<PAGE>

                                                                    EXHIBIT 10.4




                        EXECUTIVE EMPLOYMENT AGREEMENT


This EXECUTIVE EMPLOYMENT AGREEMENT (the "Agreement"), is entered into as of
April 1, 1999, by and between POZEN Inc. (the "Company") located at 3660
Quadrangle Drive, Suite 240, Chapel Hill, NC, and John R. Plachetka (the
"Employee") whose address is 321 Silver Creek Trail, Chapel Hill, NC, 27514.

WITNESSETH:

WHEREAS, the Company is engaged in certain pharmaceutical research, development,
and marketing activities; and

WHEREAS, the Company has employed and wishes to continue to employ the Employee
in the position of President, Chief Executive Officer, and Chief Scientist, and
the Employee desires to continue in the employment with the Company.

NOW THEREFORE, in consideration of the foregoing and the provisions and mutual
promises herein contained and other good and valuable consideration, the parties
hereby agree as follows:

1.   EMPLOYMENT. The Company hereby engages and employs the Employee, and the
     Employee hereby accepts engagement and employment as the President, Chief
     Executive Officer and Chief Scientist of the Company, based in the Research
     Triangle Park region, with principal responsibilities as described in
     Exhibit "A" attached hereto and such other responsibilities as may be
     assigned to him from time to time by the Board of Directors of the Company.

2.   TERM. The Employee's employment shall be for a term of three years from the
     date of execution of this Agreement, and thereafter shall be automatically
     renewed with additional one year terms to follow consecutively, subject to
     the termination and severance provisions herein later provided, unless
     amended or modified by mutual agreement of the parties.

3.   EXCLUSIVE SERVICE. The Employee agrees to devote his full time and
     attention to the performance of his duties and responsibilities on behalf
     of the Company and to comply with all policies and regulations of the
     Company.

4.   COMPENSATION. During the Term of this Agreement, the Employee's
     compensation shall be determined and paid as follows:
     (a)  Base Salary. The Employee shall receive an annual base salary of at
          least $240,000, payable in accordance with the Company's payroll
          practices. Annual increases will be made, if any, based upon
          performance, such increases to be effective as of January 1 of each
          year during the Term.
     (b)  Incentive Pay. The Employee shall be eligible for an annual cash
          incentive payment of up to 25% of his annual base salary, or such
          greater

                                                                               1
<PAGE>

          amount as set by the Compensation Committee of the Board of Directors
          by March 31 each year. The determination of the actual bonus earned,
          if any, shall be at the sole discretion of the Compensation Committee
          of the Board of Directors and based upon their assessment of the
          Employee's performance and the achievement of certain objectives which
          shall be set and mutually agreed from time to time. The Employee's
          performance shall be evaluated by the Compensation Committee on an
          annual basis, and the Compensation Committee shall adjust the
          Employee's salary at its sole discretion. Nothing in this section
          shall be construed to guarantee the Employee's incentive payment.

     (c)  Employee shall be eligible for future stock options as shall be
          awarded in the discretion of the Compensation Committee of the Board
          of Directors.

     (d)  Benefits. The Employee shall be eligible to participate in the
          Company's standard employee benefit program made available to
          employees of the Company from time to time, subject to appropriate
          premium contributions, benefit elections, etc. In addition, the
          Employee shall receive four (4) weeks of paid vacation per year.

     (e)  Disability. The Company will pay the Employee as additional salary for
          the premium costs of an individual long term disability insurance
          plan. The plan shall provide for a benefit indemnity payment schedule
          equal to no more than 70% (typically 60%) of the Employee's annual
          base salary rate. The Company shall pay the Employee as additional
          salary for such long term disability plan and the additional income
          taxes owed on the salary payments.

     (f)  Business Expenses. The Company shall reimburse the Employee for all
          reasonable expenses incurred in the furtherance of the Company's
          business and interests, including travel and entertainment. The
          Employee agrees to comply with the expense reporting policies and
          procedures of the Company.

     (g)  Adequate Office Space. The Company shall provide to the Employee
          adequate office space, facilities, and administrative support
          appropriate to the Employee's position.

     (h)  Estate Planning Costs. The Company will reimburse Executive for
          ---------------------
          estate planning legal fees and expenses incurred by him in calendar
          year 1999 up to a maximum of $15,000.

5.   TERMINATION.  This Agreement shall or may be terminated, as the case may
     be, upon the terms and conditions hereinafter provided.

