direct, rapid and sensitive high - performance liquid chromatographic method for the determination of diclofenac sodium and its application in bioailability studies

ABSTRACT

A simple [extraction less], rapid and sensitive reversed phase high-performance liquid chromatographic method, with ultraviolet detection at 280 nm, was developed to measure diclofenac sodium in plasma at concentrations suitable for bioavailability studies. Flufenamic acid was used as internal standard and the separation was performed at ambient temperature on a mg-Bondapak C18 column. The mobile phase consisted of a mixture of acetonitrile and 0.05 M phosphate buffer [11 v/v]. The pH of the mixture was adjusted to 3.5 using phosphoric acid. The limit of quantitation of diclofenac sodium was 0.05 mug/ml and the time for separation of each sample was no longer than 6.5 minutes at a flow rate of 2 ml/minute. The study of the inter- and intra-day precision and relative recovery study proved that the suggested method is accurate, sensitive and reproducible. The method was applied to test the bioavailability of the enteric coated diclofenac sodium tablets [Voltaren] in Beagle dogs