[Assessment of beta-tricalcium phosphate as a carrier for bone formation promoting agent, TAK-778-SR].
OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Ueda
Kazuhiko
K
Department of Crown and Bridge Prosthodontics, The Nippon Dental University School of Dentistry at Niigata, 951-8580 Niigata. kazuhiko@ngt.ndu.ac.jp
Watanabe
Fumihiko
F
Hata
Yoshiaki
Y
D000818:Animals; D012898:Autacoids / Q000008:administration & dosage; D001582:Benzothiepins / Q000008:administration & dosage*; D002130:Calcium Phosphates; D002214:Capsules; D004337:Drug Carriers; D005260:Female; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D012898:Autacoids; D001582:Benzothiepins; D002130:Calcium Phosphates; D002214:Capsules; D004337:Drug Carriers; C120450:TAK 778; C485817:beta-tricalcium phosphate