Abstract
In vitro drug diffusion studies were conducted, utilizing improved Franz diffusion cells, to estimate the effects of Azone and other additives (deoxycholic acid, dimethyl formamide, lecithin and 2-pyrrolidone) on the percutaneous absorption of dihydroergotamine (DHE). Rabbit skin obtained from the dorsal area was used as a barrier membrane. Among various absorption promoters tested, Azone was the most effective agent for enhancing the percutaneous absorption of DHE; the extent of enhancement ranged from 11-fold with 1.0% Azone coapplied with DHE, to 334-fold when skin was pretreated with 6.0% Azone. It was found that lecithin increased the transdermal delivery of DHE by 13.5-fold over the control. On the other hand the formulation containing 6.0% dimethyl formamide (DMF) did not show any significant difference from the control. In contrast, other additives tested including deoxycholic acid and 2-pyrrolidone showed a decrease in the amount of drug transported across the skin as compared to the control.