ABSTRACT

In the past decades in vitro assessments of dosage form performance were undertaken

almost exclusively through studies of drug release kinetics. In recent years however, we

have seen the introduction of a range of imaging techniques that allow the pharmaceutical

scientist to investigate drug release processes and to discern more clearly the dynamic

events that contribute to the underlying drug release mechanisms. This complex area of

pharmaceutical research is still in its infancy and few of these techniques are in

widespread use, but within this chapter we aim to provide the reader with a brief

introduction to illustrate the potential of some of these new approaches. There are new

microscopic and spectroscopic techniques that can provide, for example, (i) a topological

or three-dimensional (3D) internal characterization of dose form morphology, (ii) surface

and internal chemical imaging, (iii) observations of the behavior of the whole dosage form

or of individual components on a macro-, micro-, or nanoscale, and (vi) allow real-time

monitoring of product quality during the manufacturing process. It is beyond the scope of

this chapter to provide descriptions of all new methods that have been applied to

characterize medicinal products in this way (a non-exhaustive summary is provided in

Table 1), and for explanations of theory and instrumentation the reader is directed to more

specialized and authoritative reviews. This chapter will focus on the potential of a few

chosen techniques that are experiencing a growing kernel of pharmaceutical application,

and which the authors believe have a high potential for enhancing our future

understanding of the way dosage forms behave.