pH-responsive PMAA-b-PEG-b-PMAA triblock copolymer micelles for prednisone drug release and release kinetics

Abstract

pH-sensitive hydrophilic poly(methacrylic acid)-b-poly(ethylene glycol)-b-poly(methacrylic acid) (PMAA-b-PEG-b-PMAA) triblock copolymers were synthesized through atom transfer radical polymerization, and were characterized by FT-IR, 1 H NMR, and GPC. The as-synthesized polymers can self-assemble into stable and almost spherical nanomicelles in aqueous solution with an average size range from 18 to 89 nm, depending on the micellar concentrations, while they assumed well-defined spherical morphologies in PBS solutions. The micellization behavior in different media was investigated by a fluorescence spectroscopy technique, UV-Vis transmittance, and dynamic light scattering measurements. The critical micelle concentration and size of the micelles decrease with the increasing the length or molecular weights of PEG and PMAA chains. A pH-dependent phase transition behavior produces at a pH value of about 5.2, and the stable pH micellization behavior varied within a narrow pH range from ca. 4.8 to 7.4. These triblock copolymers are generally low cytotoxicity at a micellar concentration below 400 mg L -1 , as revealed by the MTT assay. The prednisone release and release kinetics studies disclosed that these pH-sensitive polymeric micelles are good carriers for the drug delivery.

Synthesis of sharply thermo and PH responsive PMA-b-PNIPAM-b-PEG-b-PNIPAM-b-PMA by RAFT radical polymerization and its schizophrenic micellization in aqueous solutions

“…In the case of PMA with electron deficient groups and PEG containing regions of high electron density, inter polymer complexes or the complexation are suitable to form due to the collapse of macromolecular chains induced by the PMA chains contracting and the enhanced association between PMA and PEG chains based on the formation of hydrogen bonds. The PMA complexes are more stable than PAA complexesby reason of hydrophobic stabilization of the hydrogen bonds by the α -methyl group [ 61 ].…”

pH‐Responsive Polymer Nanoparticles for Drug Delivery

“…In contrast to polymers synthesized from basic monomers, by using polymers synthesized from acid monomers, such as poly(methacrylic acid) (PMAA), poly(aspartic acid) (PAsp), and sulfonamide‐based polymers, it is possible to engineer nanoparticle delivery systems that become more hydrophobic in response to a decrease in pH . Bae and co‐workers developed negatively charged sulphonamide‐based oligomers (OSAs) that shift from hydrophilic to hydrophobic with a drop in pH and also have proton buffering capacity.…”

Poly(methyl methacrylate)/poly(ethylene glycol)/poly(ethylene glycol dimethacrylate) micelles: Preparation, characterization, and application as doxorubicin carriers

“…Self‐assembly linear amphiphilic copolymers composed of two chemically different homopolymers have been attractive as carriers for drug and gene encapsulation for decades . They can be used to carry lipophilic drugs that can dissolve in the core of the micelles and transport them to the target site effectively . However, the thermodynamic transition of linear regimes is comparatively weak .…”