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                                                                    Exhibit 10.3
                                                                    ------------

                                    AGREEMENT
                                    ---------

                  THIS AGREEMENT (this "Agreement"), is made, entered into and
effective as of September 25, 2000 (the "Effective Date"), by and between
Gliatech Inc. (the "Company"), located at 23420 Commerce Park Road, Cleveland,
Ohio 44122 and Raymond Silkaitis ("Employee"), residing at 2785 Belgrave Road,
Pepper Pike, Ohio 44124.

                                   WITNESSETH:
                                   -----------

                  WHEREAS, prior to the Effective Date, Employee was the Vice
President of Regulatory Affairs of the Company;

                  WHEREAS, Effective on the Effective Date, Employee's
employment with the Company shall terminate, and Employee shall resign from any
and all offices of the Company, and any other position, office or directorship
of any other entity for which Employee was serving at the request of the
Company; and

                  WHEREAS, the Company accepts Employee's resignations as of the
date referenced above; and

                  WHEREAS, the Company and Employee desire to set forth the
payments and benefits that Employee will be entitled to receive from the Company
and the continuing obligations that each party has undertaken in connection with
the cessation of Employee's employment with the Company; and

                  WHEREAS, the Company and Employee wish to resolve, settle
and/or compromise certain matters, claims and issues between them, including,
without limitation, Employee's resignation from the offices he held and from the
termination of his employment with the Company.

                  NOW, THEREFORE, in consideration of the promises and
agreements contained herein and other good and valuable consideration, the
sufficiency and receipt of which are hereby acknowledged, and intending to be
legally bound, the Company and Employee hereby agree as follows:

         1. CESSATION OF EMPLOYMENT. Effective on the Effective Date, Employee's
employment with the Company and its subsidiaries and related or affiliated
companies shall terminate. Employee hereby resigns, effective on the Effective
Date: (a) from all offices of the Company to which he has been elected by the
Board of Directors of the Company (or to which he has otherwise been appointed),
(b) from all offices of any entity that is a subsidiary of, or is otherwise
related to or affiliated with, the Company, (c) from all administrative,
fiduciary or other positions he may hold with respect to arrangements or plans
for, of or relating to the Company, and (d) from any other directorship, office,
or position of any corporation, partnership, joint venture, trust or other
enterprise (each, an "Other Entity") insofar as Employee is serving in


<PAGE>   2

the directorship, office, or position of the Other Entity at the request of the
Company. The Company hereby consents to and accepts said resignations.

         2. COMPENSATION AND BENEFITS. Subject to the conditions hereof, the
Company and Employee agree to the following:

                  a. SEVERANCE COMPENSATION. As severance compensation, the
Company shall pay Employee an amount equal to the Employee's annual base salary
of $150,000. Such amount shall be paid one-half on the day after which
Employee's right of revocation under Subparagraph 5.c.(iv) of this Agreement
expires (the "First Payment Date"), and one-half on the date that is six months
after the Effective Date.

                  b. STOCK OPTIONS. Employee has certain stock options that were
granted to Employee prior to the Effective Date. Employee's eligibility to
exercise these vested and exercisable options is governed and will continue to
be governed by the terms and conditions of the Company's Amended and Restated
1989 Stock Option Plan and the agreements previously entered into between the
Company and the Employee with respect to such stock options. Notwithstanding the
foregoing, (i) any stock options that were granted to Employee as of the
Effective Date that are not vested shall continue to vest pursuant to the
vesting schedule set forth in the agreements governing such stock options for a
period of one year after the Effective Date (the "Vesting Date"), and (ii)
Employee shall have a period of fifteen months following the Effective Date (the
"Benefit Period") in which to exercise or forfeit vested options. Employee
agrees and acknowledges that he is ineligible for any other stock options,
grants or awards, and that he forfeits upon the Effective Date any rights in or
to any other stock option grants, including without limitation, any right to
vest after the Vesting Date in any stock options that are not already vested as
of the Vesting Date.

                  c. MEDICAL COVERAGE.

