Demand for better reliability from drug delivery systems has caused designers and researchers to move away from trial-and-error approaches and toward model-based methods of product development. Developing such models requires cross-disciplinary physical, mathematical, and physiological knowledge. Combining these areas under a single cover, "Understanding Drug Release and Absorption Mechanisms" builds a firm understanding of all elements needed to conceive, build, and implement successful models of drug release. Written by experts with broad industrial and academic experience, this book discusses the underlying physical principles, shows how to build mathematical models based on these principles, and finally compares the resulting models with experimental results. The authors begin by introducing the basics of modeling, physiological details of gastrointestinal and dermal absorption pathways, rheology, mass transport and thermodynamics, dissolution and partitioning, as well as size effects on the dissolution of crystallites. From this baseline, the authors explore applications in drug release from various delivery systems, specifically matrix systems, microemulsions, and permeability through membranes. Working systematically from theory to working models, "Understanding Drug Release and Absorption Mechanisms: A Physical and Mathematical Approach" demonstrates the steps involved in designing, building, and implementing realistic and reliable models of drug release without unrealistically simplifying the theoretical parameters.