Micellar high performance liquid chromatographic determination of flunixin meglumine in bulk, pharmaceutical dosage forms, bovine liver and kidney

Core-shell Au@MIL-100 (Fe) as an enhanced substrate for flunixin meglumine ultra-sensitive detection

This study aimed to develop and validate a simple and efficient surface-enhanced Raman spectroscopy (SERS) method to determine flunixin meglumine (FM) residues in animal tissues through using core-shell Au@MIL-100 (Fe) as enhanced substrate. Au@MIL-100 (Fe) composite material was synthesized by coating metal-organic framework materials (MOFs) on the surface of gold nanoparticles using the solvothermal method. Transmission electron microscopy (TEM), UV-vis spectrum, SERS spectrum, X-ray diffraction (XRD), Infrared spectrum (FT-IR), and EDX elemental mapping results revealed that the structural composition of the compound has good properties with localized surface plasmon resonance (LSPR) properties, high adsorption capacity, excellent SERS sensitivity and stability. When it was used as SERS substrate, the results of quantitative analysis of FM in pork showed a linear range of 0.10-50 mg·L^-1 with a correlation coefficient (R²) of 0.9819, the limit of detection (LOD) of 0.15 mg·g^-1, the recovery rate of 88.94%∼104.77%, the intra- and inter- batch relative standard deviation (RSD) of 3.57%∼14.22% and 0.18%∼3.44% respectively. Further verification results of the existing standard methods showed no significant difference between the SERS and UV methods (P < 0.05), as well as demonstrating that the SERS method has optimal precision, accuracy, and practicality. These results exposed that Au@MIL-100 (Fe) as a SERS substrate has great potential in rapid and on-site detection analysis.

Green validated chromatographic methods for simultaneous determination of co-formulated oxytetracycline HCl and flunixin meglumine in the presence of their impurities in different matrices

Green analytical chemistry is an important area of chemical sciences. So, developing competent eco-friendly analytical tools is a big challenge. This study devotes two chromatographic techniques for the simultaneous determination of a binary formulated mixture of oxytetracycline HCl (OXY) and flunixin meglumine (FLU), and their impurities tetracycline (TRC) and 2-chloronicotinic acid (CNA), respectively. Primarily, a TLC densitometric method is proposed and validated using TLC plates sprayed with 5% EDTA of pH 9 as a stationary phase and (acetonitrile/ distilled water/ ethanol 7:2:1, by volume) as a developing system. Well-separated spots are detected at 267 nm where linear relations have been achieved at 0.05–2 μg/band and 0.01–2 μg/band for OXY and FLU, respectively. The second developed and validated method is HPLC which is fulfilled on Hypersil BDS column-C18. A mobile phase of distilled water with 0.1%TFA/ acetonitrile in a ratio of 82: 18, v/v firstly then 70: 30, v/v after 9 min is used in a sequential isocratic elution at 210 nm for FLU and 267 nm for OXY, TRC, and CNA. Sensitive and wide linearity ranges are achieved at 0.05–200 μg/mL for both drugs. The two methods are applied successfully in cattle meat and milk for cited drugs determination. According to ICH guidelines, a validation study has been accomplished for the proposed methods. Statistical comparison has been carried out with official and reported methods. Eventually, the greenness of both procedures is evaluated using Eco-Scale which gives eco-friendly results.

Graphical abstract

High performance liquid chromatography (HPLC) method development and validation for the determination of flunixin: Animal plasma based study

This study was designed to develop and validate a simple and efficient high performance liquid chromatography (HPLC) method to determine flunixin concentrations in Asian elephant’s (Elephas maximus) plasma. Flunixin was administered orally at a dose of 0.8 mg/kg, and blood samples were collected. Flunixin extraction was performed by adding an equal amount of acetonitrile to plasma and centrifuging at 4500 rpm for 25 minutes. The supernatant was removed, and flunixin was analyzed using HPLC-UV detection. Two methods were developed and tested utilizing two different mobile phases either with or without adding methanol (ACN: H2O vs. ACN: H2O: MeOH). Both methods showed excellent linearity and reproducibility. The limit of detection was 0.05 ug/ml and limit of quantification was 0.1 ug/ml. the efficiency of flunixin recovery was maximized by the addition of methanol to mobile phase (ACN: H2O: MeOH as 50:30:20) at 95% in comparison to 23% without methanol. In conclusion, adding methanol to HPLC methods for extraction of flunixin from elephants’ plasma yielded higher recovery rate than without methanol.

