INFLUENCE OF THE MANUFACTURING PROCESS ON THE RELEASE OF PROXYPHYLLINE FROM LIPID MATRICES

Four manufacturing processes were used to prepare lipid matrices conta ining glyceryl tristearate (70%) and tribehenate (30%). Solid dosage f orms were direct compression tablets and three others obtained by melt ing-congealing: monolithic capsules, granulate capsules and granulate tablets of four different diameters (5, 6, 7 and 12 mm). Huge differen ces in proxyphylline release rates were noticed, essentially owing to the clearly distinct dissolution surfaces of the various dosage forms. Drug release increased from monolithic capsule successively to granul ate tablets, direct compression tablet and granulate capsule. Concerni ng the granulate tablets of four different diameters, the release incr eased linearly with the dissolution surface. Except for the granulate capsule that did not give an actual matrix, the release mechanism was Fickian diffusion and did not change with either the manufacturing pro cess or with the dissolution surface.