In vitro evaluation of nimodipine permeation through human epidermis using response surface methodology

An optimization technique (response surface method) was used in order to investigate the effect of the combination of two enhancers, namely caprylic acid and cineol on nimodipine's permeation through human cadaver epidermis. Using this quadratic model it was found that at 24 h the increase of the permeation of nimodipine it was mainly due to the effect of caprylic acid. On the contrary, it was shown that at 48 and 72 h the combination of the two enhancers contributed to the increase of the permeation. The greater Q(gel)/Q(control) values, at all time intervals (24, 48 and 72 h), were obtained when the concentration of cineol and caprylic acid range from 3.0 to 5.0% (v/v) and 8.0 to 9.5% (v/v), respectively.