Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Av do Cafe s/n, Monte Alegre, Ribeirao Preto 14040-903, SP, Brazil.
Molecules. 2012 Feb 22;17(2):2219-30. doi: 10.3390/molecules17022219.
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. 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. In the studies of physical stability, a Brookfield rheometer was used to determine rheological behavior of formulations containing the vitamins. Chemical stability was determined by HPLC on a Shimadzu system with UV detection. Results showed that formulations had pseudoplastic behavior and that vitamins did not alter their apparent viscosity and thixotropy. 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%. Combined vitamins in a single formulation had a slightly lower degradation rate as compared to different preparations containing only one of the vitamins. 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.
维生素 A、C 和 E 的化学稳定性酯衍生物因其在皮肤老化治疗中令人满意的效果而成为研究的焦点。因此，本研究的目的是评估含有 1%视黄醇棕榈酸酯、抗坏血酸四异棕榈酸酯和醋酸生育酚的化妆品配方的物理和化学稳定性，单独或联合使用。在物理稳定性研究中，使用 Brookfield 流变仪来确定含有维生素的配方的流变行为。化学稳定性通过 Shimadzu 系统的 HPLC 和 UV 检测来确定。结果表明，配方具有假塑性，并且维生素不会改变其表观粘度和触变性。在化学稳定性研究中，使用一级反应方程来确定维生素衍生物的保质期，考虑到剩余浓度为 85%。与仅含有一种维生素的不同制剂相比，单一制剂中的复合维生素具有略低的降解速率。考虑到许多化妆品配方都含有维生素组合，因此建议本研究可能有助于开发更稳定的含有脂溶性维生素的配方。
