Naproxen Electrodes

By using various ionic associates as active ingredients of PCV-based polymer membranes, the properties of naproxen-sensitive electrodes were studied [78-80]. Various electrode designs were used classic electrode [79], in which the polymer membrane contains methyltrioctylammonium cation in a chloride form and BMSA electrode, in which a prepared complex of naproxen with methyltrioctylammonium (MTOA-NAP) 

The content of naproxen in Naproxen tablets (Hasco-Lek S. A., Poland, and Polfarmex, Poland) can be determined with the obtained electrodes with an error of 2% and high precision of 3%. 

An article by Kormosh et al. compares the properties of various electrodes for determination of indomethacin a classic electrode with a polymer membrane, a solid-state electrode, and a Wood alloy in PVC tube, in which membranes were prepared using PVC and graphite [81]. The active ingredient applied was an ion-pair type complex of indomethacin with Rhodamine B. The optimum sensor turned out to be the solid-state one based on PVC. By comparing it with another solid-state sensor (BMSA type electrode) 

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Oumada et al. [148] described a new chromatographic method for determining the aqueous pKa of dmg compounds that are sparingly soluble in water. The method uses a rigorous intersolvent pH scale in a mobile phase consisting of a mixture of aqueous buffer and methanol. A glass electrode, previously standardized with common aqueous buffers, was used to measure pH online. The apparent ionization constants were corrected to a zero-cosolvent pH scale. Six sparingly soluble nonsteroidal antiinflammatory weak acids (diclofenac, flurbiprofen, naproxen, ibu-profen, butibufen, fenbufen) were used successfully to illustrate the new technique. 

A simple and sensitive liquid chromatographic method coupled with ECL was developed for the separation and quantification of naproxen (a nonsteroidal antiinflammatory drug) in human urine. The method was based on the ECL of naproxen in basic NaN03 solution with a dual-electrode system. The detection limit was 1.6 x 10 g mL (S/N = 3) [58]. Furthermore, MEKC chromatography was used with ECL of Ru(bpy)3 as a fast and sensitive approach to detect an antipsychotic and antihypertensive drug, i.e., reserpine in urine. Field-amplified injection was used to minimize the effect of ionic strength in the sample and to achieve high sensitivity. In this way, the sample was analyzed directly without any pre-treatment with LOD (S/N = 3) to be 7.0 x 10 mol L [59]. 

J. Lenik, R. Dumkiewicz, C. Wardak, B. Marczewska, Naproxen ion-selective electrode and its application to pharmaceutical analysis, Acta Poloniae Pharmaceutica-Drug Research, 59 (3), 171-176, 2002. 

J. Lenik, Preparation and study of an naproxen ion-selective electrode. Materials Science and Technology C, 33 (1), 311-316, 2013. 

Industrial Applications of Boron-Doped Diamond Electrodes Detection of Sodium Thiosulfate, Naproxen and Nickel Ions and Electrocatalysis of Oxygen Reduction... 

These properties have spurred our efforts to study and develop diamond electrodes for application as amperometric detectors for industrially important compounds, for example, sodium thiosulfate and naproxen. Additionally, a novel method of detecting nickel ions in electroless deposition solutions using diamond electrodes will also be reported. Finally, the electrocatalytic activity of gold nanoparticles deposited on diamond for oxygen reduction will be evaluated. 

Naproxen, [(S)-6-methoxy ex -methyl 2-naphthalene acetic acid] is a non steroidal anti-inflammatory (NSAID), indicated for the treatment of rheumatoid, osteo and juvenile arthritis, as well as ankylosing spondylitis [16]. It is very useful for the relief of mild and moderate pain. Naproxen has also caused kidney problems and has sometimes caused blood pressure increases, especially for older people [17]. In the amperometric method, mercury [18] and Pt [19] have been used as the electrode materials of choice. However, mercury electrodes have some limitations as they are toxic and there is rapid deterioration of the electrode response. Conversely, the use of Pt electrodes shows high background current in the CV resulting in low S/B ratio with the addition of analyte and the linear dynamic range of concentrations is also very narrow. During the course of the synthesis of naproxen, other conditions such as pH, light and temperature may favor the formation of impurities such as 2-acetyl-6-methoxy naphthalene (AMN) (Scheme 1) in addition to naproxen, and it is very important to detect this compound precisely in both raw materials and final products. 

Fig. 17.3. Differential pulse voltanunograms for naproxen oxidation in 0.1 M LiClOV CHsCN on a BDD electrode for a series of concentrations (pM ) (a) 0.5 (b) 1 (c) 5 (d) 10 (e) 30 and (f) 50. The inset shows the corresponding calibration ciu-ve.

The accuracy obtained from the determination of naproxen in a real sample (Naprosyne )was also assessed using the diamond electrode. The declared amount of naproxen in Naprosyne is 500 mg. From this study, a value of 498 mg (mean - RSD of 1.4%) was obtained, which is in close agreement with the stated content. The analysis exhibited a mean recovery of 99.7% and a relative standard deviation of 2.15%, indicating adequate precision and accuracy for this electrode. This result also indicates that the excipients are electrochemically inactive and have no interference effects on the analysis of naproxen. 

Suryanarayan V, Zhang Y, Yoshihara S et al (2005) Voltammetric assay of naproxen in pharmaceutical formulations using boron-doped diamond electrode. Electroanalysis 17 925-932... 

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