Transdermal permeation of apomorphine through hairless mouse skin from microemulsions

The in vitro transdermal absorption of apomorphine from microemulsions was studied using the skin of the hairless mouse as a membrane. Two microemulsions (no. 1 and 2) were prepared and thickened both containing 3.9% of apomorphine hydrochloride. The lipophilicity of the drug was increased by forming apomorphine-octanoic acid ion-pairs. The fluxes of the drug from the microemulsions through hairless mouse skin were 100 microg h(-1) cm(-2) from no. 1 and 88 microg h(-1) cm(-2) from no. 2. Apomorphine in microemulsions, protected from light with antioxidants, showed no degradation for up to 6 months.