Validated Stability-Indicating HPLC-DAD Method for the Simultaneous Determination of Diclofenac Sodium and Diflunisal in Their Combined Dosage Form

Rasha A Shaalan

doi:10.3797/scipharm.1301-24

Abstract

A simple, rapid, and highly selective HPLC-DAD method was developed for the simultaneous determination of diclofenac sodium (DIC) and diflunisal (DIF) in pure form and in their combined formulation. Effective chromatographic separation was achieved using a Zorbax SB-C8 (4.6×250 mm, 5 μm particle size) column with a mobile phase composed of 0.05 M phosphoric acid, acetonitrile, and methanol in the ratio of 40:48:12 (by volume). The mobile phase was pumped isocratically at a flow rate of 1 mL/min, and quantification of the analytes was based on measuring their peak areas at 228 nm. The retention times for diflunisal and diclofenac were about 7.9 and 9.5 min, respectively. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Calibration curves were linear in the ranges of 5–100 μg/mL for both drugs with correlation coefficients >0.9998. The proposed method proved to be selective and stability-indicating by the resolution of the two analytes from four of their related substances and potential impurities as well as from forced-degradation (hydrolysis, oxidation, photolysis, and dry heat) products. The validated HPLC method was successfully applied to the analysis of DIC and DIF in their combined dosage form (suppositories). The proposed method made use of the diode array detector (DAD) as a tool for peak identity and purity confirmation.

Highlights

Diclofenac sodium (DIC) (Fig. 1), chemically known as sodium {2-[(2,6-dichlorophenyl)amino]phenyl}acetate [1], is a phenylacetic acid derivative non-steroidal anti-inflammatory drug (NSAID)
Other analytical techniques involved the use of potentiometric membrane sensors [10], cyclic and differential-pulse voltammetry [11], spectrophotometry [12, 13], chemometric spectrophotometry [14], spectrofluorimetry [15], infrared and Raman spectroscopy [16], gravimetry [17], GC-MS [18], HPTLC [19], and capillary zone electrophoresis [20]
This study described a simple, selective, and reliable isocratic elution HPLC-diode array detector (DAD) procedure for the assay of diclofenac sodium and diflunisal in their combined pharmaceutical dosage form

Summary

Introduction

Diclofenac sodium (DIC) (Fig. 1), chemically known as sodium {2-[(2,6-dichlorophenyl)amino]phenyl}acetate [1], is a phenylacetic acid derivative non-steroidal anti-inflammatory drug (NSAID). It is used for the relief of pain and inflammation in various conditions: musculoskeletal and joint disorders such as rheumatoid arthritis and osteoarthritis, soft tissue disorders such as sprains, and other painful conditions such as renal colic, acute gout, dysmenorrhoea, migraine, and after some surgical procedures [2]. Other analytical techniques involved the use of potentiometric membrane sensors [10], cyclic and differential-pulse voltammetry [11], spectrophotometry [12, 13], chemometric spectrophotometry [14], spectrofluorimetry [15], infrared and Raman spectroscopy [16], gravimetry [17], GC-MS [18], HPTLC [19], and capillary zone electrophoresis [20]

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Conclusion