Bebawy Lories I, El Kelani Khadiga, Fattah Laila Abdel
National Organization for Drug Control and Research, Cairo, Egypt.
J Pharm Biomed Anal. 2003 Aug 21;32(6):1219-25. doi: 10.1016/s0731-7085(03)00161-4.
A highly sensitive and specific fluorimetric method was developed for the determination of cefazolin sodium I, cefoperazone sodium II, ceftriaxone sodium III, and cefixime IV. The proposed method involves the formation of ternary complex with Tb(3+) in the presence of Tris buffer. The quenching of the terbium fluorescence due to the complex formation was quantitative for the four studied drugs. The effect of pH, concentration of Tris buffer and terbium were studied. The formation of the complex was highly dependent on the pH. The optimum pH was found to be pH 8 for cefazolin sodium I, ceftriaxone sodium III, cefixime IV and pH 10 for cefoperazone sodium II. The optimum concentration for Tb(3+) was found 1 ml of 10(-4) M solution and for Tris buffer 1 ml of the prepared solution. Under the described conditions, the proposed method was applicable over the concentration range 8.79 x 10(-6)-7.91 x 10(-5), 9.7 x 10(-6)-4.49 x 10(-)5, 6.10 x 10(-6)-2.50 x 10(-5), and 4.92 x 10(-6)-2.95 x 10(-5) mol with mean percentage accuracy of 99.79+/-0.24, 98.97+/-1.25, 100.05+/-0.79, and 100.15+/-0.54 for I, II, III, and IV, respectively. The proposed method was applied successfully for the determination of studied drugs in bulk powder and in pharmaceutical formulations. The results obtained by applying the described method were statistically analyzed and compared with those obtained by applying the official method. The proposed method was used as stability indicating method for the determination of the studied drugs in the presence of their degradation products.
开发了一种高灵敏度和特异性的荧光法，用于测定头孢唑林钠I、头孢哌酮钠II、头孢曲松钠III和头孢克肟IV。所提出的方法涉及在Tris缓冲液存在下与Tb(3+)形成三元络合物。由于络合物形成导致的铽荧光猝灭对于四种研究药物是定量的。研究了pH值、Tris缓冲液浓度和铽的影响。络合物的形成高度依赖于pH值。发现头孢唑林钠I、头孢曲松钠III、头孢克肟IV的最佳pH值为8，头孢哌酮钠II的最佳pH值为10。发现Tb(3+)的最佳浓度为1 ml 10(-4) M溶液，Tris缓冲液的最佳浓度为1 ml制备的溶液。在所描述的条件下，所提出的方法适用于8.79 x 10(-6)-7.91 x 10(-5)、9.7 x 10(-6)-4.49 x 10(-5)、6.10 x 10(-6)-2.50 x 10(-5)和4.92 x 10(-6)-2.95 x 10(-5) mol的浓度范围，I、II、III和IV的平均百分准确率分别为99.79±0.24、98.97±1.25、100.05±0.79和100.15±0.54。所提出的方法成功地应用于测定原料药和药物制剂中的研究药物。对应用所述方法获得的结果进行了统计分析，并与应用官方方法获得的结果进行了比较。所提出的方法用作在存在降解产物的情况下测定研究药物的稳定性指示方法。
