Complying with Revised Weighing Guidelines

The latest revisions to the United States Pharmacopeia (USP) General Chapters Balances and Weighing on an Analytical Balance became official on Dec 1, 2013. These revisions aim to ensure weighing accuracy and eliminate unnecessary overtesting for US pharmaceutical manufacturers and suppliers. The chapters attempt to simplify previous descriptions and reflect current state-of-the-art weighing practices. Revisions include modified balance test procedures, which focus on the determination of minimum weight, and the execution of routine testing. For accuracy testing, use of a test weight of 5%-100% of the balance capacity is now applicable. For the first time, the term "minimum weight" is officially introduced in a pharmaceutical compendium. Another consequence of the USP revisions is that a daily balance check, typical in the pharmaceutical industry, is no longer a requirement. Instead, the type and frequency of balance checks should be determined by the risk and process tolerance of the application.