Preparation and characterization of pH and thermally responsive perfluoropolyether acrylate copolymer micelles and investigation its drug-loading properties

In this study, pH and thermally responsive P(PFPHM 9 - b -DMAEMA- b -PEGMEA 480 ) was prepared by atom transfer radical polymerization (ATRP) using perfluoropolyether hydroxyethyl methacrylate (PFPHM) as hydrophobic core, 2-(Dimethylamino) ethyl methacrylate as pH and thermal response function segment, and poly (ethylene glycol) methyl ether acrylate 480 as hydrophilic shell, respectively. The chemical structure, critical micelle concentration (CMC), lower critical solution temperature (LCST), biological toxicity, stability of micelles, drug-loading performance and cumulative drug release rate of prepared P(PFPHM 9 - b -DMAEMA- b -PEGMEA 480 ) were analyzed by 19 F NMR, 1 H NMR, FTIR, DLS, UV–Vis, laser confocal microscopy and fluorescence spectrophotometer. The results show that P(PFPHM 9 - b -DMAEMA- b -PEGMEA 480 ) exhibites a CMC of 7.5 g/L, LCST of 37.6°C and excellent micelle stability. Moreover, the analysis of drug-loading indicates that the polymer displayed drug loading efficiency (DL) is 21.3% and the encapsulation efficiency (EE) is 90.0%. Its cumulative drug release rates at pH = 6.5 (42°C) is almost double of those at pH = 7.4 (42°C), pH = 6.5 (37°C) and pH = 7.4 (37°C). These results suggeste that the P(PFPHM 9 - b -DMAEMA- b -PEGMEA 480 ) at pH ranging from 6.5 to 7.4 and temperature ranging from 37 to 42°C are pH and temperature sensitive. It has great potential application as a drug loading for DOX.