Synthesis of core-multishell architectures based on epoxide and glycidol monomers as drug delivery systems

Abstract

A library of different epoxide based core-multishell architecture (CMS) was developed. Based on an anionic polymerisation process, the polymers consist of a complete polyether backbone. Using a one-pot process, it was possible to create two different shells on a hyperbranched polyglycerol core (hPG). Epoxide derivatized monomers were utilised as building blocks for the inner shell, while the outer shell was made up from ethoxyethylglycidyl ether (EEGE). Both the shells were developed through anionic ring opening polymerisation, using a “grafting-from” approach from the peripheral hydroxyl groups of the core. In order to investigate the influence of monomer on the final CMS, propylene oxide and butylene oxide were compared. A library of six products was formed, three made of propylene oxide and three of butylene oxide. Attention was further pointed on the impact of repeating units composing the inner shell of the polymer. The molar ratio between the hydroxyl groups present on the hPG core and the monomer was investigated. In particular, the ratios 1:5, 1:10 and 1:20 were studied. The entire library was characterized using GPC, NMR and DLS. The performance of each carrier was investigated by the transport capacity of model dyes. Tests were made by encapsulation of Nile red and pyrene and quantified by UV/Vis spectroscopy. Finally, transport capacity of Dexamethasone, a drug used in treatment of skin diseases, was also tested; the performance was compared with similar CMS, used as model. Quantifications were made through HPLC analysis.