Abstract |
The effect of particle size on in vivo and in vitro Zn release of ZnTCP was investigated for the purpose of understanding Zn release behavior from a sustained-release device. The tricalcium phosphate powders (Ca2.7 Zn0.3(PO4)2), with particle size of 7.5 and 553 microm (S-ZnTCP and L-ZnTCP), including a 10 mol% of Zn (6.17 w/w%), as new sustained-release preparations, were synthesized by heating, after then ground and sieved using 38 and 300 microm screens. The different powder samples were characterized by the X-ray powder diffractometry and scanning electron microscopy. The release rates from Zn-TCP powders (10 mg) were measured in 10 ml of simulated body fluid (SBF) containing 10 mg/100 ml Ca2+(SBF/H), SBF containing 5 mg/100 ml Ca2+ (SBF/L) or SBF without Ca2+ (SBF/-) at 37.0 degrees C. The in vitro Zn release profiles for the smallest and the largest particles size of ZnTCP powders (L-ZnTCP and S-ZnTCP) at various Ca concentrations in SBF were significantly higher in SBF/- and SBF/L than in SBF/H. The Zn release rate from ZnTCP with different particle sizes were found to be inversely proportional to the concentration of calcium in SBF. After injection of a ZnTCP suspension containing 30 mg of S-ZnTCP powder on the backs of the rats, the plasma Zn level increased rapidly, reaching a concentration range of around 2 microg/ml. The area under the curve values of the plasma Zn concentration (Zn-AUC) over 6 days post injection of S-ZnTCP and L-ZnTCP were significantly higher than that of the control experiment. After the injection of S-ZnTCP and L-ZnTCP suspension, the plasma alkaline phosphatase activity (AIP) levels increased to more than 300 IU/l. In contrast, the AIP for the control decreased after 2 days. The area under the curve of the AIP (AIP-AUC) for 6 days of S-ZnTCP was significantly higher than that of other groups.
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Authors | Makoto Otsuka, Sunao Marunaka, Yoshihia Matsuda, Atsuo Ito, Hiroshi Naito, Noboru Ichinose, Tadashi Kokubo, Takashi Nakamura, William I Higuchi |
Journal | Bio-medical materials and engineering
(Biomed Mater Eng)
Vol. 13
Issue 2
Pg. 103-13
( 2003)
ISSN: 0959-2989 [Print] Netherlands |
PMID | 12775901
(Publication Type: Comparative Study, Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Calcium Phosphates
- Delayed-Action Preparations
- beta-tricalcium phosphate
- Zinc
- tricalcium phosphate
- Calcium
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Topics |
- Animals
- Calcium
(blood)
- Calcium Phosphates
(chemistry)
- Delayed-Action Preparations
(therapeutic use)
- Female
- Metabolic Clearance Rate
- Osteoporosis
(blood, chemically induced, drug therapy, metabolism)
- Particle Size
- Rats
- Rats, Wistar
- Zinc
(administration & dosage, blood, chemistry, pharmacokinetics)
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