The development and validation of a Thin Layer Chromatography densitometry method for the analysis of diclofenac sodium tablets

Abstract

Aims

Diclofenac sodium is a Nonsteroidal Anti-Inflammatory Drug (NSAID) with anti-inflammatory, antipyretic, and analgesic action as a result of the blockade of prostaglandin synthesis by inhibition of the cyclooxygenase enzyme. Analysis of the active pharmaceutical ingredient as well as finished pharmaceutical product is of vital importance to help ensure that good quality products are manufactured and supplied to the patient end users. The aim of the study was to develop a simple and rapid method to enable timely release of products.

Methods

The method was developed using a mobile phase prepared with environment-friendly analytical grade solvents: toluene, acetone and glacial acetic acid (10:15:0.2 v/v/v). Diclofenac sodium reference material and samples were chromatographed using pre-coated TLC silica gel 60 F₂₅₄ glass plates with a saturation time of 25 minutes and a densitometer detection wavelength of 284 nm in the reflectance absorbance mode. Detection and part of analysis was done using densitometer TLC Scanner 3 operated with Wincats (version 1.4.3) planar chromatograph software.

Results

A Thin Layer Chromatography (TLC) method for the qualitative and quantitative analysis of diclofenac sodium tablets was developed and validated according to ICH and USP guidelines. The R_f of diclofenac sodium was at 0.60 and the method was repeatable, robust with good selectivity and specificity. Regression functions were established over the range of 250–600 ng/spot with r² of 0.993 and 0.999 for the linear and polynomial regressions respectively. The accuracy at nominal concentration was found to be 100.2%, and the results of the assay of three brands for diclofenac sodium tablets were found to meet the USP 95–105% assay limits thus demonstrating the usefulness of the method for the assay of these products.

The developed assay method for diclofenac sodium in tablets is simple, accurate, and inexpensive, with good precision and should be especially useful in resource constrained countries.