Synthesis and characterization of a novel amphiphilic block copolymer

Abstract

This thesis presents the synthesis procedure of the novel amphiphilic block copolymer poly(ethylene glycol)-b-poly(lactic acid) (PEG-b-PLA) and its various characterization techniques in order to explore the applicability of this copolymer as an agent of encapsulation for hydrophobic drugs. The synthesis consists of ring-opening polymerization (ROP) of L-lactide with stannous octoate (Sn(Oct)2) as a catalyst and poly(ethylene glycol) methyl ether (mPEG) as an initiator. The copolymer is characterized and confirmed by 1H-NMR spectroscopy, Gel Permeation Chromatography (GPC), and Fourier Transform Infrared spectroscopy (FTIR). The thermal properties of the synthesized copolymer are determined by Differential Scanning Calorimeter (DSC). The nanoscale size (100-130 nm) and its distribution is verified by Dynamic Light Scattering (DLS) and the critical micelle concentration (CMC) is determined by fluorescence spectrophotometry. The UV measurements show that the polymer has a high encapsulation efficiency (72%) and is able to enhance (28 times) the solubility of a hydrophobic drug, namely Ibuprofen, in an aqueous medium. The results of this study reveal that the novel copolymer could be a potential candidate for hydrophobic drug delivery systems.