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                                                                     EXHIBIT 4.2

                              AMENDED AND RESTATED

                                     BYLAWS

                                       OF

                           PENWEST PHARMACEUTICALS CO.

ARTICLE I.   OFFICES

        The principal office of the corporation shall be located at the
principal place of business or such other place as the board of directors may
designate. The corporation may have such other offices within or without the
state of Washington as the board of directors may designate or the business of
the corporation may require from time to time.

ARTICLE II.   SHAREHOLDERS

        SECTION 2.1.   ANNUAL MEETING. The annual meeting of the shareholders
shall be held on such date and at such time as may be determined by the board of
directors, for the purpose of electing directors and for the transaction of such
other business as may come before the meeting.

        SECTION 2.2.   SPECIAL MEETINGS. Unless otherwise set forth in the
Articles of Incorporation, special meetings of the shareholders, for any purpose
or purposes unless otherwise prescribed by the Washington Business Corporation
Act, may not be called by shareholders and may only be called by the board of
directors, the chairman of the board of directors or the president of the
corporation.

        SECTION 2.3.   PLACE OF MEETING. Meetings of the shareholders shall be
held at such place within or without the state of Washington as the board of
directors, the chairman of the board of directors or the president may
designate.

        SECTION 2.4.   FIXING OF RECORD DATE. For the purpose of determining
shareholders entitled to notice of or to vote at any meeting of shareholders or
any adjournment thereof, or shareholders entitled to receive payment of any
dividend, or in order to make a determination of shareholders for any other
proper purpose, the board of directors may fix a future date as the record date
for any such determination. Such record date shall not be more than 70 days
prior to the date on which the particular action requiring such determination of
shareholders is to be taken. If no record date is fixed for the determination of
shareholders entitled to notice of or to vote at a meeting of shareholders or
shareholders entitled to receive payment of a dividend, the day before the first
notice of a meeting is dispatched to shareholders or the date on which the
resolution of the board of directors authorizing such dividend is adopted, as
the case may be, shall be the record date for such determination. When a
determination of shareholders entitled to notice of or to vote at any meeting of
shareholders has been made as provided in this section, such determination shall
apply to any adjournment thereof unless the board of directors fixes a new
record date, which it must do if the meeting is adjourned to a date more than
120 days after the date fixed for the original meeting.

        SECTION 2.5.   VOTING LISTS. At least 10 days before each meeting of the
shareholders, the officer or agent having charge of the stock transfer books for
shares of the corporation shall prepare an alphabetical list of all its
shareholders on the record date who are entitled to vote at the meeting or any
adjournment thereof, arranged by voting group, and within each voting group by
class or series of shares, with the address of and the number of shares held by
each, which record for ten days prior to the meeting shall be kept on file at
the principal office of the corporation or at a place identified in the meeting
notice in the city where the meeting will be held. Such record shall be produced
and kept open at the time and place of the meeting and shall be subject to the
inspection of any shareholder, shareholder's agent or shareholder's attorney
during the whole time of the

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meeting. Failure to comply with the requirements of this Section shall not
affect the validity of any action taken at the meeting.

        SECTION 2.6.   NOTICE OF MEETINGS. Written notice stating the date, time
and place of a meeting of shareholders, and in the case of a special meeting of
shareholders, the purpose or purposes for which the meeting is called, shall be
given by or at the direction of the board of directors, the chairman of the
board of directors or the president to each shareholder of record entitled to
vote at such meeting (unless required by law to send notice to all shareholders
regardless of whether or not such shareholders are entitled to vote), not less
than 10 days and not more than 60 days before the meeting, except that notice of
a meeting to act on an amendment to the Articles of Incorporation, a plan of
merger or share exchange, a proposed sale, lease, exchange or other disposition
of all or substantially all of the assets of the corporation other than in the
usual course of business, or the dissolution of the corporation shall be given
not less than 20 days and not more than 60 days before the meeting. Such notice
may be transmitted by mail, private carrier or personal delivery; telegraph or
teletype; or telephone, wire or wireless equipment which transmits a facsimile
of the notice. Such notice shall be effective upon dispatch if sent to the
shareholder's address, telephone number, or other number appearing on the
records of the corporation.

        If a shareholders' meeting is adjourned to a different date, time or
place, notice need not be given of the new date, time or place if the new date,
time or place is announced at the meeting before adjournment unless a new record
date is or must be fixed. If a new record date for the adjourned meeting is or
must be fixed, however, notice of the adjourned meeting must be given to persons
who are shareholders as of the new record date.

        SECTION 2.7.   WAIVER OF NOTICE. A shareholder may waive any notice
required to be given under the provisions of these Bylaws, the Articles of
Incorporation or applicable law, whether before or after the date and time
stated therein. A valid waiver is created by any of the following methods: (a) a
writing signed by the shareholder entitled to the notice and delivered to the
corporation for inclusion in its corporate records; (b) attendance at the
meeting, unless the shareholder at the beginning of the meeting objects to
holding the meeting or transacting business at the meeting; or (c) failure to
object at the time of presentation of a matter not within the purpose or
purposes described in the meeting notice.

