The effects of external heating on the permeation of oxybutynin through human epidermal membrane.

The transdermal delivery system (TDS) of oxybutynin (OXY) is widely used for the treatment of overactive bladder patients. This report aimed to assess the effect of external heating on the pharmacokinetics of OXY after transdermal administration. Franz-type diffusion cell experiments at room temperature, 36 and 45 degrees C were performed to estimate the permeations of OXY through human epidermal membrane with an isosorbide dinitrate (ISDN) formulation as a reference. The fluxes of OXY at 36 and 45 degrees C were only approximately 1.2-fold higher than that at room temperature, while those of ISDN with heating were more than 2.5 times as high as that without heating (p < 0.001). These results indicate that the influence of heating on the permeation of OXY from the TDS of OXY may be minimal.