                                                                               2
<PAGE>

     (a)  Severance Period. In the event of termination of employment for
          reasons other than for cause or voluntary termination (as defined
          below) or in the event that the office from which the Employee
          performs his principal duties is moved more that 50 miles from the
          outer boundaries of Wake, Orange and Durham County, North Carolina, or
          in the event that the Employee's duties and responsibilities as Chief
          Executive Officer are substantially reduced, the Employee shall
          receive severance pay in an amount equal to one years' base salary
          plus the annual average bonus awarded over the previous two years. The
          Employee shall also receive all company benefits on which the Employee
          was a participant as of the date of termination, at the same average
          level, and in the same terms and conditions which applied immediately
          prior to the date of the Employee's termination of employment for one
          year following the date of termination or until the Employee obtains
          comparable coverage from another employer. At any time during the
          severance period, the Company may elect to pay a lump sum amount to
          the Employee which represents the reasonable value of such benefits
          reduced to their present value in lieu of continuing payment of
          benefits.
     (b)  Voluntary Termination. This Agreement shall be considered voluntarily
          terminated by the parties if either party provides written notice of
          his/its intent to not renew this Agreement, provided that such party
          provides at least ninety (90) days written notice to the other party
          prior to the last day of the initial term or any renewal term.
     (c)  Involuntary Termination. The Company may terminate this Agreement upon
          written notice to the Employee (or his representative) in any of the
          following events:
          (I)   In the event of death of the Employee,
          (II)  In the event that the Employee becomes permanently disabled; or
          (III) "For cause" which shall include breach of the terms of this
                Agreement; breach of the Nondisclosure, Invention, Non-
                Competition Agreement (described in Section 6 below); material
                failure by the Employee to comply with the policies or
                directives of the Board of Directors; any illegal or dishonest
                action that is materially detrimental to the Company; or failure
                to faithfully carry out the duties of his position, provided
                that the Company shall provide at least thirty (30) days written
                notice of such failure to perform during which time the employee
                may remedy the situation.

     For purposes of this Agreement, the Employee shall be considered
     permanently disabled when a qualified medical doctor mutually acceptable to
     the Company and the Employee or his personal representative shall have
     certified in writing that:  (i) he is unable because of medically
     determinable physical or mental disability to perform substantially all of
     his duties for more than one hundred eighty (180) calendar days measured
     from the last full day of work; or (ii) by reason of mental or physical
     disability, it is unlikely that he will be able, within

                                                                               3
<PAGE>

     one hundred eighty (180) calendar days, to resume substantially all
     business duties and responsibilities in which he was previously engaged and
     otherwise discharge his duties under this Agreement.

     In the event that the Employee is terminated pursuant to this Section 5 or
     upon termination of the Agreement, the Employee agrees to tender his
     resignation as a member of the Board of Directors of the Company as of the
     date of such termination.

6.   NON-DISCLOSURE, INVENTION, AND NON COMPETITION. The Employee shall execute
     the standard non-disclosure, invention, and non competition agreement,
     which is hereby made a part of this Agreement as Exhibit B attached hereto.

7.   NOTICES. Any notice required to be given shall be in writing personally
     delivered by certified mail or registered mail or by facsimile (receipt
     confirmed) to the address last shown in the Company's records.

8.   SEVERABILITY. The provisions of this Agreement shall be deemed severable,
     and the invalidity or unenforceability of any provision (or part thereof)
     of this Agreement shall in no way affect the validity or enforceability of
     any other provision (or remaining part thereof).

9.   GOVERNING LAW. This Agreement shall be governed by and construed according
     to the laws of the State of North Carolina, without reference to the choice
     of law provisions of such laws.

10.  ENTIRE AGREEMENT. This Agreement contains the entire agreement of the
     parties relating to the subject matter hereof, and the parties hereto have
     made no agreements, representations, or warranties relating to the subject
     matter of this Agreement which are not set forth herein. No modification of
     this Agreement shall be valid unless made in writing and signed by the
     parties hereto.

11.  BENEFIT. This Agreement shall be binding upon and shall inure to the
     benefit of each of the parties hereto, and to their respective
     representatives. This Agreement shall be binding upon the Company and upon
     any successor Company. The Employee may not assign any of his rights or
     obligations under this Agreement without the written consent of the Board
     of Directors.

