The Measurement of Meloxicam and Meloxicam Metabolites in Rat Plasma Using a High-Performance Liquid Chromatography-Ultraviolet Spectrophotometry Method

Abstract

A high-performance liquid chromatography-ultraviolet spectrophotometry (HPLC-UV) method for the determination of meloxicam (MEL) and meloxicam metabolites (5′-hydroxy meloxicam (5-HMEL) and 5′-carboxy meloxicam (5-CMEL)) has been developed. After extraction of MEL, 5-HMEL, and 5-CMEL from rat plasma using Oasis HLB cartridges, the extracts were separated with a Luna C18 (2) 100 A column (5 µm, 4.6 150 mm, Phenomenex) using a mobile phase of 50 mM phosphate buffer (pH 2.15, solvent A) and acetonitrile (solvent B) at a flow rate of 0.8 mL/min in a linear gradient. The detection wavelength was 360 nm, and the internal standard (IS) was piroxicam. Each calibration curve was linear in the range of 40 to 1000 ng/mL (r 2 >0.999). The extraction rates of MEL, 5-HMEL, and 5-CMEL were greater than 86.9%. The intra-and inter-day accuracies were in the range of 95.0 to 119.0%, and the precision was 0.2 to 17.0%. To the best of our knowledge, this is the first report of the quantitative and qualitative measurement of meloxicam and each metabolite using an HPLC-UV method. Key words meloxicam; meloxicam metabolite; HPLC-UVThe aim of this study was to establish a procedure to study the pharmacokinetic (PK) model of meloxicam (MEL). MEL (4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide) is a nonsteroidal anti-inflammatory drug (NSAID) that has selective inhibitory effects on the inducible isoform of cyclooxygenase-2. MEL is as effective as other NSAIDs in the treatment of rheumatoid arthritis and osteoarthritis in humans 1); it is used as an anti-inflammatory agent and analgesic in animals. 2)Generally, administrated meloxicam is first metabolized to a 5′-hydroxymethyl metabolite (5-HMEL) by CYP2C9 (major) and CYP3A4 (minor); it is then metabolized to a 5′-carboxy metabolite (5-CMEL). 3)Studies of the human plasma concentration/time profile of MEL after a single oral administration indicate that the graph exhibits bimodal peaks. 4,5) These reports suggest that MEL undergoes enterohepatic circulation. Taking these findings into account, we are planning to investigate the process by which MEL is metabolized to 5-HMEL and 5-CMEL (e.g., glucuronide conjugate, CYP metabolism). To investigate the PK model of MEL, measurement of the concentrations of MEL and its metabolites (5-HMEL and 5-CMEL) in biological samples is necessary. Several reports have examined the concentration of MEL in human and animal plasma [4][5][6][7][8][9] and the metabolism of MEL.2,3) However, these studies did not concomitantly measure 5-HMEL and 5-CMEL. The development of a system that enables the detection of MEL, 5-HMEL, and 5-CMEL is required.Various analytical methods for determining MEL in biological samples have been reported. The majority of these methods employ HPLC-ultraviolet (HPLC-UV) 2-6) or HPLCfluorescence (HPLC-FL) 10) spectrophotometry. Other reports employed LC-MS, 2) liquid chromatography-tandem mass spectrometry (LC-MS/MS), [7][8][9] flow injection analysis-chemiluminescence (FIA-CL), 11) or electroc...

Method of Determining Pyrrole–Imidazole Polyamide in Rat Plasma Using Ultra-Fast Liquid Chromatography-Ultraviolet Spectrometry

“…Method Validation Evaluation of the method was performed as follows applying the procedures previously reported. 13) The method was validated for selectivity, recovery, linearity, accuracy, and precision. The validation was conducted in accordance with the guidelines of the National Institute of Health Sciences (NIHS).…”

“…Among various PIs, GB1101 was regarded as the most promising drug. 6,7) MATERIALS AND METHODS Reagents and Solutions PI was synthesized by Nihon University School of Medicine following the method of Bando et al 12) The chemical structure of PI was shown in Fig. 1.…”

Meloxicam quantification in rabbit plasma by RP-HPLC: optimization and application to pharmacokinetic study

“…Chemically, Meloxicam (MLC) is 4-hydroxy-2-methyl-N-(5methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxamide-1, 1-dioxide ( Fig. 1a) [1], a new nonsteroidal anti-inflammatory drug (NSAID) derived from enolic acid, which exhibits cyclooxygenase (COX)-2 selectivity over COX-1 as described in a randomized double-blind study [2]. Meloxicam is used in the treatment of rheumatoid arthritis, osteoarthritis, and other joint diseases [3].…”

“…Plentiful UV-VIS, HPLC, HPLC-MS/MS, LC-MS, LC-MS-MS, LC-ESI-MS/MS, LC-MS/TOF, and LC-MS analytical methods have been documented for quantifying the MLC from different formulation either alone or in combination with pharmacotherapeutic agents in biological fluid [1,[4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]; a couple of them namely were employed liquid-liquid extraction or protein precipitation extraction (PPE) approach for quantification of MLC from biological sample [5,7,14]. In spite of that, the reported approaches are time-consuming; some of them used organic solvents and hazardous solvents for the extraction process, and some of which reported much less recovery which may be due to the drug loss during the transfer.…”

Chemometric Evaluation of Repeatability Using the Autocorrelation Method in High-Performance Liquid Chromatography with Ultraviolet Detection

“…The repeatability of HPLC analyses is generally expressed as the relative standard deviation (RSD) of peak area and/or peak height measurements. [1][2][3][4][5] As a single chromatogram normally requires more than 10 min to generate, statistical repeatability assessments based on multiple measurements involve substantial quantities of chemical samples and experimental time.…”