Mathematical modeling of moisture removal from granules

With modern world trends in the growth of consumption of products of various industries and the environmental situation, the problem of rational use of energy and raw materials in industrial production in order to obtain the maximum amount of finished product of a given quality. An important step in solving this problem is to create an adequate mathematical model of the process. A simplified model of the process of dehydration of the aqueous solution film on the surface of a single granule in the production of multilayer composites in a granulator dryer has been developed. Simulation of pellet dehydration includes analysis of heat distribution in a spherical material and in a film of liquid (heat exchange) covering the sphere, and the process of evaporation of the mixture film (mass transfer), which take place simultaneously. The results can be applied at the stages of design and testing of the granulator.

Droplet Impact Phenomena in Fluidized Bed Coating Process with a Wurster Insert

The aim of this study is to determine favorable process conditions for the coating of placebo tablets. Tablets made of microcrystalline cellulose are coated with hydroxypropyl cellulose polymer and Advantia™ Prime polymeric mixture film in lab-scale fluid-bed environment with a Wurster tube. In order to determine favorable process conditions (concentration, Wurster tube position, inlet air temperature, and atomization pressure), evaluation factors expressing process efficiency were calculated. Stereomicroscopy analysis provided good results with respect to the coating layer adherence and consistency. Results showed that the increased number of the coating cycles contributes to the desired featureless film morphology, when sufficiently high temperature and pressure are applied, thus resulting in high intra- and intertablet uniformity. Additionally, this paper analyzes the coating process from a mechanistic perspective of the underlying phenomena occurring on a tablet surface. Provided diagrams can help efficiently in detecting proper conditions that will result in coated tablets with strictly defined aimed properties. Process and formulation properties synergically result in a preferential occurrence of a deposition mechanism for all experiments conducted. Moreover, collision is found as a prevalent impact regime for the coating process studied. Finally, our intention here is to correlate hydrodynamic conditions and droplet breakup occurrence with a droplet diameter.