US Pharmacopeia Aiding FDA In Improved Tests For Heparin Contamination
The United States Pharmacopeial (USP) Convention announces that it is working with FDA to develop more sensitive methods for detecting contaminants recently found in the widely used blood-thinning drug heparin. This contamination is suspected of causing severe allergic reactions in some patients and has resulted in over 60 deaths. The suspected contaminant, over-sulfated chondroitin, is derived from the dietary supplement chondroitin.
The chemically-induced over-sulfated form can mimic blood-thinning properties. Consequently, heparin adulterated in this manner may pass existing quality tests. It is likely (but still being determined) that any deliberate adulteration was done for economic reasons, because over-sulfated chondroitin is a much less expensive ingredient than genuine heparin.
USP publishes official quality standards for medicines in the United States Pharmacopeia-National Formulary (USP-NF) and has worked with FDA for over 100 years in a unique public-private partnership that helps assure the quality of medicines in the United States. Following a recall in January of suspect heparin products, FDA in March asked USP to assist in re-assessing current tests and possibly developing new methods for detecting over-sulfated chondroitin in the heparin drug substance before it is made into a final product. This work is ongoing and will result in updated heparin monographs. Heparin has been sold in the United States since the 1940s and has had a USP monograph since 1950, which has been updated several times.
According to Roger L. Williams, M.D., USP's chief executive officer, "It is difficult for analytical procedures to detect and identify all adulterants. USP monographs are designed to test for known impurities that result from manufacture or degradation, not for unknown contaminants that may be added either accidentally or deliberately. USP will continue to work closely with FDA and other partners to develop the most effective approaches to assure the safety of heparin."
The availability of a good public monograph in the USP with allied reference materials is one of a series of safety nets that work to assure that U.S. patients and practitioners have access to good quality medicines. Other safety nets include dedicated and trusted drug ingredient and product manufacturers who follow good manufacturing practices (GMPs) and sound sampling protocols in support of batch release testing. Oversight from FDA is also key in assuring product quality along complicated and at times lengthy supply and distribution pathways.