China Science

For the prediction of the air; product temperatures, the product moisture,; 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,; the constant for the exchange rate between both zones; to use these values for other sets of experiments to test the model. The adaptation of the 3 parameters (limit moisture, critical moisture,; 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; 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,; equipment-related parameters. Hence, the model can be used to theoretically investigate the influence of different process paramaters. The mean difference between the predicted,; 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,; the exchange rate constant. The model is useful for the prediction of the air; product temperatures, the product moisture,; air humidity during a coating process in the Bohle Lab-Coater using round, biconvex tablets.

Susanne Page1?Karl-Heinrich Baumann2?Peter Kleinebudde3Email:Kleinebudde@uni-duesseldorf.de
[1] Institute of Pharmaceutics; Biopharmaceutics, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Str 4, D-06120 Halle, Germany ;[2] Department of Engineering, Martin-Luther-University Halle-Wittenberg, Geusaer Str 132, D-06217 Merseburg, Germany ;[3] Institute of Pharmaceutics; Biopharmaceutics, Heinrich-Heine-University Duesseldorf, Universitaetsstr 1, 40627 Düsseldorf, Germany ;[4] Present address: F. Hoffmann-La Roche Ltd, Basel, Switzerland