                           (i) Employee and his eligible dependents shall be
         allowed to continue as a plan participant in the Company's group health
         plan (medical, dental and vision coverage) (the "Health Plan") for a
         period of one year following the Effective Date (the "Severance
         Period") on the same basis that the Company's active employees
         participate in such plan during that period.

                           (ii) For a period of six months following the end of
         the Severance Period, Employee may continue, at his cost, his
         participation in the Health Plan pursuant to the health care
         continuation coverage requirements of federal law.

                  d. PROFESSIONAL FEES. The Company and Employee acknowledge and
agree that each shall be responsible for the payment of their respective legal
fees and costs (and related disbursements) incurred in connection with
Employee's cessation of employment and all matters relating to the negotiation
and execution of the releases and all other matters covered by this Agreement.

                  e. COMPANY BENEFIT PLANS. Except as provided above in Section
2.c of this Agreement, Employee's post-Effective Date eligibility for benefits,
if any, as a past employee of the Company under the Company's retirement and
welfare benefit plans shall be as set forth in



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the respective plan documents and shall be based on his employment termination
on the Effective Date, and his entitlement to benefits for the period of his
participation therein shall be determined pursuant to the terms thereof.

                  f. BUSINESS EXPENSES. The Company will reimburse Employee for
any reasonable business expenses incurred by Employee prior to the Effective
Date that are reimbursable pursuant to the Company's expense reimbursement
policies.

                  g. VACATION PAY. Employee shall be paid for accrued but unused
vacation time determined as of the Effective Date, with such payment to be made
on the First Payment Date.

                  h. ACCRUED SALARY. Employee shall be paid in accordance with
the Company's normal payroll cycle any base salary amount earned but unpaid as
of the Effective Date.

                  i. OUTPLACEMENT. Employee shall be entitled to reimbursement
by the Company for the costs of outplacement services utilized by Employee after
the Effective Date up to $9,000 in total, promptly after Employee provides
receipts or other documentation establishing that he has incurred such costs and
the amount thereof.

                  j. WITHHOLDING. The Company shall withhold such amounts from
the payments described herein as are required by applicable tax or other law.

                  k. DIRECTORS' AND OFFICERS' LIABILITY INSURANCE. The Company
shall maintain, for a period of not less than three years from the Effective
Date, the Company's current directors' and officers' liability insurance policy
(or a successor policy providing substantially comparable coverage) to the
extent that it provides coverage for events occurring prior to the Effective
Date.

                  l. MITIGATION. Employee shall not be required to mitigate the
amount of any payment or benefit provided for in this Agreement by seeking other
employment or otherwise.

                  m. REFERENCES. The Company shall provide to any potential
future employer of Employee which requests information from the Company with
respect to Employee, the period of Employee's employment with the Company and
his title with the Company.

         3. NON-COMPETITION.

                  a. During the Benefit Period, Employee shall not, directly or
indirectly, do or suffer to be done any of the following: own, manage, control
or participate in the ownership, management, or control of, or be employed or
engaged by or otherwise affiliated or associated as a consultant, independent
contractor or otherwise with any other corporation, partnership, proprietorship,
firm, association, or other business entity, or otherwise engage in any
business, which is in competition with the Company's business in the United
States; provided, however, that the ownership of not more than one percent of
any class of publicly-traded securities of any entity shall not be deemed a
violation of this Agreement. For purposes of this Agreement, the "Company's
business" shall mean any business in which the Company actively engages now, and



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any business in which the Company has actively engaged in the two (2) year
period prior to the date hereof, with respect to the discovery and development
of products designed to inhibit post surgical scarring and adhesions in lumbar
surgery.