Analytical capabilities of micellar liquid chromatography and application to residue and contaminant analysis: A review

Green chemistry is the use of chemistry to reduce or eliminate the use of generation of feedstocks, products, by-products, solvents, reagents, etc. that are hazardous to human health or the environment. One of the branches of green chemistry is micellar liquid chromatography. Micellar liquid chromatography is a reversed-phase liquid chromatographic mode with mobile phases containing a surfactant above its critical micellar concentration. The applications of micellar liquid chromatography for the determination of numerous compounds in pharmaceutical formulation, biological samples, food, environmental samples, and feeds have been growing rapidly. Micellar liquid chromatography technique has several advantages over other chromatographic techniques. Its main advantage is the small amount of organic modifiers used such as acetonitrile and methanol and the safety and recyclability of the mobile phase. In our work, we discuss the development of "green chemistry" and present what micellar liquid chromatography is. This article presents application methods with the use of micellar liquid chromatography for analysis on antibacterial substances, melamine, biogenic amines, plant protection products, flavonoids, as well as peptides in biological matrices such as milk, eggs, tissues, honey, and feed.

Lateral flow immunoassay for 5-hydroxyflunixin based on near-infrared fluorescence molecule as an alternative label to gold nanoparticles

A high-affinity monoclonal antibody (mAb) has been prepared and separately a gold nanoparticle (AuNP)-based and a near-infrared (NIR) fluorescence-based lateral flow immunoassay (LFA) developed for determination of 5-hydroxyflunixin residue in raw milk. The AuNP and IRDye® 800CW were used to label anti-5-hydroxyflunixin mAb to form the AuNP-mAb and NIR dye-mAb conjugates, respectively. Quantitative determination of 5-hydroxyflunixin was achieved by imaging the optical or fluorescence intensity of the AuNP-mAb and NIR dye-mAb captured on the test line. As a result, the detection limits of the AuNP-based LFA and NIR dye-based LFA were 0.82 and 0.073 ng/mL in raw milk, respectively. The considerable improvement on assay sensitivity of the NIR-based LFA can be attributed to the lower background and less antibody consumption per test than that of the AuNP-based LFA. The spiking experiment by the NIR-based LFA yielded 85.7-112.6% recovery with a relative standard deviation below 14%, indicating that it has satisfactory assay accuracy and precision. Furthermore, the analytical results of actual samples by the NIR dye-based LFA were consistent with that by instrumental analysis. Therefore, these results demonstrated that the NIR dye is an ideal alternative label to the conventional AuNP for the development of LFA for veterinary drugs in animal-origin food. Graphical abstract.

Determination of Flunixin in Swine Plasma, Urine and Feces by UPLCMS/ MS and its Application in the Real Samples

Background:

Flunixin is a Non-Steroidal Anti-Inflammatory Drug (NSAID), because it can effectively alleviate the organism of pyrexia, inflammation and pain, it has been widely used in veterinary practice. In order to better study flunixin in the body's absorbed, distributed, metabolized and excreted, our team developed a UPLC-MS/MS method for determination of flunixin in swine plasma, urine and feces.

Methods:

Flunixin was extracted from the sample by liquid-liquid extraction and cleaned-up using a mixed-mode Oasis MCX solid-phase extraction column. Analysis was performed on UPLC-MS/MS operating in Multiple Reaction Monitoring (MRM) mode. Internal standard was used for quantitation of target drug.

Results:

Recoveries of fortified samples ranged from 90.2% to 101.4%, with Relative Standard Deviations (RSD) lower than 17.0%. The Limits Of Detection (LODs) and Quantification (LOQs) in plasma were 0.25 and 0.5 µg L-1, in urine were 0.25 and 0.5 µg L-1, and in feces were 0.5 and 1 µg kg-1, respectively. This validated method was successfully applied to the determination of flunixin in real samples. The half-life of flunixin after the last dose in pigs was 7.37±1.60 h after intramuscular administration of 2.2 mg/kg of flunixin, and approximately 6.8% and 1.9% of the administered dose was excreted as parent compound in urine and feces respectively.

Conclusion:

The developed UPLC-MS/MS method for determination of flunixin in swine plasma, urine and feces was validated and successfully applied to monitor flunixin from real samples.

