Determination of coating thickness of minitablets and pellets by dynamic image analysis

The study was focused on the feasibility of measuring film thickness on minitablets and pellets by means of dynamic image analysis using Camsizer XT. Minitablets with diameters of 2.0mm or 2.5mm and pellets in the size range of 0.7-0.8mm with the polymer coating thickness of 80-170 μm were prepared and analyzed. In minitablets the film thickness was measured on the walls and edges and the difference was significant. The results were compared with the results obtained with the use of three microscopic methods (scanning and stereoscopic microscopy). Good correlation between dynamic image analysis and microscopic techniques was shown in the case of the film thickness in pellets and 2.0mm minitablets, but the measurement of the coating layer of larger particles (minitablets 2.5mm) was not sufficiently precise due to the non-isometric shape of these objects and the limited measuring range of the apparatus. Short analysis time, no need for sample preparation and a large number of objects under examination are main advantages of the proposed film thickness measurement by use of a dynamic image analysis.