An Extensive Insight On Physico-Chemical Characterization Of Hot-Melt Coating Excipients

Hot-melt coatings (HMC) are widely used to provide drug protection, to increase aesthetic value of products, to reduce acidity if vitamins, to provide lubrication and modified drug release. In hot-melt coating the substrates are coated with molten form of coating materials. Substrates used for coating are beads, capsules, granules, pellets, pills, spherules and tablets. Hot-melt coating devoid of solvent use, solvent disposal, solvent evaporation and solvent treatment is not required; as a result powders with very high specific surface areas can be coated rapidly. HMC technique not only protects the operators from solvent but also protect the environment. Hot-melt coating materials are mostly hydrophilic as well as hydrophobic in nature. Majority of hot-melt coating materials are obtained from natural, semi-synthetic and synthetic sources. Generally, lipids are the smart option to polymer coatings as they need melting before application directly on the substrate and make the technique cost effective. Depending upon sources of the lipids, the physico-chemical properties of them may change. Different lipids can be used in coating and selection of the right lipid for the application requires knowledge of their physico-chemical properties and its associated effect on drug release.