ABSTRACT:
Microencapsulation is a technique by which thin coatings of wall material are formed around the substances which may be solids, liquids or even gases, enclosed in microscopic particles. Microencapsulated products (micro particles) are the small entities that have an active agent know as the core material surrounded by a shell known as the coating material or embedded into a matrix structure. Several properties can be attained by macro packaging techniques; however, the uniqueness of microencapsulation is the smallness of the coated particles and their subsequent use and adaptation to a wide variety of dosage forms and not has been technically feasible. The reasons for microencapsulation are countless. Microencapsulation system offers potential advantages over conventional drug delivery systems and also established as unique carrier systems for many pharmaceuticals. Although significant advances have been made in the field of microencapsulation, still many challenges need to be rectified during the appropriate selection of core materials, coating materials and process techniques. The review covers encapsulation materials, coating material, classification of microcapsules, physics of release through the capsule wall and / or desorption from carrier, techniques of preparation, characterization/ evaluation of microspheres many uses to which microcapsules are put.