In Vitro Physical and Imaging Techniques to Evaluate Drug Release Mechanisms from Hydrophilic Matrix Tablets

Drug release from hydrophilic tablets is controlled by the physical changes in tablet structure associated with hydration, gelling, swelling and eventual dilution of the drug and polymer within the tablet. The rate-controlling processes are physical rather than chemical and are therefore well suited to being followed using physical and imaging methods. This chapter provides an introduction of how modern imaging and more established in vitro techniques have been applied to the characterisation of hydrophilic matrices. It details how the rapid advances in instrumentation and characterisation technology are increasingly providing pharmaceutical scientists with new opportunities to gain unrivalled information in many aspects of the behaviour of hydrophilic matrices and their related performance characteristics.