Controlled-release cellulose esters matrices for water-soluble diclofenac sodium: compression and dissolution studies.

Matrix tablets comprising of a blend of cellulose acetate butyrate (CAB) or cellulose acetate propionate (CAP) and alpha-lactose monohydrate were prepared by direct compression to control the release of diclofenac sodium. Tablet formulations containing CAP75000 or CAB50-54 exhibited highest extents, but lowest onsets of plastic deformation and lowest release rates in buffer medium, while tablets containing CAP15000 or CAB35-39 exhibited lowest extents, but highest rates of plastic deformation and highest release rates in buffer medium. The DA values obtained from Heckel plots and the DI values obtained from Kawakita plots showed similar trends. A plot of compression pressure or crushing strengths against T50% showed curvilinear relationship for all tablets. Tablets containing 40 % CAB35-39 (formulation F7D) was considered the best formulation in terms of T50%, compressibility and compactability.