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.