        SECTION 2.8.   PROXIES. A shareholder may vote either in person or by
proxy. A shareholder may vote by proxy by means of a proxy appointment form
which is executed in writing by the shareholder, such shareholder's agent, or
such shareholder's attorney-in-fact. Such proxy shall be effective when received
by the secretary or other officer or agent authorized to tabulate votes. A proxy
appointment is valid for 11 months after the date of its execution, unless
otherwise expressly provided in the appointment form.

        SECTION 2.9.   PARTICIPATION BY COMMUNICATION EQUIPMENT. At the
discretion of the board of directors, shareholders may participate in a meeting
of the shareholders by any means of communication by which all persons
participating in the meeting can hear each other during the meeting, and
participation by such means shall constitute presence in person at the meeting.

        SECTION 2.10.   QUORUM. Unless the Articles of Incorporation or law
provide otherwise, a majority of the votes entitled to be cast on a matter by a
voting group that, pursuant to the Articles of Incorporation, is entitled to
vote on such matter, represented in person or by proxy, shall constitute a
quorum of that voting group for action on that matter. Once a share is
represented at a meeting, other than to object to holding the meeting or
transacting business, it is deemed to be present for purposes of a quorum for
the remainder of the meeting and for any adjournment of that meeting unless a
new record date is or must be fixed for the adjourned meeting. At such
reconvened meeting, any business may be transacted which might have been
transacted at the adjourned meeting.

        SECTION 2.11.   MANNER OF ACTING. If a quorum exists with respect to a
matter, action on such matter other than the election of directors is approved
by a voting group if the votes cast within the voting group

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favoring the action exceed the votes cast within the voting group opposing the
action, unless the question is one upon which a different vote is required by
the Articles of Incorporation or applicable law.

        SECTION 2.12.   VOTING OF SHARES. Each outstanding share, regardless of
class, shall be entitled to one vote on each matter submitted to a vote at a
meeting of shareholders, except as may be otherwise provided in the Articles of
Incorporation.

        SECTION 2.13.   VOTING FOR DIRECTORS. Each shareholder entitled to vote
at an election of directors may vote, in person or by proxy, the number of
shares owned by such shareholder for as many persons as there are directors to
be elected and for whose election such shareholder has a right to vote. Unless
otherwise provided in the Articles of Incorporation, the candidates elected are
those receiving the largest number of votes cast, up to the number of directors
to be elected.

        SECTION 2.14.   ACTION BY SHAREHOLDERS WITHOUT A MEETING. Any action
which may or is required to be taken at a meeting of the shareholders may be
taken without a meeting if one or more written consents setting forth the action
taken shall be signed, either before or after the action taken, by all the
shareholders entitled to vote with respect to the subject matter thereof. Action
taken by written consent of the shareholders is effective when all consents are
in possession of the corporation, unless the consent specifies a later effective
date.

        SECTION 2.15.   SHAREHOLDER NOMINATIONS. Nominations for the election of
directors may be made by the board of directors or by any shareholder entitled
to vote in the election of the directors generally. In the case of nominations
by a shareholder, written notice of the intent to make a nomination at a meeting
of shareholders must be received by the secretary of the corporation not later
than 120 days in advance of the date of such meeting in the case of an annual
meeting and not more than seven days following the date of notice of the meeting
in the case of a special meeting. The notice must include, among other things:
(i) the name, address and stock ownership of the nominating shareholder and a
representation that such shareholder is entitled to vote at such meeting and
that such shareholder intends to appear in person or by proxy at the meeting to
nominate the person or persons specified in the notice, (ii) the name, age and
address of each person to be nominated, (iii) the number of shares of capital
stock of the corporation beneficially owned by each nominee, (iv) a statement
that the nominee is willing to be nominated, and (v) such other information
regarding each nominee as would be required to be included in a proxy statement
filed pursuant to the proxy rules of the Securities and Exchange Commission if
the corporation were soliciting proxies for the election of such nominees. If
the facts warrant, the board of directors, or the chairman of the shareholders'
meeting at which directors are to be elected, shall determine and declare that a
nomination was not made in accordance with the foregoing procedure, and, if it
is so determined, the defective nomination shall be disregarded. The right of
shareholders to make nominations pursuant to the foregoing procedure is subject
to the superior rights, if any, of the holders of any class or series of stock
having a preference over the common stock. The procedures set forth in this
Section for nomination for the election of directors by shareholders are in
addition to, and not in limitation of, any procedures now in effect or hereafter
adopted by or at the direction of the board of directors or any committee
thereof.

