Magnesium Stearate

Type of Posting: Notice of Adoption of Harmonized Standard

Posting Date: 29–Apr–2011

Official Date: 01–May–2012

Expert Committee: Monographs—Excipients

A harmonized standard for Magnesium Stearate has been approved by the Pharmacopeial Discussion Group (PDG) as described in its PDG Sign-Off Cover Page. Having reached Stage 6 of the PDG process, the Magnesium Stearate monograph has been formally approved by the USP Monographs—Excipients Expert Committee in accordance with the Rules and Procedures of the 2010–2015 Council of Experts.

Changes from the existing USP–NF monograph include:

  • Added AA tests for Lead, Cadmium, and Nickel, and replaced the wet chemistry test for lead.
  • Adjusted the System Suitability requirements for the test for Relative Content of Stearic and Palmitic Acids to have an RSD specification of NMT 3.0%.
  • Added a requirement to Labeling to indicate that the fatty acids are derived from edible sources, consistent with the Definition.

The Magnesium Stearate monograph will be incorporated into and become official with USP 35–NF 30.

Should you have any questions about the Magnesium Stearate monograph, please contact Kevin Moore (301-816-8369 or For any questions about the PDG and its processes, please see the Pharmacopeial Harmonization Web page or contact Mario Sindaco (301-816-8246 or