LUBRICANTS: SIGNIFICANCE IN TABLET DEVELOPMENT PROCESS

Lubrication plays an important role in efficient manufacturing of pharmaceutical solid dosage forms; lubricants are necessary ingredients in vigorous formulations to achieve this. Lubricants are commonly added additives to many pharmaceutical solid formulations. Following compression, a tablet must be ejected out of the tablet press die. Lubricants reduce the friction between the tablet and the die metal surface which decreases the ejection force and helps to make sure that the tablet is totally ejected. High friction during Compression can cause a series of problems, including inadequate tablet quality from capping or even fragmentation during ejection Introduction In this review, the basic conditions on lubrication is introduced, in which the relationships between lubrication and friction/adhesion forces are discussed. Then, the application of lubrication in the growth of pharmaceutical products and manufacturing processes is discussed with an emphasis on magnesium stearate. In particular, the effect of its hydration state (anhydrate, monohydrate, di-hydrate, and tri-hydrate) and its fine particles characteristics on lubrication efficiency, as well as product and process performance is summarized. In addition, the impact of lubrication on the dynamics of compaction/compression processes and on the mechanical properties of compacts/tablets is presented. Furthermore, the online monitoring of magnesium stearate in a blending process is briefly mentioned. Finally, the chemical compatibility of active pharmaceutical ingredient (API) with magnesium stearate and its reactive impurities is reviewed with examples from the literature illustrating the various reaction mechanisms involved.