        SECTION 2.16.   BUSINESS FOR SHAREHOLDERS MEETINGS

                2.16.1. BUSINESS AT ANNUAL MEETINGS. In addition to the election
of directors, other proper business may be transacted at an annual meeting of
shareholders, provided that such business is properly brought before such
meeting. To be properly brought before an annual meeting, business must be (a)
specified in the notice of meeting (or any supplement thereto), (b) otherwise
brought before the meeting by or at the direction of the board of directors or
the chairman of the meeting or (c) otherwise properly brought before the meeting
by a shareholder pursuant to written notice thereof, in accordance with
Subsection 2.16.3 hereof, and received by the secretary not less than 60 nor
more than 90 days prior to the date specified in Subsection 2.1 hereof for such
annual meeting (or if less than 70 days notice or prior public disclosure of the
date of the annual meeting is given or made to the shareholders, not later than
the 10th day following the day on which the notice of the date of the annual
meeting was mailed or such public disclosure was made). Any such shareholder
notice shall set forth (i)

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the name and address of the shareholder proposing such business; (ii) a
representation that the shareholder is entitled to vote at such meeting and a
statement of the number of shares of the corporation that are beneficially owned
by the shareholder; (iii) a representation that the shareholder intends to
appear in person or by proxy at the meeting to propose such business; and (iv)
as to each matter the shareholder proposes to bring before the meeting, a brief
description of the business desired to be brought before the meeting, the
reasons for conducting such business at the meeting, the language of the
proposal (if appropriate), and any material interest of the shareholder in such
business. No business shall be conducted at any annual meeting of shareholders
except in accordance with this Subsection 2.16.1. If the facts warrant, the
board of directors or the chairman of the annual meeting of shareholders may
determine and declare (a) that a proposal does not constitute proper business to
be transacted at the meeting or (b) that business was not properly brought
before the meeting in accordance with the provisions of this Subsection 2.16.1,
and, if in either case it is so determined, any such business shall not be
transacted. The procedures set forth in this Subsection 2.16.1 are in addition
to, and not in lieu of, the requirements set forth in Rule a-8 under Section 14
of the Securities Exchange Act of 1934, as amended, or any successor provision.

                2.16.2. BUSINESS AT SPECIAL MEETINGS. At any special meeting of
the shareholders, only such business as is specified in the notice of such
special meeting given by or at the direction of the person or persons calling
such meeting, in accordance with Subsection 2.2 hereof, shall come before such
meeting.

                2.16.3. NOTICE TO CORPORATION. Any written notice required to be
delivered by a shareholder to the corporation pursuant to Subsection 2.16.1
hereof must be given either by personal delivery or by registered or certified
mail, postage prepaid, to the secretary at the corporation's principal executive
offices.

ARTICLE III.   BOARD OF DIRECTORS

        SECTION 3.1.   GENERAL POWERS. All corporate powers shall be exercised
by or under the authority of, and the business and affairs of the corporation
shall be managed under the direction of, the board of directors, except as may
be otherwise provided by these Bylaws, the Articles of Incorporation or law.

        SECTION 3.2.   NUMBER, TENURE AND QUALIFICATION. The board of directors
shall be composed of not less than five nor more than ten directors, the
specific number to be set by resolution of the board of directors. The number of
directors may be increased or decreased from time to time by amendment to or in
the manner provided in these Bylaws. No decrease, however, shall have the effect
of shortening the term of any incumbent director unless such director resigns or
is removed in accordance with the provisions of these Bylaws.

        The directors shall be divided into three classes, designated Class I,
Class II and Class III. Initially, Class I directors shall be elected for a term
ending at the first annual meeting of shareholders after their election, Class
II directors shall be elected for a term ending at the second annual meeting of
shareholders after their election, and Class III directors shall be elected for
a term ending at the third annual meeting of shareholders after their election.
At each annual meeting of shareholders thereafter, successors to the class of
directors whose term expires at that annual meeting shall be elected to serve
until the third succeeding annual meeting of shareholders. If the number of
directors is changed in the manner provided by the Bylaws, any increase or
decrease shall be apportioned among the classes so that the number of directors
in each class is as nearly equal as possible. A director shall hold office until
the annual meeting of shareholders at which such director's term expires and
until such director's successor shall be elected and shall qualify, subject,
however, to prior death, resignation, retirement, disqualification or removal
from office. Vacancies on the Board of Directors, including vacancies resulting
from an increase in the number of directors, may be filled only by the
affirmative vote of a majority of all the directors then in office (although
less than a quorum) or by the sole remaining director. The term of a director
elected to fill a vacancy shall expire at the next shareholders' meeting at
which directors are elected.

        Directors need not be residents of the state of Washington or
shareholders of the corporation.

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        SECTION 3.3.   ANNUAL AND OTHER REGULAR MEETINGS. An annual meeting of
the board of directors shall be held immediately after and at the same place as
the annual meeting of shareholders. The board of directors may specify by
resolution the time and place, either within or without the state of Washington,
for holding any other regular meetings of the board of directors without notice
other than such resolution.

