Studies on the Mechanism of Tablet Compression and Disintegration. VIII: Phenomena of Disintegration and Waterpenetration caused by Microstructure of Aluminum Silicate

Disintegration of aluminum silicate tablets differs greatly according to whether the tablets are dry or moist. The same is true of the amount of air that escapes when tablets are thrown into water. These data are presented in Table I. These two phenomena in moist tablets disappear when tablets are dried. The reason for these phenomena is the fine structure of the bottle-neck type capillary indicated in Table I in Part VII of this series. In such cases, condensed water closes the neck of capillary, even at a comparatively low equilibrium vapor pressure and stops immediate penetration of water even if internal space is void. Calculated from the data in Tables I and II (Part VII), liberation of air from the bottle-neck capillary decreases by 62.4% when the vapor pressure reaches equilibrium in the air of 60% relative humidity at 20°. This is approximately in accordance with the present experimental results shown in Table I of this report. The same may be said of water penetration. Sedimentation volume of disintegrated substance also differs according to whether the tablet is dry or moist. This is due to the difference in the state of layering in water by different amount of air liberated. Sedimentation volume is extremely large compared to tablet volume. Since the sedimentation volume is more stable than tablet volume in water, tablets in water will possess potential energy of disintegration.