title: A novel skeletal drug delivery system using self-setting bioactive glass bone cement. IV: Cephalexin release from cement containing polymer-coated bulk powder.
abstract: A novel device consisting of Eudragit-coated cephalexin as a model drug and a self-setting bioactive cement based upon CaO-SiO2-P2O5 glass was investigated. The glass cement hardened within 5 min of mixing with a phosphate buffer. After setting, in vitro drug release from homogeneous or heterogeneous drug-loaded cement pellets in a simulated body fluid (SBF) at pH 7.25 and 37 degrees C continued for over 2 weeks. The hardened cement gradually formed low-crystallinity hydroxyapatite and decreased in volume by about 5% during drug release in SBF. Consequently, 30% of the loaded drug was initially released from the homogeneous cement system, and thereafter it was released more slowly. Since the heterogeneous system consisting of the cement and a 50% polymer coated, drug-loaded pellet avoided this drug's burst, the drug was released over a longer period than that in the homogeneous system. The heterogeneous system released the polymer-coated drug very slowly, because it completely avoided the initial burst, and sustained the release over a long period.
authors.affiliation: Department of Pharmaceutical Technology, Kobe Pharmaceutical University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Otsuka
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda
authors.forename: T
authors.initials: T
authors.lastname: Kokubo
authors.forename: S
authors.initials: S
authors.lastname: Yoshihara
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Yamamuro
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001843:Bone Cements / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry; D002124:Calcium Fluoride / Q000737:chemistry; D002506:Cephalexin / Q000008:administration & dosage* / Q000737:chemistry; D003461:Crystallography; D003692:Delayed-Action Preparations; D016503:Drug Delivery Systems; D004343:Drug Implants; D017886:Durapatite / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010087:Oxides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D011108:Polymers; D011208:Powders; D012822:Silicon Dioxide / Q000737:chemistry; D013053:Spectrophotometry; D013499:Surface Properties; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D017610:Calcium Compounds; D003692:Delayed-Action Preparations; D004343:Drug Implants; D010087:Oxides; D010710:Phosphates; D011108:Polymers; D011208:Powders; D012822:Silicon Dioxide; D017886:Durapatite; C016538:lime; D002124:Calcium Fluoride; D002506:Cephalexin