of this instrument for examination or
         signature by Lessee does not constitute a reservation of or option to
         lease, and it is not effective as a lease or otherwise until execution
         and delivery by both District and Lessee.

34.9     Quiet Possession. Provided Lessee has performed all of the terms,
         covenants, agreements and conditions of this Lease, including the
         payment of rental and all other sums due hereunder, Lessee shall
         peaceably and quietly hold and enjoy the Premises against District and
         all persons claiming by, through or under District, for the term herein
         described subject to the provisions and conditions of this Lease.
         Lessee's right to use the Premises as herein provided shall be subject
         to restrictions or other limitations or prohibitions resulting from any
         laws, statutes, ordinances, and governmental rules, regulations or
         requirements now in force or which may hereafter be in force, and no
         such event shall in any way affect this Lease, abate rent, relieve
         Lessee of any liabilities or obligations under this Lease or give rise
         to any claim whatsoever against District.

34.10    Light and Air Easement. Any diminution or shutting off of light or air
         by any structure which may be erected on lands adjacent to the Building
         shall in no way affect this Lease, abate rent or otherwise impose any
         liability on District.

35.      BROKERS.

35.1     Brokers. Lessee warrants that it has had no dealing with any real
         estate broker or agents in connection with the negotiation of this
         Lease excepting only the Staubach Company and BT Commercial and it
         knows of no other real estate broker or agent who is entitled to a
         commission in connection with this Lease.

35.2     Commission. District shall be responsible for any real estate
         commission or other related costs or fees in this transaction due to BT
         Commercial. Lessee agrees to and does hereby indemnify and hold
         District harmless from and against any and all other costs,
         liabilities, losses, damages, claims, causes of action or proceedings
         which may result from any broker, agent or finder, licensed or
         otherwise, claiming through, under or by reason of the conduct of
         Lessee in connection with this transaction.

                                       20

<PAGE>

The parties hereto have executed this Lease on the dated specified immediately
adjacent to their respective signatures.

"Lessee"          DrugAbuse Science, Inc.
                  330 Distel Circle, Suite 150
                  Los Altos, California 94022
                  Telephone:  (650) 462-1000
                  Facsimile:  (650) 462-1003

By: /s/ Philippe Pouletty                 Dated:
   -------------------------------              --------------------

Title:  CEO

"District":       Midpeninsula Regional Open Space District
                  330 Distel Circle
                  Los Altos, California 94022
                  Telephone:  (650) 691-1200
                  Facsimile:  (650) 691-0485

By: /s/ L. Craig Britton                  Dated:  2/24/00
   -------------------------------              --------------------
   L. Craig Britton
   General Manager

                                     21

<PAGE>

                                    EXHIBIT A

                            DIAGRAM OF LEASE PREMISES

                                       of

                          330 Distel Circle, Suite 150
                           Los Altos, California 94022

                                       E-1

<PAGE>

                                    EXHIBIT B

                              RULES AND REGULATIONS

1.       No new or additional sign, placard, picture, advertisement, name or
         notice shall be inscribed, displayed or printed or affixed on or to any
         part of the outside or inside of the Building without written consent
         of District first had and obtained and Lessee shall be provided space
         for signage on the road side monument and front entrance subject to
         District's approval and consistent with building standards (note wood
         design). All costs of signage shall be the responsibility of Lessee.
         All approved signs or letter on doors shall be printed, painted,
         affixed or inscribed at the expense of the Lessee unless otherwise
         agreed.

         Lessee shall not place anything or allow anything to be placed near the
         glass of any window, door, partition or wall which may appear unsightly
         from outside the Premises, provided, however, that District may furnish
         and install a Building standard window covering at all exterior
         windows. Lessee shall not without prior written consent of District
         cause or otherwise sunscreen any window.

2.       The sidewalks, halls, passages, exits, entrances, elevators and
         stairways shall not be obstructed by any of the Lessees or used by them
         for any purpose other than for ingress and egress from their respective
         Premises.

3.       Lessee shall not alter any exterior lock or install any new or
         additional exterior locks or any bolts on any doors or windows of the
         Premises. Lessee shall have the right to install a security system for
         its computer facilities and nothing herein contained shall abrogate or
         modify the right to do so.

4.       The toilet rooms, urinals, wash bowls and other apparatus shall not be
         used for any purpose other than for which they were constructed and no
         foreign substance of any kind whatsoever shall be thrown therein and
         the expense of any breakage, stoppage or damage resulting from the
         violation of the rule shall be borne by the Lessee who, or whose
         employees or invitees shall have caused it.

5.       Lessee shall not overload the floor of the Premises or in any way
         deface the Premises or any part thereof.

6.       No furniture, freight or equipment of any kind shall be brought into
         the common areas of the Building without prior notice to District and
         all moving of the same shall be done at such time and in such manner as
         District shall designate. District shall have the right to prescribe
         the weight, size, and position of all safes and other heavy equipment
         brought into the Building and also the times and manner of moving the
         same in and out of the Building: Safes or other heavy objects shall, if
         considered necessary by District, stand on supports of such thickness
         as is necessary to properly distribute the weight. District will not be
         responsible for loss or damage to any such safe or property from any
         cause and all

                                       E-2

<PAGE>

         damage done to the Building by moving or maintaining any such safe
         or other property shall be repaired at the expense of the Lessee.

