Yoshifumi Osako

A fuzzy control system of high shear granulation using image processing

Abstract A novel system has been developed to control granule growth in a high shear (speed) granulation. The system basically consisted of an image processing and a fuzzy control system. An image probe composed of a CCD camera, air purge unit and high energy xenon (Xe) lightning system was also developed to continuously take granule images through the sidewall of the vessel. The images were digitized by the image processing system and granule median diameter and shape factor were calculated automatically. Median diameter and shape factor of granules sampled out during granulation were also calculated by manually, and then compared with the automatically computed ones. Close agreement between both measurements was obtained, showing the developed system could continuously monitor granule growth during high shear granulation. A fuzzy control system using a linguistic algorithm employing if-then rules with a process lag element taken into consideration was developed to control granule growth accurately without any excessive growth (overshoot). This newly developed system was applied to actual high shear granulation of pharmaceutical powders and validity of the system was investigated. It was found that the system could control granule growth with high accuracy, regardless of changes in operating conditions.

Feedback control in high shear granulation of pharmaceutical powders.

A novel system has been developed to control granule growth in high shear granulation. The system basically consisted of an image-processing device and a fuzzy control system. A computer-controlled image processor, an air purge unit, a high-energy xenon lighting system and an image probe with a CCD camera comprised the image processing device. A fuzzy control system using a linguistic algorithm employing if-then rules with a process lag element taken into consideration has been developed to accurately control granule growth without any excessive growth. This newly developed system was applied to actual high shear granulation of pharmaceutical powders and validity of the system was investigated. It was found that the system could control granule growth with high accuracy, regardless of changes in physical properties of starting materials and the operating conditions.

Quantitative evaluation of kneading and extrusion processes by pressure transmission characteristics of wet kneaded masses

This study is devoted to the quantitative evaluation of wet kneaded masses prepared by a paddle-type kneader, and the analysis of the kneading process and the following extrusion granulation process. A compaction tester of wet kneaded masses has been developed and the compression properties of the masses are characterized by a pressure transmission between the upper and lower punches of the tester. The dispersion condition of a binder liquid among the wet kneaded masses prepared under various kneading times is investigated. The extrusion pressure through a single ejection hole on the lower punch is also measured. The pressure transmission is found to have a linear relationship between the dispersion of binder liquid and the extrusion pressure. This results lead to a conclusion that the proposed method provides the generalized measuring means of wet kneaded masses. An extrusion granulation by a dome-type extruder is conducted using wet kneaded masses and physical properties of the extruded pellets (granules), such as friability, specific surface area and disintegration time, are investigated. Good linearity can be found between the pressure transmission and the physical properties of the pellets. As the result of these findings, the kneading condition, i.e. the dispersion of binder liquid among the wet kneaded masses, can be quantitatively analyzed and the physical properties of pellets prepared by extrusion granulation can be accurately predicted by the pressure transmission measured by the newly developed compression tester.