Influence of dimethyl sulfoxide (DMSO) on the percutaneous absorption of salicylic acid and sodium salicylate from ointments

Dimethyl sulfoxide (DMSO), 15 percent by weight, was incorporated into selected ointment bases containing 10 percent salicylic acid or 11.6 percent sodium salicylate. Percutaneous absorption was studied by determining salicylate blood levels in New Zealand white rabbits at regular intervals for 8 hr. following application of the ointment to the shaved intact skin and confinement by a specially designed bandage. DMSO in hydrophilic ointment and hydrophilic petrolatum produced more rapid drug absorption and higher salicylate blood levels than the control systems. Polyethylene glycol ointment and a polyoxyethylene (20) stearyl ether gel with DMSO did not produce any significant change in the absorption pattern. The salicylate blood levels obtained from percutaneous absorption of sodium salicylate in hydrophilic ointment containing DMSO were lower than with control systems. In the case of hydrophilic petrolatum, there were no significant differences in absorption patterns of sodium salicylate with or without DMSO. Sodium salicylate did not appear to be absorbed from polyethylene glycol ointment whether or not DMSO was included.