Studies on the Mechanism of Tablet Compression and Disintegration. IV: Evolution of Wetting Heat and its Reduction by Compressional Force

Generation of wetting heat when a tablet enters water results in the warming of air entrapped inside the tablet with consequent increase of volume and this becomes the cause of disintegration of tablets. Aluminum silicate generates a great deal of wetting heat but it has a special characteristic of losing this wetting heat by compression. The values of watting heat calculated from adsorption isotherm of compressed samples reported in Part I of this series are indicated in Table III, and the experimental values of some samples, before and after compression, measured by Bunsen's ice calorimeter, are indicated in Tables I and II. They all indicate decrease of wetting heat by compression. Since the specific heat of these samples was 0.171, internal temperature of a tablet is considered to become fairly high.