Determination of Meloxicam in Egg Whites and Yolks Using Reverse Phase Chromatography

Microanalysis of Two Members of Oxicam Drugs by Quenching the Fluorescence of Newly Isolated Carbonaceous Materials From Incense Ash

For the first time ever, useful fluorescent (FL) carbonaceous materials (CMTS) were isolated from incense ash using facile procedure on two steps; dispersion of the CMTS in water followed by filtration. The CMTS were characterized using the following techniques; dynamic light scattering (DLS), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy. The CMTS exhibit excitation wavelength dependent fluorescence emission, so it can be used as a FL probe. The FL probe was employed for sensing and quantitative determination of two members of oxicam family (tenoxicam (TEN) and meloxicam (MEL)) that belongs to non-steroidal anti-inflammatory drugs (NSAIDs). The method is based on the quenching of the FL intensity of the isolated CMTS by inner filter effect mechanism (IFE). The FL intensity decreases in linear relationship with increasing the concentrations of the two cited drugs within the range of 4.0 - 30.0 µg/mL with mean percentage recoveries of 100.04 ± 0.95 and 100.07 ± 1.06 with detection limits of 1.31 µg/mL and 1.06 µg/mL for TEN and MEL, respectively. Finally, the developed sensing system was validated as per ICH guidelines and it was proved to be accurate and precise and applied successfully for quantitative determination of the two cited drugs in their capsule dosage forms with excellent percentage recoveries reaching to 97.66 ± 0.39and 98.19 ± 1.12 for TEN and MEL, respectively.

Using a stable isotope-labeled internal standard for liquid chromatography-tandem mass spectrometry quantitation of meloxicam in human plasma

A sensitive and highly efficient LC-ESI-MS/MS method using a stable isotope-labeled internal standard (SIL IS) to detect meloxicam in human plasma was developed and validated. Sample preparation used only 50 μL human plasma with one-step methanol protein precipitation. A gradient mobile phase system was adopted for chromatographic separation on a Poroshell 120 SB-C₁₈ column (2.1 × 50 mm, 2.7 μm). Positive ion pattern was chosen for quantification under multiple reaction monitoring. Ion pairs were [M + H]⁺ m/z 352.1 → 115.1 for meloxicam and [M + H]⁺ m/z 355.1 → 187.1 for meloxicam-d3 (SIL IS). Total run time was 4.0 min. Standard curve was linear over a concentration range from 8.00 to 1600 ng mL^-1 . This method was fully validated to evaluate its performance, including specificity, carryover, sensitivity, linearity, accuracy, precision, recovery, matrix effects, stability, dilution reliability and incurred sample reanalysis, which provided a reliable basis for pharmacokinetic studies of meloxicam in 28 healthy Chinese volunteers. After a single-dose oral administration of 7.5 mg meloxicam, the main pharmacokinetic parameters were as follows: C_max , 814.79 ± 201.37 ng mL^-1 ; T_max , 4.54 ± 1.42 h; AUC_0-t , 24,572.04 ± 5766.93 ng·h mL^-1 ; AUC_0-∞ , 25,810.89 ± 6796.60 ng·h mL^-1 and t_1/2 , 21.11 ± 5.35 h.

Breed differences in the pharmacokinetics of orally administered meloxicam in domestic chickens (Gallus domesticus)

OBJECTIVE

To determine the pharmacokinetics of meloxicam in Wyandotte hens and duration and quantity of drug residues in their eggs following PO administration of a single dose (1 mg of meloxicam/kg [0.45 mg of meloxicam/lb]) and compare results with those previously published for White Leghorn hens.

ANIMALS

8 healthy adult Wyandotte hens.

PROCEDURES

Hens were administered 1 mg of meloxicam/kg, PO, once. A blood sample was collected immediately before and at intervals up to 48 hours after drug administration. The hens' eggs were collected for 3 weeks after drug administration. Samples of the hens' plasma and egg whites (albumen) and yolks were analyzed with high-performance liquid chromatography.

RESULTS

Mean ± SD terminal half-life, maximum concentration, and time to maximum concentration were 5.53 ± 1.37 hours, 6.25 ± 1.53 μg/mL, and 3.25 ± 2.12 hours, respectively. Mean ± SD number of days meloxicam was detected in egg whites and yolks after drug administration was 4.25 ± 2 days and 9.0 ± 1.5 days, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Compared with White Leghorn hens, meloxicam in Wyandotte hens had a longer terminal half-life, greater area under the plasma concentration-versus-time curve from time 0 to infinity, a smaller elimination rate constant, and a longer mean residence time-versus-time curve from time 0 to infinity, and drug persisted longer in their egg yolks. Therefore, the oral dosing interval of meloxicam may be greater for Wyandotte hens. Results may aid veterinarians on appropriate dosing of meloxicam to Wyandotte hens and inform regulatory agencies on appropriate withdrawal times.