                  b. In the event Employee shall violate any provision of this
Paragraph 3 as to which there is a specific time period during which he is
prohibited from taking certain actions or from engaging in certain activities as
set forth in such provision, then, in such event, such violation shall toll the
running of such time period from the date of such violation until such violation
shall cease. The foregoing shall in no way limit the Company's rights under
Paragraph 8 of this Agreement.

                  c. Employee has carefully considered the nature and extent of
the restrictions upon him and the rights and remedies conferred upon the Company
under this Paragraph 3 and this Agreement, and hereby acknowledges and agrees
that the same are reasonable in time and territory, are designed to eliminate
competition which otherwise would be unfair to the Company, do not stifle the
inherent skill and experience of Employee, would not operate as a bar to
Employee's sole means of support, are fully required to protect the legitimate
interests of the Company and do not confer a benefit upon the Company
disproportionate to the detriment of Employee. Employee further acknowledges
that his obligations in this Paragraph 3 are made in consideration of, and are
adequately supported by the payments by the Company to Employee described
herein.

                  d. Employee's obligations under this Paragraph 3 shall
terminate in the event the Company breaches any of its obligations under this
Agreement and fails to cure such breach within fifteen days after written notice
by Employee to the Company specifying the circumstances that constitute such
breach.

         4. NO SOLICITATION OF EMPLOYEES. Employee agrees that he will not:

                  (i) Employ, assist in employing, or otherwise associate in
         business with any person who is, or has been in the 12 month period
         prior to such individual's association with Employee an employee,
         officer or agent of the Company, or any of its affiliated, related or
         subsidiary entities, unless such employee was involuntarily terminated
         by the Company.

                  (ii) Induce any person who is an employee, officer or agent of
         the Company, or any of its affiliated, related, or subsidiary entities
         to terminate such relationship.

         5. RELEASE BY EMPLOYEE.

                  a. Employee for himself and his dependents, successors,
assigns, heirs, executors and administrators (and his and their legal
representatives of every kind), hereby releases, dismisses, remisses and forever
discharges the Company from any and all arbitrations, claims (including claims
for attorney's fees), demands, damages, suits, proceedings, actions and/or
causes of action of any kind and every description, whether known or unknown,
which Employee now has or may have had for, upon, or by reason of any cause
whatsoever (except that this release shall not apply to (i) the obligations of
the Company arising under this Agreement



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and (ii) Employee's rights of indemnification by the Company, if any, pursuant
to any agreement between the Company and Employee, against the Company
("claims"), including but not limited to:

                  (i) any and all claims, directly or indirectly, arising out of
         or relating to: (A) Employee's past employment or service with the
         Company; and (B) the cessation of Employee's employment with the
         Company, Employee's resignation as Vice President of Regulatory Affairs
         of the Company and Employee's resignation from any other position
         described in Paragraph 1 of this Agreement.

                  (ii) any and all claims of discrimination, including but not
         limited to claims of discrimination on the basis of sex, race, age,
         national origin, marital status, religion or disability, including,
         specifically, but without limiting the generality of the foregoing, any
         claims under the Age Discrimination in Employment Act, as amended (the
         "ADEA"), Title VII of the Civil Rights Act of 1964, as amended, the
         Americans with Disabilities Act of 1990, the Family and Medical Leave
         Act of 1993 and Ohio Revised Code Chapter 4112;

                  (iii) any and all claims of wrongful or unjust discharge or
         breach of any contract or promise, express or implied; and

                  (iv) any and all claims under or relating to any and all
         employee compensation, employee benefit, employee severance or employee
         incentive bonus plans and arrangements, all of which Employee agrees
         are forfeited upon the Effective Date; provided that he shall remain
         entitled to the amounts and benefits described in Paragraph 2 above.
         Employee agrees that he intends to release any and all workers
         compensation claims he may have against the Company by this Agreement,
         and further agrees to execute any documentation as may be reasonably
         required to perfect such release when presented to him by the Company.

