APPLICATIONS OF THE ENVIRONMENTAL SCANNING ELECTRON-MICROSCOPE TO THEANALYSIS OF PHARMACEUTICAL FORMULATIONS

Electron microscopy has been used for several years as a routine tool for the study of pharmaceutical formulations. However, it is usually d esirable to obtain information on these systems in the wet state, and there are concerns regarding the interpretation of information provide d by conventional electron microscopy where samples are subjected to p reparation techniques which may include freezing, drying, fracturing, and coating. The environmental scanning electron microscope (ESEM) has been used to analyse a number of pharmaceutical samples in their natu ral state. Results obtained from these samples, including biodegradabl e matrices, microparticulate systems (both degradable and non-biodegra dable), and bioadhesive matrices, will be discussed and the merits and limitations of the ESEM will be highlighted.