        SECTION 3.4.   SPECIAL MEETINGS. Special meetings of the board of
directors may be called by the board of directors, the chairman of the board,
the president or any two or more directors. Notice of special meetings of the
board of directors stating the date, time and place thereof shall be given at
least two days prior to the date set for such meeting by the person or persons
authorized to call such meeting, or by the secretary at the direction of the
person or persons authorized to call such meeting. The notice may be oral or
written. Oral notice may be communicated in person or by telephone, wire or
wireless equipment, which does not transmit a facsimile of the notice. Oral
notice is effective when communicated. Written notice may be transmitted by
mail, private carrier, or personal delivery; telegraph or teletype; or
telephone, wire, or wireless equipment which transmits a facsimile of the
notice. Written notice is effective upon dispatch if such notice is sent to the
director's address, telephone number, or other number appearing on the records
of the corporation. If no place for such meeting is designated in the notice
thereof, the meeting shall be held at the principal office of the corporation.
Any director may waive notice of any meeting at any time. Whenever any notice is
required to be given to any director pursuant to applicable law, a waiver
thereof in writing signed by the director, entitled to notice, shall be deemed
equivalent to the giving of notice. The attendance of a director at a meeting
shall constitute a waiver of notice of the meeting except where a director
attends a meeting for the express purpose of objecting to the transaction of any
business because the meeting is not lawfully convened. Unless otherwise required
by law, neither the business to be transacted at, nor the purpose of, any
regular or special meeting of the board of directors need be specified in the
notice or waiver of notice of such meeting.

        SECTION 3.5.   QUORUM. A majority of the number of directors specified
in or fixed in accordance with these Bylaws shall constitute a quorum for the
transaction of any business at any meeting of directors. If less than a majority
shall attend a meeting, a majority of the directors present may adjourn the
meeting from time to time without further notice, and a quorum present at such
adjourned meeting may transact business.

        SECTION 3.6.   MANNER OF ACTING. If a quorum is present when a vote is
taken, the affirmative vote of a majority of directors present is the act of the
board of directors, except as may be otherwise provided in the Articles of
Incorporation or the Washington Business Corporation Act.

        SECTION 3.7.   PARTICIPATION BY CONFERENCE TELEPHONE. Directors may
participate in a regular or special meeting of the board by, or conduct the
meeting through the use of, any means of communication by which all directors
participating can hear each other during the meeting and participation by such
means shall constitute presence in person at the meeting.

        SECTION 3.8.   PRESUMPTION OF ASSENT. A director who is present at a
meeting of the board of directors at which action is taken shall be deemed to
have assented to the action taken unless (a) the director objects at the
beginning of the meeting, or promptly upon the director's arrival, to holding
the meeting or transacting any business thereat, (b) the director's dissent or
abstention from the action taken is entered in the minutes of the meeting, or
(c) the director delivers written notice of the director's dissent or abstention
to the presiding officer of the meeting before its adjournment or to the
corporation within a reasonable time after adjournment of the meeting. Such
right of dissent or abstention shall not apply to a director who voted in favor
of the action taken.

        SECTION 3.9.   ACTION BY BOARD WITHOUT A MEETING. Any action permitted
or required to be taken at a meeting of the board of directors may be taken
without a meeting if one or more written consents setting forth the action so
taken are signed, either before or after the action taken, by all the directors
and delivered to the corporation. Action taken by written consent is effective
when the last director signs the consent, unless the consent specifies a later
effective date.

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        SECTION 3.10.   BOARD COMMITTEES. The board of directors may by
resolution designate from among its members an executive committee and one or
more other committees, each of which must have two or more members and shall be
governed by the same rules regarding meetings, action without meetings, notice,
waiver of notice, and quorum and voting requirements as applied to the board of
directors. To the extent provided in such resolutions, each such committee shall
have and may exercise the authority of the board of directors, except as limited
by applicable law. The designation of any such committee and the delegation
thereto of authority shall not relieve the board of directors, or any members
thereof, of any responsibility imposed by law.

        SECTION 3.11.   RESIGNATION. Any director may resign at any time by
delivering written notice to the chairman of the board, the president, the
secretary or the board of directors. A resignation is effective when the notice
is delivered unless the notice specifies a later effective date. Unless
otherwise specified in the notice, the acceptance of such resignation shall not
be necessary to make it effective.

        SECTION 3.12.   REMOVAL. Any director or the entire Board may be removed
only for cause by the affirmative vote of the holders of not less than
two-thirds of the shares entitled to vote in the election of such director or
directors. Such action may only be taken at a special meeting of the
shareholders called expressly for that purpose, providing that notice of the
proposed removal, which shall include a statement of the charges alleged against
the director, shall have been duly given to the shareholders together with or as
a part of the notice of meeting.

