Potency Test Failure...
Common compounding problems causing a sample to fail: case studies
Berenice Dethier, Research Chemist II
A potency test measures the amount of API in a formulation to ensure the product is within its specifications. Criteria for acceptance are set by the client and/or follow the industry benchmarks (generally set by USP).
Several factors can contribute to a failing potency result. Investigating the root cause of the failing potency test is an important practice to characterize the true cause(s) of the failure. The goal of the out of specification (OOS) investigation is to identify what, how, and why the failure occurred. To answer all three questions, OOS investigations should include a comprehensive review of all aspects of the formulation procedure. The review typically includes everything between the acceptability of the raw materials to the validity of the potency test result. Understanding the factors that contributed to the potency failure allows the pharmacist a more strategic approach in eliminating future failures. The more specific the findings into the failure, the easier it is to properly address.