OOS Investigation Part 1
United States Pharmacopeia monographs establish standards for identity, strength, quality, and purity of medicines. Monographs list tests and acceptance criteria (usually expressed in percentage ranges or limits). Drug substances and products should meet the acceptance criteria to be considered acceptable for its intended use. An Out of Specification (OOS) occurs when a test fails to meet acceptance criteria. An OOS Investigation follows an OOS test result and is performed to determine if there is a root cause. In this article we will look specifically at potential causes of potency OOS results of finished drug products. Understanding the factors that contributed to the potency failure allows the pharmacist and laboratory to define a strategic approach in eliminating future failures. The more specific the findings, the easier it is to properly address the cause.