A dual constant-composition titration system as in vitro resorption model for comparing dissolution rates of calcium phosphates biomaterials
A dual constant-composition titration system as in vitro resorption model for comparing dissolution rates of calcium phosphates biomaterials
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DOI：
10.1002/jbm.b.10009
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发表时间：
2003-05-15
影响因子：
3.4
通讯作者：
Takagi, S
中科院分区：
文献类型：
--
作者：
Chow, LC;Markovic, M;Takagi, S
据推测，磷酸钙骨移植材料的体内再吸收速率与其在具有模拟破骨细胞产生的酸性环境的离子组成的脱矿质溶液中的溶解速率密切相关。因此，应该可以使用体外模型来产生磷酸钙材料的溶解速率数据，作为预测体内吸收特性的起点。对骨吸收细胞的细胞外液的直接pH测量表明pH低至3。在本研究中，采用双恒定成分溶出系统作为体外骨吸收模型来比较不同磷酸钙材料的溶出速率。将已知尺寸（6 毫米深 x 3 毫米高）的 NIST 标准参考羟基磷灰石 (HA)、二水合磷酸二钙 (DCPD) 和磷酸钙水泥 (CPC) 圆盘在 37 摄氏度下溶解在无机成分与血清相似的溶液中 ([Ca] = 1.15 mmol/l；[P] = 1.2 mmol/l；[KCl] = 133 mmol/l) pH值为3.0。 Ca 离子特异性电极和 pH 电极用于控制滴定剂的添加，以分别补偿脱盐溶液中钙和磷酸盐浓度的增加。从滴定数据获得溶解速率和化学计量（Ca/P 摩尔比）。每种固体在溶解过程中以近似恒定的速率溶解。 HA 的溶解速率以 mg cm(-2) min(-1) 表示（平均值 +/- 标准偏差，n = 5）：6.58 +/- 1.22； DCPD：21.0+/-2.6；每次点击费用：8.21 +/- 0.73。 DCPD 的溶解速度比 HA 快三倍 (p < 0.05)。 CPC 的溶解速度比 HA 快 1.2 倍，但差异无统计学意义 (p > 0.05)。该模型可用于研究磷酸钙骨移植材料和涂层在各种矿物质饱和条件下的溶解速率和化学计量。 (C) 2003 年 Wiley 期刊公司。
It has been postulated that the in vivo resorption rates of calcium-phosphate bone-graft materials are closely related to their dissolution rates in demineralizing solutions having ionic compositions mimicking the acidic environment produced by osteoclasts. Thus, it should be possible to use an in vitro model to produce dissolution-rate data of calcium-phosphate materials as a starting point for predicting in vivo resorption properties. Direct pH measurements of the extracellular fluid from bone-resorbing cells showed that the pH was as low as 3. In the present study, a dual constant-composition dissolution system was used as an in vitro resorption model to compare dissolution rates of different calcium-phosphate materials. NIST standard reference hydroxyapatite (HA), dicalcium-phosphate dihydrate (DCPD), and calcium-phosphate cement (CPC) discs of known dimensions (6-mm d x 3-mm h) were allowed to dissolve at 37 degreesC in a solution that had an inorganic composition similar to that of serum ([Ca] = 1.15 mmol/l; [P] = 1.2 mmol/l; [KCl] = 133 mmol/l) and a pH of 3.0. A Ca ion-specific electrode and a pH electrode were used to control the addition of titrants to compensate for the increases in calcium and phosphate concentrations, respectively, in the demineralizing solution. The rate and stoichiometry (Ca/P molar ratio) of dissolution were obtained from the titration data. Each solid dissolved at an approximately constant rate during the dissolution process. The dissolution rates, expressed in mg cm(-2) min(-1), (mean +/- standard deviation, n = 5) were for HA: 6.58 +/- 1.22; DCPD: 21.0 +/- 2.6; and CPC: 8.21 +/- 0.73. DCPD dissolved three times faster than HA (p < 0.05). CPC dissolved 1.2 times faster than HA but the difference was not statistically significant (p > 0.05). This model can be used to study the rate and stoichiometry of dissolution of calcium-phosphate bone-graft materials and coatings under a wide range of mineral saturation conditions. (C) 2003 Wiley Periodicals, Inc.