Chapter 3 - Analytical Techniques in Solid-state Characterization

Abstract

This chapter discusses many of the common analytical techniques used to characterize pharmaceutical solids. The microscopic methods can be divided into two categories: optical microscopy techniques that probe features on the order of a micron or larger, and electron microscopy techniques that study materials at submicron level. Thermal analysis techniques are commonly used to characterize pharmaceutical solids. In general, thermal techniques rely upon the change in the properties of a material as it is heated. Differential scanning calorimetry is one of the most common analytical techniques used to characterize pharmaceutical solids. In this technique, a sample and a reference are heated simultaneously while keeping them both at the same temperature. Solid-state nuclear magnetic resonance spectroscopy (SSNMR) is an extremely powerful technique for the characterization of pharmaceutical solids. It is nondestructive and noninvasive, quantitative and selective, and can be used to study structure and dynamics. SSNMR has emerged as a structural technique by combining advanced SSNMR experiments with theoretical predictions to rival crystallography as a method to determine the three-dimensional structure of molecules in a crystal lattice.