Penwest Pharmaceuticals (PPCO) 10-Q 2002 Q3 Quarterly report

EXHIBIT 99.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

         In connection with the Quarterly Report on Form 10-Q of Penwest Pharmaceuticals Co. (the “Company”) for the period ended September 30, 2002 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned, Tod R. Hamachek, Chief Executive Officer of the Company hereby certifies, pursuant to 18 U.S.C. Section 1350, that:

         (1)  The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

         (2)  The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: November 13, 2002 /s/ Tod R. Hamacheck
Tod R. Hamachek
Chairman of the Board and Chief Executive Officer

EXHIBIT 99.1

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

         In connection with the Quarterly Report on Form 10-Q of Penwest Pharmaceuticals Co. (the “Company”) for the period ended September 30, 2002 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned, Jennifer L. Good, Chief Financial Officer of the Company, hereby certifies, pursuant to 18 U.S.C. Section 1350, that:

         (1)  The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

         (2)  The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: November 13, 2002 /s/ Jennifer L. Good
Jennifer L. Good
Sr. Vice President, Finance and Chief Financial Officer