Dissolution from tablets prepared using ethyl cellulose microcapsules

Microcapsules containing sodium phenobartitone cores in ethyl cellulose have been used to prepare tablets at from 3-9 to 358-9 MPa compression pressures. The tensile strength of these tablets is related linearly to the core: wall ratio and to the microcapsule size. Dissolution of the drug from the microcapsules, is also related to the core:wall ratio and microcapsule size, but except at low compression pressures is almost independent of the pressure used during preparation. The tablet matrix remains intact during the dissolution and the equations developed by Schwartz, Simonelli & Higuchi (1968) are followed. Large microcapsules 1:2 core: wall ratio produce friable tablets with rapid release of contents.