September 15, 2003

POLYDEX PHARMACEUTICALS REPORTS
SECOND QUARTER RESULTS

16% Increase in Sales - Quarter over Quarter

Toronto, Ontario, September 15, 2003 -- Polydex Pharmaceuticals Limited (NASDAQ:POLXF) (BSE:PXL) reports sales in this quarter have increased by $410,969 or 16% from the previous year's second quarter and reported a second quarter net loss of $236,805 or $0.08 per share. The decline in overall results is primarily due to increased corporate administrative costs and a foreign exchange loss.

The second quarter was highlighted by continued progress in the development of the Company's key human pharmaceutical compounds.

Ushercell's safety study clinical trials have been ongoing at international sites in collaboration with CONRAD, World Health Organization, Family Health International and the HIV Prevention Trials Network. The data analysis of these trials is expected by the Company's fiscal year end, January 31, 2004. A clinical trial completed in Cameroon, in collaboration with FHI remains in the data analysis phase. Plans for commencement of large-scale clinical trials, to assess the efficacy of Ushercell as a contraceptive, remain on course with enrollment scheduled for the fall and trials beginning, as planned, by the end of this year 2003.

Usherdex, the Company's Cystic Fibrosis product, is also progressing through Phase II human clinical trials, under sub-license with BCY Lifesciences Inc., and results from these clinical trials are also expected by December 31, 2003.

Polydex Pharmaceuticals Ltd., based in Toronto, Ontario, Canada, is engaged in the research, manufacture and marketing of biotechnology-based products. Polydex's business approach with respect to the development of the human pharmaceutical pipeline is to research and license out potential products to valued partners for development, thereby minimizing R&D expenditures while retaining a royalty revenue stream from successful products. This is the reason that the search for development partners is so important, and is an integral part of all of the potential human pharmaceutical products in the Polydex pipeline.

Note: This press release may contain forward-looking statements, within the meaning of the United States Securities Act of 1933, as amended, and the United States Securities Exchange Act of 1934, as amended, regarding Polydex Pharmaceuticals Limited. Actual events or results may differ materially from the Company's expectations, which are subject to a number of known and unknown risks and uncertainties including but not limited to changing market conditions, future actions by the U.S. Food and Drug Administration or equivalent foreign regulatory authorities as well as results of pending or future clinical trials. Other risk factors discussed in the Company's filings with the United States Securities and Exchange Commission may also affect the actual results achieved by the Company.

CONTACT:
Polydex Pharmaceuticals Limited
George G. Usher, President
(416) 755-2231
or e-mail: gu-dextran@rogers.com

Investor Relations
North Arm Capital Services
Linda Hughes, Toll-free 1-877-945-1621
or e-mail: Linda@northarm.com