Novel zwitterionic ABA-type triblock copolymer for pH- and salt-controlled release of risperidone

Novel dual stimuli-responsive ABC triblock copolymer: RAFT synthesis, "schizophrenic" micellization, and its performance as an anticancer drug delivery nanosystem

A novel pH- and thermo-responsive ABC triblock copolymer {poly[(2-succinyloxyethyl methacrylate)-b-(N-isopropylacrylamide)-b-[(N-4-vinylbenzyl),N,N-diethylamine]]} [P(SEMA-b-NIPAAm-b-VEA)] was successfully synthesized via reversible addition of fragmentation chain transfer (RAFT) polymerization technique. The molecular weights of PHEMA, PNIPAAm, and PVEA segments in the synthesized triblock copolymer were calculated to be 10,670, 6140, and 9060gmol^-1, respectively, from proton nuclear magnetic resonance (¹H NMR) spectroscopy. The "schizophrenic" self-assembly behavior of the synthesized P(SEMA-b-NIPAAm-b-VEA) triblock copolymer under pH and thermal stimulus were investigated by means of ¹H NMR and ultraviolet-visible (UV-vis) spectroscopies as well as dynamic light scattering (DLS) and zeta potential (ξ) measurements. The doxorubicin hydrochloride (DOX)-loading capacity, and stimuli-responsive drug release ability of the synthesized triblock copolymer were also investigated. The biocompatibility of the synthesized triblock copolymer was confirmed through the assessing survival rate of breast cancer cell line (MCF7) using MTT assay. In contrast, DOX-loaded triblock copolymer exhibited an efficient anticancer performance in comparison with free DOX verified by MTT and DAPI staining assays. As the results, we envision that the synthesized P(SEMA-b-NIPAAm-b-VEA) triblock copolymer can be applied as an enhanced anticancer drug delivery nanosystem, mainly due to its smart physicochemical and biocompatibility properties.

Novel 'schizophrenic' diblock copolymer synthesized via RAFT polymerization: poly(2-succinyloxyethyl methacrylate)-b-poly[(N-4-vinylbenzyl),N,N-diethylamine]

This article describes the synthesis and characterization of a novel 'schizophrenic' diblock copolymer [poly(2-succinyloxyethyl methacrylate)-b-poly[(N-4-vinylbenzyl),N,N-diethylamine)]; PSEMA-b-PVEA] via reversible addition of fragmentation chain transfer (RAFT) polymerization technique. The chemical structures of all samples as representatives were characterized by means of Fourier transform infrared (FTIR), and 1H nuclear magnetic resonance (NMR) spectroscopies. The molecular weights of PHEMA and PVEA segments were calculated to be 9770 and 12,630 gmol-1, respectively, from 1H NMR spectroscopy. The self-assembly behavior of the synthesized PSEMA-b-PVEA diblock copolymer was investigated by means of 1H NMR spectroscopy, dynamic light scattering (DLS) measurements, and transmission electron microscopy (TEM) observation. The average sizes of the PSEMA-b-PVEA micelles at pHs 3.0, 6.0, and 10.0 were obtained to be 294, 237, and 201 nm, respectively, from DLS analysis. The zeta potential measurements at various pHs demonstrated that the synthesized PSEMA-b-PVEA diblock copolymer has zwitterionic properties, and the range of isoelectric point's (IEP's) was determined as 5.8-7.3. It is expected that the synthesized PSEMA-b-PVEA diblock copolymer considered as a prospective candidate in nanomedicine applications such as drug delivery, mainly due to its excellent 'schizophrenic' micellization behavior.