Thermosensitive PMMA core/oligo(ethylene glycol)-based shell microgels as drug carriers in detoxification treatment

The core-shell structured polymer microgels were synthesized by coating the hydrophobic poly(methyl methacrylate) (PMMA) sphere cores with hydrophilic nonlinear poly(ethylene glycol)-based gel shell layer. The uniqueness of these core-shell microgels lies in the integration of the PMMA core microsphere with strong hydrophobicity and the novel oligo(ethylene glycol)-based gel layer with well-defined thermosensitivity for improving loading/release efficacy of two detoxification drugs (chlorpromazine and diltiazem). The hydrophilic shell is composed of hydrophilic copolymer of 2-(2-methoxyethoxy)ethyl methacrylate (MEO(2)MA) with oligo(ethylene glycol) methyl ether methacrylates (MEO(5)MA). It was found that the molar ratio of two shell monomers n(MEO(2)MA)/n(MEO(5)MA) of 1:6 was an ideal matching value for production of the P(MEO(2)MA)/P(MEO(2)MA-co-MEO(5)MA) core-shell microgels with tunable volume phase transition temperature and excellent colloidal stability across the physiologically important temperature range. Moreover, chlorpromazine- and diltiazem-loaded microgels can show an obvious thermosensitive release and in vitro sustained-release characteristic up to 80 h.

Automated summary

Core-shell structured polymer microgels were synthesized by coating hydrophobic PMMA sphere cores with hydrophilic nonlinear poly(ethylene glycol)-based gel shell layer. The unique integration of strong hydrophobic PMMA core microsphere and novel thermosensitive oligo(ethylene glycol)-based gel layer enhanced loading/release efficacy of detoxification drugs. The hydrophilic shell composed of MEO(2)MA and MEO(5)MA copolymers demonstrated excellent colloidal stability and tunable volume phase transition temperature, leading to thermosensitive release and sustained-release characteristics of drug-loaded microgels.