Effect of different terpene-containing essential oils on percutaneous absorption of trazodone hydrochloride through mouse epidermis

The aim of our study was to investigate the enhancing effect of several essential oils in the percutaneous absorption of trazodone hydrochloride (TZN). For this purpose, fennel oil, eucalyptus oil, citronella oil, and mentha oil were applied on the skin membrane in three different ways: included in the transdermal device, as a pretreatment, or both. To investigate the effect of penetration enhancers used in this study on the percutaneous absorption of TZN through mouse epidermis, Keshary-Chien diffusion cells were employed. The receptor phase was constantly stirring saline phosphate buffer of pH 7.4 at 37 +/- 1 degrees C. Results showed that pretreatment of skin with essential oils increases the flux values of TZN compared with the values obtained when the same essential oils were included in the transdermal devices. The percutaneous penetration flux for TZN was increased with skin pretreatment by 10% essential oils in the following order: fennel oil > eucalyptus oil > citronella oil > mentha oil. The amount of TZN retained in the skin after pretreatment with essential oils was found to be very similar in all cases and much higher than in the experiments without skin pretreatment.