Elemental Impurities General Chapter Revisions Move Forward

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Revisions to the United States Pharmacopeia (USP) General ChapterHeavy Metals have been much discussed over the past decade.

Revisions to the United States Pharmacopeia (USP) General Chapter<231>Heavy Metals have been much discussed over the past decade. USP is in the process of replacing this chapter with General Chapters <232> Elemental Impurities-Limits and <233> Elemental Impurities-Methods, which were published in USP 35-NF 30, Second Supplement. The official date for the new chapters-originally Dec. 1, 2012-was briefly postponed due to an appeals process but was recently re-established as Feb. 1, 2013, as described in today’s PharmTechnews article.

Industry has expressed concerns about the new chapters, such as described in a November 2012 PharmTech article, “An Industry Perspective on Harmonization and Implementation of ICH and USP Requirements,” which was authored by a subgroup of an industry coalition called the Coalition for the Rational Implementation of the USP Elemental Impurities Requirements. The authors noted concerns about alignment between USP and the International Conference on Harmonization (ICH).

USP’s Executive Committee noted, in the Jan. 28, 2013 Revision Bulletin, that their decision to make the chapters official “does not preclude their further revision based on new information, including new information arising from ICH…”


Although the new chapters now have an official date, their provisions are not yet in effect, and will not be until at least May 1, 2014.  This unusually long time between chapter publication and implementation was designed to give the industry extra time to figure out what methods and equipment to use and to validate these methods. In an August 2012 PharmTecharticle entitled “Elemental Impurity Analysis: How to Manage the Pharmacopeial Changes Ahead,” Alan Cross noted that while the implementation time is long, it seems short given the number of existing monographs that specify a heavy-metals limit (1000 out of the more than 4000 monographs in the USP-NF).

Work on new methods is moving forward. In June 2012, PharmTech hosted a webinar about the revised USP chapters that focused on new testing procedures and practices for detecting elemental impurities and looked at ICP-based tests versus qualitative colorimetric tests.  You can still access the on-demand webcast, “Screening Methods for Elemental Impurities: Proposed Compendial Requirements” by clicking here. You can also join the conversation by submitting a comment below.