In the diploma thesis, we focused on analyzing the wetted surface during the tablet coating process. A measuring setup was prepared comprising of a high speed camera, a strong light, a syringe pump and a computer, which was used to evaluate how the wetted areas of the tablet changes when water drops fall on its surface. Volumes for different liquid flow rates and the time delays of the drop of the second droplet were determined, and the change in the size of the wetted surface when changing these two parameters were analyzed. For a larger wetted surface a larger flow is needed, resulting in a large droplet volume or a short time delay for the second droplet to fall. The largest wetted surface for the G30 needle was at a flow rate of 550 μl/min, the smallest at a flow rate of 10 μl/min, the largest wetted area for the G34 needle was at a flow rate of 450 μl/min and the smallest at a flow rate of 6 μl/min.
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