Delivering medicine to the general circulation through the skin is associated with grater advantages compared to that by the oral route and hence the purpose of this investigation was to study the potential of rosiglitazone maleate for transdermal delivery using passive diffusion and iontophoresis. Physicochemical parameters of rosiglitazone maleate like solubility, pKa, octanol/vehicle and skin/vehicle partition co-efficient were determined. Solubility study was carried out in binary vehicle of ethanol-water. Rosiglitazone maleate was delivered from hydro-alcoholic vehicle of different composition and in vitro skin permeability through full thickness ear skin of domestic pigs (Sus domesticus) was observed in a Franz-diffusion cell using 0.9% NaCl as the receptor fluid. For iontophoretic diffusion, a current density of 0.5mA/cm2 was used. Permeation rate of rosiglitazone maleate had increased with increase in donor drug concentration (P<0.01) up to the level of 213.71 μmol/ml in both passive diffusion and iontophoresis, but thereafter increase in steady state flux was not statistically significant indicating the donor concentration of 213.71 μmol/ml was optimum. Highest steady state flux (0.571 ± 0.031μmol/cm2hr) was recorded in iontophoresis, which was approximately 7 times higher than the target flux calculated on the basis of minimum effective concentration. As the target flux of rosiglitazone maleate is moderate (1.09 μmol/hr) and good skin permeability was observed in the study, it appears that rosiglitazone maleate is a promising candidate for transdermal delivery.
Key words: Diabetes, Franz diffusion cell, Passive diffusion, Iontophoresis, Pigskin