RHEOCALC 3.3 FREE

Tocopheryl acetate is a free radical scavenger that may reduce DNA damage and the rate of death in keratinocytes. Maia Campos showed a significant effect of a vitamin C derivative in the improvement of skin hydration, which is very important for normal skin metabolism, prevention of skin alterations and early aging. Ascorbyl tetraisopalmitate, a precursor of Vitamin C reduces cell damage triggered by UVB and effectively suppresses UVB-induced pigmentation. Retinyl palmitate acts on the epithelization of dry and rough skin, as well as on the improvement of abnormal keratinization. The greater stability of ester forms of vitamins A, C and E led to studies that demonstrated their effectiveness in cosmetic formulations. However, esterified vitamin derivatives (retinyl palmitate, ascorbyl tetraisopalmitate and tocopheryl acetate) having improved stability have been preferentially used in topical formulations. Considering that many cosmetic formulations contain vitamin combinations it is suggested that the present study may contribute to the development of more stable formulations containing liposoluble vitamins.ДЄ special interest in vitamins A, C and E has been observed in recent years due to their useful role in the treatment of skin aging and protection of human skin against UV-induced damage. Combined vitamins in a single formulation had a slightly lower degradation rate as compared to different preparations containing only one of the vitamins.

In the chemical stability studies, first-order reaction equations were used for determinations of the shelf-life of vitamins derivatives considering a remaining concentration of 85%. Results showed that formulations had pseudoplastic behavior and that vitamins did not alter their apparent viscosity and thixotropy. Chemical stability was determined by HPLC on a Shimadzu system with UV detection. In the studies of physical stability, a Brookfield rheometer was used to determine rheological behavior of formulations containing the vitamins.

Accordingly, the aim of this study was to evaluate the physical and chemical stability of a cosmetic formulation containing 1% retinyl palmitate, ascorbyl tetraisopalmitate and tocopheryl acetate, alone or in combination. Chemically stable ester derivatives of vitamins A, C and E have become a focus of interest for their role in the satisfactory results in skin aging treatments.

Rheocalc 3.3