Heparin

February 28th: Baxter International Inc. requests a voluntary recall of its anticoagulant medication heparin. This molecule is derived from animal (commonly pork) organ tissue. As seen on the right, heparin is a disaccharride with varying sugar constituents. The most common disaccharide combination (left) contains an amide and a sulfate group, both of which are de-ptrotected and attract a positive sodium ion. It is sodium heparin that is injected as medication to thin the blood of patients for a variety of indications.

So what happened? Well, over 700 people had adverse reactions after receiving heparin for dialysis or venous thromboembolism (blood clot) to name two indications.

Baxter International Inc. sells the drug and has something like 50% of America's market share. The company receives the main active ingredient from a company called Scientific Protein Laboratories. SPL, for short, is based out of Wisconsin but relies on a factory in China for extraction of the api (active pharmaceutical ingredient) from pig organs. To make a long story short, China's State FDA did not inspect this particular factory because it only produces exports. USA's FDA accidently inspected the wrong factory due to a mix up in database input and the fact that the other factory had a like sounding name(C&EN, Feb 25, 2008, Vol 86, #08, p.8).

More recently, the contaminant has been identified as Chondroitin Sulfate (right - C&EN, Mar 19, 2008). The molecule is commonly found in cartilage of animals (like pigs) and has been used by the alternative medicine community to treat arthritis. In this case, the Chondroitin Sulfate, had more sulfate groups than are commonly found in nature and is considered a purposely introduced contaminant. The over sulfated Chondroitin Sulfate is cheap and because of its structure it mimics heparin in regulatory and potency tests.

Chinese companies, that rely on SPL for this API, have also recalled the drug. Other heparin producers are being encouraged to increase output (their API producers have been approved by the FDA).

This is a growing concern. The trend of the chemical industry has been to expand its laboratory work to international ground (cheaper labor, more supportive government). The burden on the FDA to ensure the authenticity of imported drugs grows. This will be an ongoing challenge and a very important one.

A joke at every end:

What did the bra say to the hat?
"You go on ahead, I'll give those two a lift."