Temarotene (Ro 15-0778) is an orally active and potent small molecule compound that modulates human immune function in vitro.Temarotene may be used in the study of lichen planus.

ODC mRNA:0.5 μM

The study examines how retinoids regulate ornithine decarboxylase (ODC) gene expression in human keratinocyte cultures grown in a serum-free environment with 0.15 mM Ca2+. Keratinocytes were treated with varying concentrations (0.1 nM to 10 μM) of all-trans-retinoic acid, 13-cis-retinoic acid, or arotinoid Ro15-0778. Following a 24-hour treatment, a dose-dependent decrease in ODC mRNA levels was observed, with both types of retinoic acids showing an estimated half-maximal inhibitory concentration (IC50) of about 10 nM, and Ro15-0778 being slightly less potent with an IC50 of approximately 0.1-0.5 μM. This suppression of ODC mRNA was noticeable after about 3 hours of treatment, reaching near maximum inhibition by 12 hours. Further analysis revealed that a 24-hour exposure to 0.5 μM all-trans-retinoic acid not only decreased ODC mRNA levels but also reduced ODC enzyme activity significantly.

This preliminary study aims to evaluate the plasma and skin concentrations of Ro 15-0778 and its phenolic metabolite Ro 14-6113 in hairless rats administered an oral dose of 10 mg/kg Temarotene daily for 10 days. By collecting blood (2-3 mL) and skin (200-300 mg) samples at intervals from 0.5 to 240 hours post the final dose, the study utilizes a sensitive HPLC method for the concurrent analysis of both compounds, achieving detection limits of 2 ng/mL in plasma and 10 ng/g in total skin (epidermis and dermis). Results indicate that, after 10 hours, plasma levels of Ro 14-6113 were found to be 5-13 times greater than those of Ro 15-0778, and 4-10 times higher in skin within the initial 48 hours. Notably, the skin concentrations of both compounds exceeded their respective plasma levels.