7.       Lessee shall not use, keep or permit to be used or kept any foul or
         noxious gas or substance in the Premises, or permit or suffer the
         Premises to be occupied or used in a manner offensive or objectionable
         to the District or other occupants of the Building by reason of noise,
         odors and/or vibrations, or interface in any way with other Lessees or
         those having business therein, nor shall any animals or birds be
         brought in or kept in or about the Premises or the Building.

8.       No cooking shall be done or permitted by any Lessee on the Premises,
         nor shall the Premises be used for the storage of merchandise, for
         washing clothes, for lodging, or for any improper, objectionable or
         immoral purposes. The brewing of coffee or tea or the use of a
         microwave oven shall not be considered "cooking".

9.       Lessee shall not use or keep in the Premises or the Building any
         kerosene, gasoline or inflammable or combustible fluid or material, or
         use any method of heating or air conditioning other than that supplied
         by District.

10.      District will direct electricians as to where and how telephone and
         telegraph wires are to be introduced. No boring or cutting for wires
         will be allowed without the consent of the District. The location of
         telephones, call boxes and other office equipment affixed to the
         Premises shall be subject to the approval of District, but consent is
         hereby given to install facilities reasonably necessary to the
         installation of the telephone and computer system within the Premises.

11.      On Saturdays, Sundays and legal holidays, and everyday between the
         hours of 6:00 p.m. and 8:00 a.m. the following day, access to the
         Building or to the halls, corridors, elevators or stairways in the
         Building, or to the Premises may be refused unless the person seeking
         access is known to the person or employee of the Building in charge and
         has a pass or is properly identified. The District shall in no case be
         liable for damages for any error with regard to the admission to or
         exclusion from the Building of any person.

         In case of invasion, mob, riot, public excitement, or other commotion,
         the District reserves the right to prevent access to the Building
         during the continuance of the same by closing of the doors or
         otherwise, for the safety of the Lessees and protection of property in
         the Building and the Building.

12.      District reserves the right to exclude or expel from the Building any
         person who, in the judgment of District, is intoxicated or under the
         influence of liquor or drugs, or who shall in any manner to any act in
         violation of any of the rules and regulations of the Building. Lessee,
         Lessee's invitees, customers, agents, employees, or guests shall not
         disrupt or annoy or cause a disturbance to the operations of the
         District.

13.      No vending machine or machines of any description shall be installed,
         maintained or operated upon the Premises without the written consent of
         the District.

                                       E-3

<PAGE>

14.      District shall have the right, exercisable without notices and without
         liability to Lessee, to change the name and street address of the
         Building of which the Premises are a part.

15.      Lessee shall not disturb, solicit, or canvass any occupancy of the
         Building and shall cooperate to prevent same.

16.      Without the written consent of District, Lessee shall not use the name
         of the Building in connection with or in promoting or advertising the
         business of Lessee except as Lessee's address.

17.      District shall have the right to control and operate the public
         portions of the Building; and the public facilities, and heating and
         air conditioning as well as facilities furnished for the common use of
         the Lessees, in such manner as it deems best for the benefit of the
         Lessees generally.

18.      All entrance doors in the Premises shall be left locked when the
         Premises is not in use, and all doors opening to public corridors shall
         be kept closed except for normal ingress and egress from the Premises.

19.      Lessee shall not bring any animal or pet into the building or anywhere
         on the property

20.      Lessee shall comply with applicable municipal ordinances regulating
         smoking in places of employment. Smoking within the Premises and common
         areas is prohibited.

                                       E-4

<PAGE>

                            DRUGABUSE SCIENCES, INC.
                            CERTIFICATE OF SECRETARY

                  The undersigned, Jeffrey P. Higgins, hereby certifies as
follows:

                  1. He is the duly elected,  qualified and acting Secretary
of DrugAbuse  Sciences,  Inc., a California corporation (the "Company."

                  2. Philippe Pouletty, M.D. is the Chairman and Chief
Executive Officer of the Company and is authorized to sign leases or similar
documents on behalf of the Company:

                  3. The signature below is the true signature of the
Philippe Pouletty, M.D.

<TABLE>
<CAPTION>
       NAME                                              TITLE                                SIGNATURE
       ----                                              -----                                ----------
<S>                                      <C>                                    <C>
Philippe Pouletty, M.D.                  Chairman and Chief Executive Officer   /s/ Philippe Pouletty
                                                                                --------------------------------------
</TABLE>

                  IN WITNESS  WHEREOF,  the  undersigned  has executed  this
Certificate this 18 day of February, 2000.

                                        /s/ Jeff Higgins
                                        -----------------------------
                                        Jeffrey P. Higgins, Secretary<PAGE>

          CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED
          AND FILED SEPARATELY WITH THE COMMISSION, CONFIDENTIAL TREATMENT
          HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

                                                                 EXHIBIT 10.19

                    DRUGABUSE SCIENCES, INC. SUPPLY AGREEMENT

         This Supply Agreement is made and entered into effective on and as of
June 9, 2000 by and between the Pharmaceutical Group of Mallinckrodt Inc.
("Mallinckrodt") and DrugAbuse Sciences ("DAS").

