Microcrystalline cellulose (MCC) has emerged as the most resourceful excipient of all times in drug research. Thanks to its profusion in terms of grades available for different needs and its physical properties that support a variety of functionality requirements especially for the most frequently used unit dosage forms. MCC can be used as a bulking agent, disintegrant, binder, lubricant, and glidant besides being a stability enhancer and a secondary suspending agent. It can be used in direct compression of most drugs and saves material, capital, equipment, and labor. Its ever increasing applications in drug research include its utility in immediate release (tablets and liquids) dosage forms, sustained release dosage forms (multiparticulates and matrix tablets), topical preparations, oral liquids, organoleptic enhancements as in chewable and mouth dissolving tablets, anti-reflux, and nutraceuticals. The review discusses these applications in sufficient detail citing examples and investigating the justifications for such functions.

Despite many research studies being conducted in the field of drug delivery, none of them have been able to match the characteristic features and advantages offered by oral unit dosage forms such as tablets and capsules. With the advent of this form of drug delivery, the subsequent researches of betterment of this delivery system emerged, which included sophisticated machinery and superior tabletting aids. These tabletting aids, which we affectionately call excipients, have been an imperative part of tabletting that forms the basis of delivering potent or non potent drugs in the form of such effective and patient-friendly unit dosage forms. The most basic and important excipients categories involved in tabletting include diluents/bulking agents, disintegrants, binders, lubricants, and glidants and many examples of each can be cited from the oldest to the newest literature. Each of these categories of excipients has a specific proven cause for its requirement in tabletting and the absence of which can cause serious consequences. Many excipients offer multiple advantages and can serve dual purposes. However, microcrystalline cellulose (MCC) is an excipient that can play the roles of almost every category listed above for tablet research. Because of this, MCC is the most versatile and user friendly excipient among numerous available. The development of MCC has made an extremely valuable tabletting agent available to the pharmaceutical industry and since its introduction in late 1950s, it stands today as the single most important tablet excipient developed in modern times. Its incorporation in one way or the other can be seen in almost every finished unit dosage form.

MCC is derived from a special grade of purified alpha wood cellulose by severe acid hydrolysis to remove the amorphous cellulose portions, yielding particles consisting of bundle-like needle-like microcrystals