                  b. Employee understands and acknowledges that the Company does
not admit any violation of law, liability or invasion of any of his rights and
that any such violation, liability or invasion is expressly denied. The
consideration provided under this Agreement is made for the purpose of settling
and extinguishing all claims and rights (and every other similar or dissimilar
matter) that Employee ever had or now may have or ever will have against the
Company to the extent provided in this Paragraph 5. Employee further agrees and
acknowledges that no representations, promises or inducements have been made by
the Company other than as appear in this Agreement.

                  c. Employee further understands and acknowledges that:

                  (i) The release provided for in this Paragraph 5, including
         claims under the ADEA to and including the date of this Agreement, is
         in exchange for the additional consideration provided for in this
         Agreement, to which consideration he was not heretofore entitled;

                  (ii) He has been advised by the Company to consult with legal
         counsel prior to executing this Agreement and the release provided for
         in this Paragraph 5, has had an



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         opportunity to consult with and to be advised by legal counsel of his
         choice, fully understands the terms of this Agreement, and enters into
         this Agreement freely, voluntarily and intending to be bound;

                  (iii) He has been given a period of twenty-one days to review
         and consider the terms of this Agreement, and the release contained
         herein, prior to its execution and that he may use as much of the
         twenty-one day period as he desires; and

                  (iv) He may, within seven days after execution, revoke this
         Agreement. Revocation shall be made by delivering a written notice of
         revocation to the Chief Operating Officer at the Company. For such
         revocation to be effective, written notice must be actually received by
         the Chief Operating Officer at the Company no later than the close of
         business on the seventh day after Employee executes this Agreement. If
         Employee does exercise his right to revoke this Agreement, all of the
         terms and conditions of the Agreement shall be of no force and effect
         and the Company shall have no obligation to satisfy the terms or make
         any payment to Employee as set forth in Paragraph 2 of this Agreement.

                  d. Employee will never file a lawsuit or other complaint
asserting any claim that is released in this Paragraph 5.

                  e. Employee waives and releases any claim that he has or may
have to reemployment.

                  f. For purposes of the above provisions of this Paragraph 5,
the "Company" shall include its present and former predecessors, subsidiaries,
divisions, related or affiliated companies, officers, directors, stockholders,
members, employees, heirs, successors, assigns, representatives, agents,
accountants and counsel.

         6. CONFIDENTIAL INFORMATION.

                  a. Employee acknowledges and agrees that in the performance of
his duties as an officer and employee of the Company he was brought into
frequent contact with, had or may have had access to, and/or became informed of
confidential and proprietary information of the Company and/or information which
is a competitive asset of the Company (collectively, "Confidential Information")
and the disclosure of which would be harmful to the interests of the Company or
its subsidiaries. Confidential Information shall include, without limitation:
(a) customer and distributor information such as names, addresses, sales
histories, purchasing habits, credit status, pricing levels, etc., (b) certain
prospective customer and distributor information lists, etc., (c) product and
systems specifications, schematics, designs, concepts for new or improved
products and services and other products and services data, (d) product and
material costs, (e) suppliers' and prospective suppliers' names, addresses and
contracts, (f) future corporate planning data, (g) production methods and
equipment, (h) marketing strategies, (i) the Company's financial results and
business condition, (j) any of the foregoing which belong to any other person or
company but to which Employee has had access by reason of his employment with
the Company, (k) pre-clinical and clinical testing procedures and other related
information, and (l) any other information which constitutes a "trade secret"
under federal or state law. Such



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Confidential Information is more fully described in Subparagraph (b) of this
Paragraph 6. Employee acknowledges that the Confidential Information of the
Company gained by Employee during his association with the Company was developed
by and/or for the Company through substantial expenditure of time, effort and
money and constitutes valuable and unique property of the Company.

