Transdermal delivery of carvedilol in rats: probing the percutaneous permeation enhancement mechanism of soybean extract-chitosan mixture.

BACKGROUND: This study was designed for investigating the effect of soybean (SS) extract and chitosan (CTN) in facilitating the permeation of carvedilol (CDL) across rat epidermis. METHOD: Transdermal flux of carvedilol through heat-separated rat epidermis was investigated in vitro using vertical Keshary-Chien diffusion cells. Biophysical and microscopic manifestations of epidermis treated with SS-extract, CTN, and SS extract-CTN mixture were investigated by using DSC, TEWL, SEM, and TEM. Biochemical estimations of cholesterol, sphingosine, and triglycerides were carried out for treated excised as well as viable rat epidermis. The antihypertensive activity of the patches in comparison to that after oral administration of carvedilol was studied in deoxycorticosterone acetate-induced hypertensive rats. RESULTS: The solubility of CDL was found to be maximum in the presence of 1% (w/v) SS extract. The K(IPM/PB) of CDL decreased with increase in concentration of SS extract. The in vitro permeation of CDL across rat epidermis increased and was maximum with combination of SS extract and chitosan (CTN). Biochemical and microscopic studies revealed the initiation of reversal of barrier integrity after 12 hours. Furthermore, the application of patches containing SS extract-CTN mixture resulted in sustained release of carvedilol, which was able to control the hypertension in deoxycorticosterone acetate (DOCA) induced hypertensive rats through 24 hours. CTN was found to potentiate the permeation enhancing activity of SS extract. CONCLUSION: The developed transdermal patches of CDL containing SS extract-CTN mixture exhibited better performance as compared to oral administration in controlling hypertension in rats.