Modified conventional hard gelatin capsules as fast disintegrating dosage form in the oral cavity

Fast disintegrating capsules for administration in the oral cavity were prepared either by perforation or by vacuum-drying of conventional hard capsules. When compared to other fast disintegrating dosage forms (e.g. lyophilized sponges or tablets), these capsules have various advantages, in particular, a high drug loading capacity and no compression steps. The disintegration time of conventional hard gelatin capsules (HGC) was reduced from 91 to 39 s by introducing 6-10 small holes (diameter =25-50 microm) into the capsule shell. Vacuum-drying of conventional hard gelatin capsules resulted in brittle capsules, which broke rapidly in the oral cavity. The brittleness of the hard gelatin capsules correlated well with their moisture content. The critical moisture value for sufficient brittleness of hard gelatin capsules was <4% w/w. In contrast, HPMC capsules remained flexible, even at low moisture content. The moisture uptake of various capsule fillers was in the order of Avicel PH101 > lactose > Avicel PH112 > or = mannitol. Hard gelatin capsules filled with mannitol and packaged in bottles with silica gel kept their desired brittleness during 6 months storage at various relative humidities.