75078-91-0

The aim of this preliminary report is to measure plasma and skin concentrations of Ro 15-0778 and its phenolic metabolite Ro 14-6113 in hairless rats receiving orally 10 mg/kg of Temarotene once daily during 10 days. Blood (2-3 mL) and skin (200-300 mg) samples are taken at different time points between 0.5 and 240 h after the last dose. A highly sensitive HPLC method is used for simultaneous determination of the two compounds with a quantification limit of 2 ng/mL in plasma and 10 ng/g in total skin (epidermis and dermis). After 10 h, plasma concentrations of Ro 14-6113 are 5-13 times higher than for Ro 15-0778. Ro 14-6113 concentrations in the skin are 4-10 times higher than for Ro 15-0778 within the initial 48 h. The concentrations of both compounds in the skin are higher than concentrations in plasma^[1].