title: Dissolution medium responsive simvastatin release from biodegradable apatite cements and the therapeutic effect in osteoporosis rats.
abstract: Bio-convertible artificial bone with slow release of anti-osteoporosis drug is useful to treat osteoporosis. Apatite cement containing 6% simvastatin (APD) had lower crystallinity than natural bone. In-vitro drug release tests in simulated body fluid (pH 7.8) and acetate buffer (pH 4.5) were performed at 37.0 C as physical models of osteoblast and osteoclast conditions (SOB and SOC). The device had lower drug release rate under SOB, but significantly higher rates under SOC.  The simvastatin release rate changed depending on dissolution media, it repeated twice, and the rate under SOC was 15 times higher than under SOB. The device showed dissolution medium responsive drug release.  After implantation of the APD in osteoporosis rats, the bone mineral density was evaluated by the x-ray computed tomography.  The result indicated that the bone mineral density of APD implanted rat was significantly higher than that of control diseased.  The result indicated that the device was therapeutically useful to bone regeneration.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hamada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohshima
authors.forename: Makoto
authors.initials: M
authors.lastname: Otsuka
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001031:Apatites / Q000008:administration & dosage* / Q000737:chemistry; D001826:Body Fluids; D001843:Bone Cements / Q000737:chemistry / Q000494:pharmacology*; D050071:Bone Density Conservation Agents / Q000737:chemistry / Q000493:pharmacokinetics* / Q000494:pharmacology / Q000627:therapeutic use; D016503:Drug Delivery Systems; D005260:Female; D008954:Models, Biological; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D019821:Simvastatin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D014057:Tomography, X-Ray Computed
chemical_list: D001031:Apatites; D001843:Bone Cements; D050071:Bone Density Conservation Agents; D019821:Simvastatin