Percutaneous absorption of flufenamic acid in rabbits: effect of dimethyl sulfoxide and various nonionic surface-active agents

Eight nonionic surface-active agents were each incorporated at a concentration of 10% into a white petrolatum ointment base containing 10% flufenamic acid with or without dimethyl sulfoxide. Percutaneous absorption was studied by determining the plasma concentration of flufenamic acid in New Zealand White rabbits at regular intervals for 8 hr following application of the ointment. The percutaneous absorption of flufenamic acid was significantly increased when sorbitan trioleate, polyoxyl 8 stearate, or polyoxyethylene 2 oleyl ether were added to the ointment containing flufenamic acid and white petrolatum. The percutaneous absorption of flufenamic acid was increased significantly when sorbitan monopalmitate, sorbitan trioleate, polyoxyl 8 stearate, polyoxyethylene 20 cetyl ether, or polyoxyethylene 2 oleyl ether were added to the ointment containing dimethylsulfoxide, flufenamic acid, and white petrolatum.