Ibuprofen liposomes were prepared using soybean lecithin by mechanical dispersion method. The appropriate conditions to prepare such a thin film of lipid were found when 20 ml of chloroform was used to dissolve ibuprofen and soybean lecithin and the evaporation temperature was set at 35 C for 3 hours. Milky suspension was obtained after 2 hours of hydration of the thin film with 3 ml of sterile water. Electron microscopic analysis showed that the spherical vesicle with multilamellar structure was formed. The 1;0.144 molar ratio of soybean lecithin to ibuprofer provided the significantly highest size and percentage drug entrapment without crystal of drug (P<0.05). The 9:1 molar ratio of soybean lecithin to cholesterol led to decrease in size and the percentage drug entrapment. Addition of 2.50 mole% of stearylamine reduced size and the percentage drug entrapment whilst 0.001-0.025% of (+-)-alpha-tocopherol increased size with no change in the percentage drug entrapment. The concentration of ibuprofen had more influence on size and the percentage drug entrapment of ibuprofen liposomes than other lipophilic components added in the liposomal preparation. The comparison of freshly prepared ibuprofen liposomes and after storage at 4 C for 1 month was found to be only two formulations with no change in size and the percentage drug entrapment. The first one was ibuprofen liposomes containing 9:1 molar ratio fo soybean lecithin to cholesterol with 2.50 mole% of stearylamine ane the latter was that containing 9:1 molar ratio of soybean lecithin to cholesterol with 2.50 mole% of stearylamine and 0.0125% of (+-)-alpha-tocopherol. They were still as milky suspension. Electron microscopic analysis showed that they were unchanged spherical shapes.
