Preparation and evaluation of orally disintegrating tablets containing vitamin E as a model fat-soluble drug

The purpose of the present study was to develop orally disintegrating tablets (ODTs) containing fat-soluble drugs that disintegrate rapidly while having appropriate tablet strength. We chose vitamin E (VE) as a model drug; d-α-tocopheryl acetate, as the oily VE (VE-OI), and d-α-tocopheryl acid succinate, as the powder VE (VE-PO), were used. The oily VE was added directly to ODTs (VE-OI ODTs) and also used for the preparation of two types of VE granule, i.e., granules prepared using adsorption to calcium silicate (VE-FL granules) and granules prepared using spray-drying with gelatin (VE-SD granules); each type of granule was added to ODTs (VE-FL ODTs and VE-SD ODTs). Powder VE was added directly to ODTs (VE-PO ODTs). Various VE ODTs were prepared using these four additional methods with varying amounts of VE per tablet and were evaluated with respect to their manufacturability, physicochemical characteristics, and stability. It was demonstrated that a tablet porosity of 30% to 35% and tensile strength of 7 kg/cm(2) or greater are required to provide VE ODTs with rapid disintegration and appropriate tablet strength, and that VE-SD granules and powder VE are suitable forms of VE to be added. When stability tests of VE-SD ODTs and VE-PO ODTs were performed, VE-PO ODTs exhibited prolongation of disintegration time and increased tensile strength, whereas VE-SD ODTs showed none of these changes. These changes were thought to be attributable to a decrease in the pore size of VE-PO ODTs resulting from the softening and migration of powder VE under hot storage conditions.