         WHEREAS, DAS has need of a certain compound known as Naltrexone Base
Anhydrous (hereinafter "Product") and is desirous of having Product
manufactured and supplied by Mallinckrodt on the conditions set forth herein;
and

         WHEREAS, Mallinckrodt currently manufactures and markets Product and is
capable and desirous of undertaking the supply of Product for DAS in accordance
with the terms and conditions set forth herein;

         NOW, THEREFORE, in consideration of the promises, covenants and
representations of the parties set forth herein, and other good and sufficient
consideration receipt of which is hereby acknowledged, DAS and Mallinckrodt
agree as follows:

         1.   SUPPLY OF PRODUCT.

              (a)  For the consideration provided herein and in accordance
                   with all terms, conditions, representations and warranties
                   set forth herein, and for the term hereof, Mallinckrodt
                   will provide DAS with such amounts of Product as DAS shall
                   request. DAS agrees that it shall purchase [******]
                   Mallinckrodt hereunder during every Contract Year during
                   the term of this Agreement. For purposes of the preceding
                   sentence "Contract Year" shall mean (i) for the first year
                   of this Agreement, the period beginning on June 9, 2000
                   and ending on June 30, 2001, and (ii) for each year
                   thereafter during the term of this Agreement, the twelve
                   (12) month period beginning on July 1 and ending on June
                   30. All Product supplied hereunder shall be manufactured
                   by Mallinckrodt strictly in accordance with the
                   Specifications (defined below) and current Good
                   Manufacturing Practices ("cGMP") as determined by the
                   United States Food and Drug Administration ("FDA") using
                   the manufacturing process described in Mallinckrodt's Drug
                   Master File. If and as applicable, Mallinckrodt shall
                   comply with the cGMP of those countries outside the United
                   States represented on Exhibit B.

              (b)  The specifications for Product (including, without
                   limitation, specifications for all components and raw
                   materials, whether active or inactive) are described on
                   Exhibit A attached hereto ("Specifications").

              (c)  Notwithstanding anything to the contrary herein and if, for
                   any Contract Year after the first Contract Year of this
                   Agreement, Mallinckrodt [******] hereunder, [******]
                   thereafter, shall be [******] sold by Mallinckrodt to all
                   unaffiliated parties and to other Mallinckrodt business

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION, CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.
<PAGE>

          CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED
          AND FILED SEPARATELY WITH THE COMMISSION, CONFIDENTIAL TREATMENT
          HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

              units in such subsequent Contract Year as the [******] business
              units in such immediately previous Contract Year.

    2.   RAW MATERIALS.

         Subject to the provisions of Section 4 below, all raw materials and
         other resources required in connection with the production of Product
         to be supplied hereunder shall be provided by Mallinckrodt [******].

    3.   QUALITY CONTROL.

         (a)  Mallinckrodt will take all steps reasonably necessary to ensure
              that it has the facilities, equipment, instrumentation, resources
              and trained personnel to provide all raw materials, in-process and
              product assays, analysis and other testing (including preparing,
              submitting and maintaining a foreign Drug Master File for Product
              if required by DAS), as compliance with cGMP standards, other FDA
              standards, or the standards of the regulatory agencies of European
              countries listed in Exhibit B may require in connection with
              Mallinckrodt's supply of Product. Mallinckrodt shall provide a
              complete certificate of analysis for each lot of Product supplied
              hereunder at the time of shipment.

         (b)  Mallinckrodt shall maintain complete and accurate documentation of
              all validation data, stability testing data, batch records,
              quality control and laboratory testing and any other data required
              under cGMP or other FDA requirements or the requirements of the
              regulatory agencies of European countries listed in Exhibit B in
              connection with the supply of Product hereunder.

         (c)  Mallinckrodt warrants that it will not engage in any act which
              causes any packaged and labeled Product produced by Mallinckrodt
              to become adulterated or misbranded, and agrees that such Product
              will not be adulterated or misbranded, within the meaning of the
              federal Food, Drug and Cosmetic Act, as amended, when Product is
              delivered to DAS.

         (d)  Mallinckrodt agrees to inform DAS of any significant changes
              related to the Product Drug Master File ("DMF") that would
              required a NDA supplement from DAS, and Mallinckrodt agrees to
              continue to supply unmodified Product to DAS as ordered under the
              terms of and subject to the conditions and limitations of this
              Agreement for a maximum of two (2) years after DAS is informed in
              writing of the new DMF change filing with all applicable
              regulatory agencies.

    4.   COMPENSATION SERVICES PERFORMED BY MALLINCKRODT.

         (a)  For each kilogram of Product supplied hereunder produced in
              accordance with the requirements hereof, DAS shall pay
              Mallinckrodt, for Product to

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION, CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

                                        2
<PAGE>

          CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED
          AND FILED SEPARATELY WITH THE COMMISSION, CONFIDENTIAL TREATMENT
          HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

              be produced and delivered in any particular Contract Year during
              the term hereof; as follows (the "Product Price"):

              (i)   [******]

              (ii)  [******] and

              (iii) [******]; for the sake of clarity, this means that if, for
                    example, [******]

              The Product Price set forth in the immediately preceding sentence
              [******] From and after the [******] in accordance with the
              following procedures; provided, however, that if the [******]
              Within [******] prior to the end of [******] just commenced as a
              consequence of such increases or decreases ("Annual Adjustment
              Notice"). The amount of any increase or decrease in the Product
              Price as set forth in any Annual Adjustment Notice shall be
              effective for all Product invoiced by Mallinckrodt to DAS in
              accordance herewith during the Contract Year for which such Annual
              Adjustment Notice is issued.

         (b)  At the time of shipment by Mallinckrodt to DAS of any lot of
              Product hereunder, Mallinckrodt shall submit to DAS an invoice
              setting forth the total amount of Product being shipped to DAS and
              the amount due to Mallinckrodt under subscate of analysis and a
              certification that the Product for which DAS is being billed has
              been produced fully in conformance with applicable Specifications,
              cGMP and the requirements hereof. Any such invoice shall be
              payable by DAS in United States dollars [******].

