Reactive oxygen species (ROS) in colloidal systems: Are PEG-free surfactants the answer?

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 beta-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. beta-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. (C) 2022 The Author(s). Published by Elsevier Inc.

Automated summary

The study evaluated polyglycerol- and saccharide-surfactants as PEG-free alternatives for polyethylene glycol-surfactants, revealing that PEG-free-surfactants showed superior performance in addressing oxidation, ROS formation, and degradation of oxidation-prone active ingredients.