Chinese drug tainted with form of chondroitin
The U.S. Food and Drug Administration announced on March 20 that it had identified the contaminant in batches of tainted heparin linked to multiple deaths and more than 700 severe allergic reactions nationwide. The Chinese-manufactured blood thinner was found to be contaminated with an oversulfated form of chondroitin sulfate, a popular dietary supplement used to maintain joint health.
Products from Braun Medical and Baxter International were recalled. Both companies were supplied with heparin from a Chinese company named Changzhuo SPL, though it is unknown whether the contamination originated with Changzhuo or further downstream.
Also unknown is whether the contamination was deliberate or accidental. "There are two schools of thought on how this could have happened, and both have different implications for manufacturers," said Adam Ismail, associate director of the industry consulting firm LDI Group, based in Salt Lake City, Utah.
Because heparin and chondroitin are chemically related and derived from similar sources, with heparin derived from pig and cow lungs and intestines and chondroitin sulfate from tracheal cartilage, there may have been accidental contamination early in the supply chain, which might mean that low levels of heparin could potentially be found as an adulterant in chondroitin products.
But many observers believe that the contaminant was deliberately introduced, either because it is cheaper than heparin and chemically similar or because China experienced a raw materials shortage and couldn't meet demand. Much of the heparin supply originates with crude family operations who extract it from pig tissue and sell it to consolidators, who pass it to raw material suppliers.
"This is a biological compound that is not found in nature," said Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research. Woodcock said that the hypersulfated form of chondroitin sulfate identified as the contaminant in recalled heparin can only be produced in a laboratory.
Just as the heparin recall got under way, the FDA announced that it was in the process of establishing eight full-time positions in China. The positions, expected to be filled in the next 18 months, will increase cooperation between the FDA and Chinese regulators on quality control issues.
According to Ismail, manufacturers who sell the dietary supplement will doubtless face questions from consumers and retailer about their supply chain. "They should use some of the new enzymatic methods [of testing] that can differentiate between chondroitin and heparin and share that evidence with their customers," Ismail said.