12.  The Employee understands and agrees that the Company will suffer
     irreparable harm in the event that the Employee breaches any of his
     obligations under this Agreement and that monetary damages will be
     inadequate to compensate the Company for such breach. Accordingly, the
     Employee agrees that, in the event of a breach or threatened breach by the
     Employee of any of the provisions of this Agreement, the Company, in
     addition to and not in limitation of any other rights, remedies, or damages
     available to the Company at law or in equity, shall be

                                                                               4
<PAGE>

     entitled to a permanent injunction in order to prevent or to restrain any
     such breach by the Employee, or by the Employee's partners, agents,
     representatives, servants, employers, employees and/or any and all persons
     directly or indirectly acting for or with him; provided such injunction
     shall not affect the Employee's ownership rights in the Company or
     compensation earned or due the Employee.



IN WITNESS WHEREOF, the parties hereto have executed this Executive Employment
Agreement and affixed their seals as of the day and year first above written.

SIGNATURES:

/s/ John R. Plachetka
-----------------------------------
John R. Plachetka, Pharm.D.
President & CEO

/s/ Joseph J. Ruvane, Jr.
-----------------------------------
Joseph J. Ruvane, Jr.
Chairman

________________________________________________________________________________

                                                                               5


<PAGE>

                                   Exhibit A
                     President and Chief Executive Officer
                     -------------------------------------
                               Responsibilities



Report to:   Board of Directors


Supervise:   Executive Staff


1.   Provides leadership to the Company and its employees with final
     responsibility for the achievement of the Company's annual and long-term
     strategic goals.

2.   Set Company strategy, including long and short-term objectives, in
     accordance with guidance from the Board of Directors.

3.   Select and develop a first-rate executive staff. Set corporate standards
     and expectations for executive staff performance. Delegate appropriate
     levels of authority and responsibility to senior staff. Establish a culture
     of high achievement and team rewards and recognition for all Company
     employees.

4.   Approve Company's drug development strategy and product portfolio. Approve
     internal Company operating policies and procedures to insure compliance
     with all appropriate laws and regulations, in accordance with sound
     business practices.

5.   Responsible for approving and achieving annual budget targets for expense,
     revenue, and capital investment.

6.   Represent the Company to key outside contacts, including investment
     community, regulatory agencies, potential strategic partners and customers.

                                                                               6
<PAGE>

                                   Exhibit B

NON-DISCLOSURE, INVENTION AND NON-COMPETITION AGREEMENT

     THIS NON-DISCLOSURE, INVENTION AND NON-COMPETITION AGREEMENT (the
"Agreement") is effective for all purposes and in all respects, by and between
POZEN Inc., a Delaware corporation (hereinafter referred to as "Employer"), and
John R. Plachetka, Pharm.D. (hereinafter referred to as "Employee").

     WHEREAS, Employer is about to employ Employee in a position of trust and
confidence to aid Employer in its business; and

     WHEREAS, Employer desires to receive from Employee a covenant not to
disclose certain information relating to Employer's business and certain other
covenants; and

     WHEREAS, as a material inducement to Employer to employ Employee and to pay
to Employee compensation for such services, Employee has agreed to such
covenants; and

     WHEREAS, Employer and Employee desire to set forth in writing the terms and
conditions of their agreements and understandings.

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

     1.   Disclosure of Information.  Employee acknowledges that, in and as a
          -------------------------
result of his employment by Employer, he will be making use of, acquiring and/or
adding to confidential information of a special and unique nature and value,
including, without limitation, Employer's trade secrets, products, systems,
programs, procedures, manuals, guides (as periodically updated or supplemented),
confidential reports and communications (including, without limitation, customer
site information, technical information on the performance and reliability of
Employer's products and the development or acquisition of future products or
product enhancements by Employer) and lists of customers, as well as the nature
and type of the services rendered by Employer and the fees paid by Employer's
customers. Employee further acknowledges that any information and materials
received by Employer from third parties in confidence (or subject to non-
disclosure covenants) shall be deemed to be and shall be confidential
information within the meaning of this Section 1. As a material inducement to
Employer to employ Employee and to pay to Employee compensation for such
services to be rendered to Employer by Employee (it being understood and agreed
by the parties hereto that such compensation shall also be paid and received in
consideration hereof), Employee covenants and agrees that he shall not, except
with the prior written consent of the Board of Directors of Employer, at any
time during or following the term of his

                                                                               7
<PAGE>

employment with Employer, directly or indirectly, divulge, reveal, report,
publish, transfer or disclose, for any purpose whatsoever, any of such
confidential information which has been obtained by or disclosed to him as a
result of his employment with Employer, including, without limitation, any
Proprietary Information, as defined in Section 2 hereof. The aforementioned
obligation of confidentiality and non-disclosure shall not apply when:

