Retinol derivative as bioinitiator in the synthesis of hydroxyl-functionalized polymethacrylates for micellar delivery systems

Amphiphilic copolymers containing 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) units were synthesized by controlled atom transfer radical polymerization (ATRP) applying bromoester modified retinol (RETBr) as a novel initiator. Analogous series of copolymers with adjustable hydrophilic-hydrophobic balance was obtained with the use of a standard initiator, i.e. ethyl α-bromoisobutyrate (EBriB). The self-assembling particles, prepared by the solvent evaporation, were loaded with vitamin C (VitC) or ferulic acid (FA). The hydrophilic/hydrophobic ratio in the copolymer was indicated as a crucial factor to regulate efficiencies of encapsulation processes in the range of 53–98%. In vitro release of bioactive substance was carried out in phosphate buffer solution (PBS) at pH 7.4 with the maximum amount of VitC after 1h (27–62%) or FA within 2 h (71–97%). The polymeric systems with satisfactory encapsulation characteristics and release profiles are attractive micellar carriers of antioxidants, which, due to their activities could be also delivered using the popular approaches in cosmetology like masks, under-eye patches, or wraps.