    5.   FORECASTS, ORDER PLACEMENT AND DELIVERY.

         (a)  Three (3) months prior to anticipated manufacture of Product,
              Mallinckrodt will notify DAS in writing of the anticipated
              manufacture date. No less than [******] prior to the anticipated
              manufacture date that has been provided by Mallinckrodt to DAS in
              accordance with the preceding sentence, [******] (in accordance
              with the requirements and procedures hereof) [******] with the
              amounts to be so delivered, or according to any reasonable
              alternative schedule, and Mallinckrodt shall deliver Product
              according to such schedule and in the quantities specified.

         (b)  Product shall be ordered by DAS only in writing. Mallinckrodt will
              not accept verbal orders of any kind for the production of
              Product. Any written work order will contain the following
              information: (i) the precise quantity of Product desired and
              required delivery dates (consistent with subsection (a) set forth
              immediately above), (ii) the anticipated shipping destination for
              Product and (iii) such other information as DAS wishes to

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION, CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

                                       3
<PAGE>

              provide or that Mallinckrodt might find necessary or useful in
              completing a specific work order.

         (c)  Product shall be delivered F.O.B. North American shipping
              destination (with the specific destination to be determined by
              DAS), freight prepaid by Mallinckrodt, no earlier than three (3)
              days prior to the requested delivery date, and no later than the
              delivery date. Mallinckrodt will be responsible to make such
              arrangements regarding the shipping of Product to designated
              destinations as DAS shall reasonably request.

    6.   ACCEPTANCE AND REJECTIONS AND RECALLS.

         (a)  If DAS reasonably determines that any Product is defective in
              material or workmanship, not in conformance with applicable
              Specifications, is adulterated or misbranded, or is otherwise not
              in conformity with this Supply Agreement (Product meeting any or
              all of such circumstances hereinafter referred to as a "Defective
              Product"), then (DAS), in addition to any other rights it may have
              under this Supply Agreement, may reject and return any such
              Products to Mallinckrodt. At the time of any such rejection, DAS
              shall provide Mallinckrodt with a written notice describing in
              detail the circumstances surrounding the rejection and DAS'
              reasons therefor. If DAS rejects any such Products it will, at
              Mallinckrodt's option, either return them to Mallinckrodt or
              destroy or dispose of them in the least expensive and most
              environmentally sound manner. In any event, Mallinckrodt shall be
              responsible for the costs of any such return, destruction or
              disposal. It is understood that DAS' sole remedies hereunder in
              the event of a Defective Product it has rejected will either be
              (i) the replacement by Mallinckrodt of rejected Products that have
              either been returned or destroyed with Products that are not
              Defective Products or (ii) a full refund of any amount paid
              hereunder by DAS for such Defective Products, including all
              reasonable transportation and testing costs.

         (b)  Any Product received by DAS from Mallinckrodt that has not been
              rejected by DAS within sixty (60) days after receipt shall be
              deemed to have been accepted, except where such Product contains a
              nonconformity that was not discovered by DAS after reasonable
              inspection, in which case DAS shall have an additional sixty (60)
              days after it discovers such nonconformity within which to reject
              such Product according to the procedures set forth in Section 6(a)
              above.

         (c)  If DAS reasonably decides to or is required to initiate a product
              recall, withdrawal or field correction with respect to, or if
              there is any governmental seizure of, its products containing any
              Product supplied hereunder which action is due, in whole or in
              part, to (i) a failure of any of the Product manufactured by
              Mallinckrodt hereunder to conform to applicable Specifications
              (including, without limitation, it being

                                       4
<PAGE>

              adulterated or misbranded), or any warranty or other requirement
              set forth in this Supply Agreement, (ii) the failure by
              Mallinckrodt to comply in all material respects with any
              applicable law, rule, regulation, standard, court order or decree
              or (iii) the negligent or intentional wrongful act or omission of
              Mallinckrodt in connection with the production of Product
              hereunder, DAS will notify Mallinckrodt promptly of the details
              regarding such action, including providing copies of all relevant
              documentation concerning such action. Mallinckrodt will fully
              cooperate with and use diligent efforts to assist DAS in
              investigating any such situation. All regulatory contacts that are
              made and all activities concerning seizure, recall, withdrawal or
              field correction will be coordinated by DAS and Mallinckrodt. The
              costs of the same shall be apportioned as set forth below.

         (d)  If any such recall, withdrawal, field correction or seizure occurs
              due solely to (i) a failure of any Product sold by Mallinckrodt
              hereunder to conform to applicable Specifications (including,
              without limitation, it being adulterated or misbranded) or any
              warranty or other requirement set forth in this Supply Agreement,
              (ii) the failure by Mallinckrodt to comply in all material
              respects with any applicable law, rule, regulation, standard,
              court order or decree or (iii) the negligent or intentional
              wrongful act or omission of Mallinckrodt in connection with the
              production of Product hereunder, then Mallinckrodt shall bear the
              full cost and expense of any such seizure, recall, withdrawal or
              field correction. If any such recall, withdrawal, field correction
              or seizure occurs due solely to (i) any pharmaceutical product
              manufactured, sold or distributed by DAS that contains Product
              failing to conform to its applicable specifications (including,
              without limitation, it being adulterated or misbranded) or
              otherwise being defective, (ii) the failure of DAS to comply in
              all material respects with any applicable law, rule, regulation,
              standard, court order or decree or (iii) the negligent or
              intentional wrongful act or omission of DAS, then DAS shall bear
              the full cost and expense of any such seizure, recall, withdrawal
              or field correction, If both Mallinckrodt and DAS contribute to
              the cause of a seizure, recall, withdrawal or field correction,
              the cost and expenses thereof will be shared in proportion to each
              party's contribution to the problem.

