Provitamin supramolecular polymer micelle with pH responsiveness to control release, bioavailability enhancement and potentiation of cytotoxic efficacy.

Encapsulation techniques to generate core/shell systems provide a method that improves physicochemical properties, which are very important in biological applications. β-carotene is a common carotenoid that has shown preventive effects in skin diseases and vitamin A deficiency but this compound has limited water solubility and bioavailability, which hinder its broad application. The use of polyrotaxane compounds formed from cyclodextrins has allowed supramolecular polymer micelles (SMPMs) to be synthesized to encapsulate β-carotene. The polymeric compound Pluronic F127® was also used to create core/shell nanoparticles (NPs) that contain β-carotene. Bioactive compound encapsulation was fully confirmed by nuclear magnetic resonance spectroscopy and by scanning and transmission electron microscopy. The method based on cyclodextrin and lecithin allow to release slowly when the systems were exposed to an aqueous medium by pH control, with an increase of 16 times of bioavailability comparing with free carotenoid. This allowed to potentiate the cytotoxic activity on a melanoma cell line by enhancing the water solubility to more than 28 mg/L, and present promising applications of SMPMs to provitamins.