Washington: The US FDA officials on Wednesday claimed that they have identified a contaminant found in batches of Baxter International Inc's blood-thinner heparin, causing serious reactions and some 19 deaths, and they are now nosing about to know how the chemical got into the drug.

The FDA officials reported that they are currently investigating “whether the contaminant chemical -- over-sulfated chondroitin sulfate -- was purposely or inadvertently added during manufacturing in China”. The officials reported that no new deaths have been reported since the stacks of heparin, whose key ingredient was imported from China, were recalled on Feb. 28.

Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research, said, "The contaminant is oversulfated chondroitin sulfate, a chemical that does not occur naturally. We don't know whether the contaminant was introduced intentionally or by accident."

Woodcock said, "We cannot rule in or out whether this was accidentally or deliberately introduced into the product. We are investigating how it got in."

According to Woodcock, Chondroitin sulfate is a natural compound that occurs widely and is used as a dietary supplement but the oversulfated version has not been widely studied. It is widely sold as a dietary supplement to treat joint pain. The over-sulfated version is not known to occur naturally and therefore likely was chemically modified. The chemical imitates the blood-thinning actions of heparin but is not FDA-approved for use in medicines. In some batches of heparin, the contaminant accounted for between 2 % and 50 % of the samples. Chondroitin sulfate is widely available from animal sources, and is quite cheaper than getting raw heparin from pig intestines.

However Woodcock said, it was still unclear whether the contaminant was the cause of up to 19 deaths and hundreds of serious breathing problems and other reactions reported to the FDA.

Previous year, the FDA detected pet food ingredients imported from China were infected, which killed more than 200 cats and dogs and causing widespread alarm. The Chinese maker involved was later indicted in the United States for fraud over adding the chemical melamine in an attempt to bolster the value of its ingredient.

Sen. Edward M. Kennedy, D-Mass., chairman of the Health, Education, Labor and Pensions Committee, said, "Whether this contaminant was introduced intentionally or by accident, the full force of the law must be brought to bear to bring those responsible to justice. To guard against future abuses, every drug manufacturer needs to inform FDA of where it sources its ingredients and what it is doing to ensure that these ingredients are pure and potent."

Sen. Charles E. Schumer, D-NY, said, "The FDA should have identified this contaminant before it hit U.S. shores and caused so many health problems for patients. The agency's ability to perform foreign inspections is woefully inadequate. We will continue to push for greater funding, staff, and oversight to better enable the FDA to protect the public's health."