製剤からの薬物溶出のシミュレーション(第6報)非透過性粒子による妨害効果

Abstract

The diffusion obstruction effect caused by the impermeable particle was tested, using glass beads (GB) dispersed in the silicone rubber membrane and drug release from the O/W emulsion was measured by varying the volume fraction (VF) of oil phase (droplet phase). Permeability of salicylic acid (SA) through the membrane and the effective diffusion coefficient of SA were decreased with an increase in the VF of GB. The obstruction effect was proved by the above mentioned phenomena, but no size effect of GB was observed. Wang's equation may be useful for these systems. The drug release from emulsion was decreased with an increase in the VF of oil phase and was compared with the theoretically releasable amount (TQ3) of SA which can be calculated from the volume of donor, membrane, and receptor phase and the partition coefficients of membrane and droplet. The obstruction effect of droplet on the drug release from emulsion was also proved by the decreasing of the ratio of percent release and TQ3 with an increase in the VF of oil phase. In designing creams or emulsions, we must take into account the VF of oil phase (droplet phase) which relates to the drug release from the preparations.