title: Preparation and characterization of theophylline loaded chitosan/beta-cyclodextrin microspheres.
abstract: The purpose of this project was to develop sustained release chitosan/beta-cyclodextrin microspheres of theophylline (TH) prepared by spray drying method. The effect of several formulation variables on the characteristics of microspheres was studied. The B microspheres had a narrower particle size distribution with the diameter between l and 10 microm. SEM showed spherical microspheres with smooth or slightly wrinkled surfaces. FT-IR spectroscopy revealed that hydrogen bonds were formed between TH and chitosan or beta-cyclodextrin. The drug entrapments significantly increased from 13.33 to 35.70% with an increase of the ratio of drug/polymer. The encapsulation efficiencies were from 85.16 to 91.40%. The in vitro release of TH from microspheres was related to the pH of the medium, swelling ability, especially in the ratio of drug/polymer. The B microspheres had a prolonged release pattern with the release rate of 60.20% (pH 6.8) within 8 h.
authors.affiliation: College of Marine Life Science, Ocean University of China, 5# Yushan Road, Qingdao 266003, PR China.
authors.forename: Wei Fen
authors.initials: WF
authors.lastname: Zhang
authors.forename: Xi Guang
authors.initials: XG
authors.lastname: Chen
authors.forename: Pi Wu
authors.initials: PW
authors.lastname: Li
authors.forename: Qiang Zhi
authors.initials: QZ
authors.lastname: He
authors.forename: Hui Yun
authors.initials: HY
authors.lastname: Zhou
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D048271:Chitosan / Q000737:chemistry*; D004339:Drug Compounding; D016503:Drug Delivery Systems; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007259:Infrared Rays; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D015233:Models, Statistical; D011108:Polymers / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013806:Theophylline / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D047392:beta-Cyclodextrins; D048271:Chitosan; D013806:Theophylline; C031215:betadex