          (a) Public Domain. The information disclosed to Employee was in the
              -------------
public domain at the time of disclosure, or at any time after disclosure has
become a part of the public domain by publication or otherwise through sources
other than Employee, directly or indirectly, and without fault on the part of
Employee in failing to keep such information confidential; or

          (b) Requirement of Law or Order. Disclosure is required by law or
              ---------------------------
court order, provided Employee gives Employer prior written notice of any such
disclosure; or

          (c) Agreement. Disclosure is made with the prior written agreement of
              ---------
the Board of Directors of Employer; or

          (d) Prior Information. The information is encompassed by the ideas and
              -----------------
inventions listed on Schedule A hereto or was in Employee's possession at the
                     ----------
time of disclosure, as shown by written records in existence prior to such time,
and such information has not been transferred to Employer, and was not acquired,
directly or indirectly, from the Employer; or

          (e) Third Party Disclosure.  The information is lawfully disclosed to
              ----------------------
Employee after the termination of his employment by a third party who is under
no obligation of confidentiality to Employer with respect to such information;
or

          (f) Independently Developed. Such information is independently
              -----------------------
developed by Employee subsequent to the termination of his active participation
in the business of Employer, as demonstrated by written records of Employee
which are contemporaneously maintained.

     2.   Definition of Proprietary Information.  For purposes of this
          -------------------------------------
Agreement, the term "Proprietary Information" shall mean all of the following
materials and information (whether or not reduced to writing and whether or not
patentable or protectable by copyright) which Employee receives, receives access
to, conceives of or develops, in whole or in part, as a direct or indirect
result of his employment with Employer, in the course of his employment with
Employer (in any capacity, whether executive, managerial, planning, technical,
sales, research, development, manufacturing, engineering or otherwise) or
through the use of any of Employer's facilities or resources:

               (i)   Manufactured products, assembled or unassembled, and any
related goods or systems and any and all future products, software or systems
developed or derived therefrom;

                                                                               8
<PAGE>

               (ii)  With respect to the items described in Section 2(i) above,
all hardware and software relating to design or manufacture; all source and
object codes to such hardware and software; all specifications, design concepts,
documents and manuals; all security systems relating to the product or
procedures, including, without limitation, software security systems;

               (iii) Trade secrets, production processes, marketing techniques,
mailing lists, purchasing information, price lists, pricing policies, quoting
procedures, financial information, customer and prospect names and requirements,
customer data, customer site information and other materials or information
relating to the manner in which Employer does business;

               (iv)  Discoveries, concepts and ideas, whether or not patentable
or protectable by copyright, including, without limitation, the nature and
results of research and development activities, technical information on product
or program performance and reliability, processes, formulas, techniques, "know-
how", source codes, object codes, designs, drawings and specifications;

               (v)   Any other material or information related to the business
or activities of Employer which is not generally known to others engaged in
similar businesses or activities;

               (vi)  Any other material or information that has been created,
discovered or developed, or otherwise becomes known to Employer which has
commercial value in the business in which Employer is engaged; and

               (vii) All ideas which are derived from or relate to Employee's
access to or knowledge of any of the above-enumerated materials and information.

     Failure to mark any of the Proprietary Information as confidential shall
not affect its status as part of the Proprietary Information under the terms of
this Agreement.

     3.   Ownership of Information.
          ------------------------

          (i)   Employee hereby assigns to Employer all of Employee's right,
title and interest in any idea (whether or not patentable or protectable by
copyright), product, invention, discovery, computer software program or other
computer-related equipment or technology, conceived or developed in whole or in
part, or in which Employee may have aided in its development, while employed by
Employer, including, without limitation, any Proprietary Information. If any one
or more of the aforementioned are deemed in any way to fall within the
definition of "work made for hire", as such term is defined in 17 U.S.C. (S)
101, such work shall be considered "work made for hire", the copyright of which
shall be owned solely, completely and exclusively by Employer. If any of the
aforementioned are considered to be work not included in the categories of work
covered by the "work made for hire" definition contained in 17 U.S.C. (S) 101,
such work shall be

                                                                               9
<PAGE>

owned solely by, or assigned or transferred completely and exclusively to,
Employer. Employee agrees to execute any instruments and to do all other things
reasonably requested by Employer (both during and after Employee's employment
with Employer) in order to more fully vest in Employer all ownership rights in
those items thereby transferred by Employee to Employer. Employee further agrees
to disclose immediately to Employer all Proprietary Information conceived of or
developed in whole or in part by him during the term of his employment with
Employer and to assign to Employer any right, title or interest he may have in
such Proprietary Information.

