1st Edition

# Understanding Drug Release and Absorption Mechanisms A Physical and Mathematical Approach

648 Pages 167 B/W Illustrations
by CRC Press

648 Pages
by CRC Press

Also available as eBook on:

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 ofall 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.

Mathematical Modeling
Introduction
Model Building
Model Fitting
Models Comparison
Conclusions
References
Gastrointestinal Tract
Macro- and Microscopic Anatomy of the Gastrointestinal Tract
Intestinal Absorption
Human and Animal GI Tract: A Comparison
Skin
Anatomy
Skin Delivery Strategies
Animal Model of Skin Delivery
References
Rheology
Introduction
Viscosity and Newtonian Fluids
Shear-Dependent Viscosity and Non-Newtonian Fluids
Shear Flows
Not Only Viscosity: Normal Stress Differences and Other Material Functions
Extensional Flows and Complex Flows
Time-Dependence: Thixotropy and Viscoelasticity
Linear Viscoelasticity
Rheological Properties and Structural Features
Conclusive Considerations on Rheology Applications to Drug Delivery Systems
References
Mass Transport
Introduction
Thermodynamic Concepts
Kinetics
Fick’s Equation
Effect of Initial and Boundary Conditions
Conclusions
References
Drug Dissolution and Partitioning
Introduction
Dissolution
Partitioning
Dissolution and Partitioning
Conclusions
References
Dissolution of Crystallites: Effects of Size on Solubility
Introduction
Thermodynamic Concepts
Experimental Methods and Limitations
Conclusions
References
Drug Release from Matrix Systems
Introduction
Matrices
Mathematical Modeling
Conclusions
References
Drug Release from Microemulsions
Introduction
Microemulsions: Structure
Microemulsions: Thermodynamics
Microemulsions: Experimental Characterization
Microemulsions and Drug Release
Conclusions
References
Drug Permeation through Membranes
Introduction
Synthetic Membranes
Biological Membranes
Conclusions
References Index