Abstract
Dilatometric method was proposed to measure the volume increase of disintegrants due to swelling in water as a function of time. Potato starch, corn starch, and crystalline cellulose were used for the experiments. Time necessary for complete swelling was 60 sec for all disintegrants. Corn starch showed the shortest time of 20 sec. Two characteristic values for swelling of a disintegrant, k and b, were obtained from linear plot of t/Q and t, where Q is the swelling volume at time t. The values of 1/k and 1/b show the initial rate of the volume increase and the maximum swelling volume, respectively. The swelling pressure of ion exchange resin particles of various cross linking degree was calculated from water vapor adsorption isotherms. Highly cross linked resins showed a high pressure and a low swelling volume. Disintegration time depended on the degree of cross linking when the resin particles were contained in a tablet as a disintegrant. Low cross-linked resin particles gave good disintegration to a tablet. It was concluded from these results that the tablet disintegration time was affected by volume increase due to swelling and the swelling pressure was sufficient to disintegrate the tablet even if the pressure was low.
