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Indirect Methods For Determination of The Protective Effects of Coating Films on The Surface of Crystals |
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| Authors: | Bajdik J Pintye-Hódi K Novák Cs Kelemen A Regdon G Er?s I |
| Institution: | 1.Department of Pharmaceutical Technology, University of Szeged, E?tv?s u. 6, H-6720, Szeged, Hungary ;2.Research Group for Technical Analytical Chemistry of the Hungarian Academy of Sciences & Institute of General and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111, Budapest, Hungary ;3.Department of Medical Informatics, University of Szeged, Korányi fasor 9, H-6720, Szeged, Hungary ; |
| Abstract: | The extents of the protective effects of coating films on the surface of crystals were determined. Three different samples were made with different quantities of coating fluid (Sepifilm LP 010 in 10% aqueous solution). Since the atomizing rate was constant, the coating time increased in parallel with the volume of coating fluid applied. The direct measurement of film thickness and smoothness is very difficult, and therefore indirect methods were used. Dimenhydrinate was chosen as model drug; this is a heat-sensitive antihistamine with a low melting point. This temperature can be reached during the tableting process. The behaviour of samples on exposure to heat was examined by differential scanning calorimetry. The water uptakes of the samples were determined with an Enslin apparatus. Plasticity was studied with an instrumented tablet machine. These indirect methods (thermal conductivity, water uptake and plasticity measurements) revealed connections between the results of the various experiments. An overlong coating time decreased the protective effect of the coating film. This revised version was published online in August 2006 with corrections to the Cover Date. |
| Keywords: | dimenhydrinate DSC film coating HPMC plasticity thermalconductivity water uptake |
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