Effect of benzyl alcohol on rat skin as a solvent of liquid droplet dispersion ointment.

The action of benzyl alcohol (BA) as a major solvent of a liquid droplet dispersion ointment (LDDS), a preparation enabling excellent percutaneous absorption of drugs, was evaluated and compared with Azone and dimethyl sulfoxide (DMSO), which are known percutaneous absorption enhancers. Using a water sorption-desorption test, BA was found to increase hygroscopicity and decrease water-holding capacity to the same extent as Azone and DMSO. Differential scanning calorimetry (DSC) determination of the whole stratum corneum, and its lipids and proteins confirmed that BA and Azone act on the stratum corneum lipids while DMSO acts on its lipids and proteins. Furthermore, DSC and X-ray diffraction spectrum determinations of lipids in the stratum corneum suggest that the action of BA is moderate and reversible. The effect of BA may be one of the factors underlying the high percutaneous absorption found with LDDS.