Topic overview

Start with the big picture

A stability study follows product batches under long-term, intermediate, and accelerated conditions, with storage conditions selected according to climatic zone. Testing checks potency and quality attributes such as appearance, pH, dissolution, impurities, and preservative content. Significant changes can affect the suitability of the data for shelf-life assignment. Shelf-life, or t90, is the time at which potency first reaches 90% of its labeled value; it is estimated using regression of stability-indicating assay data and a 95% confidence interval. Stress and photostability studies help characterize degradation, while in-use studies assess products during labelled use. The broader evaluation also considers storage category, container-closure performance, microbiological stability, and designs such as bracketing and matrixing.