Mathematical modeling of coating time in dry particulate coating using mild vibration field with bead media described by DEM simulation

Abstract

• A simple stochastic saturation model for dry coating process was developed. • Model introduces assumption one collision causes one particle to adhere on the core. • Unfixed coating particle on the surface of core decrease over time on the model. • Change in the coating ratio is determined by the number of collisions and particles. To theoretically understand the previously reported dry particulate coating process using a mild vibration field with a bead media, a mathematical analysis model of the dry coating system was developed. In this coating process, an ordered mixture with coarse host particles (drug-loaded ion exchange resin, diameter approximately 100 µm) and fine guest particles (acrylic polymer particle, primary particle size of approximately 100 nm) is formed using a vibrating a vessel. Second, the guest particles on the host particulate surface are firmly fixed using the collision of coated particles zirconia beads (diameter 1.5 mm). Our model assumes that the unfixed guest particles are fixed by particle-to-particle collisions ( C c ) provided by the apparatus, thereby increasing the coating ratio. C c was estimated using the discrete element method and some experimental results. The model includes parameters such as the number of C c , host particles and unfixed guest particles. The coating time simulated by the established model equation in this study fits well with the experimental results of the dry process. It depends on the ratio of the number of collisions contributing to the increased coating ratio to the number of unfixed guest particles on the surface of host particles.