Differential pulse voltammetric determination of diclofenac in pharmaceutical preparations and human serum

This article describes a differential pulse voltammetric (DPV) method for the determination of diclofenac in pharmaceutical preparations and human serum. The proposed method was based on electro-oxidation of diclofenac at platinum electrode in 0.1 M TBAClO₄/acetonitrile solution. The well-defined two oxidation peaks were observed at 0.87 and 1.27 V, respectively. Calibration curves that obtained by using current values measured for second peak were linear over the concentration range of 1.5-17.5 μg mL^-1and 2-20 μg mL^-1 in supporting electrolyte and serum, respectively. Precision and accuracy were also checked in all media. Intra- and inter-day precision values for diclofenac were less than 3.87, and accuracy (relative error) was better than 4.12%. The method developed in this study is accurate, precise and can be easily applied to Diclomec, Dicloflam and Voltaren tablets as pharmaceutical preparation. In addition, the proposed technique was successfully applied to spiked human serum samples. No electro-active interferences from the endogenous substances were found in human serum.

本文介绍了一种用于测定药物制剂及人血清中双氯芬酸的差分脉冲伏安法（differential pulse voltammetric, DPV）。该方法基于双氯芬酸在0.1 M TBAClO₄/乙腈溶液的铂电极上的电氧化反应，分别在0.87 V和1.27 V处观测到两个峰形良好的氧化峰。以第二氧化峰的电流值绘制校准曲线，在支持电解质体系与血清体系中，校准曲线分别在1.5~17.5 μg·mL⁻¹及2~20 μg·mL⁻¹的浓度范围内呈良好线性关系。本研究对所有测试体系均进行了精密度与准确度考察：双氯芬酸的日内及日间精密度均小于3.87，准确度（相对误差）优于4.12%。本研究开发的该方法准确度高、精密度好，可便捷应用于Diclomec、Dicloflam及Voltaren片剂等药物制剂的检测。此外，该方法还成功应用于加标人血清样本的检测，在人血清中未发现内源性物质产生的电活性干扰。