Chemical Test Refined to Detect Tainted Heparin

Scientists from the US Food and Drug Administration (Silver Spring, MD, USA) identified the culprit, a substance called over-sulfated chondroitin sulfate (OSCS). They developed a 96-well plate format assay for sensitive detection of OSCS in heparin active pharmaceutical ingredient (API) and crude heparin based on Leclerc polythiophene polymer (LPTP) and heparinase digestion of heparin. OSCS is a synthetic dietary supplement derived from chondroitin sulfate type A that some people take to treat osteoarthritis. Scientists concluded that OSCS, which is inexpensive, had been intentionally added to heparin as a so-called “economically motivated adulterant” (EMA), to boost profits. Current tests to detect EMAs in heparin are difficult to perform and must be done in laboratories.

To overcome these challenges, the investigators developed a simple color test in which normal heparin samples turn red in color, but OSCS contaminated samples do not change color. In the present study, they wanted to know whether their test could detect additional EMAs. They found that the test could detect several other possible EMAs, such as those that could be made by over-sulfation of waste products formed during heparin production. The colorimetric microplate LPTP/heparinase test detected OSCS in heparin sodium API by the naked eye down to the 0.1% level and in crude heparin down to the 0.1% level with a plate reader.

The investigators concluded on the basis of their results, a portable test to detect even tiny amounts of different EMAs could be developed to insure the safety of the heparin supply chain. Like heparin, OSCS also prevents blood from forming dangerous clots, but unlike heparin, OSCS can trigger potentially fatal anaphylactic reactions in sensitive individuals. The study was published on August 5, 2011, in the journal Analytical Chemistry.

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US Food and Drug Administration