Pharmaceutical Pellets – A Versatile Carrier for Oral Controlled Delivery of Drugs

During recent years, considerable energy and expense have been paid to devise methods for producing dosage forms having unique morphologies in order to fulfill various requirements for utilizing a variety of medicinal substances. Drug loaded spherical multi­-particulates, also known as pellets, are one such dosage form. Pellets have been extensively investigated to develop controlled and delayed release oral formulations that release the active ingredients in the gastrointestinal tract at predetermined rates. The reason for their wide acceptance lies in their versatility that it can be used to target tissue in order to maximize the drug delivery at the desired site of action within the given period of time in the gastrointestinal tract.

As compared to single dosage form pellets are technically more complicated to manufacture, but it possess a number of advantages also. For instance, the pelletized product shows maximum drug absorption and reduced peak plasma fluctuation as they gets uniformly distributed in the gastrointestinal tract as subunits, thereby, Pellets are less susceptible to dose dumping and customized release profiles (pulsed, sustained or delayed) can be achieved by careful selection of polymers and method of preparation. Different chemically compatible as well as incompatible pellets can be combined together and delivered in the gastrointestinal tract either at the same sites or different sites. Even pellets of the same drug with different with release rates can be given in a single dosage form example capsule.

Scientifically, pellets are substantially spherical mechanically strong agglomerates of powder particles, prepared by a specialized granulation process, known as pelletization, which was formed by the agglomeration of fine powdered excipient and drugs together that leads to the formation of small free flowing spherical or semi spherical. Although both granulation and pelletization are agglomeration processes but they differ in the sense that in case of former, agglomerate produced are porous (20­50%) and irregular (size range 0.1 to 2.0 mm), whereas, pellets possess a uniform shape and size that ranges from 0.5­2.0 mm, about 10% of low porosity and are free­flowing.

Pharmaceutically pellets are versatile multi-particulate solid dosage form that can be amenable to both encapsulation into hard gelatin capsules or compression to form tablets and, therefore, may form an excellent carrier system for the controlled oral delivery of both low and high dose drugs.

The pellet produced via extrusion spheronization, freeze pelletization technology, cryopelletization and various other techniques are versatile carrier for oral controlled release dosage form .The major disadvantage of pellets produced by extrusion spheronization is that it is a time consuming process as it utilizes granulating liquid such as water and thus requiring drying phase while other novel pelletization techniques like cryopelletization involves freeze drying to remove water. But a major limitation is the use of nitrogen at ­196°C. Due to good technological and biopharmaceutical advantages pelletization have gained importance in the modern pharmaceutical sciences and expected to play a major role as a carrier to control the release of drug.

Most of the pharmaceutical companies develop pellets for wide range of active pharmaceutical ingredients.