Effect of penetration enhancers on transdermal delivery of propofol.

To develop a transdermal dosage form of propofol (PF), in vitro skin permeability and in vivo absorbability of PF were investigated in rats, and the effectiveness of enhancers on the transdermal delivery of PF was estimated. Propylene glycol (PG), isopropyl myristate and macrogol were used as co-solvent type enhancers. L(-)-Menthol (MEN), D(+)-limonene, oleic acid, stearic acid, sucrose fatty acid esters and sodium dodecyl sulfate (SDS) were used as membrane-acting type enhancers. Among the co-solvent type enhancers, PG showed the highest enhancing effect in vitro. Furthermore, the synergistic effect of the combined use of PG and membrane-acting type enhancers was confirmed. Higher values of permeation parameters were observed with the combined use of PG and MEN, sucrose fatty acid esters or SDS. For the in vivo experiment, the addition of a smaller amount of PG was preferable to the amount used in the in vitro experiment. The synergistic effect of enhancers was observed with the combined use of PG and MEN. Our findings suggest that the combination of PG and MEN was useful as enhancers for the transdermal absorption of PF. These results provide useful information to develop a transdermal dosage form of PF as a sedative or a hypnotic.