Microencapsulation- An Overeview

Microencapsulation is a process by which very tiny droplets or particles of liquid or solid material are surrounded or coated with a continuous film of polymeric material. These micro-capsules have a number of benefits such as converting liquids to solids, separating reactive compounds, providing environmental protection, improved material handling properties. Active materials are then encapsulated in micron-sized capsules of barrier polymers (gelatin, plastic, wax ...). The reasons for microencapsulation are countless. In some cases, the core must be isolated from its surroundings, as in isolating vitamins from the deteriorating effects of oxygen, retarding evaporation of a volatile core, improving the handling properties of a sticky material, or isolating a reactive core from chemical attack. In other cases, the objective is not to isolate the core completely but to control the rate at which it leaves the microcapsule, as in the controlled release of drugs or pesticides. The problem may be as simple as masking the taste or odor of the core, or as complex as increasing the selectivity of an adsorption or extraction process. A range of materials are suited for use as the capsule material : lipids, wax crystal starch modified starch cellulose phospholipids and other polymers. After designing the right biodegradable polymers, micro encapsulation has permitted control release delivery system. These revolutionary systems allow controlling the rate, duration and distribution of active drug. The present review deals with the technical aspects as well as various applications of microencapsulation.