无机牛骨的体外溶解行为研究

Solubility behavior of anorganic bovine bone in vitro

目的探讨无机牛骨(ABB)的体外溶解行为。方法在37℃恒温水浴系统中以ABB为固体滴定物,运用半导体激光散射系统确定滴定终点,利用滴定终点的固体滴定总量和溶液pH值获取ABB在0.1mol/L氯化钾溶液中的溶解度等温线。以合成羟基磷灰石(HA)的溶解度等温线作为对照。使用X射线衍射(XRD)、能谱弥散X射线谱(EDX)、透射电镜(TEM)和选区电子衍射(SAED)对ABB在两种pH值下(pH=3.99,4.46)的溶解-再沉淀物进行分析。结果37℃下ABB在pH为4～5的0.1mol/L氯化钾溶液中的溶解度是合成HA的5～20倍,且溶解度随pH值降低而升高。溶解-再沉淀物为HA,结晶度和钙磷比随pH值降低而降低。结论ABB的溶解度与溶液的pH值密切相关,溶液pH值的改变影响ABB溶解-再沉淀物的结晶度。

Objective To explore the in vivo solubility behavior of anorganic bovine bone （ABB）. Methods The titration end-point of the solid ABB used was monitored by a low-angle laser- scattering system. The solubility isotherm of ABB in 0.1 mol/L aqueous KCl was determined by total titration and the pH value of solution while that of synthetic hydroxyapatite was used as a comparison. The equilibrium compositions were characterized by X-ray diffraction （XRD）, energy dispersive X-ray spectroscopy （EDX）, transmission electron microscopy （TEM） and select area electron diffraction （SAED） under the pH of 3.99 and 4.46, respectively. Results The solubility of ABB in 0.1 mol/L aqueous KCl Increased 5 - 20 times than that of synthetic hydroxyapatite at 37℃, ranging from the pH of 4 - 5. The solubility increased significantly while pH value decreasing. No other phase than HA was detected in the precipitates. The crystallinity and calcium to phosphate ratio of the equilibrium compositions decreased with pH value. Conclusions Solubility of ABB was highly related to the solution pH, The change of solution acidity would affect the crystallinity of equilibrium composition.