Mefenamic acid, (MFA) 2-(2, 3-dimethylphenyl) amino benzoic acid is a member of fenamate group of non- steroidal anti-inflammatory drug used in the therapy of pain phenomena and blockade of inflammatory areas; for the stimulation of the immune system in patients with arthritis and arthrosis. It is used for the treatment of mild to moderate pain, including headache, dental pain, post-operative and post-partum pain, dysmenorrhoea, as well as musculoskeletal disorders and sport injuries. The degree of menstrual blood loss is reduced with the treatment of MFA and it is also used to treat autoimmune haemolytic anaemia. Measurement of plasma levels of MFA may provide valuable information for MFA treatment in premature infants with symptomatic patent ductus arteriosus and for preventing possible toxic effects. However, the excessive intake of MFA leads to diarrhoea, vomiting, lactic acidosis, purpura, hepatic necrosis, liver injury, acute colitis in patients, morbidity and mortality in humans. Consequently, the development of a simple, inexpensive, sensitive and accurate analytical method for determination of MFA is of considerable importance.
Herein, we report the selective and sensitive determination of mefenamic acid on single walled carbon nanotubes modified glassy carbon electrode (GCE) employing square wave voltammetry for the first time. The developed sensor exhibited amelioration in the peak current response with a negative shift in the peak potential in comparison to multi walled carbon nanotubes modified GCE and bare GCE. Voltammetric studies indicated the oxidation of mefenamic acid at the electrode surface through a one electron and one proton irreversible step and fundamentally controlled by adsorption. A good linear relationship has been found between the anodic peak current and mefenamic acid concentration in the range of 0.1 – 35 µM with limits of quantification and detection as 44.7 and 13.4 nM, respectively. The interfering effect of physiologically common interferents on the current response of mefenamic acid has been reported. Furthermore, the proposed method was successfully applied to the determination of mefenamic acid in pharmaceutical formulations and human plasma samples.