Determination of diclofenac in pharmaceutical preparations by voltammetry and gas chromatography methods

Rapid, sensitive and specific methods were developed for the determination of diclofenac in pharmaceutical preparations by linear sweep voltammetry (LSV) and gas chromatography (GC) with mass spectrometry (MS) detection. The linearity was established over the concentration range of 5â35 μg/mL for LSV and 0.25â5 μg/mL for GCâMS method. The intra- and inter-day relative standard deviation (RSD) was less than 4.39% and 4.62% for LSV and GCâMS, respectively. Limits of quantification (LOQ) were determined as 4.8 and 0.15 μg/mL for LSV and GCâMS, respectively. No interference was found from tablet excipients at the selected assay conditions. The methods were applied for the quality control of commercial diclofenac dosage forms to quantify the drug and to check the formulation content uniformity. Keywords: Diclofenac, Sweep voltammetry, Chromatographyâmass spectrometry, Pharmaceutical preparatio

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.</p