Spectrophotometric Methods for Simultaneous Determination of Oxytetracycline HCl and Flunixin Meglumine in Their Veterinary Pharmaceutical Formulation

Four precise, accurate, selective, and sensitive UV-spectrophotometric methods were developed and validated for the simultaneous determination of a binary mixture of Oxytetracycline HCl (OXY) and Flunixin Meglumine (FLU). The first method, dual wavelength (DW), depends on measuring the difference in absorbance (ΔA 273.4-327 nm) for the determination of OXY where FLU is zero while FLU is determined at ΔA 251.7-275.7 nm. The second method, first-derivative spectrophotometric method (1D), depends on measuring the peak amplitude of the first derivative selectively at 377 and 266.7 nm for the determination of OXY and FLU, respectively. The third method, ratio difference method, depends on the difference in amplitudes of the ratio spectra at ΔP 286.5-324.8 nm and ΔP 249.6-286.3 nm for the determination of OXY and FLU, respectively. The fourth method, first derivative of ratio spectra method (1DD), depends on measuring the amplitude peak to peak of the first derivative of ratio spectra at 296.7 to 369 nm and 259.1 to 304.7 nm for the determination of OXY and FLU, respectively. Different factors affecting the applied spectrophotometric methods were studied. The proposed methods were validated according to ICH guidelines. Satisfactory results were obtained for determination of both drugs in laboratory prepared mixture and pharmaceutical dosage form. The developed methods are compared favourably with the official ones.

Development and Validation of a Stability-Indicating HPLC Method for the Simultaneous Determination of Florfenicol and Flunixin Meglumine Combination in an Injectable Solution

The combination of the powerful antimicrobial agent florfenicol and the nonsteroidal anti-inflammatory flunixin meglumine is used for the treatment of bovine respiratory disease (BRD) and control of BRD-associated pyrexia, in beef and nonlactating dairy cattle. This study describes the development and validation of an HPLC-UV method for the simultaneous determination of florfenicol and flunixin, in an injectable preparation with a mixture of excipients. The proposed RP-HPLC method was developed by a reversed phase- (RP-) C18e (250 mm × 4.6 mm, 5 μm) column at room temperature, with an isocratic mobile phase of acetonitrile and water mixture, and pH was adjusted to 2.8 using diluted phosphoric acid, a flow rate of 1.0 mL/min, and ultraviolet detection at 268 nm. The stability-indicating method was developed by exposing the drugs to stress conditions of acid and base hydrolysis, oxidation, photodegradation, and thermal degradation; the obtained degraded products were successfully separated from the APIs. This method was validated in accordance with FDA and ICH guidelines and showed excellent linearity, accuracy, precision, specificity, robustness, LOD, LOQ, and system suitability results within the acceptance criteria.

Voltammetric Determination of Flunixin on Molecularly Imprinted Polypyrrole Modified Glassy Carbon Electrode

A novel electrochemical sensing approach, based on electropolymerization of a molecularly imprinted polypyrrole (MIPpy) film onto a glassy carbon electrode (GCE) surface, was developed for the detection of flunixin (FXN). The sensing conditions and the performance of the constructed sensor were assessed by cyclic, differential pulse and (DPV) square wave voltammetry (SWV). The sensor exhibited high sensitivity, with linear responses in the range of 5.0 to 50.0 µM with detection limits of 1.5 and 1.0 µM for DPV and SWV, respectively. In addition, the sensor showed high selectivity towards FXN in comparison to other interferents. The sensor was successfully utilized for the direct determination of FXN in buffalo raw milk samples.

Micellar Liquid Chromatography from Green Analysis Perspective

Micellar liquid chromatography (MLC) is a simple well-established branch of high-performance liquid chromatography. The applications of MLC for the determination of numerous compounds in pharmaceutical formulations, biological samples, food, and environmental samples have been growing very rapidly. MLC technique has several advantages over other techniques, such as simultaneous separation of charged and uncharged solutes, rapid gradient capability, direct on-column injection of physiological fluids, unique separation selectivity, high reproducibility, robustness, enhanced luminescence detection, low cost, and safety. This review is devoted to the evaluation of the agreement of MLC with the principles of green chemistry which recently represents a universal trend. Also, it provides an overview on the basics of MLC, in addition to a survey of MLC methods published in the past five years for the assay of various compounds in different matrices.