mobic and acetonitrile

A new method of analysis has been developed and validated for the determination of meloxicam in egg whites and yolks. Following a liquid extraction for the whites and a solid phase extraction for the yolks, samples were separated on an XBridge C18 column and quantified using ultraviolet detection at 360 nm. The mobile phase was a mixture of water with glacial acetic acid and acetonitrile, with a flow rate of 1 mL/min. The procedure produced a linear graph over the concentration range 5-1500 ng/mL with a lower limit of quantification of 5 ng/mL. Intra- and inter-assay variability was 10% or less for both the whites and yolks. The average recovery for whites was 96% and the average recovery in yolks was 97%.

Topics: Acetic Acid; Acetonitriles; Chromatography, Reverse-Phase; Egg White; Egg Yolk; Linear Models; Meloxicam; Reproducibility of Results; Sensitivity and Specificity; Solid Phase Extraction; Thiazines; Thiazoles

A simple cloud-point extraction method for the determination of meloxicam in human serum was developed. Meloxicam was extracted from serum sample after adding 1 mL of 3% (v/v) Triton X-114 aqueous solution in the presence of 1M HCl and 60 mg NaCl. The meloxicam, present in the surfactant-rich phase, was enriched again with acetonitrile. Tenoxicam was used as the external standard. The separation was achieved on a C18 analytical column with a mobile phase consisting of aqueous acetic acid (1%, v/v) and acetonitrile (54:46, v/v). UV detection was performed at 360 nm. The response was linear over the range 45-2000 ng mL(-1) in human serum, and intra- and interday precisions of less than 15.0% were obtained. The relative error was within +/-3.0%. The recoveries of meloxicam were larger than 92.0%. The method was compared with liquid-liquid extraction. The results showed that the new method has a considerable LOQ and higher recoveries but poorer precision than liquid-liquid extraction, which exhibited poor recoveries of less than 86.0%, precisions of less than 5.0% and relative errors of less than 7.0%. The method was used for the determination of meloxicam in healthy human volunteers.

Topics: Acetic Acid; Acetonitriles; Adult; Anti-Inflammatory Agents, Non-Steroidal; Chromatography, High Pressure Liquid; Detergents; Drug Stability; Humans; Meloxicam; Piroxicam; Polyethylene Glycols; Reproducibility of Results; Sensitivity and Specificity; Solvents; Thiazines; Thiazoles