Yohei Hoashi

Solventless dry powder coating for sustained drug release using mechanochemical treatment based on the tri-component system of acetaminophen, carnauba wax and glidant

Objective: Solventless dry powder coating methods have many advantages compared to solvent-based methods: they are more economical, simpler, safer, more environmentally friendly and easier to scale up. The purpose of this study was to investigate a highly effective dry powder coating method using the mechanofusion system, a mechanochemical treatment equipped with high compressive and shearing force.Materials and methods: Acetaminophen (AAP) and carnauba wax (CW) were selected as core particles of the model drug and coating material, respectively. Mixtures of AAP and CW with and without talc were processed using the mechanofusion system.Results: Sustained AAP release was observed by selecting appropriate processing conditions for the rotation speed and the slit size. The dissolution rate of AAP processed with CW substantially decreased with an increase in talc content up to 40% of the amount of CW loaded. Increasing the coating amount by two-step addition of CW led to more effective coating and extended drug release. Scanning electron micrographs indicated that CW adhered and showed satisfactory coverage of the surface of AAP particles.Conclusion: Effective CW coating onto the AAP surface was successfully achieved by strictly controlling the processing conditions and the composition of core particles, coating material and glidant. Our mechanochemical dry powder coating method using the mechanofusion system is a simple and promising means of solventless pharmaceutical coating.

A completely solvent-free process for the improvement of erythritol compactibility

OBJECTIVE We obtained improvement of erythritol compactibility by formulating composite particles composed of erythritol and porous silica using a twin-screw kneader. METHODS Erythritol-based tablets formulated with composite particles were directly compacted, and we estimated their hardness and the friability. The compression properties of the erythritol powder bed including composite particles were estimated using a Heckel analysis and force-displacement profiles, and we investigated the physical states of the composite particles by powder X-ray diffractometry, a thermal analysis and a nitrogen gas adsorption study. RESULTS A direct-compacted erythritol tablet formulated with composite particles, prepared at the melting temperature of erythritol (120 °C), exhibited high hardness and low friability. A pressure transmission study revealed the higher plasticity and lower elasticity of an erythritol powder bed formulated with composite particles prepared at 120 °C. Physical states of the composite particles indicated that erythritol in the composite particles was adsorbed onto porous silica with a subsequent decrease in the erythritol crystallinity as a result of high mechanical force at the melting temperature of erythritol. CONCLUSION The improvement of the erythritol compactibility formulated with composite particles through processing with a twin-screw kneader at 120 °C. This was affected by the reduction of the erythritol crystallinity in the composite particles.