Effect of vehicle on the performance of active moisturizing substances.

Purpose The work is aimed at the description and study of the hydration effect of different active substances (hyaluronic acid, sericin, glycerol, and urea) incorporated in two different vehicles commonly used for compounding pharmaceutical ingredients, gel, and emulsion. Methods The effects of the formulations were investigated by instrumental methods in vivo after their administration to the skin of volar forearms in a group of 20 healthy volunteers (women, mean age of 28 years). Hydration effect was observed by corneometry and barrier properties ( TEWL) by tewametr at regular time intervals (1-26 h) after application of the prepared samples. Results The results indicate that the active substances incorporated in the emulsion moisturize the skin better compared to the same substances contained in the gel. Furthermore, it was found that these ingredients, whether they are present in the emulsion or in the gel, prevent TEWL in a similar manner. Conclusion The study showed that differences exist among the tested active ingredients in their ability to moisturize the skin. These differences are dependent not only on the type and concentration of the active substance used but also on the type of vehicle in which they are applied. It was also found that the active substances influence the viscosity of the prepared formulations. [ABSTRACT FROM AUTHOR]