Developing stability-indicating HPLC method for the determination of sodium diclofenac in the presence of its degradation products

ABSTRACT

A stability indicating reversed-phase liquid chromatographic [HPLC] method was developed for the determination of Sodium Diclofenac in the presence of its degradation products. The chromatography was performed on a C18 column. Eluents were monitored by UV detection at 254 nm using the mobile phase acetonitrile-sodium acetate [pH 5.5; 0.02 M] [70 30, v/v], using mefenamic acid as internal standard. The method was statistically validated for linearity, accuracy, precision and specificity. The linearity of Sodium Diclofenac peak area responses was demonstrated within the concentration range of 50 to 150 mcg ml. Correlation coefficients were around 0.999. The limits of detection and quantitation were 1 and 2.5 mcg/ml, respectively. The method was demonstrated to be precise, accurate and specific with no interference from the injectable solution excipients and good resolution of the drug peak from the peaks of the degradation products. The retention time for Sodium Diclofenac was 2.08 minutes, and retention times for its degradation products were 0.97, 1.30, 1.68 and 2.53 minutes. The stability-indicating nature of this method was confirmed by accelerated degradation of Sodium Diclofenac, Solutions of Sodium Diclofenac 10 meg/mI, were stored in 0.1 NHCI, 0.1 NNaOH at room temperature [approximately 25°C] for 2 weeks which produced degradation products, afterwards these solutions were injected in HPLC apparatus, and the peaks of the degradation products did not interfere with Sodium Diclofenac peak The retention time of Sodium Diclofenac was of 2.08 mm, while of its degradation products were 0.97, 1.30, 1.68, 2.53 respectively. The results indicated that the proposed method could be used in a stability assay