Buspirone transdermal administration for menopausal syndromes, in vitro and in animal model studies

Menopausal syndromes can seriously disturb the quality of women's life. In this work, we have investigated transdermal administration of buspirone, a 5-HT_1A receptor agonist, for treatment of the major menopausal syndrome, hot flushes. To the best of our knowledge, this is the first time buspirone has been proposed for the treatment of hot flushes. We designed a buspirone transdermal system containing the drug in an ethosomal carrier. Pharmacokinetic data in rats following transdermal administration indicate that buspirone was present in plasma for 12h, reaching a C_max value of 120.07±86.97ng/ml after 2h. A F_rel value of 0.89 was estimated for transdermal vs. oral buspirone. The effect of transdermal buspirone on hot flushes was evaluated in ovariectomized rats by monitoring tail skin temperature changes. Temperature alleviation (1.6±0.7°C) to normal values was observed 3h post-buspirone administration with the effect lasting for at least 3h. Histological examination of the skin at the application site indicated that transdermal ethosomal buspirone is safe. The significant findings presented here encourage further studies with ethosomal buspirone transdermal system for treatment of menopausal syndromes.