An Update on Metals Testing in Drugs

Greetings from Toronto, where I'm attending the annual scientific meeting of the U.S. Pharmacopeia (USP), the pharmaceutical standards-setting organization in the U.S. USP publishes the book "United States Pharmacopeia-National Formulary" (USP-NF), which sets packaging, storage, labeling, testing, and acceptance standards for drug ingredients and products. shutterstock_37104634After last year's meeting, I wrote about USP's effort to update the current test for metals in pharmaceuticals--a 100-year-old metal sulfide precipitation method--to a modern, instrument-based approach, as well as to set toxicologically-based limits for metals in pharmaceutical products. USP was aiming to have the draft chapter written and out for comment this summer, with the final chapter published in January, 2010. I sat down this afternoon with Anthony De Stefano, USP's vice president for general chapters, to get an update on how the process is going. The response last fall to the proposed testing changes and new limits was strong enough, De Stefano says, that USP decided to hold an extra workshop in the spring to collect additional comments from industry and other stakeholders. The USP advisory panel in charge of the changes then used the feedback to create a set of recommendations (pdf):
  • All pharmaceutical manufacturers will have to test for or otherwise document the absence of the "big four" metals: arsenic, cadmium, lead, and mercury.
  • Manufacturers will have to watch for an additional twelve catalysts as necessary: chromium, copper, iridium, manganese, molybdenum, nickel, osmium, palladium, platinum, rhodium, ruthenium, and vanadium.
  • USP will suggest two spectroscopic tests based on inductively coupled plasma spectroscopy, but manufacturers will be free to use their own test if they can meet the validation criteria.
USP plans to have the draft chapters up on their website shortly, as well as two Pharmacopeial Forum Stimuli articles explaining the metals limits and responding to comments. When the chapters get finalized will depend on the feedback USP gets on the drafts, De Stefano says. After that, implementation of the new tests and limits will likely take several years. Image credit: Shutterstock

Author: Jyllian Kemsley

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