Morelli Basilio
Dipartimento di Chimica, Università degli Studi di Bari, Campus Universitario, Via E. Orabona 4, 70124 Bari, Italy.
J Pharm Biomed Anal. 2003 Jun 1;32(2):257-67. doi: 10.1016/s0731-7085(02)00690-8.
Derivative spectrophotometry (ratio-spectra 1st- and 2nd-derivative and zero-crossing 2nd-derivative techniques) was applied for the determination of some cephalosporins in two component mixtures. Cefotaxime sodium salt (C(16)H(16)O(7)N(5)S(2)Na) and cefadroxil monohydrate (C(16)H(17)N(3)O(5)S.H(2)O) were examined. In all procedures, the calibration plots are linear up to 43 microg/ml of each antibiotic, with r ranging from 0.9997 to 0.9999. In the ratio-spectra method, the measurements were taken at 239.5 and 291.5 nm (cefotaxime, 1st-derivative), 238 and 283 nm (cefadroxil, 1st-derivative), 284 and 303 nm (cefotaxime, 2nd-derivative), and 229.5 and 245.5 nm (cefadroxil, 2nd-derivative). Detection limits at P=0.05 level of significance, calculated by a statistical treatment of calibration data, ranged from 0.15 to 0.58 microg/ml. LOD and LOQ ranged, respectively, from 0.19 to 0.51 and from 0.63 to 1.70 microg/ml. By the zero-crossing 2nd-derivative method, lines of regression are linear at 257 and 279 nm (cefotaxime) and 242 and 296 nm (cefadroxil). Detection limits from 0.28 to 0.51 microg/ml. LOD and LOQ from 0.27 to 0.41 and from 0.90 to 1.37 microg/ml, respectively. All the samples were tested for stability in solution and in the course of actual analysis, up to 80 h from their preparation. The developed derivative spectrophotometric methods were applied to synthetic mixtures and the RSD values ranged between 0.05 and 1.35% (ratio-spectra technique) and 0.01 and 1.07% (zero-crossing technique). The methods were also applied to vials and tablets for these drugs. The recoveries obtained were between 100.9 and 102.4% (ratio-spectra) and between 99.8 and 102.0% (zero-crossing). The procedures are simple, rapid, and did not require any preliminary separation or treatment of the samples. Instrumentation commonly available was utilised. The cephalosporins analysed are frequently used antibiotics of relevant clinical and pharmacological importance; hence this work would be of interest for the readers of journals devoted to pharmaceutical and biomedical analysis.
采用导数分光光度法（一阶和二阶导数比率光谱法以及二阶导数零交叉技术）测定两组分混合物中的一些头孢菌素。对头孢噻肟钠（C(16)H(16)O(7)N(5)S(2)Na）和头孢羟氨苄一水合物（C(16)H(17)N(3)O(5)S·H(2)O）进行了检测。在所有方法中，每种抗生素的校准曲线在浓度高达43μg/ml时呈线性，相关系数r在0.9997至0.9999之间。在比率光谱法中，测量波长为239.5和291.5nm（头孢噻肟，一阶导数）、238和283nm（头孢羟氨苄，一阶导数）、284和303nm（头孢噻肟，二阶导数）以及229.5和245.5nm（头孢羟氨苄，二阶导数）。通过对校准数据进行统计处理计算得出，在显著性水平P = 0.05时的检测限为0.15至0.58μg/ml。最低检测限（LOD）和定量限（LOQ）分别为0.19至0.51μg/ml和0.63至1.70μg/ml。采用二阶导数零交叉法时，头孢噻肟在257和279nm处以及头孢羟氨苄在242和296nm处的回归曲线呈线性。检测限为0.28至0.51μg/ml。LOD和LOQ分别为0.27至0.41μg/ml和0.90至1.37μg/ml。对所有样品在溶液中的稳定性以及实际分析过程中（制备后长达80小时）进行了测试。所建立的导数分光光度法应用于合成混合物，相对标准偏差（RSD）值在0.05%至1.35%（比率光谱法）和0.01%至1.07%（零交叉法）之间。这些方法还应用于这些药物的小瓶和片剂。回收率在100.9%至102.4%（比率光谱法）和99.8%至102.0%（零交叉法）之间。该方法简便、快速，无需对样品进行任何初步分离或处理。使用的是常见的仪器设备。所分析的头孢菌素是具有重要临床和药理学意义的常用抗生素；因此，这项工作对于致力于药物和生物医学分析的期刊读者来说会有一定的参考价值。
