Measurement of Rates of Water Penetration into Tablets by Microcalorimetry

A method of measuring the rate of water penetration into tablets was proposed in which a heat conduction microcalorimeter was employed. Heat evolved when the tablets were immersed in water. The rate of generation of the heat was determined by a deconvolution method. The rate of water penetration into tablets when they were placed in water was determined by assuming to correspond to the generation rate of heat. For model experiments of water penetration into tablets, hydrophilic MCC was used as a basic component of the tablet, and hydrophobic phenytoin as an active ingredient. The time required for total water penetration of MCC tablets increased with tablet compression pressure, and the rate of water penetration into the tablets increased with phenytoin content.