Stability Studies of Pharmaceuticals
C. Ralph Buncher, Jia-Yeong Tsay · 2019
I. Introduction.......................................................................................... 391 II. Designs of Stability Study................................................................... 392 III. Methods for Shelf-Life Determination................................................ 396 A. ANCOVA Modeling of Simple Stability Studies ........................ 396 B. ANCOVA Modeling of Stability Studies Designed with Multiple Factors ............................................................................ 403 IV. Alternative Approaches for Shelf-Life Determination ....................... 416 Acknowledgments ........................................................................................... 417 References........................................................................................................ 417 The stability of a drug substance or drug product is the capacity of that substance or product to remain within the established acceptance criteria to ensure its identity, strength, quality, and purity within a specified period of time. Regulatory agencies require that adequate testing be performed by an applicant to demonstrate the stability of the drug substance or product in support of the approval for a marketing registration application. The purpose of stability testing is to provide evidence on how the quality of a drug substance or product varies with time under the influence of a variety of environmental factors, such as temperature, humidity, and light. This assessment is used to establish the recommended storage conditions and a retest period for the drug substance or a shelf-life for the drug product.