Excipient selection in oral solid dosage formulations containing moisture sensitive drugs

Abstract

Moisture sensitivity of active pharmaceutical ingredients (APIs) presents a formidable challenge in the formulation of oral dosage forms. The interaction of moisture with APIs is crucial to an understanding of water-based processes, e.g. manufacturing or prediction of solid dosage form stability and shelf-life. Unwarranted moisture sorption by either APIs or excipients can result in unstable oral solid formulations. The appropriate selection of excipients for the core formulation and appropriate moisture barrier film coating helps to remedy the moisture-related issues with APIs and thus can improve the storage stability of the final formulations. In this chapter, we review the nature and extent of the moisture sensitivity and possible approaches taken to overcome it. Use of excipients that bind tightly with water reduce its potential interaction with the API. In addition, application of a barrier coating to reduce rate and extent of moisture ingress into the core of the solid dosage form during the storage (in original packaging or while in-use), are some of the many simple options that have been considered and described.