    7.   REGULATORY COMPLIANCE.

         (a)  Mallinckrodt will comply in all material respects with all
              federal, state and local laws, regulations and standards
              applicable to production by Mallinckrodt and its performance of
              its obligations hereunder, and will also use best efforts to
              comply with any applicable laws, regulations and standards of
              those European countries set forth on Exhibit B.

         (b)  Mallinckrodt will promptly furnish DAS with pertinent portions of
              all FDA (or other applicable regulatory authority) inspection
              reports and

                                       5
<PAGE>

              related correspondence directly related to and affecting its
              performance hereunder as and when such reports and correspondence
              become available to Mallinckrodt.

         (c)  Mallinckrodt will notify DAS immediately upon receipt of, and
              promptly provide DAS a copy of, the relevant portions of any
              warning (including any FDA Form 483), citation, notice,
              indictment, claim, lawsuit or proceeding issued or instituted by
              any federal, foreign, state or local governmental entity or agency
              against Mallinckrodt or any of its affiliates or of any revocation
              of any license or permit issued to Mallinckrodt or any of its
              affiliates, to the extent that any such occurrence relates to
              Mallinckrodt's performance hereunder.

    8.   CERTAIN REPRESENTATIONS AND WARRANTIES OF MALLINCKRODT.

         (a)  Mallinckrodt represents and warrants that all Product sold
              hereunder will (i) be produced in full compliance with cGMPs
              applicable to the Product, and (ii) will meet all Specifications,
              and (iii) will have a minimum shelf-life of twenty-four (24)
              months after the date of delivery to DAS (i.e., that Product
              during the entire shelf-life will comply with the Specifications).
              Upon request from DAS, Mallinckrodt will provide to DAS all data
              it has collected concerning the shelf-life of the Product beyond
              the twenty-four (24) month period referenced above.

         (b)  Mallinckrodt represents and warrants that there is no claim, suit,
              proceeding or investigation pending or, to the knowledge of
              Mallinckrodt, threatened against Mallinckrodt or any of its
              affiliates which might prevent or interfere with Mallinckrodt's
              performance under this Supply Agreement.

         (c)  Mallinckrodt represents and warrants to DAS that Product sold
              hereunder by Mallinckrodt will not be:

              (i)   in violation of Sections 5 or 12 of the Federal Trade
                    Commission Act or improperly labeled under applicable
                    Federal Trade Commission Trade Practice Rules, or other
                    similar European laws (for the countries set forth on
                    Exhibit B), as and to the extent applicable hereunder,

              (ii)  adulterated or misbranded within the meaning of the federal
                    Food, Drug and Cosmetic Act, as amended, within the meaning
                    of any regulations of any Regulatory Agency of European
                    countries listed in Exhibit B or any state or municipal law
                    in which the definition of adulteration and misbranding are
                    substantially identical to those contained in the United
                    States Federal Food, Drug and Cosmetic Act, or articles
                    which may not under the provisions of Sections 404 or 505 of
                    said Act be introduced into interstate commerce or which

                                       6
<PAGE>

                    may not under similar provisions of any foreign, state or
                    municipal law be introduced into commerce,

              (iii) manufactured or sold in violation of the federal Controlled
                    Substances Act, as amended, or any substantially similar
                    legislation of applicable European country (for the
                    countries set forth on Exhibit B) or state law,

              (iv)  manufactured or sold in violation of any of the provisions
                    of the Fair Labor Standards Act of 1938, as amended,

              (v)   manufactured or sold in violation of The Occupational Safety
                    and Health Act of 1970, as amended,

              (vi)  manufactured in violation of any applicable federal, state
                    or local environmental law or regulation, or

              (vii) manufactured in violation of any agreement (commercial or
                    otherwise), judgment, order or decree to which Mallinckrodt
                    is a party.

         (d)  Mallinckrodt certifies that neither it nor any of its affiliates
              nor any member of their staff has been disqualified or debarred by
              the FDA, or any other domestic regulatory authority, or any other
              applicable regulatory agency of any of the European countries set
              forth in Exhibit B for any purpose.

         (e)  Mallinckrodt warrants and represents that neither it nor any of
              its affiliates nor any member of their staff have been charged
              with or convicted under federal law, or other applicable laws of
              the European countries set forth in Exhibit B, for conduct
              relating to the development or approval, or otherwise relating to
              the regulation of any drug product under the Generic Drug
              Enforcement Act of 1992 or any other relevant statute, law or
              regulation.

         (f)  Mallinckrodt hereby represents and warrants that: Mallinckrodt has
              all rights and licenses necessary to manufacture and sell the
              Product to DAS.

