Hilali Abdelilah, Jiménez Juan Carlos, Callejón Manuel, Bello Miguel Angel, Guiraúm Alfonso
Department of Analytical Chemistry, Faculty of Chemistry, University of Seville, 41012 Seville, Spain.
J Pharm Biomed Anal. 2005 Jul 15;38(4):768-75. doi: 10.1016/j.jpba.2005.02.011.
Imipenem shows a fast chemical conversion to the more stable imin form (identical to that from biochemical dehydropeptidase degradation) in aqueous solutions that shows a wave at lower cathodic potential than the imipenem one. The aim of this work is the study of the electrochemical behaviour of the primary metabolite of imipenem (M1) and the proposal of electrochemical methods for the determination of M1 in human urine samples. Electrochemical studies were realized in phosphate buffer solutions over pH range 2.0-8.0 using differential pulse polarography, dc-tast polarography, cyclic voltammetry and linear sweep voltammetry (staircase). In acidic media, a non-reversible diffusion-controlled reduction involving two electrons and two protons occurs and the mechanism for the reduction was suggested. A differential pulse polarographic method for the determination of M1 in the concentration range 10(-6) to 10(-4)M with a detection limit of 4.5 x 10(-7)M was proposed. Also, a method based on controlled adsorptive pre-concentration of M1 on the hanging mercury drop electrode (HMDE) followed by linear sweep voltammetry allows its determination in the concentration range 2 x 10(-9) to 4 x 10(-8)M with a detection limit of 1.05 x 10(-9)M. The proposed methods have been used for the direct determination of M1 in spiked human urine and real human-derived urine with good results and should be appropriate for monitoring purposes.
亚胺培南在水溶液中会快速化学转化为更稳定的亚胺形式（与生化脱氢肽酶降解产生的形式相同），该亚胺形式在比亚胺培南更低的阴极电位处显示出一个波。本工作的目的是研究亚胺培南主要代谢物（M1）的电化学行为，并提出用于测定人尿液样品中M1的电化学方法。使用差分脉冲极谱法、直流极谱法、循环伏安法和线性扫描伏安法（阶梯伏安法）在pH范围为2.0 - 8.0的磷酸盐缓冲溶液中进行电化学研究。在酸性介质中，发生了涉及两个电子和两个质子的不可逆扩散控制还原反应，并提出了还原反应的机理。提出了一种差分脉冲极谱法，用于测定浓度范围为10⁻⁶至10⁻⁴M的M1，检测限为4.5×10⁻⁷M。此外，一种基于M1在悬汞滴电极（HMDE）上的可控吸附预富集，随后进行线性扫描伏安法的方法，可在浓度范围为2×10⁻⁹至4×10⁻⁸M内测定M1，检测限为1.05×10⁻⁹M。所提出的方法已用于直接测定加标人尿液和实际人源尿液中的M1，结果良好，应适用于监测目的。
