Synthesis and in vitro evaluation of pH-sensitive PEG-I-dC16 block polymer micelles for anticancer drug delivery

Abstract Objectives To develop an acid trigger release of antitumour drug delivery carriers, pH-sensitive amphiphilic poly (ethyleneglycol)-imine-benzoic-dipalmitate (PEG-I-dC16) polymers were designed and synthesized and the drug-loaded micelles were evaluated in vitro. Methods PEG-I-dC16 synthesized by Schiff base synthetic method and characterized by 1H-NMR. To determine the drug-loading capacity, doxorubicin (DOX) was encapsulated in the micelles using membrane dialysis method. Zeta potential, particle size, drug-loading capacity, in vitro drug release in different pH conditions and cytotoxicity evaluation of micelles were carried out comparing with non-acid liable PEG–amide–benzoic–dipalmitate (PEG-A-dC16) polymers micelles. The cellular uptake and intracellular distribution of DOX were detected by flow cytometry and confocal laser scanning microscope. Key findings Drug-loading capacity and encapsulation efficiency of micelle (PEG molecular weight 2k) were 12.7 ± 1.1% and 49.8 ± 2.2%, respectively. The average particle size was 72.3 ± 2.5 nm. The DOX release rate of PEG-I-dC16 micelles is much higher at pH 6.5 than at pH 7.4. DOX cellular uptake and nuclear accumulation of PEG-I-dC16 micelles were more efficiency than that of PEG-A-dC16 micelles. Conclusion The pH-sensitive PEG-I-dC16 micelles could be a promising drug delivery system for anticancer drugs.