Thermo-gelling injectable nanogels, with no burst release of loaded drug, were prepared by a simple route by combining self assembled nanocapsules of amphiphilically modified chitosan with glycerophosphate di-sodium salt and glycerol. The potential as a depot drug delivery system was demonstrated in vivo through the therapeutic effect of ethosuximide (ESM) loaded nanogels, suppressing spike wave discharges (SWDs) in Long Evan rat model. Simultaneously clearance of gels from the site of administration was monitored non-invasively using MRI. The gel structure was characterized using TEM and SEM, confirming the gels to be an assembly of nanocapsules and using two-photon microscopy to visualize the network structure. In vitro drug release studies using ESM revealed that the nanogels exhibited extended, mostly Fickian release. Finally, all investigated formulations displayed excellent cytotoxicity data determined by MTT assay using human retinal pigmented epithelium cells. All presented properties are highly desirable for injectable depot gels for drug delivery.

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Smart hydrogels play an increasingly important role in biomedical applications, since materials that are both biocompatible and multi‐stimuli‐responsive are highly desirable. A simple, organic solvent‐free method is presented to synthesize a biocompatible hydrogel that undergoes a sol–gel transition in response to multiple stimuli. Methoxy‐poly(ethylene glycol) (mPEG) is modified into carboxylic‐acid‐terminated‐methoxy‐poly(ethylene glycol) (mPEG‐acid), which is then grafted onto chitosan via amide linkages yielding mPEG‐g‐chitosan. Grafting of mPEG onto hydrophobic chitosan imparts hydrophilic properties to the resultant polymer. The mPEG‐g‐chitosan gel exhibits a controllable multi‐stimuli‐responsive property. The balance between hydrophilicity and hydrophobicity is believed to confer mPEG‐g‐chitosan with stimuli‐responsive behavior. The effect of salt concentration, solute concentration, temperature, and pH on the sol–gel transition of mPEG‐g‐chitosan is evaluated and the underlying mechanisms of mPEG‐g‐chitosan polymer packing and gelation property is discussed.

Naringin-carrying CHC-β-GP-glycerol colloidal hydrogel can be used to inhibit induction of experimental periodontitis with favorable handling and inflammation-responsive characteristics.