Polyoxazolines based mixed micelles as PEG free formulations for an effective quercetin antioxidant topical delivery

[Display omitted] •Amphiphilic polyoxazolines have less impact on cell viability than its poly(ethylene glycol) equivalent.•First formulation for topical delivery with polyoxazolines as a non ionic surfactant.•Stable nanosized formulations successfully encapsulate quercetin antioxidant.•Loaded mixed-micelles improved cell viability and antioxidant activity compared to crude quercetin. This study aims to prove the value of the polyoxazolines polymer family as surfactant in formulations for topical application and as an alternative to PEG overuse. The amphiphilic polyoxazolines (POx) were demonstrated to have less impact on cell viability of mice fibroblasts (NIH3T3) than their PEG counterparts. Mixed micelles, made of POx and phosphatidylcholine, were manufactured using thin film and high pressure homogenizer process. The mixed micelles were optimized to produce nanosized vesicles of about 20 nm with a spherical shape and stable over 28 days. The natural lipophilic antioxidant, quercetin, was successfully encapsulated (encapsulation efficiency 94 ± 4% and drug loading 3.6 ± 0.2%) in the mixed micelles with no morphological variation. Once loaded in the formulation, the quercetin impact on cell viability of NIH3T3 was decreased while its antioxidant activity remained unchanged. This work highlights the capacity of amphiphilic POx to create, in association with phospholipids, stable nanoformulations which show promise for topical delivery of antioxidant and ensure skin protection against oxidative stress.