Chiang Mai Journal of Science

A high performance thin layer chromatographic method for the determination of diclofenac sodium in pharmaceutical formulations was developed. The drug was extracted from the sample (emulgel) then various aliquots of this solution were spotted automatically by means of Camag Linomat IV (Switzerland) on a silica gel 60 F₂₅₄ aluminium plate, using a mixture of toluene : ethyl acetate : glacial acetic acid (60:40:1, v/v/v) as mobile phase. The spot areas were quantified by densitometry at 282 nm. Linear calibration curve was obtained over the range 5-80 µg.mL^-1 (r² = 0.9993). The method was applied to the determination of diclofenac sodium in Diclogel^®, Voltaren® emulgel and Dosanac^® emulsiongel with the average percentage recoveries of 104.21±1.59, 112.41±1.93 and 101.27±4.59, respectively. The standard deviation of diclofenac sodium in Dosanac^® emulsiongel was higher than those obtained from Diclogel® and Voltaren^® emulgel, probably owing to the matrices present in the sample. But the recoveries of the added diclofenac sodium in the samples are quite good. The average percentage labelled amount of diclofenac sodium in Diclogel^®, Voltaren^® emulgel and Dosanac^® emulsiongel were 94.61±0.06, 97.87±0.11 and 94.81±0.03, respectively. They are not exceed the percentage labelled amount claimed, (not less than 90% and not more than 110%, USP 28) 1]. The proposed method is simple, rapid, sensitive, reproducible and accurate. It also consumed less reagents compared with the HPLC method. Therefore this method is suitable for routine analysis of this drug in raw materials and formulations.