         (g)  EXCEPT AS SET FORTH ABOVE IN THIS SECTION 8, MALLINCKRODT MAKES NO
              OTHER WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, CONCERNING
              ITS PERFORMANCE HEREUNDER, INCLUDING ANY WARRANTY OF
              MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT
              TO "PRODUCT." UNDER NO CIRCUMSTANCES WILL MALLINCKRODT BE LIABLE
              HEREUNDER FOR CONSEQUENTIAL, INDIRECT, EXEMPLARY OR SPECIAL
              DAMAGES OF ANY KIND (INCLUDING, WITHOUT LIMITATION, LOST PROFITS),
              WHETHER OR NOT IN ANY PARTICULAR

                                       7
<PAGE>

          CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED
          AND FILED SEPARATELY WITH THE COMMISSION, CONFIDENTIAL TREATMENT
          HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

              CIRCUMSTANCE SUCH DAMAGES ARE FORESEEABLE AND WHETHER OR NOT
              MALLINCKRODT HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

    9.   FACILITY ACCESS.

         DAS, through its employees, consultants or other representatives will
         have the right during normal business hours and at a time mutually
         agreed to inspect Mallinckrodt's manufacturing operations to determine
         whether or not Mallinckrodt is complying in all respects with its
         obligations hereunder. DAS warrants that all such inspections and
         audits shall be carried out in a manner calculated not to unreasonably
         interfere with Mallinckrodt's conduct of business and to insure the
         continued confidentiality of Mallinckrodt's business and technical
         information. Further, DAS agrees to comply with all of Mallinckrodt's
         safety and security requirements during any visits to the Mallinckrodt
         facilities. Following an inspection which will in any way affect the
         production of Product for supply to DAS by the FDA or any other
         European Community authority (as set forth on Exhibit B), Mallinckrodt
         will notify DAS in writing of any material issues that may be pertinent
         to the supply of Product to DAS. The parties agree to cooperate in good
         faith and engage in an active dialogue in an effort to resolve any
         issues resulting from any such inspections.

    10.  FORCE MAJEURE.

         Neither party to this Supply Agreement shall be liable for or be in
         breach of any provision hereof for any failure or delay on its part to
         perform any obligation (other then the obligation to make payments when
         due) under any provision of this Supply Agreement because of an event
         of "force majeure," including, but not limited to, any act of God,
         fire, flood, explosion, unusually severe weather, war, insurrection,
         riot, sabotage, labor unrest, strikes or work stoppages or any other
         cause whatsoever, whether similar or dissimilar to those enumerated
         herein, beyond any reasonable possibility of control of such party, if
         and only if the party affected shall have used all reasonable efforts
         under the circumstances to avoid such occurrence and to remedy it
         promptly if it shall have occurred. If an event of force majeure
         [******].

    11.  RELATIONSHIP OF PARTIES.

         For all purposes hereof, Mallinckrodt shall be deemed to be an
         independent contractor and this Supply Agreement shall not create an
         agency, partnership, joint venture, or employer/employee relationship
         between DAS and Mallinckrodt, and nothing hereunder shall be deemed to
         authorize either party hereto to act for, represent or bind the other
         or any of its affiliates except as expressly provided in this Supply
         Agreement.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION, CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

                                       8
<PAGE>

    12.  CONFIDENTIALITY.

         (a)  DAS and Mallinckrodt shall maintain in confidence and not use or
              disclose to any third party, except as is specifically
              contemplated herein or is otherwise necessary to perform their
              respective obligations under this Supply Agreement, and then only
              on a confidential basis satisfactory to both parties, any
              information, including without limitation business and technical
              information, experience or data regarding any facility, programs,
              laboratories, processes, products, costs, equipment operation or
              customers, relating to the manufacture or sale of Product
              hereunder. The foregoing obligations of confidentiality and
              non-use shall survive the termination or expiration of this Supply
              Agreement for a period of five (5) years. Nothing herein shall
              prevent either party from disclosing any information required by
              statute or governmental regulations to be disclosed in a judicial
              or administrative proceeding, after the disclosing party has been
              given a reasonable opportunity, to the extent possible, to pursue
              all legal remedies for maintaining such information in confidence,
              or from using information which (i) has been published or has
              become part of the public domain other than by acts, omissions or
              fault of such party, (ii) was lawfully received by such party from
              a third party free of any obligation of confidence to such third
              party, (iii) or a party can demonstrate from its records was
              already in its possession prior to receipt thereof, directly or
              indirectly, from the other party. The party asserting the
              applicability of one of the exclusions from the obligation of
              confidentiality set forth in the immediately preceding sentence
              shall have the burden of proving the applicability of any such
              exclusion in any particular circumstance.

         (b)  Each party acknowledges that any breach by it of the
              confidentiality obligations set forth in this Section 12 would
              cause the other party irreparable harm for which compensation by
              monetary damages would be inadequate and, therefore, the party
              that has been harmed by any such breach shall have the right to an
              injunction or decree for specific performance, in addition to any
              other rights and remedies such party may have at law or in equity.

         (c)  Upon any termination of this Agreement, each recipient party will
              promptly return or destroy, at the discretion of the disclosing
              party, any confidential information of the disclosing party.

    13.  INDEMNIFICATION.

         (a)  Subject to the provisions of Section 8(g) hereof, Mallinckrodt (on
              behalf of itself and its affiliates) hereby agrees to indemnify,
              defend and hold harmless DAS and its affiliates from and against
              any and all demands, claims, actions, causes of action,
              assessments, losses, damages, injuries, liabilities, costs and
              expenses, including without limitation, interest, penalties and
              reasonable attorneys' fees and expenses (collectively

                                       9
<PAGE>

          CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED
          AND FILED SEPARATELY WITH THE COMMISSION, CONFIDENTIAL TREATMENT
          HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

              "Damages") asserted against, resulting to, imposed upon or
              incurred by DAS or its affiliates, directly or indirectly related
              to, arising out of or resulting from:

              (i)   any breach or failure of any of the representations,
                    warranties and covenants of Mallinckrodt contained herein,
                    including (without limitation) any breach or failure by
                    Mallinckrodt to perform any obligations contained herein,
                    and

              (ii)  any failure of Mallinckrodt to observe or comply in all
                    material respects with any laws, rules or regulations for
                    which and to the extent Mallinckrodt has promised compliance
                    hereunder.

