New, Environment Friendly Approach for Synthesis of Amphiphilic PCL–PEG–PCL Triblock Copolymer: An Efficient Carrier for Fabrication of Nanomicelles

Abstract

Ring opening copolymerization is the most frequently applied reaction for the synthesis of polycaprolactone–polyethylene glycol–polycaprolactone (PCL–PEG–PCL). In this reaction, a number of expensive and toxic organic solvents are being used for the purpose of purification and extraction of the prepared copolymer. Exposure to these organic solvents can cause serious issues to the human health and also impart serious environmental pollution. In the current work, a new, economical and organic solvent free approach was used for the synthesis of triblock copolymer. The results of the current studies confirmed the successful formation of triblock copolymer as revealed by Fourier transform infrared spectra, 13carbon nuclear magnetic resonance (13C-NMR) and proton nuclear magnetic resonance (1H-NMR). Gel permeation chromatography analysis ensured the homo-distribution of the prepared copolymer. The prepared copolymer was further evaluated as a carrier for the drug loading. Nanomicelles were successfully prepared by the nanoprecipitation technique and exhibited an average size distribution of 42.50 nm and an encapsulation efficiency of 90%. The prepared nanomicelles also exhibited safety at the concentration of 50 µg/ml and a long-term storage stability. All these studies suggested the success of the new simplest and economical method for the synthesis of PCL–PEG–PCL and its subsequent applications as a carrier for fabrication and efficient delivery of hydrophobic drug molecules.