Introduction

Abstract

Most pharmaceutical products contain particles, as active ingredient (API) and/or as excipient. The nature of these particles—e.g. particle size distribution (PSD), particle shape, morphology and powder flowability—is generally essential for product quality, during processing of powders and liquids to tablets, capsules, suspensions, emulsions and ointments as well as for the quality of the final product in terms of content uniformity, efficacy and stability. In view of their complex and particulate nature, pharmaceutical products and their manufacturing process require careful design and control. The quality of the final products should meet various strict requirements for e.g. content uniformity, tablet strength and stability and viscosity of dispersions, as well as for patient safety. Most often, quality aspects relate to the particle size distribution, particle shape, specific surface area and particulate concentration of the base materials. Since determination of these aspects is relatively easy, optimum relevant characteristic parameters are laid down in the form of specifications. In addition, some performance aspects of powders and dispersions, such as flow and viscosity behavior, are usually specified. This chapter describes the properties and characteristic features of particles, powders and dispersions and their relevance to pharmaceutical products. Also, it gives an overview of the main measurement methods that are relevant for pharmaceutical products. At the end of this chapter, the contents of this book are summarized.