Potentiometric determination of anti-inflammatory drug etodolac in pharmaceutical samples and its greenness assessment

In this study, potentiometric determination of anti-inflammatory drug etodolac in pharmaceutical samples was carried out. Firstly, etodolac–phosphotungstic acid ion pair was synthesized. Then, poly(vinyl chloride) (PVC) membrane sensors were prepared using the synthesized ion pair as electroactive material (ionophore). Potentiometric performance properties of the prepared sensors were tested under laboratory conditions using etodolac solutions. The working conditions were investigated using the sensor that exhibited the best potentiometric performance among the prepared sensors. The composition of this sensor contains 32.0% PVC, 64.0% o-nitrophenyl octyl ether (o–NPOE) and 4.0% etodolac–phosphotungstic acid ion pair. The developed sensor had a low detection limit of 4.66 × 10^–6 M in a wide concentration range of 1.0 × 10^–1–1.0 × 10^–5 M. At the same time, the proposed sensor had good selectivity, good reproducibility and short response time (< 10 s). Greenness assessment of the prepared sensor was evaluated using Green Analytical Procedure Index (GAPI) and Analytical Greenness metric (AGREE) methods. Finally, the produced sensors were applied in pharmaceutical samples containing etodolac, and high recoveries were obtained.