美他环素与β-环糊精形成包合物的荧光光谱研究及其分析应用

Study and application of fluorescent spectrum of inclusion complex of MTC with β-CD

用荧光光谱法研究了美他环素(MTC)与β-环糊精(β-CD)形成包合物的荧光光谱特性。对美他环素与β-环糊精形成包合物的条件、作用机理进行了研究,探讨了可能的包合方式,测定了包合物的包合常数和热力学参数ΔH、ΔS和ΔG,验证了包合反应驱动力。实验结果表明:MTC与β-CD可形成1∶1的包合物,包合物的包合常数为382.19mol/L。包合过程中,ΔH=-99.10kJ/moL,ΔS=-286.42J·moL-1·K-1,常温下ΔG<0。说明包合反应为自发反应,且是一个焓驱动过程。在Tris-HCl缓冲溶液中,β-CD的加入生成包结物可显著增强美他环素的荧光强度,据此建立了测定药物制剂中美他环素的新方法。该方法的定量线性范围为1.93×10-7～1.45×10-5mol/L,检出限为1.45×10-8mol/L,相对标准偏差为1.2%(n=13)。对药物制剂中美他环素的含量进行了测定,测定结果与标示量吻合,平均回收率为102%。

Fluorescence spectral characteristics of the inclusion complex of metacycline （MTC） with β-CD were studied by fluorimetry. In this the formation conditions for the inclusion complex of MTC with β-CD and the reaction mechanism have been studied. At the same time, the conceivale inclusive mode has been discussed too. And then the thermodynamic parameters AH, AS and AG of the inclusion complex of MTC with β-CD have been calculated, and the driving force of the inclusion reaction has been certified. The experiments indicated that MTC can form a 1 ： 1 inclusion complex with β-CD and the form constant was 382.19 mol/L. In the inclusive process, ΔH = - 99.10 kJ/mol, ΔS = - 286.42 J·mol^-1·K^-1 and under normal temperature ΔG 〈 0. So it illustrated that this process is spontaneous, and the driving force is the change of enthalpy. In tris-HCl buffer solution, β-CD can considerably enhane the fluorescence intensity of MTC. A new method for the determination of MTC in pharmacological preparations by fluorimetry has been developed. The linear range of this method was 1.93×10^-7 - 1.45 ×10^-5 mol/L, the detection limit was 1.45 ×10^-8mol/L and the relative standard deviation of the method was 1.2% （ n = 13）. And the quantity of MTC contained in pharmacological preparations was measured by fluorescence spectrophotometry, the result was completely consistent with the standard value, and the average recovery was 102%.