PELLETS AND PELLETIZATION TECHNIQUES: A CRITICAL REVIEW

Abstract

In the pharmaceutical industry, pellets can be defined as small, free-flowing, spherical particulates manufactured by the agglomeration of fine powders or granules of drug substances and excipients using appropriate processing equipment. Pelletization has gained a great interest in recent years due to its various advantages over other similar techniques; such as uniformity of dose and flexibility in dosage form design. There are a number of pelletization techniques currently used by pharmaceutical industry. Among them Extrusion-spheronization and solution/suspension layering are most commonly used in pharmaceutical industries. Other novel techniques include balling, compression, cryopelletization, dry powder layering, hot melt extrusion etc. In this review, a brief account of all the important techniques with special reference to extrusion-spheronization and solution layering is included.Extrusion–spheronization is a multistep process involving dry mixing, wet granulation, extrusion, spheronization, drying, and screening; whereas solution or suspension layering involves deposition of successive layers of drug and binder solution/ suspension on started seeds, which can be either an inert material or granules of same drug. Every technique has their own advantages and limitations, therefore a thorough understanding of the process variables is important before choosing a pelletization method