Enhancement of percutaneous absorption of naproxen by phospholipids

The skin penetration of naproxen from various phospholipid gel formulations through human cadaver skin was investigated in diffusion chambers. Presence of phospholipids decreased the skin penetration of naproxen from aqueous gels. The addition of 32% (m/m) ethanol or propylene glycol in the aqueous gel formulation, with the presence of phospholipids, apparently increased the percutaneous absorption of naproxen. The penetration enhancement effect of phospholipid with ethanol was, however, more significant than that of phospholipid with propylene glycol. The effect of ethanol concentration on the ability of phospholipids to increase penetration of naproxen, was evaluated in pretreatment studies. The results showed that more than 8% (m/v) ethanol is needed for the enhancing effect of phospholipids. The concentration of phospholipid and the presence of unsaturated fatty acids in phospholipids are also important factors affecting the transdermal flux of naproxen. In conclusion, in the presence of cosolvent, phospholipids increase the transdermal flux of naproxen. (C) 1998 Elsevier Science B.V. All rights reserved.