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AAPS PharmSciTech. 2006 June; 7(2): E87–E94.
Published online 2006 May 5. doi:  10.1208/pt070243
PMCID: PMC2750294

Mathematical modeling of an aqueous film coating process in a Bohle Lab-Coater: Part 2: Application of the model


For the prediction of the air and product temperatures, the product moisture, and the air humidity during a coating process in a Bohle Lab-Coater, a model was developed. The purpose of this work was to determine the limit moisture, the critical moisture, and the constant for the exchange rate between both zones and to use these values for other sets of experiments to test the model. The adaptation of the 3 parameters (limit moisture, critical moisture, and exchange rate constant), was done by calculation of the product temperature in both zones for several sets of parameters in order to minimize the sum of square deviation between the calculated and the measured product temperatures. This set of parameters was used to test the validity of the model. By applying the model, the product temperature could be predicted based on the product, process, and equipment-related parameters. Hence, the model can be used to theoretically investigate the influence of different process paramaters. The mean difference between the predicted, and measured product temperatures in the steady state is ≈2 up to 3 K using the determined parameter set for the limit moisture, the critical moisture, and the exchange rate constant. The model is useful for the prediction of the air and product temperatures, the product moisture, and air humidity during a coating process in the Bohle Lab-Coater using round, biconvex tablets.

Keywords: film coating, mathematical modeling, heat and mass transfer, convection, particle movement

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.
1. Tobiska S, Kleinebudde P. A simple method for evaluating the mixing efficiency of a new type of pan coater. Int J Pharm. 2001;224:141–149. doi: 10.1016/S0378-5173(01)00742-6. [PubMed] [Cross Ref]
2. Okutgen E, Jordan M, Hogan JE, Aulton ME. Effects of tablet core dimensional instability on the generation of internal stresses within film coats. Part II. Temperature and relative humidity variation within a tablet bed during aqueous film coating in an Accela-Cota. Drug Dev Ind Pharm. 1991;17:1191–1199. doi: 10.3109/03639049109043853. [Cross Ref]

Articles from AAPS PharmSciTech are provided here courtesy of American Association of Pharmaceutical Scientists