Chapter 19 - Rational Design of Oral Modified-Release Drug Delivery Systems

Abstract

Oral modified release (MR) dosage forms are developed by altering the kinetics and site of drug release and absorption in order to achieve specific clinical objectives, such as improved patient compliance, optimized efficacy, and reduced adverse events. Typically, drug release from MR systems is modified by one or more of the following mechanisms: diffusion, dissolution, swelling, erosion, and osmotic pressure. This chapter introduces basic design principles, drug release mechanisms, models, and rate-controlling materials of different types of delivery technologies, including extended, delayed, and multimodal drug release systems. It describes the systematic multidisciplinary approach, methods, and techniques essential to the rational design of MR delivery systems; it also addresses the importance of fundamental understanding of physicochemical, biopharmaceutical, pharmacokinetic, and pharmacodynamic properties of the drug molecules and their interplays with anatomical, physiological, and biochemical characteristics of the digestive tract. It also discusses key elements, strategy, and process to achieve drug delivery performance when designing and evaluating new MR dosage forms. Case studies are provided to emphasize the criticality of understanding drug properties, delivery technology, and assessment of MR feasibility for ensuring effective and efficient product design.