          (ii)  Employee hereby represents and warrants that Employee has fully
disclosed to Employer on Schedule A hereto any idea, invention, product,
                         ----------
improvement, computer software program or other equipment or technology related
to therapeutic pharmaceuticals (an "Invention") not covered in Section 3(i)
above which, prior to his employment with Employer, Employee conceived of or
developed, wholly or in part, and in which Employee has any right, title or
proprietary interest and which directly relate to Employer's business, but which
has not been published or filed with the United States Patent or Copyright
Offices or assigned or transferred to Employer. If there is no such list of
Schedule A, Employee represents that Employee has made no such Inventions at the
----------
time of signing this Agreement or Employee hereby assigns such Inventions to
Employer.

          (iii) Notwithstanding anything in this Agreement to the contrary, the
obligation of Employee to assign or offer to assign his rights in an Invention
to Employer shall not extend or apply to an Invention that Employee developed
entirely on his own time without using Employer's equipment, supplies, facility
or trade secret information unless such Invention (a) relates to Employer's
business or actual or demonstrably anticipated research or development, or (b)
results from any work performed by Employee for Employer. Employee shall bear
the burden of proof in establishing that his Invention qualifies for exclusion
under this Section 3(iii). With respect to Section 3(iii), it is agreed and
acknowledged that during Employee's employment, Employer may enter other lines
of business, which are related or unrelated to its current lines of business, in
which case this Agreement would be expanded to cover such new lines of business.

     4.   Injunctive Relief.  Employee understands and agrees that Employer will
          -----------------
suffer irreparable harm in the event that Employee breaches any of his
obligations under this Agreement and that monetary damages will be inadequate to
compensate Employer for such breach. Accordingly, Employee agrees that, in the
event of a breach or threatened breach by Employee of any of the provisions of
this Agreement, Employer, in addition to and not in limitation of any other
rights, remedies or damages available to Employer at law or in equity, shall be
entitled to a permanent injunction in order to prevent or to restrain any such
breach by Employee, or any of employee's partners, agents, representatives,
servants, employers, employees and/or any and all persons directly or indirectly
acting for or with him.

     5.   Records.  All notes, data, tapes, reference materials, sketches,
          -------
drawings, memoranda, models and records in any way relating to any of the
information referred to

                                                                              10
<PAGE>

in Sections 1, 2 and 3 hereof (including, without limitation, any Proprietary
Information) or to Employer's business shall belong exclusively to Employer, and
Employee agrees to turn over to Employer all such materials and all copies of
such materials in his possession or then under his control at the request of
Employer or, in the absence of such a request, upon the termination of
Employee's employment with Employer.

     6.   Accounting for Profits.  Employee covenants and agrees that, if he
          ----------------------
shall violate any of his covenants or agreements under this Agreement, Employer
shall be entitled to an accounting and repayment of all profits, compensation,
commissions, remunerations or benefits which Employee directly or indirectly has
realized and/or may realize as a result of, growing out of or in connection with
any such violation; such remedy shall be in addition to and not in limitation of
any injunctive relief or other rights or remedies to which Employer is or may be
entitled at law, in equity or under this Agreement.

     7.   Covenant Not to Compete.  It is recognized and understood by the
          -----------------------
parties hereto that Employee, through Employee's association with Employer as an
employee, shall acquire a considerable amount of knowledge and goodwill with
respect to the business of Employer, which knowledge and goodwill are extremely
valuable to Employer and which would be extremely detrimental to Employer if
used by Employee to compete with Employer. It is, therefore, understood and
agreed by the parties hereto that, because of the nature of the business of
Employer, it is necessary to afford fair protection to Employer from such
competition by Employee. Consequently, as a material inducement to employ
Employee in the aforementioned positions, Employee covenants and agrees to the
following:

          (a) Except as otherwise approved in writing by Employer, Employee
agrees:

              (i)   that Employee will not, directly or indirectly, with or
through any family member or former director, officer or employee of Employer,
or acting along or as a member of a partnership or as an officer, holder of or
investor in as much as 5% of any security of any class, director, employee,
consultant or representative of any corporation or other business entity:

              (ii)  at any time while engaged as an employee of Employer and for
a period of one (1) year following termination as an employee, interfere with,
or seek to interfere with, the relationship between Employer or any affiliate of
Employer and the following: (a) any of the employees of such entities; (b) any
of the customers of such entities then existing or existing at any time within
three (3) years prior to termination of Employee's employment by Employer; or
(c) any of the suppliers of such entities then existing or existing at any time
within three (3) years prior to termination of Employee's employment by
Employer.

