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Hot-melt coating (HMC) as a solvent-free technology grants faster and more economic coating processes with reduced risk of dissolving the drug during the process. Moreover, traditional coating equipment can be modified to enable the HMC process. Despite the indubitable advantages and feasibility of the process, HMC is not well-known to pharmaceutical industry and its employment is still limited. The main aspect hindering the widespread application of this technique is the need of materials alternative to the conventional polymeric coatings. The current work reviews the published HMC formulations and describes the properties that have led to their selection. As these materials are mainly solid lipid excipients, attention should be paid to their crystallization and solid state behavior, and their impact on the performance of coated drug products, particularly on the stable drug release profile. Although different drug release profiles can be easily tailored, much development work is needed to respond to the unmet requirements of a stable formulation. Ensuring stable solid-state behavior and providing a mechanistic understanding of the macroscopic properties are essential steps towards fulfilling these requirements and establishing of HMC as advanced coating technology for manufacturing of pharmaceutical products., (Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.)

Solvent-free hot-melt coating processing is a novel and cost-efficient approach to manufacturing taste-masked multiparticulate systems. However, most API powders are fine and cohesive and not processable by hot-melt coating. The aim of this study was to produce dense and abrasion-resistant granules with high drug content (>80%) via roller compaction for hot-melt coating process optimization. The selected API was ibuprofen sodium dihydrate, a salt of ibuprofen with improved bioavailability and poor intrinsic compactibility. The formulation and roller compaction process were developed for the production of granules with 94%w/w of API and low friability (∼30%), using sorbitol and isomalt as excipients. The strong bonding mechanism relied on powder jamming prior to the rollers and was investigated via scanning electron microscopy, differential scanning calorimetry and small and wide angle X-ray scattering. It was shown that sorbitol crystals are solubilized during roller compaction and recrystallize as sorbitol hydrate, acting as strong solid bridges. The robustness of the roller compaction process and the re-compaction of fines were investigated. A statistical design of experiments was conducted to evaluate the hot-melt coating process for taste masking of ibuprofen sodium granules. Taste masking required coating ratios higher than 40%w/w of granule batch, emphasizing the need for high-drug-content and abrasion-resistant granules., (Copyright © 2016 Elsevier B.V. All rights reserved.)