Changes of Surface Area in the Dissolution Process of Crystalline Substances. IV. Dissolution and Simulation Curves Estimated from Changes of Surface Area and Cube Root Law

Abstract

The dissolution of n-propyl p-hydroxybenzoate was conducted under the sink condition, and was simulated from the changes of surface area during the dissolution process and by means of the cube root law. The surface area of the samples was estimated by using a LUZEX image analyzer. The two simulation methods gave almost the same dissolution rate constants.Dissolution of systems prepared by mixing sieved samples at various weight ratios was also carried out, and these dissolution processes were simulated by means of the cube root law. The apparent mean diameter of the mixed systems was well estimated in terms of particle size and weight ratio of the components. Hence, the mixed systems were converted into several imaginary equivalent systems, and the applicability of the cube root law and the validity of the estimation of apparent mean diameter of the mixed system were examined.