LAUSR

HYPOTHESIS Evaluation and comparison of polyglycerol- (PG-) and saccharide- (SA-) surfactants as "PEG-free"-alternative for polyethylene glycol- (PEG-) surfactants to tackle autoxidation, reactive oxygen species (ROS) formation and degradation of oxidation-prone active ingredients in colloidal systems. EXPERIMENTS 30 different surfactants were screened for hydroperoxides (HPO), aldehydes, and acid formation serving as autoxidative markers. In a comparative set-up, selected surfactants of each head group type were investigated for temperature- and photo-induced ROS formation. Oxidation markers, as well as the degradation of ß-carotene as model active ingredient in colloidal systems were monitored. FINDINGS The screening revealed elevated HPO and aldehyde levels for both PG and PEG surfactants, unlike SA surfactants, suggesting similar autooxidation processes due to their polyether substructure. However, in a comparative set-up, PEG-surfactants showed irrespective of the stress conditions or the colloidal systems at least 4-fold higher HPO and aldehyde concentrations, as well as more pronounced pH drops compared to PG- and SA-surfactants. ß-Carotene oxidation was 40- to 50-fold lower in colloidal systems based on PG- or SA-surfactants, confirming reduced ROS formation by "PEG-free"-surfactants. Moreover, superior autoxidation and degradation stability under oxidative conditions resulted in improved colloidal stability of PG- and SA-surfactant based systems. Hence, "PEG-free"- surfactants represent a causal approach to mitigate autoxidation processes in oxidation-prone pharmaceutical and cosmetic products.