Transdermal microemulsions containing resveratrol preparation, characterization and application with solid microneedles

Resveratrol is a natural polyphenolic with anti-cancer, anti-angiogenic, cardioprotective, anti-diabetic, anti-viral and neuroprotective activities as well as being a powerful antioxidant. Despite its rapid absorption, intestinal and hepatic metabolism reduces the systemic bioavailability of resveratrol. In this study, it was aimed to develop an optimum topical formulation of resveratrol to overcome the disadvantages of oral administration. Optimum micromeulsion (ME9) and macroemulsion (E21) formulations containing the same amount of resveratrol (0.05% (w/w)) were developed. In addition, a standard alcohol solution containing the same amount of resveratrol was prepared. The amount of resveratrol penetrated through the pig ear skin at the end of 24 hours was determined within ex vivo studies. In the second stage, the ideal formulations were compared in terms of the amount of resveratrol penetrate through the solid microneedle treated pig ear skin. Resveratrol amount passed to the receptor medium was found to be 0.008 ± 0.0002 mg/cm2 in ME9, 0.0027 ± 0.0001 mg/cm2 in E21 and 0.021 ± 0.0001 mg/cm2 in standart solution. There was a significant difference between the amount of resveratrol penetrate from the ME9, E21 and standard solution to the receptor medium at the end of 24 hours (p<0.05). Resveratrol quantity found in the receptor medium was increased up to 1.6, 2.04 and 1.8 times in the standard solution, ME9 and E21 formulations, respectively. In this study, it was assumed that the resveratrol-containing microemulsion combined with solid microneedles would be more effective to overcome barrier layer of the skin, thus contributing to more effective treatments.