Introduction

This chapter provides background information to support Detection of Asbestos in Pharmaceutical Talc 〈901〉. It describes analytical procedures for X-ray diffraction (XRD)—also termed X-ray powder diffraction (XRPD)—and polarized light microscopy (PLM), both of which can be effective for testing of asbestos in talc. Some of the principles applied in this method were first described in the J4-1 method developed by the Cosmetics, Toiletries, and Fragrance Association (CTFA)(1) and applied to the analysis of talc for asbestos, which was implemented in 1976, although the method applied only to the analysis of amphibole asbestos. The original asbestos test, which was added to the Talc monograph in 2005, expanded on this protocol, applying the principles to chrysotile and amphibole asbestos. For a full description of the current update to this procedure, see the related USP publication (2).