title: Synthesis of mesoporous silica-gel core-shell structural microparticles and their multiple drug delivery.
abstract: BACKGROUND
  Release of two drugs safely and independently should be necessary in medical or reaction engineering fields to overcome many complex problems such as multi-drug resistance in treatment of disease.
  
  
  OBJECTIVE
  Core-shell structural microparticles that can load/release two drugs simultaneously are designed and prepared.
  
  
  METHODS
  The microparticles are composed of mesoporous silica core and hyaluronate (HA)/poly (N-isopropylacrylamide) hybrid gel shell.
  
  
  METHODS
  The synthesis processes are monitored by powder x-ray diffraction and Fourier transform infrared spectroscopy. The properties of microparticles are characterized by nuclear magnetic resonance, dynamic light scattering and transmission electron microscope methods. Two kinds of drugs are loaded into the mesoporous-core and gel-shell, respectively, and then released under various conditions.
  
  
  RESULTS
  The microparticles show uniform spherical shapes with core-shell structures. When temperature is higher than the lower critical solution temperature, the microparticles shrink abruptly and assemble. The drug release rates have been found to depend on the concentration of the microparticle suspensions and pH of the release medium.
  
  
  CONCLUSIONS
  The swellability of the microparticles are controlled by the HA size and gel crosslink density; and the main effect factors on drug releasing behavior are the drug properties and drug diffusion ability.
  
  
  CONCLUSIONS
  The experimental results confirmed different drugs could be safely loaded into the core-shell structural microparticles and released independently, which might be potential carriers for drugs or catalysts. These microparticles would be expected to make sense for applying in medical or reaction engineering fields.
authors.affiliation: Key Laboratory for Advanced Materials and Department of Chemistry, East China University of Science and Technology , Shanghai , China.
authors.forename: Xiangye
authors.initials: X
authors.lastname: Li
authors.forename: Dongyan
authors.initials: D
authors.lastname: Zhi
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Shouhong
authors.initials: S
authors.lastname: Xu
authors.forename: Honglai
authors.initials: H
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Hu
mesh_terms: D000178:Acrylamides; D002626:Chemistry, Pharmaceutical; D004317:Doxorubicin / Q000008:administration & dosage; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems; D065546:Drug Liberation; D006820:Hyaluronic Acid / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D010316:Particle Size; D016062:Porosity; D012235:Rhodamines / Q000008:administration & dosage; D058428:Silica Gel / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D000178:Acrylamides; D004337:Drug Carriers; D012235:Rhodamines; D058428:Silica Gel; D004317:Doxorubicin; D006820:Hyaluronic Acid; C067295:N-isopropylacrylamide
keywords: Core-shell structure; hybrid gel; mesoporous silica; multiple drug release; temperature sensitive