Assessment of .BETA.-Tricalcium Phosphate as a Carrier for Bone Formation Promoting Agent, TAK-778-SR

• Published in: Nihon Hotetsu Shika Gakkai zasshi Vol. 49; no. 2; pp. 211 - 220
• Main Authors: Ueda, Kazuhiko, Watanabe, Fumihiko, Hata, Yoshiaki
• Format: Journal Article
• Language: Japanese
• Published: Japan 2005
• Subjects: Animals; Autacoids - administration & dosage; Benzothiepins - administration & dosage; Calcium Phosphates; Capsules; Drug Carriers; Female; Osteogenesis - drug effects; Rats; Rats, Sprague-Dawley
• ISSN: 0389-5386; 1883-177X; 1883-177X
• DOI: 10.2186/jjps.49.211

The aim of this study was to evaluate the combination of TAK-778-SR which was sustained-release microcapsules of a bone formation stimulant, TAK-778, and its carrier beta-tricalcium phosphate (beta-TCP) blocks (pore rates 60%, 75% respectively). The difference of their abilities in bone-formation was evaluated histomorphologically by varying the following conditions: with or without TAK-778, pore ratio of carrier and embedding period. Nine-week-old female SD rats were used. After removing the parietal bone from the head with a trephine bar, the defects were refilled by beta-TCP blocks immersed with or without TAK-778 under the following conditions: saline solution, release microcapsules only, and release microcapsules with TAK-778 (TAK-778-SR). These rats were sacrificed after 5 and 10 weeks and their histological specimens were prepared. Morphological change was observed and the formation rates of each new bone were compared using an NIH imaging program. A significant amount of new bone was morphologically observed in all beta-TCP samples that were treated with TAK-778-SR. A high rate of new bone formation was confirmed in the 10-week samples (pore rate 75%, with TAK-778-SR) with the NIH imaging. 1. beta-TCP and release microcapsules did not disturb the recovery process. 2. Five- and 10-week samples (pore rate 60%) were absorbed marginally. 3. Absorption was observed in the 5-week samples (pore rate 75%), and it was accelerated further at 10 weeks. 4. An accelerating bone-formation effect of TAK-778-SR was confirmed and beta-TCP block was proved to be highly useful as a carriage material.