        Where a question of the removal of a director for cause is to be
presented for shareholder consideration, an opportunity must be provided to such
director to present his or her defense to the shareholders by a statement which
must accompany or precede the notice of the special meeting of the shareholders,
or, if provided to shareholders prior to the notice of the special meeting, the
initial solicitation of proxies seeking authority to vote for the removal of
such director for cause. If not provided, then such proxies may not be voted for
removal. The director involved shall be served with notice of the meeting at
which such action is proposed to be taken together with a statement of the
specific charges and shall be given an opportunity to be present and to be heard
at the meeting at which his or her removal is considered.

        SECTION 3.13.   VACANCIES. A vacancy on the board of directors may occur
by the resignation, removal or death of an existing director, or by reason of
increasing the number of directors on the board of directors as provided in
these Bylaws. Unless the Articles of Incorporation provide otherwise, any
vacancy occurring on the board of directors may be filled by only the
affirmative vote of a majority of all the directors then in office (although
less than a quorum) or by the sole remaining director. Any vacant office held by
a director elected by the holders of one or more classes or series of shares
entitled to vote and be counted collectively thereon shall be filled only by the
vote of the holders of such class or series of shares. A director elected to
fill a vacancy shall serve only until the next election of directors by the
shareholders.

        SECTION 3.14.   COMPENSATION. By resolution of the board of directors,
the directors may be paid a fixed sum plus their expenses, if any, for
attendance at meetings of the board of directors or committee thereof, or a
stated salary as director, or any other form of compensation (including
corporation common stock or options to purchase common stock), or a combination
of the foregoing. No such payment shall preclude any director from serving the
corporation in any other capacity and receiving compensation therefor.

ARTICLE IV.   OFFICERS

        SECTION 4.1.   AUTHORIZED OFFICERS. The corporation shall have a
president and may have one or more vice presidents (who may be designated as
Vice Presidents, Senior Vice Presidents or Executive Vice Presidents), and a
secretary, each of whom shall be appointed by the board of directors. Such other
officers and assistant officers, including a chairman of the board, as may be
deemed necessary or appropriate may be appointed by the board of directors. By
resolution, the board of directors may designate any officer as chief

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executive officer, chief operating officer, chief financial officer, or any
similar designation. Any two or more offices may be held by the same person.

        SECTION 4.2.   APPOINTMENT AND TERM OF OFFICE. The officers of the
corporation shall be appointed by the board of directors for such term as the
board may deem advisable. Each officer shall hold office until a successor shall
have been appointed regardless of such officer's term of office, subject to such
officer's earlier death, resignation or removal.

        SECTION 4.3.   RESIGNATION. Any officer may resign at any time by
delivering written notice to the chairman of the board, the president or the
board of directors. A resignation is effective when the notice is delivered
unless the notice specifies a later effective date. Unless otherwise specified
in the notice, the acceptance of such resignation shall not be necessary to make
it effective.

        SECTION 4.4.   REMOVAL. Any officer appointed by the board of directors
may be removed by the board of directors with or without cause. The removal
shall be without prejudice to the contract rights, if any, of the person so
removed. Appointment of an officer does not itself create contract rights.

        SECTION 4.5.   POWERS AND DUTIES. The officers of the corporation shall
have the authority and shall perform the duties prescribed by the board of
directors.

        SECTION 4.6.   COMPENSATION OF OFFICERS AND EMPLOYEES. The board of
directors shall fix the compensation of officers and may fix the compensation of
other employees from time to time. No officer shall be prevented from receiving
a salary by reason of the fact that such officer is also a director of the
corporation.

ARTICLE V.   CONTRACTS, LOANS, CHECKS AND DEPOSITS

        SECTION 5.1.   CONTRACTS. The board of directors may authorize any
officer or officers, agent or agents, to enter into any contract or execute and
deliver any instrument in the name of and on behalf of the corporation, and that
authority may be general or confined to specific instances.

        SECTION 5.2.   LOANS. No loans shall be contracted on behalf of the
corporation and no evidences of indebtedness shall be issued in its name unless
authorized by a resolution of the board of directors, which authority may be
general.

        SECTION 5.3.   CHECKS, DRAFTS, ETC. All checks, drafts or other orders
for the payment of money, notes or other evidences of indebtedness issued in the
name of the corporation shall be signed by the officer or officers, or agent or
agents, of the corporation and in the manner as shall from time to time be
prescribed by resolution of the board of directors.

        SECTION 5.4.   DEPOSITS. All funds of the corporation not otherwise
employed shall be deposited from time to time to the credit of the corporation
in the banks, trust companies or other depositories as the board of directors
may select.

