Study on the Kinetics of Vitamin U Release from a Cosmetic Formulation

S-Methylmethionine (SMM), also called vitamin U, shows antihistamine, anti-inflammatory, radioprotective and anti-irritant activity, as well as enhanced wound healing. In addition, vitamin U affects the regeneration and renewal of the skin hydrolipid mantle and offers some UVB-protective effects on the skin. Since there are currently no reports in the scientific literature concerning the release of vitamin U from cosmetic formulations, the present study was undertaken as a preliminary and exploratory pilot investigation. The research focused on evaluating the release behavior of SMM (synthetic methylmethionine), a compound recognized for its potential skin-regenerating, soothing, and protective properties, from several commonly used topical delivery systems. Therefore, the various topical formulations, including oil-in-water (O/W) and water-in-oil (W/O) emulsions, as well as hydrogel formulations, were evaluated as potential, effective vitamin U skin delivery systems. Vitamin U-loaded emulsions (O/W and W/O) differing in droplet size in the internal phase and a hydrogel were prepared. The physicochemical properties of the formulations, such as emulsion type, stability, viscosity, pH and droplet size, were evaluated. The study of vitamin U release was performed in thermostatic diffusion chambers at a temperature of T = 32 °C using the Spectra/Por Standard Regenerated Cellulose dialysis membrane. A phosphate buffer (PBS) with pH 7.4 was used as the receptor solution. The concentration of the released S-Methylmethionine was analyzed with ninhydrin-based spectrophotometric assays. The obtained results showed that the type of the formulation significantly influenced the SMM release. The highest release of SMM was observed from hydrogel and O/W emulsions.