                  b. Employee will keep in strict confidence, and will not,
directly or indirectly, at any time, disclose, furnish, disseminate, make
available, use or suffer to be used in any manner any Confidential Information
of the Company without limitation as to when or how Employee may have acquired
such Confidential Information. Employee specifically acknowledges that
Confidential Information includes any and all information, whether reduced to
writing (or in a form from which information can be obtained, translated, or
derived into reasonably usable form), or maintained in the mind or memory of
Employee and whether compiled or created by the Company, which derives
independent economic value from not being readily known to or ascertainable by
proper means by others who can obtain economic value from the disclosure or use
of such information, that reasonable efforts have been put forth by the Company
to maintain the secrecy of confidential or proprietary or trade secret
information, that such information is and will remain the sole property of the
Company, and that any retention or use by Employee of confidential or
proprietary or trade secret information after the termination of Employee's
employment with and services for the Company shall constitute a misappropriation
of the Company's Confidential Information.

                  c. Employee will immediately return to the Company (to the
extent he has not already returned), equipment, software, electronic files,
computers, including any laptop, in good condition, all property of the Company,
including, without limitation, property, documents and/or all other materials
(including copies, reproductions, summaries and/or analyses) which constitute,
refer or relate to Confidential Information of the Company.

                  d. Employee further acknowledges that his obligation of
confidentiality shall survive, regardless of any other breach of this Agreement
or any other agreement, by any party hereto, until and unless such Confidential
Information of the Company shall have become, through no fault of Employee
generally known to the public or Employee is required by law (after providing
the Company with notice and opportunity to contest such requirement) to make
disclosure. Employee's obligations under this Paragraph 6 are in addition to,
and not in limitation or preemption of, all other obligations of confidentiality
which Employee may have to the Company under general legal or equitable
principles or statutes.

         7. DISCLOSURE.

                  a. From the date of this Agreement through the end of the
Severance Period, Employee will communicate the contents of Paragraphs 3, 4, 6,
8.b., 9 and 11 of this Agreement to any person, firm, association, or
corporation other than the Company which he intends to be employed by,
associated in business with, or represent.

                  b. Employee shall take no action with respect to the Company's
common stock that is in violation of the federal securities laws.



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         8. BREACH.

                  a. If Employee breaches any of the provisions of this
Agreement (and in the case of a breach that is capable of being cured, fails to
cure such breach within fifteen days after written notice by the Company to
Employee specifying the circumstances that constitute such breach), then the
Company may, at its sole option, immediately terminate all remaining payments
and benefits described in this Agreement, including the vesting or
exercisability of any stock options under Paragraph 2.b., and obtain
reimbursement from Employee of all payments and benefits already provided
pursuant to Paragraph 2 of this Agreement, plus any expenses and damages
incurred as a result of the breach (including, without limitation, reasonable
attorneys' fees), with the remainder of this Agreement, and all promises and
covenants herein, remaining in full force and effect.

                  (i) Notwithstanding the foregoing, the Company will not
         terminate pursuant to Paragraph 8.a. above any benefits to which
         Employee is entitled under any tax-qualified retirement plan of the
         Company, and Employee's rights under Part 6 of Subtitle B of Title I of
         the Employee Retirement Income Security Act of 1974 as amended, if any,
         will not be reduced by any action taken by the Company under Paragraph
         8.a. above.

                  (ii) Employee may challenge any Company action under Paragraph
         8.a. above.

                  b. Employee acknowledges and agrees that the remedy at law
available to the Company for breach by Employee of any of his obligations under
Paragraphs 3, 4, 6 and 7 of this Agreement would be inadequate and that damages
flowing from such a breach would not readily be susceptible to being measured in
monetary terms. Accordingly, Employee acknowledges, consents and agrees that, in
addition to any other rights or remedies which the Company may have at law, in
equity or under this Agreement, upon adequate proof of Employee's violation of
any provision of Paragraphs 3, 4 or 6 of this Agreement, the Company shall be
entitled to immediate injunctive relief and may obtain a temporary order
restraining any threatened or further breach, without the necessity of proof of
actual damage.

