Aerosol-OT microemulsions as transdermal carriers of tetracaine hydrochloride

The aerosol-OT (AOT)/water/isopropyl myristate microemulsion was investigat ed as a carrier in transdermal drug delivery of tetracaine hydrochloride. T he study included in vivo analgesic studies on rats and histopathological, irritation, and oxidative stress measurements on mice. The tetracaine hydro chloride encapsulated in AOT/water/isopropyl myristate showed an eightfold enhancement in the analgesic response of drug compared to the aqueous solut ion of the drug as measured by the tail-flick method The analgesic response of tetracaine hydrochloride, however, highly depended on the concentration of AOT and water of the microemulsion. The preliminary histopathological, irritation, and oxidative stress studies showed that AOT/water/isopropyl my ristate microemulsion system is a safe transdermal carrier of tetracaine hy drochloride with a concentration of AOT in isopropyl myristate lip to 21:79 w/w.