Selection, Evaluation, and Control of the Assay of the Pharmaceutical Product IV: Screening Bulk Drug Stability and Defining the Assay of Choice

Statistical evaluation of biological assays of bulk streptovitacin A subjected to 70° and room temperature for 60 days permitted the conclusion that the drug was stable in the bulk form. The assay of choice was defined against Saccharomyces pastorianus rather than against Trichomonas vaginalis. The point is made that operational potency is best defined by assay replication on various days but comparison of lot potencies and production procedures is best made by assay on one given day against the same standards.