          (b) The parties hereto agree that in the event that either the length
of time or the geographic area set forth in paragraph (a) is deemed too
restrictive in any

                                                                              11
<PAGE>

court proceeding, that the court may reduce such restrictions to those which it
deems reasonable under the circumstances.

          (c) Employee agrees and acknowledges that Employer does not have any
adequate remedy at law for the breach or threatened breach by him of this
covenant and agrees that Employer may in addition to the other remedies which
may be available to it under this Agreement, file a suit in equity to enjoin
Employee from such breach or threatened breach.


     8.   Reasonableness of Restrictions.
          ------------------------------

          (a) Employee has carefully read and considered the provisions of
Sections 1 through 7 hereof and, having done so, agrees that the restrictions
set forth therein are fair and reasonable and are reasonably required for the
protection of the interests of Employer, its officers, directors, stockholders
and employees.

          (b) In the event that, notwithstanding the foregoing, any part of the
covenants set forth in Sections 1 through 7 hereof shall be held to be invalid
and unenforceable, the court so deciding may reduce or limit the terms of such
provision to allow such provision to be enforced.

     9.   Burden and Benefit.  This Agreement shall be binding upon, and shall
          ------------------
inure to the benefit of, Employer and Employee, and their respective heirs,
personal and legal representatives, and, in the case of Employer, its successors
and assigns.

     10.  Governing Law.  In view of the fact that the principal office of
          -------------
Employer is located in the State of North Carolina, it is understood and agreed
that the construction and interpretation of this Agreement shall at all times
and in all respects be governed by the laws of the State of North Carolina.

     11.  Severability.  The provisions of this Agreement shall be deemed
          ------------
severable, and the invalidity or unenforceability of any one or more of the
provisions hereof shall not affect the validity or enforceability of the other
provisions hereof.

     12.  Employer.  As used herein, the term "Employer" shall also include any
          --------
corporation which is at any time the parent or a subsidiary of Employer, or any
corporation or entity which is an affiliate of Employer by virtue of common
(although not identical) ownership, and for which Employee is providing services
in any form during his employment with Employer or any such other corporation or
entity.

     13.  Notices.  Any notice required to be given hereunder shall be
          -------
sufficient if in writing, and sent by certified or registered mail, return
receipt requested, first-class postage prepaid, in the case of Employee, to his
address as shown on Employer's records, and in the case of Employer, to its
principal office in the State of North Carolina.

                                                                              12
<PAGE>

     14.  Entire Agreement.  This Agreement contains the entire agreement and
          ----------------
understandings by and between Employer and Employee with respect to the
covenants herein described, and no representations, promises, agreements or
understandings, written or oral, not herein contained shall be of any force or
effect. Nothing contained in this Agreement shall be deemed or construed to
constitute an agreement by Employer to employ or continue to employ Employee. No
change or modification hereof shall be valid or binding unless the same is in
writing and signed by the parties hereto. No waiver of any provision of this
Agreement shall be valid unless the same is in writing and signed by the party
against whom such waiver is sought to be enforced; moreover, no valid waiver of
any provision of this Agreement at any time shall be deemed a waiver of any
other provision of this Agreement at such time nor will it be deemed a valid
waiver of such provision at any other time.

     15.  Headings.  The headings and other captions in this Agreement are for
          --------
convenience and reference only and shall not be used in interpreting, construing
or enforcing any of the provisions of this Agreement.

     16.  Effective Date.  This Agreement shall be effective as of the April 1,
          --------------
1999.




     IN WITNESS WHEREOF, Employer and Employee have duly executed this Agreement
as of the day and year first above written.


     EMPLOYER:

     POZEN INC.

     /s/ John E. Barnhardt
     -------------------------------------------
     John E. Barnhardt
     Vice President, Finance & Administration



     EMPLOYEE:

     /s/ John R. Plachetka
     -------------------------------------------
     John R. Plachetka, Pharm.D.
     President & CEO

                                                                              13
<PAGE>

                                  SCHEDULE A
     Inventions, Ideas, Products, Etc. Not Covered in Section 3(i) of the
Agreement


[Note:  If Employee has no such items to disclose, write "NONE" on this line:
___________.]

________________________________________________________________________________


                                                                              14