ABSTRACT This work describes a novel, simple, fast, reliable, and environmentally friendly analytical method for the determination of the anti‐inflammatory and analgesic drug flunixin meglumine (FM) in veterinary pharmaceutical formulations. The method uses capillary electrophoresis with capacitively coupled contactless conductivity detection (CE‐C 4 D) to quantify meglumine ( N ‐methylglucamine), the counterion of flunixin in FM. This approach allows the use of the less expensive and more readily available meglumine, rather than FM or flunixin, as the standard reagent. Lithium ions were used as an internal standard, and the migration time of the meglumine was 2.2 min using a capillary with a total length of 50 cm (42 cm effective) and 50 µm (i.d.), filled with a background electrolyte (BGE) composed of 2‐( N ‐morpholino)ethanesulfonic acid (MES) and histidine (His), each at 20 mmol L −1 . Good linearity was attained ( R 2 = 0.992) in a concentration range of 100–2500 µg mL −1 . The limits of detection (LOD) and quantification (LOQ) were calculated as 22.7 and 75.6 µg mL −1 , respectively. The accuracy of the method was assessed using recovery tests at three concentration levels, resulting in recoveries ranging from 89% to 104%. The intra‐ and inter‐day precisions ranged from 2.3% to 4.2%. The proposed CE‐C 4 D was successfully applied to determine FM in commercial veterinary formulations.
Araujo et al. (Sat,) studied this question.