Preparing of pellets by extrusion/spheronization using different types of equipment and process conditions.

INTRODUCTION: The focus of this work was to produce matrix pellets made by extrusion/ spheronization using two types of equipment. The aim was to accomplish the laboratory-scale I process that has been already optimized and accepted with another type of equipment (laboratory-scale II). METHODS: A matrix pellet formulation consisting of MCC, Eudragit NE 30D and diclofenac sodium was used in the two types of equipment. Physico-chemical parameters and the dissolution profiles of the pellets in phosphate buffer pH 6.8 were compared. RESULTS: Pellets from both processes were similar in shape and tensile strength. They differed in particle size and dissolution profile. This may be contributed to different spheronization conditions.

[Evaluation of phenomena detected on the surface of stirred coating liquid]. / Felületen lejátszódó jelenségek szerepének vizsgálata a bevonó folyadékok eloállítása során.

The main objective of this work was to study the effect of conditions of coating fluids through the properties of the coating fluid, film and coated product. With a more accurate understanding of the process the effects of the factors can be defined and by means of this the optimal composition can be determined and problem-free coating can be carried out. In this work the evaporation was studied. The effects of different operational factors on evaporation were studied through fluids of different compositions. In case of fluids containing ethanol a significant loss can be detected after a short period of time and this fact cannot be changed by the use of an antifoaming agent. The highest difference in effect of a given factor was detected for the stirring rate. The effect of the operational factors changed depending on the Composition. Stirring rate showed the highest sensitivity to the presence of the volatile component. These results can help to determine the critical control points and the optimal stirring circumstances.

Rapid method to study the sedimentation of a pigment suspension prepared for coating fluids.

Film coating fluids commonly contain a pigment suspension. The sedimentation of insoluble particles in the coating suspension is one of the main problems during the formulation of the coating fluid. The aims of this work were to investigate the suitability of an energy-dispersive X-ray fluorescence analyser for rapid measurement of the sedimentation of titanium dioxide in aqueous suspensions. The suspensions were produced with a high-speed Ultra-Turrax. The process factors evaluated were the stirring rate, time and volume, and the process of sedimentation of the pigment. The enrichment of the pigment at the bottom of the sample holder was followed by means of the very rapid method of energy-dispersive X-ray fluorescence analysis. It can be concluded that the sedimentation of the particles is described by the Weibull equation. With an appropriate combination of the factors, a threefold increase in the sedimentation time was achieved. The mathematically based information (sedimentation time, kinetics of sedimentation, etc.) is essential for an exact evaluation of the preparation of the coating fluid. The understanding of the process through use of this test method leads to the ability to identify the critical control points of film coating.