Where Does Heparin Come From?

Today, the WSJ continues its coverage of the possible link between severe allergic reactions to Baxter's unconjugated heparin products, particularly when used in bolus fashion, and the products' manufacture, which includes the use of raw material from a plant in China. According to the WSJ, Baxter is attempting to determine the source of the adverse reactions by comparing the chemical profiles of potentially affected heparin lots with those of quality-control batches.

A search for a description of heparin's manufacturing process is surprisingly elusive, especially given the long-term and widespread manner in which the agent has been prescribed in hospital. An extensive search of the medical literature suggests that a detailed "methods" description is long buried somewhere in an article from nineteen-dickety-two. Today's WSJ provides a superficial (understandably) description of the process: "[R]aw [pig] intestines are exposed to an enzyme and then to a resin that separates the heparin from the rest of the liquid. The end product is heat-treated to destroy microorganisms." A web page at the site of Scientific Protein Laboratories, the chemical supplier of Baxter's heparin, provides the following graphic outlining the processing of heparin at both its Wisconsin and Chinese facilities.