Design and in vitro evaluation of dapsone-loaded micropellets of ethyl cellulose.

A controlled-release dosage form was manufactured by dispersing ethyl cellulose sol in acetone into a medium of mineral oil. Dapsone was used as the model drug. The powdered drug was dispersed in the ethyl cellulose sol, and the formulation variables affecting the production of the discrete and spherical micropellets and their size distribution were investigated. The percentage of SPAN 80 in the formulation affected the yield and physical properties of the micropellets. The in vitro drug release followed first-order diffusion-controlled dissolution. More than 85% of the drug was released over 5 hr for all formulation batches, with delayed release over the drug dissolution profile.