The filling of granules into hard gelatine capsules

Four different granule size fractions of Sorbitol instant(R) were filled in to hard gelatine capsules on a tamp filling (Bosch) and a dosator nozzle ma chine (Zanasi) to allow comparison of the filling principles. An acceptable filling performance was always achieved and was independent of the machine type employed. Tamp filling was found to be slightly better for the coarse r granule size fractions, because it does not seem to rely on a firm plug f ormation. A direct relationship between the angle of internal flow (Varthal is and Pilpel, 1976) and the coefficient of fill weight variation was found for both systems. Using the dosator nozzle machine, the plug formed was al ways denser than the maximum bulk density, whereas on the tamp filling mach ine for smallest granule size the maximum plug density could not be achieve d with the settings employed. The results suggest that in situations where a low plug density is an essential prerequisite for drug dissolution and bi oavailability the tamp filling machine appears the more suitable filling pr inciple. However, if a greater extent of compression is required in order t o fill large dose drugs or to use a smaller capsule size, the dosator nozzl e principle might work more successfully for granules. (C) 1999 Elsevier Sc ience B.V. All rights reserved.