Two alkyl polyglucoside natural surfactants varying in chain length in stabilization of lactobionic acid containing emulsions: physicochemical characterization and in vitro irritation potential assessment

Abstract

There is a growing need for research into new skin and environmentally-friendly actives and surfactants in the field of cosmetics. This paper focuses on different natural alkylpolyglucoside (APG) emulsifiers (cetearyl alcohol and coco glucoside; arachidyl behenyl alcohol and arachidyl glucoside), which can form lyotropic liquid crystals, in order to promote them as cosmetic excipients. APG-based emulsions as carriers for extremely hygroscopic and acidic cosmetic active, lactobionic acid (LA), belonging to alpha-hydroxy acids (AHAs) were also studied. In the first part of the study, physicochemical properties (assessed by rheology, polarization microscopy and pH and conductivity measurements) and in vitro safety profile (skin irritation test using a cytotoxicity assay) of vehicles were determined in order to compare and estimate their applicability as cosmetic excipients. In the second part, the same methods were conducted in order to establish how those emulsions perform as carriers for different percents of LA. The study showed that both vehicles based on different APGs could be promoted as cosmetic excipients. Either of the APG based emulsions could be vehicles for 6% LA. Cetearyl alcohol and coco glucoside, more hydrophillic emulsifier, is acceptable carrier for 10% LA due to better cytotoxicity profile. The importance of a better cytotoxicity profile without neglecting satisfying physical stability for cosmetic formulations was emphasized.