         9. CONTINUED AVAILABILITY AND COOPERATION.

                  a. Employee shall cooperate fully in all reasonable respects
with the Company, with the Company's counsel, and with the Company's insurer in
connection with any present and future actual or threatened litigation or
administrative proceeding involving the Company that relates to events,
occurrences or conduct occurring (or claimed to have occurred) during the period
of Employee's employment by the Company. This cooperation by Employee shall
include, but not be limited to:

                  (i) making himself reasonably available for interviews and
         discussions with the Company's counsel as well as for depositions and
         trial testimony;

                  (ii) if depositions or trial testimony are to occur, making
         himself reasonably available and cooperating in the preparation
         therefor as and to the extent that the Company or the Company's counsel
         reasonably requests;




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                  (iii) refraining from impeding in any way the Company's
         prosecution or defense of such litigation or administrative proceeding;
         and

                  (iv) cooperating fully in the development and presentation of
         the Company's prosecution or defense of such litigation or
         administrative proceeding.

                  b. Employee shall be reimbursed by the Company for reasonable
travel, lodging, telephone and similar expenses incurred in connection with such
cooperation, which the Company shall reasonably endeavor to schedule at times
not conflicting with the reasonable requirements of any employer of Employee, or
with the requirements of any third party with whom Employee has a business
relationship permitted hereunder that provides remuneration to Employee.
Employee shall not unreasonably withhold his availability for such cooperation.
Employee shall not be entitled to compensation from the Company for such
cooperation during the Benefit Period, and shall be compensated at a reasonable
hourly rate mutually agreed to by Employee and the Company for such cooperation
following the Benefit Period.

         10. SUCCESSORS AND BINDING AGREEMENT.

                  a. This Agreement shall be binding upon and inure to the
benefit of the Company and any successor of or to the Company, including,
without limitation, any persons acquiring, directly or indirectly, all or
substantially all of the business and/or assets of the Company whether by
purchase, merger, consolidation, reorganization, or otherwise (and such
successor shall thereafter be deemed included in the definition of "the Company"
for purposes of this Agreement), but shall not otherwise be assignable or
delegable by the Company.

                  b. This Agreement shall inure to the benefit of and be
enforceable by Employee's personal or legal representatives, executors,
administrators, successors, heirs, distributees, and/or legatees.

                  c. This Agreement is personal in nature and none of the
parties hereto shall, without the consent of the other parties, assign, transfer
or delegate this Agreement or any rights or obligations hereunder except as
expressly provided in Subparagraphs (a) and (b) of this Paragraph 10.

                  d. This Agreement is intended to be for the exclusive benefit
of the parties hereto, and except as provided in Subparagraphs (a) and (b) of
this Paragraph 10, no third party shall have any rights hereunder.

         11. NON-DISCLOSURE; STATEMENTS TO THIRD PARTIES.

                  a. Except as otherwise provided in Paragraph 7, all provisions
of this Agreement and the circumstances giving rise hereto are and shall remain
confidential and shall not be disclosed to any person not a party hereto (other
than (i) Employee's spouse, if any, (ii) each party's attorney, financial
advisor and/or tax advisor to the extent necessary for such advisor to render
appropriate legal, financial and tax advice, and (iii) persons or entities that
fall within the scope of Paragraphs 3 and 4 of this Agreement, but only to the
extent required thereby), except as necessary to carry out the provisions of
this Agreement, and except as may be required by law. Notwithstanding the
foregoing, this Agreement may be disclosed and described as well



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as filed with or provided to the Securities and Exchange Commission or any other
governmental instrumentality or agency, including the Internal Revenue Service,
if the Company deems such filing or provision to be necessary.

                  b. Because the purpose of this Agreement is to settle amicably
any and all potential disputes or claims among the parties, neither Employee nor
the Company shall, directly or indirectly, make or cause to be made any
statements to any third parties criticizing or disparaging the other or
commenting on the character or business reputation of the other. Employee
further hereby agrees not: (i) to comment to others concerning the status, plans
or prospects of the business of the Company, or (ii) to engage in any act or
omission that would be detrimental, financially or otherwise, to the Company, or
that would subject the Company to public disrespect, scandal, or ridicule. For
purposes of this Subparagraph 11.b., the "Company" shall mean the Company and
its present and former predecessors, subsidiaries, divisions, related or
affiliated companies, officers, directors, stockholders, members, employees,
heirs, successors, assigns, representatives, agents, accountants and counsel.

