The USP has been working on changing the guidelines for testing heavy metals for several years. More specifically, the USP chapter to change will be <231> . The new USP chapters that will be effective are <232> and <233>.
The previous chapter provided a test developed centuries ago. It was performed using wet chemistry analysis and determined if certain elements (Pb, Hg, Bi, As, Sb, Sn, Cd, As, Cu and Mo) were present in an API or finished product by colourimetric procedure. The test was not specific or sensitive enough.
The new chapters in the USP are for the limits of the heavy metals or what are now known as the elemental impurities and the second chapter is for the procedures to be used. Two different classes are listed in the general chapter.
According to USP, the first is Class 1 and addresses four major metals: arsenic, cadmium, lead and mercury. These are required for all drug products regardless of the likelihood of the presence of impurities, according the USP. The second, Class 2, are the elemental impurities that need to be tested only when added during the manufacturing of the article.
If you have not tested your products according to the new USP, contact us today to ensure compliance. The analytical chemistry department at Gibraltar Laboratories performs this testing on a routine basis to ensure your medical devices are safe