Human blood samples were obtained from healthy volunteers and
patients that consumed the mefenamic acid at Ali-Nasab hospital
(Tabriz, Iran). To prepare serum samples, they were drawn into the test tube, centrifuged at 3000 rpm for 10 min and then allowed to
stand at 4 1C until the phase separation was done. The serum
samples were kept in a freezer (80 1C) until analysis. A 500 μL
of each serum sample was transferred into a 25 mL volumetric
flask and diluted to the mark with deionized water. Finally, the
concentration of mefenamic acid in the obtained sample solution
was determined as described in