WASHINGTON - U.S. health officials have identified a contaminant in batches of a blood thinner associated with 19 deaths and are trying to determine how the chemical got into the drug.
The lots of heparin were recalled Feb. 28, and Food and Drug Administration officials say no new deaths have been reported since then.
Dr. Janet Woodcock, head of the FDA's Center for Drug Evaluation and Research, says the contaminant is oversulphated condroitin sulphate.
Condroitin sulphate is a natural compound that occurs widely and is used as a dietary supplement but the oversulphated version has not been widely studied.
Woodcock says the investigation is continuing and officials are currently unable to determine if the contaminate was introduced accidentally or deliberately.
The lots of heparin linked to hundreds of allergic reactions were marketed by Baxter International and produced in China. The FDA said Chinese officials have been highly co-operative in the investigation.
Meanwhile, the FDA has initiated testing of heparin entering this country and Woodcock said the agency feels "doctors and patients now can be confident that the product on the market has been tested and is safe.''
Condroitin sulphate is a compound in the same family as heparin, so preliminary testing did not identify it, Woodcock said. She said more exacting tests by the government and university researchers uncovered the contaminant.
Oversulphated condroitin sulphate would be less expensive to make than heparin, but FDA officials said they could not estimate the cost difference.
The investigation comes just a year after melamine was identified as a contaminate in pet food from China. Officials said an agreement signed at that time with China helped smooth the way for the current investigation.
FDA officials said they could not yet directly associate the oversulphated condroitin sulphate to the deaths and side-effects, but it is the lone contaminant they have found in the product.
Heparin is derived from pig intestines, and China is the world's leading supplier. Tiny family-run workshops near slaughterhouses send batches of raw ingredients to larger middlemen before they reach factories.
