製剤からの薬物溶出のシミュレーション(第2報) : 軟膏基剤中での薬物の拡散と溶解

抄録

Diffusion coefficients and dissolution rate constants of Sudan III (model compound) in a gelatinous ointment base prepared from polyethylene, hydrated vegetable oil, and liquid petrolatum were measured by using a drug-release cell. Simulation technique using a computer can be applied to the measurement of diffusion and dissolution of Sudan III in a semi-solid material, the release percentage in the liquid phase was calculated step by step on the basis of the proposed model, and a good agreement was found between the calculated and experimental release percentages for various ointment bases. Poly-dispersed powder was handled as a gathering of mono-dispersed sphere and the theoretically resonable results were obtained from the model calculation that smaller particles dissolve faster than larger particles and that dissolution rate of particles affects the release percentage. Diffusion coefficient and dissolution rate constant, which is a constant under a stationary state, were inversely proportional to the viscosity of liquid component in an ointment base. The proposed theory and simulation technique are useful for the analysis of the diffusion of drugs and dissolution of a drug powder in an ointment base.