engleski

Coating of microcrystalline cellulose tablets in a fluid-bed unit with a Wurster insert

Fertilizer and detergent manufacturing, food processing, cosmetic and especially pharmaceutical industries use fluid-bed coating technology to improve properties like color, taste, composition, flowability and compressibility of various particulate systems. In this paper, the coating process of placebo pharmaceutical system is studied. Tablets of microcrystalline cellulose (MCC) were coated in a batch fluid-bed process system with a Wurster tube. Aqueous solution of hydroxypropyl methylcellulose (HPMC) was used as coating formulation that has to be deposited on the surface of placebo ingredient. Ultimate goal would certainly be reaching high deposition uniformity on the surface of MCC tablet with minor loss of coating agent. This research deals with detection of the process conditions and properties of inlet process stream that will lead underlying phenomena in desired direction and result in a collective of tablets with high coating uniformity. The effects of temperature of inlet air stream, the flow rate of coating medium as process variables, and concentration of HPMC solution as the property of the inlet process stream on the coating efficiency are defined as well. Contributions of macroscopic variables in forming the process response, coating efficiency, were statistically determined by using two-level factorial design. Statistical analysis indicates a significant effect of the inlet air temperature on the coating efficiency. Additionally, adhesion of coating agent in the deposition process has been considered. Measuring of contact angle with goniometer technique suggests a notable compatibility of MCC tablets and aqueous solutions of HPMC in their adhesion to tablet coated with HPMC film.

Coating process, Wurster fluidized bed, Coating efficiency, Coating uniformity

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