Purity, identity and sterility are different questions
A certificate of analysis is a report of specified tests. One passing result does not answer every quality question.
Read the document, not just the percentage
FDA Q7 guidance describes a certificate of analysis as batch-specific information: material identification, test results, acceptance limits and accountable issuer details. Match the report to the material and batch under discussion. A certificate from another batch is not evidence about this one.
Separate the measurements
Identity asks whether the substance is the intended one. Purity and impurity tests address specified unwanted components. FDA Q6A treats identity, sterility and endotoxin testing as distinct attributes; a result for one does not establish the others. A purity percentage alone therefore cannot establish sterility.
Keep the conclusion within the tests
Ask which methods were used and which attributes were not tested. FDA notes that one chromatographic retention time alone is not sufficiently specific for identity. These guidance documents explain pharmaceutical quality principles; citing them does not certify a supplier, a retail sample or suitability for human use.
Follow the sources
- 1FDA: Q7A Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients FDA quality guidance
- 2FDA: Q6A Specifications, Test Procedures and Acceptance Criteria FDA quality guidance