Pharmaceuticals: Design and development of drug delivery systems

Of the many techniques that are useful for investigating pharmaceutical solids, methods based on diffraction are probably the most powerful, having the potential to yield structural data. As pharmaceutical materials are generally handled in the form of bulk powder, powder X-ray diffraction (PXRD) is the method of choice. This chapter reviews applications of PXRD in the field of pharmaceutical development with a particular emphasis on the design and development of drug delivery systems. The applications cover almost every possible use of PXRD and also exploit the new technological developments in instrumentation (e.g., position-sensitive detectors and synchrotron radiation) and software. Applications include characterization of polymorphic forms, assessment of crystallinity, quantitative analysis of polymorphic mixtures, elucidation of lattice parameters and crystal structure, and real-time studies of polymorphic phase transformations as a function of temperature, compaction, and pressure.