         (b)  DAS hereby agrees to indemnify, defend and hold harmless
              Mallinckrodt and any of its affiliates from and against any and
              all Damages asserted against, resulting to, imposed upon or
              incurred by Mallinckrodt, directly or indirectly related to,
              arising out of or resulting from:

              (i)   any breach or failure of any of the representations,
                    warranties and covenants of DAS contained herein,

              (ii)  any failure of DAS to observe or comply in all material
                    respects with any laws, rules or regulations directly
                    related to DAS' performance hereunder, and

              (iii) DAS' or DAS' agents', distributors' or customers' use,
                    processing, transportation possession, disposal or sale of
                    any dosage Product manufactured by DAS, and whether used
                    alone or in combination with any other material.

         (c)  In the event of any claim being made against a party (the
              "Indemnified Party"), which triggers the indemnity obligations of
              the other party (the "Indemnifying Party") as set forth above,
              such indemnification shall be conditioned on compliance with the
              procedure outlined below. Provided that prompt notice is given of
              any claim or suit, the Indemnifying Party shall have the right to
              defend, contest, or otherwise protect against any such claim or
              suit, including by way of settlement and release, at its own
              expense and cost. The Indemnifying Party shall be entitled to sole
              control of the defense and settlement of any such claim or suit,
              and the Indemnified Party shall cooperate and provide such
              assistance as the Indemnifying Party may reasonably request in
              connection with the defense of the matter subject to
              indemnification.

    14.  TERM AND TERMINATION.

         (a)  Unless sooner terminated in accordance herewith, the initial
              term of this Supply Agreement shall be for a period commencing
              on June 9, 2000 and ending June 30, 2005, and shall
              automatically be renewed for additional one (1) year terms
              thereafter unless either party shall give written notice to the
              other, at least six (6) months prior to the end of the initial
              term or any renewal term, that it does not wish the Supply
              Agreement to be renewed for an additional one (1) year period.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION, CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

                                       10
<PAGE>

          CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED
          AND FILED SEPARATELY WITH THE COMMISSION, CONFIDENTIAL TREATMENT
          HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

         (b)  In addition to any other right of termination specifically
              provided for hereunder, this Supply Agreement may be terminated by
              either party for cause upon written notice to the other. For
              purposes of the preceding sentence, "cause" shall mean (without
              limitation):

              (i)   any material breach of this Agreement by a party which shall
                    go uncorrected for a period of thirty (30) days after
                    written notice of such breach has been given to the
                    defaulting party,

              (ii)  the institution by a party of voluntary proceedings in
                    bankruptcy or under any insolvency law or law for the relief
                    of debtors,

              (iii) the making by a party of an assignment for the benefit of
                    creditors or any dissolution or liquidation,

              (iv)  the filing of an involuntary petition under any bankruptcy
                    or insolvency law against a party, unless such petition is
                    dismissed or set aside within sixty (60) days from the of
                    its filing, or

              (v)   the appointment of a receiver or trustee for the assets or
                    business of a party, unless such appointment is dismissed or
                    set aside within sixty (60) days from the date of such
                    appointment.

         (c)  The representations and warranties of the parties hereunder,
              covenants which by their terms have effect after the termination
              or expiration hereof, and the parties' indemnification and
              confidentiality obligations shall survive termination or
              expiration of this Supply Agreement.

         (d)  In the event of any termination or expiration of this Supply
              Agreement, for any reason, Mallinckrodt shall (i) notwithstanding
              the effective date of any termination or the expiration, as the
              case may be, complete any orders for Product that were made by DAS
              and accepted by Mallinckrodt prior to such date, and DAS shall pay
              Mallinckrodt for any Product produced in accordance with such
              orders at the then applicable Product Price in effect on the
              effective date of termination hereunder or expiration (as the case
              may be). No less than [******] or expiration (as the case may be)
              to be shipped according to Section 5c; provided that, [******]
              Mallinckrodt pursuant to Section 14(b).

    15.  REMEDIES CUMULATIVE.

         The remedies provided in this Supply Agreement shall be cumulative and
         shall not preclude assertion by any party hereto of any other rights
         (whether legal or equitable in nature) or the seeking of any other
         remedies against party other party hereto.

[*] CERTAIN INFORMATION IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY
WITH THE COMMISSION, CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO
THE OMITTED PORTIONS.

                                       11
<PAGE>

    16.  BINDING EFFECT AND ASSIGNMENT.

         This Supply Agreement shall inure to the benefit of and be binding upon
         the parties hereto, their successors and assigns; provided, however,
         that neither party shall, without the prior written consent of the
         other party, assign or transfer any of its rights, benefits,
         obligations, or other interest under this Supply Agreement to any other
         party, except that, without seeking consent of the other party, either
         party may assign this Supply Agreement to any entity or person it
         controls, it is controlled by or is under common control with, or to
         any entity or person that acquires all or substantially all of its
         stock, assets or business or acquires that portion of its business to
         which this Supply Agreement relates, whether by merger, acquisition,
         sale or otherwise.

