Effect of dimethylsulfoxide concentration on the permeability of neonatal rat stratum corneum to alkanols.

The effect of dimethylsulfoxide (DMSO) concentration on the permeability of neonatal rat stratum corneum to 14C labeled propan-1-ol and hexan-1-ol was studied in vitro. The permeability coefficients were determined from a range of DMSO-water systems. After soaking in water overnight, the same stratum corneum was used with water as both delivery and recipient phases for the alkanols. Concentrations below 70% DMSO reduced the penetration rate as a result of the solvent effect of DMSO and the formation of a DMSO-alkanol complex. Above 70% DMSO permeability increased, with a permeability coefficient greater than that from water being achieved at concentrations in excess of 80% DMSO. The second run, with water as delivery phase, showed that the effect was reversible below 70% DMSO, but that at higher concentrations DMSO had produced an irreversible change in the permeability of stratum corneum. We hypothesize a hydrogen bond-mediated mechanism for the increased permeability.