Content uniformity acceptance limit for a validation batch--suppositories, transdermal systems, and inhalations.

BACKGROUND: The USP test for 'Uniformity of Dosage Units' specified by USP Chapter <905> is required of every drug product sold in the United States. Dosage-unit uniformity is determined either by weight variation or by assay of individual units. The USP acceptance criteria for content uniformity states that the relative standard deviation (RSD) of a sample of 30 units should not exceed 7.8%.

PURPOSE: This article provides a methodology for deriving an upper acceptance limit on the RSD of dosage units from a validation batch of suppositories, transdermal systems, or inhalations such that future batches will have a 95% chance of passing the USP content uniformity RSD acceptance criterion (the RSD of 30 dosage units does not exceed 7.8%).