    17.  NOTICE.

         All notices, consents, approvals or other notifications required to be
         sent by one party to the other party hereunder shall be in writing and
         shall be deemed served upon the other party if delivered by hand or
         sent by United States registered or certified mail, postage prepaid,
         with return receipt requested, or by facsimile, or air courier,
         addressed to such other party at the address set out below, or the last
         address of such party as shall have been communicated to the other
         party. If a party changes its address, written notice shall be given
         promptly to the other party of the new address. Notice shall be deemed
         given on the day it is sent (in the case of delivery by method other
         than hand delivery) or the date of delivery (in the case of delivery by
         hand) in accordance with the provisions of this paragraph. The
         addresses for notices are as follows:

                  If to Mallinckrodt:

                           Mallinckrodt Inc.
                           c/o Pharmaceuticals Group
                           675 McDonnell Boulevard
                           Hazelwood, Missouri  63042
                           Attn:  Pat E. Cunningham
                                  Vice President Pharmaceuticals Group

                  with a copy to:

                           Mallinckrodt Inc.
                           675 McDonnell Boulevard
                           Hazelwood, Missouri  63042
                           Attn:  C. Stephen Kriegh
                                  Staff Vice President

                                       12
<PAGE>

                  If to DAS:

                           DrugAbuse Sciences
                           330 Distel Circle, Suite 150
                           Los Altos, CA  94022
                           Attn:  Philippe Pouletty,
                                  Chairman and Chief Executive Officer
                           Telephone:  (650) 417-2300
                           Fax:  (650) 417-2400

    18.  GOVERNING LAW AND JURISDICTION.

         This Agreement shall be governed by and construed in accordance with
         the substantive and procedural laws (as opposed to the conflicts of law
         provisions) of the State of New York.

    19.  WAIVER.

         The failure by any party to exercise any of its rights hereunder or to
         enforce any of the terms or conditions of this Supply Agreement on any
         occasion shall not constitute or be deemed a waiver of that party's
         rights thereafter to exercise any rights hereunder or to enforce each
         and every term and condition of this Supply Agreement.

    20.  MODIFICATIONS.

         This Supply Agreement may not be amended or modified except by a
         writing specifically referring to this Supply Agreement and executed by
         duly authorized representatives of both parties. The obligations of the
         parties are governed by the terms and conditions of this Supply
         Agreement and none of the general terms and conditions of any DAS
         purchase order or any Mallinckrodt acknowledgment or any substantially
         similar documents of either party will in any case be controlling or
         supersede the provisions hereof.

    21.  SEVERABILITY.

         A determination that any portion of this Supply Agreement is
         unenforceable or invalid shall not affect the enforceability or
         validity of any of the remaining portions hereof or of this Supply
         Agreement as a whole. In the event that any part of any of the
         covenants, sections or provisions herein may be determined by a court
         of law or equity to be overly broad or against applicable precedent or
         public policy, thereby making such covenants, sections or provisions
         invalid or unenforceable, the parties shall attempt to reach agreement
         with respect to a valid and enforceable substitute for the deleted
         provisions, which shall be as close in its intent and effect as
         possible to the deleted portions.

                                       13
<PAGE>

    22.  HEADINGS.

         The parties agree that the section and article headings are inserted
         only for ease of reference, shall not be construed as part of this
         Supply Agreement, and shall have no effect upon the construction or
         interpretation of any part hereof.

    23.  COUNTERPARTS.

         This Supply Agreement may be executed in several counterparts, and each
         executed counterpart shall be considered an original of this Supply
         Agreement.

    24.  ENTIRE AGREEMENT.

         This Supply Agreement represents the entire agreement and understanding
         of the parties hereto with respect to its subject matter and supersedes
         any and all prior agreements, understanding or discussions, whether
         written or oral, between the parties.

                                       14
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Supply
Agreement to be executed as of the day and year first above written.

                                        MALLINCKRODT INC.
DRUGABUSE SCIENCES, INC.                Pharmaceuticals Group

By:      /s/ Philippe Pouletty          By:      /s/ Pat E. Cunningham
   ----------------------------------      ---------------------------------
Name Printed:  Philippe Pouletty, M.D.     Pat E. Cunningham
Title Printed: Chairman and CEO            Vice President, Pharmaceuticals Group

Date:  June 8, 2000                        Date:  June 8, 2000

<PAGE>

                                    EXHIBIT A

                             PRODUCT SPECIFICATIONS

                            NALTREXONE BASE ANHYDROUS

<TABLE>
<S>                                        <C>       <C>      <C>     <C>
ITEM CODE:                                  [******]

FORMULA:                                    [******]

CAS REGISTRY No.:                           [******]

MOLECLLNIZ WEIGHT:                          [******]

APPEARANCE:                                 [******]

IDENTIFICATION:                             [******]

WATER CONTENT:                              [******]

TITRATION ASSAY:                            [******]

HEAVY METALS:                               [******]

RELATED SUBSTANCES:                         [******]

                                            [******] [******] [******] [******]

                                            [******]

HPLC ASSAY:                                 [******]

BIO-BURDEN/ENDOTOXIN LIMITS:

                                            DrugAbuse Sciences as part of our
                                            scale up and R&D efforts will be
                                            determining [******]. These limits
                                            will be based on the process and
                                            agreed upon by the parties at a
                                            later date.
</TABLE>

<PAGE>

                                    EXHIBIT B

                               EUROPEAN COUNTRIES

France
Germany
Italy
Netherlands
Norway
Portugal
Spain
Sweden
Switzerland
United Kingdom

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