Pelletization Technology: a Quick Review

Pelletization process first came into existence way back during the 1950s, when the first product was introduced to the market. These pelletized dosage forms have gained popularity considerably from then because of their distinct advantages, such as ease of capsule filling because of better flow properties of the perfectly spherical pellets; enhancement of drug dissolution; ease of coating; sustained, controlled, or site-specific delivery of the drug from coated pellets; uniform packing; even distribution in the GI tract; and less GI irritation. Pelletized dosage forms can be prepared by a number of techniques, including drug layering on nonpareil sugar or microcrystalline cellulose beads, spray drying, spray congealing, roto granulation, hot-melt extrusion, and spheronization of low melting materials or extrusion-spheronization of a wet mass. The present review outlines the recent findings on the manufacturing and evaluation of spherical pellets. The techniques namely extrusion-spheronization, hot melt extrusion, freeze pelletization, cryopelletization have been discussed along with formulation requirements for the process, parameters affecting pelletization. Evaluation of quality of the pellets is discussed with reference to the size distribution, shape, surface morphology, specific surface area, friability, tensile strength. INTRODUCTION: Since the time of immemorial centuries, oral drug administration has been one of the most convenient and widely accepted routes of delivery for most therapeutic agents. Traditionally, oral dosage forms are classified as single unit and multiple unit dosage forms. Multiparticulate dosage forms are receiving a immense attention as alternative drug delivery system for oral drug delivery even though single unit dosage forms have been widely used for decades. The most commonly used pharmaceutical solid dosage forms today include granules, pellets, tablets and capsules, out of which tablets being the most popular dosage form, accounting for 70% of all ethical pharmaceutical preparations produced 1, . But soon it was sensed that some of the formulating and clinical problems (free flowing property, dose dumping, dysphagia, etc.) comes along with the single dose formulations. This soon led to the dividing of monolithic dosage forms into multiples. Multiple unit dosage forms (MUDFs), are formulated as granules, pellets, or mini tablets 3, . The concept of this multiple unit dosage forms answers many formulating problems and is a common strategy to control the release of drug as showing the reproducible release profiles when compared to SUDFs. These MUDFs, can either be filled in to hard capsules or compacted in to bigger tablets or can be dispensed in a dose pouches or packlets.