ARTICLE VI.   SHARES

        SECTION 6.1.   CERTIFICATES FOR SHARES. The shares of the corporation
may be represented by certificates in such form as prescribed by law and the
board of directors. Signatures of the corporate officers on the certificate may
be facsimiles if the certificate is manually signed on behalf of a transfer
agent, or registered by a registrar, other than the corporation itself or an
employee of the corporation. All certificates shall be consecutively numbered or
otherwise identified. All certificates shall bear such legend or legends as
prescribed by the board of directors or these Bylaws.

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        SECTION 6.2.   ISSUANCE OF SHARES. Shares of the corporation shall be
issued only when authorized by the board of directors, which authorization shall
include the consideration to be received for each share.

        SECTION 6.3.   BENEFICIAL OWNERSHIP. Except as otherwise permitted by
these Bylaws, the person in whose name shares stand on the books of the
corporation shall be deemed by the corporation to be the owner thereof for all
purposes. The board of directors may adopt by resolution a procedure whereby a
shareholder of the corporation may certify in writing to the corporation that
all or a portion of the shares registered in the name of such shareholder are
held for the account of a specified person or persons. Upon receipt by the
corporation of a certification complying with such procedure, the persons
specified in the certification shall be deemed, for the purpose or purposes set
forth in the certification, to be the holders of record of the number of shares
specified in place of the shareholder making the certification.

        SECTION 6.4.   TRANSFER OF SHARES. Transfer of shares of the corporation
shall be made only on the stock transfer books of the corporation by the holder
of record thereof or by such holder's legal representative who shall furnish
proper evidence of authority to transfer, or by such holder's attorney thereunto
authorized by power of attorney duly executed and filed with the secretary of
the corporation, on surrender for cancellation of the certificate for the
shares. All certificates surrendered to the corporation for transfer shall be
canceled and no new certificate shall be issued until the former certificate for
a like number of shares shall have been surrendered and canceled.

        SECTION 6.5.   LOST OR DESTROYED CERTIFICATES. In the case of a lost,
destroyed or mutilated certificate, a new certificate may be issued therefor
upon such terms and indemnity to the corporation as the board of directors may
prescribe.

        SECTION 6.6.   STOCK TRANSFER RECORDS. The stock transfer books shall be
kept at the principal office of the corporation or at the office of the
corporation's transfer agent or registrar. The name and address of the person to
whom the shares represented by any certificate, together with the class, number
of shares and date of issue, shall be entered on the stock transfer books of the
corporation. Except as otherwise provided in these Bylaws, the person in whose
name shares stand on the books of the corporation shall be deemed by the
corporation to be the owner thereof for all purposes.

ARTICLE VII.   SEAL

        This corporation need not have a corporate seal. If the directors adopt
a corporate seal, the seal of the corporation shall be circular in form and
consist of the name of the corporation, the state and year of incorporation, and
the words "Corporate Seal."

ARTICLE VIII.   INDEMNIFICATION OF DIRECTORS, OFFICERS, EMPLOYEES AND AGENTS

        SECTION 8.1.   POWER TO INDEMNIFY. The corporation shall have the
following powers:

                8.1.1.  POWER TO INDEMNIFY. The corporation may indemnify and
hold harmless to the full extent permitted by applicable law each person who was
or is made a party to or is threatened to be made a party to or is involved
(including, without limitation, as a witness) in any actual or threatened
action, suit or other proceeding, whether civil, criminal, administrative or
investigative, by reason of that fact that he or she is or was a director,
officer, employee or agent of the corporation or, being or having been such a
director, officer, employee or agent, he or she is or was serving at the request
of the corporation as a director, officer, employee, agent, trustee, or in any
other capacity of another corporation or of a partnership, joint venture, trust
or other enterprise, including service with respect to employee benefit plans,
whether the basis of such proceeding is alleged action or omission in an
official capacity or in any other capacity while serving as a director, officer,
employee, agent, trustee or in any other capacity, against all expense,
liability and loss (including, without

                                       -8-

<PAGE>   9

limitation, attorneys' fees, judgments, fines, ERISA excise taxes or penalties
and amounts to be paid in settlement) actually and reasonably incurred or
suffered by such person in connection therewith. Such indemnification may
continue as to a person who has ceased to be a director, officer, employee or
agent of the corporation and shall inure to the benefit of his or her heirs and
personal representatives.

                8.1.2.  POWER TO PAY EXPENSES IN ADVANCE OF FINAL DISPOSITION.
The corporation may pay expenses incurred in defending any such proceeding in
advance of the final disposition of any such proceeding; provided, however, that
the payment of such expenses in advance of the final disposition of a proceeding
shall be made to or on behalf of a director, officer, employee or agent only
upon delivery to the corporation of an undertaking, by or on behalf of such
director, officer, employee or agent, to repay all amounts so advanced if it
shall ultimately be determined, that such director, officer, employee or agent
is not entitled to be indemnified under this Article or otherwise, which
undertaking may be unsecured and may be accepted without reference to financial
ability to make repayment.