         12. NOTICES. For all purposes of this Agreement, all communications
provided for herein shall be in writing and shall be deemed to have been duly
given when delivered, addressed to the Company (to the attention of the Chief
Employee Officer) at its principal executive offices and to Employee at his
principal residence, 2785 Belgrave Road, Pepper Pike, Ohio 44124, or to such
other address as any party may have furnished to the other in writing and in
accordance herewith. Notices of change of address shall be effective only upon
receipt.

         13. MISCELLANEOUS. No provision of this Agreement may be modified,
waived or discharged unless such modification, waiver or discharge is agreed to
in writing signed by Employee and the Company. No waiver by either party hereto
at any time of any breach by the other party hereto or compliance with any
condition or provision of this Agreement to be performed by such other party
shall be deemed a waiver of similar or dissimilar provisions or conditions at
the same or at any prior or subsequent time. No agreements or representations,
oral or otherwise, expressed or implied with respect to the subject matter
hereof have been made by any of the parties that are not set forth expressly in
this Agreement and every one of them (if, in fact, there have been any) is
hereby terminated without liability or any other legal effect whatsoever.

         14. ENTIRE AGREEMENT. This Agreement shall constitute the entire
agreement among the parties hereto with respect to the subject matter hereof and
shall supersede all prior verbal or written agreements, covenants,
communications, understandings, commitments, representations or warranties,
whether oral or written, by any party hereto or any of its representatives
pertaining to such subject matter.

         15. GOVERNING LAW. Any dispute, controversy, or claim of whatever
nature arising out of or relating to this Agreement or breach thereof shall be
governed by and under the laws of the State of Ohio. The parties agree that any
and all disputes, controversies, or claims of whatever nature arising out of or
relating to this agreement or breach thereof shall be resolved by a court of
general jurisdiction in Cleveland, Ohio, and the parties hereby consent to the
exclusive jurisdiction of such court in any action or proceeding arising under
or brought to challenge, enforce, or interpret any of the terms of this
Agreement.




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         16. VALIDITY. The invalidity or unenforceability of any provision of
this Agreement shall not affect the validity or enforceability of any other
provision of this Agreement, which shall nevertheless remain in full force and
effect.

         17. COUNTERPARTS. This Agreement may be executed in one or more
counterparts, each of which shall be deemed to be an original, but all of which
together shall constitute one and the same Agreement.

         18. CAPTIONS AND PARAGRAPH HEADINGS. Captions and Paragraph headings
used herein are for convenience and are not part of this Agreement and shall not
be used in construing it.

         19. FURTHER ASSURANCES. Each party hereto shall execute such additional
documents, and do such additional things, as may reasonably be requested by the
other party to effectuate the purposes and provisions of this Agreement.



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                  IN WITNESS WHEREOF, the parties have executed and delivered
this Agreement as of the date first set forth above.

                                          GLIATECH INC.

                                          By: /s/ Rodney E. Dausch
                                              -------------------------------
                                          Name  Rodney E. Dausch
                                          Title  Chief Operating Officer


                                          Date: /s/ September 25, 2000
                                                -----------------------------




Witness: /s/ Adam D. Gridley              /s/ Raymond Silkaitis
         ---------------------------      -------------------------------
                                          Raymond Silkaitis



Date: September 25, 2000                  Date: September 25, 2000
      ------------------------------            -----------------------------





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