title: Preparation of uniform-sized pH-sensitive quaternized chitosan microsphere by combining membrane emulsification technique and thermal-gelation method.
abstract: In this study, uniform-sized pH-sensitive quaternized chitosan microsphere was prepared by combining Shirasu porous glass (SPG) membrane emulsification technique and a novel thermal-gelation method. In this preparation process, the mixture of quaternized chitosan solution and alpha-beta-glycerophosphate (alpha-beta-GP) was used as water phase and dispersed in oil phase to form uniform W/O emulsion by SPG membrane emulsification technique. The droplets solidified into microspheres at 37 degrees C by thermal-gelation method. The whole process was simple and mild. The influence of process conditions on the property of prepared microspheres was investigated and the optimized preparation condition was obtained. As a result, the coefficient of variation (C.V.) of obtained microspheres diameters was below 15%. The obtained microsphere had porous structure and showed apparent pH-sensitivity. It dissolved rapidly in acid solution (pH 5) and kept stable in neutral solution (pH 7.4). The pH-sensitivity of microspheres also affected its drug release behavior. Bovine serum albumin (BSA) as a model drug was encapsulated in microspheres, and it was released rapidly in acid solution and slowly in neutral medium. The novel quaternized chitosan microspheres with pH-sensitivity can be used as drug delivery system in the biomedical field, such as tumor-targeted drug carrier.
authors.affiliation: State Key Lab of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Lian-Yan
authors.initials: LY
authors.lastname: Wang
authors.forename: Zhi-Guo
authors.initials: ZG
authors.lastname: Su
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Ma
mesh_terms: D004655:Emulsions; D005782:Gels; D006863:Hydrogen-Ion Concentration; D008863:Microspheres; D010316:Particle Size; D013696:Temperature
chemical_list: D004655:Emulsions; D005782:Gels