Goyal Rajendra N, Oyama Munetaka, Umar Akrajas A, Tyagi Anuradha, Bachheti Neeta
Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India.
J Pharm Biomed Anal. 2007 Sep 3;44(5):1147-53. doi: 10.1016/j.jpba.2007.05.033. Epub 2007 Jun 2.
The electrochemical behavior of a corticosteroid methylprednisolone (MP), used for doping, has been studied at gold nanoparticles modified indium tin oxide (nanoAu/ITO) electrode. The nanoAu/ITO electrode exhibited an effective catalytic response towards its oxidation and lowered its oxidation potential by approximately 127 mV when compared with bare ITO electrode. Oxidation of MP has been carried out in phosphate containing electrolyte in the pH range 2.13-10.00 and a well-defined oxidation peak was noticed. Linear concentration curves are obtained over the concentration range 0.01-1.0 microM with a detection limit of 2.68 x 10(-7)M at nanoAu/ITO electrode. A diffusion coefficient of 2.36 x 10(-6)cm(2)/s is calculated for MP using chronoamperometry. The proposed method is effectively applied to detect the concentration of MP in pharmaceutical formulations and human blood plasma and urine samples. A comparison of MP concentration determined in blood plasma and urine by the proposed method and GC/MS indicated that the results are essentially similar. It is believed that the method will be useful in determining this drug in case of doping.
已在金纳米颗粒修饰的氧化铟锡（nanoAu/ITO）电极上研究了用于兴奋剂检测的皮质类固醇甲泼尼龙（MP）的电化学行为。与裸ITO电极相比，nanoAu/ITO电极对其氧化表现出有效的催化响应，并使其氧化电位降低了约127 mV。MP在pH范围为2.13 - 10.00的含磷酸盐电解质中进行氧化，观察到一个明确的氧化峰。在nanoAu/ITO电极上，在0.01 - 1.0 microM的浓度范围内获得了线性浓度曲线，检测限为2.68×10⁻⁷M。使用计时电流法计算出MP的扩散系数为2.36×10⁻⁶cm²/s。所提出的方法有效地应用于检测药物制剂以及人血浆和尿液样本中MP的浓度。通过所提出的方法和气相色谱/质谱法测定的血浆和尿液中MP浓度的比较表明，结果基本相似。据信该方法在兴奋剂检测中测定这种药物时将很有用。
