A Novel Skeletal Drug Delivery System Using Self-Setting Bioactive Glass Bone Cement IV: Cephalexin Release From Cement Containing Polymer-Coated Bulk Powder
Affiliations: Department of Pharmaceutical Technology, Kobe Pharmaceutical University, Motoyama-Kitamachi 4-19-1, Higashi-Nada, Kobe 658, Japan | Faculty of Engineering, Kyoto University, Sakyo, Kyoto 606-01 | Nippon Electric Glass Co., Ohtsu 520, Japan | Research Center for Biomedical Engineering, Kyoto University, Sakyo, Kyoto 606, Japan | Faculty of Medicine, Kyoto University, Sakyo, Kyoto 606, Japan
Note: [] Requests for reprints should be addressed to Makoto Otsuka, Ph.D., Department of Pharmaceutical Technology, Kobe Pharmaceutical University, Motoyarna-Kitamachi 4-19-1, Higashi-Nada, Kobe 658, Japan.
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 37deg;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.
Keywords: hydroxyapatite, bioactive material for artificial bone or teeth, self-setting bone cement, bioactive bone glass cement, drug delivery system for skeletal tissue, drug release test
