DARU Journal of Pharmaceutical Sciences153A rapid and sensitive modified HPLC method for determination of diclofenac in human plasma and its application in pharmacokinetic studies132138Emami J.Ghassami N.Talari R.20151006A sensitive, accurate and rapid reverse phase HPLC method was developed to quantitate plasma levels of diclofenac sodium in human plasma. The drug, internal standard (naproxene) and orthophosphoric acid 1 M, were added to plasma samples and vortexed for 20 sec. A mixture of hexane /isopropyl alcohol ( 90:10 ) was then added and vortexed for 2 min. Samples were centrifuged and the supernatant layer was separated, evaporated to dryness under nitrogen gas stream, reconstituted in mobile phase and an aliquot of 50 μl was analyzed on a μ-bondapack C18 (150 × 4.6mm) column, with 45% acetonitrile in deionised water and 0.5% orthophosphoric acid, (pH = 3.5) at 276 nm.  The standard curve covering 0.005 - 4 μg/ml concentration range, was linear, relative errors were within 0.13 to 16 % and the CV % ranged from 1.24 to 8.75. The limits of quantitation and detection of the method were 0.005 μg/mL and 0.002μg/mL, respectively. The method was suitable for bioavailability and pharmacokinetic studies of diclofenac in humans and applied in a randomized, two-way cross over bioequivalance study of two different diclofenac sodium preparations with twelve subjects and with a one-week washout periodhttps://daru.tums.ac.ir/index.php/daru/article/view/318https://daru.tums.ac.ir/index.php/daru/article/download/318/318