                8.1.3.  POWER TO ENTER INTO CONTRACTS. The corporation may enter
 into contracts with any person who is or was a director, officer, employee and
agent of the corporation in furtherance of the provisions of this Article and
may create a trust fund, grant a security interest in property of the
corporation, or use other means (including, without limitation, a letter of
credit) to ensure the payment of such amounts as may be necessary to effect
indemnification as provided in this Article.

                8.1.4.  EXPANSION OF POWERS. If the Washington Business
Corporation Act is amended in the future to expand or increase the power of the
corporation to indemnify, to pay expenses in advance of final disposition, to
enter into contracts, or to expand or increase any similar or related power,
then, without any further requirement of action by the shareholders or directors
of the corporation, the powers described in this Article shall be expanded and
increased to the fullest extent permitted by the Washington Business Corporation
Act, as so amended.

                8.1.5.  LIMITATION ON POWERS. No indemnification shall be
provided under this Article to any such person if the corporation is prohibited
by the nonexclusive provisions of the Washington Business Corporation Act or
other applicable law as then in effect from paying such indemnification.

        SECTION 8.2.   INDEMNIFICATION OF DIRECTORS, OFFICERS, EMPLOYEES AND
AGENTS.

                8.2.1.  DIRECTORS AND OFFICERS. The corporation shall indemnify
and hold harmless any person who is or was a director or officer of the
corporation and pay expenses in advance of final disposition of a proceeding, to
the full extent to which the corporation is empowered.

                8.2.2.  EMPLOYEES AND AGENTS. The corporation may, by action of
its board of directors from time to time, indemnify and hold harmless any person
who is or was an employee or agent of the corporation and pay expenses in
advance of final disposition of a proceeding, to the full extent to which the
corporation is empowered, or to any lesser extent which the board of directors
may determine.

                8.2.3.  CHARACTER OF RIGHTS. The rights to indemnification and
payment of expenses in advance of final disposition of a proceeding conferred by
or pursuant to this Article shall be contract rights.

                8.2.4.  ENFORCEMENT. A director, officer, employee or agent
("claimants") shall be presumed to be entitled to indemnification and/or payment
of expenses under this Article upon submission of a written claim (and, in an
action brought to enforce a claim for expenses incurred in defending any
proceeding in advance of its final disposition, where the undertaking in
Subsection 8.1.2 above has been delivered to the corporation) and thereafter the
corporation shall have the burden of proof to overcome the presumption that the
claimant is so entitled.

                                       -9-

<PAGE>   10

        If a claim under this Article is not paid in full by the corporation
within 60 days after a written claim has been received by the corporation,
except in the case of a claim for expenses incurred in defending a proceeding in
advance of its final disposition, in which case the applicable period shall be
20 days, the claimant may at any time thereafter bring suit against the
corporation to recover the unpaid amount of the claim and, to the extent
successful in whole or in part, the claimant shall be entitled to be paid also
the expense of prosecuting such claim. Neither the failure of the corporation
(including its board of directors, its shareholders or independent legal
counsel) to have made a determination prior to the commencement of such action
that indemnification of or reimbursement or advancement of expenses to the
claimant is proper in the circumstances nor an actual determination by the
corporation (including its board of directors, its shareholders or independent
legal counsel) that the claimant is not entitled to indemnification or to the
reimbursement or advancement of expenses shall be a defense to the action or
create a presumption that the claimant is not so entitled.

                8.2.5.  RIGHTS NOT EXCLUSIVE. The right to indemnification and
payment of expenses in advance of final disposition of a proceeding conferred in
this Article shall not be exclusive of any other right which any person may have
or hereafter acquire under any statute, the Articles of Incorporation, these
Bylaws, any agreement, vote of shareholders or disinterested directors or
otherwise.

        SECTION 8.3.   INSURANCE. The corporation may maintain insurance, at its
expense, to protect itself and any director, officer, employee, agent or trustee
of the corporation or another corporation, partnership, joint venture, trust or
other enterprise against any expense, liability or loss, whether or not the
corporation would have the power to indemnify such person against such expense,
liability or loss under the Washington Business Corporation Act.

        SECTION 8.4.   SURVIVAL OF BENEFITS. Any repeal or modification of this
Article shall not adversely affect any right of any person that existed at the
time of such repeal or modification.

        SECTION 8.5.   SEVERABILITY. If any provision of this Article or any
application thereof shall be invalid, unenforceable or contrary to applicable
law, the remainder of this Article, or the application of such provision to
persons or circumstances other than those as to which it is held invalid,
unenforceable or contrary to applicable law, shall not be affected thereby and
shall continue in full force and effect.

        SECTION 8.6.   APPLICABLE LAW. For purposes of this Article, "applicable
law" shall at all times be construed as the applicable law in effect at the date
indemnification may be sought, or the law in effect at the date of the action,
omission or other event giving rise to the situation for which indemnification
may be sought, whichever is selected by the person seeking indemnification. As
of the date hereof, applicable law shall include RCW 23B.08.500 through .600, as
amended.

