The purpose of the present study was to evaluate the permeation profiles of unlabeled
corticosterone (CS) drug from gels and adhesive patches as transdermal delivery systems. The
effect of polyvinylpyrrolidone and certain chemical enhancers octylpyrrolidone (OP) and
dodecylpyrrolidone (DDP) on the flux of drug through hairless mouse skin was also studied.
The results show that presence of solubilizing agents such as hydroxypropyl–beta-cyclodextrin
(HP- -CD) decreased the drug flux from hydroxypropyl methylcellulose (HPMC) gel dermal
base and controlled the diffusion kinetics. Increasing the drug thermodynamic activity by its
autoclaving with 0.25% polyvinylpyrrolidone (PVP) (supersaturation) improved the drug flux
through the skin by 3 fold from HPMC gel base dermal preparations. The results also reveal
that chemical enhancer/HP- -CD mixtures represent a suitable combination for controlling the
release as well as increasing the flux of drug through skin. The addition of 5% HP- -CD to OP
solution not only increased the drug flux but also showed a controlled release that approached
the zero order. Use of the chemical enhancer DDP in presence of HP- -CD shows a 10-fold
increase in CS flux from HPMC gel base. The results of transdermal patches show that
increasing the concentration of OP increased the cumulative amounts of Labeled corticosterone
(3H-CS) permeated through the skin from two adhesives patches Duro-tak 2516 and 2287.
There is a difference between the two adhesives patches in terms of skin permeation. The rate of
drug permeated from the Duro-tak 2516 patch is 2 times greater than Duro-tak 2287, where
there permeability coefficient is 9.05 and 4.67 x 10–9 respectively.