title: Programmable delivery of hydrophilic drug using dually responsive hydrogel cages.
abstract: Micro-capsules normally encapsulate therapeutic agents only inside their cavities. In this paper, we report on the synthesis of dually responsive poly(N-isopropylacrylamide) (PNiPAM)-co-acrylic acid (AA) hydrogel cages sub-micrometer in size and the use of these cages as drug carriers. The cavity structure of the cages can enhance volume phase transition compared to solid gel particles, thus favoring drug loading and release. TEM images and FT-IR spectra confirmed that the model drug isoniazid (INH) is located in two regions: within the shell and inside the cavity of the cages. The drugs residing in the shell can form hydrogen bonds with the cage matrix, while the drugs in the cavity are interaction free with the carrier. This difference from the residency of drugs exploited to a structure induced drug release which was programmable controlled by external pH and temperature. In vitro drug release studies showed that in a neutral medium (pH=7.4), major drugs were preserved within the shell, while in an acidic medium (pH=1.2), nearly all of the drugs were released due to the dissociation of hydrogen bonds.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Jingxia
authors.initials: J
authors.lastname: Gu
authors.forename: Fan
authors.initials: F
authors.lastname: Xia
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Xiaozhong
authors.initials: X
authors.lastname: Qu
authors.forename: Zhenzhong
authors.initials: Z
authors.lastname: Yang
authors.forename: Lei
authors.initials: L
authors.lastname: Jiang
mesh_terms: D000179:Acrylates; D000180:Acrylic Resins; D002626:Chemistry, Pharmaceutical; D003102:Colloids; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004343:Drug Implants; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D008027:Light; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D012542:Scattering, Radiation; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000179:Acrylates; D000180:Acrylic Resins; D003102:Colloids; D004337:Drug Carriers; D004343:Drug Implants; D020100:Hydrogels; C052970:poly-N-isopropylacrylamide