EVALUATION OF DRUG DELIVERY SYSTEMS BY ELECTRON-MICROSCOPY TECHNIQUES

This review covers the applications of electron microscopic techniques to the characterization and evaluation of drug delivery systems. Vari ous electron microscopic (EM) related techniques such as transmission electron microscopy, scanning electron microscopy (SEM), SEM with ener gy dispersive X-ray microanalysis, and freeze-fracture electron micros copy are extensively used for this purpose. Microcapsules, microsphere s, nanocapsules, liposomes, polymeric carriers and other drug delivery systems are characterized using EM related techniques for their surfa ce topography, size and shape analysis, biodegradation, in vitro - in vivo evaluation and drug excipient interactions and characterization. Electron microscopy methods are very useful in understanding the mecha nism of drug carrier formation, drug release in in vitro - in vivo sit uations, and drug carrier - body fluid interactions. EM techniques hav e also been used to study ultra-structural disposition of drug carrier s in body compartments.