ARTICLE IX.   BOOKS AND RECORDS

        The corporation shall keep correct and complete books and records of
account, stock transfer books, minutes of the proceedings of its shareholders
and the board of directors and such other records as may be necessary or
advisable.

ARTICLE X.   FISCAL YEAR

        The fiscal year of the corporation shall be determined by resolution
adopted by the board of directors. In the absence of such a resolution, the
fiscal year shall be the calendar year.

ARTICLE XI.   AMENDMENTS TO BYLAWS

        The board of directors shall have the power to adopt, amend or repeal
the Bylaws of the corporation, at a duly called meeting or by written consent.
The shareholders shall also have the power to adopt, amend or repeal

                                      -10-

<PAGE>   11

the Bylaws of the corporation upon the affirmative vote of the holders of
two-thirds of the outstanding shares entitled to vote thereon.

                                      -11-<PAGE>   1
                                                                     EXHIBIT 4.3

------                                                                 ------
NUMBER          [PENWEST LOGO AND NAME OF COMPANY APPEARS HERE]        SHARES
------                                                                 ------

INCORPORATED UNDER THE LAWS                              SEE REVERSE FOR CERTAIN
OF THE STATE OF WASHINGTON                               DEFINITIONS
                                                         CUSIP 709754 105
--------------------------------------------------------------------------------
  This certifies that

  is the record holder of
--------------------------------------------------------------------------------

              FULLY PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK,
                               $.001 PAR VALUE, OF
                           PENWEST PHARMACEUTICALS CO.
transferable only on the books of the Corporation by the holder hereof in person
or by duly authorized Attorney upon surrender of this certificate properly
endorsed. This certificate is not valid until countersigned by the Transfer
Agent and registered by the Registrar.

     WITNESS the facsimile seal of the Corporation and the facsimile signatures
of its duly authorized officers.

     Dated:

     /s/ Edmund O. Belsheim, Jr.                  /s/ Tod R. Hamachek

        SECRETARY                                    CHAIRMAN OF THE BOARD
                                                     AND CHIEF EXECUTIVE OFFICER

                          [corporate seal appears here]

COUNTERSIGNED AND REGISTERED:
    CHASE MELLON SHAREHOLDER SERVICES, L.L.C.
                         TRANSFER AGENT
                         AND REGISTRAR

 By:
                       AUTHORIZED SIGNATURE

<PAGE>   2
         This Certificate evidences shares of Common Stock of the Corporation.
The Corporation is also authorized to issue shares of Preferred Stock as well as
shares of different series within a class. The Corporation will furnish to any
shareholder, upon request and without charge, a full statement of the
designations, relative rights, preferences and limitations of the shares of each
class authorized to be issued, and the variations in rights, preferences and
limitations determined for each series, and the authority of the Corporation's
Board of Directors to determine variations for any future series.

         The following abbreviations, when used in the inscription on the face
of this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

     TEN COM -    as tenants in common
     TEN ENT -    as tenants by the entireties
     JT TEN  -    as joint tenants with right of survivorship and not as tenants
                  in common

     UNIF GIFT MIN ACT - __________ Custodian ___________
                           (Cust)               (Minor)
                         under Uniform Gifts to Minors Act _____________________
                                                                  (State)

     UNIF TRF MIN ACT - __________ Custodian ____________
                           (Cust)               (Minor)
                        under Uniform Transfers to Minors Act __________________
                                                                   (State)

    Additional abbreviations may also be used though not in the above list.

FOR VALUE RECEIVED ____________________hereby sell, assign and transfer unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE

 ____________________
|                    |
|____________________|

--------------------------------------------------------------------------------
                  (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS,
                        INCLUDING ZIP CODE, OF ASSIGNEE)
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

                                                                          Shares
--------------------------------------------------------------------------------
of the common stock represented by the within Certificate, and do hereby
irrevocably constitute and appoint
                                                                        Attorney
--------------------------------------------------------------------------------
to transfer the said stock on the books of the within named Corporation with
full power of substitution in the premises.

Dated_____________________

                                          X_____________________________________

                                          X_____________________________________

                                          NOTICE: THE SIGNATURES TO THIS
                                          ASSIGNMENT MUST CORRESPOND WITH THE
                                          NAMES AS WRITTEN UPON THE FACE OF
                                          THE CERTIFICATE IN EVERY PARTICULAR
                                          WITHOUT ALTERATION OR ENLARGEMENT
                                          OR ANY CHANGE WHATEVER.

SIGNATURE(S) GUARANTEED:

By: _____________________________

THE SIGNATURE(S) MUST BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS,
STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN
AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO S.E.C. RULE
17Ad-15.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00028-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00028-of-00352.parquet"}]]