The aim of this paper is to provide a simple and easy method for determination of meloxicam in rat muscle and plasma, based on dissolution of tissue samples with SolvableTM and measurement with a column-switching high performance liquid chromatographic system. After tissue and plasma samples were extracted with SolvableTM and methanol, samples were injected into a precolumn (Hypersil ODS) in 0.05 M phosphate buffer (pH 3), and after clean-up and enrichment the analytes were transferred to an analytical column (YMC Pack Pro C18) by backflushing with 0.05 M phosphate buffer (pH 6)-methanol (60:40, v/v). The eluate was monitored with a UV-detector set at 360 nm. Coefficients of determination (r2) for muscle and plasma were both more than 0.999. The limits of quantification (LOQ) in muscle and plasma were 50 ng/g and 20 ng/mL, respectively. The accuracy and precision were achieved in the range of 50-2500 ng/g in muscle and 20-2500 ng/mL in plasma. Our method could be successfully applied to evaluate the pharmacokinetics of topically administrated meloxicam.
Surface derivatization of poly(p-phenylene terephthalamide) (PPTA) fibers was studied to prepare novel stationary phases in liquid chromatography (LC). As one type of surface derivatization of synthetic fibers, alkyl or perfluoroalkyl chains as functional groups were introduced to the surfaces of PPTA fibers. When each functionalized fiber-packed column was used for LC, increases in retention power with respect to a variety of compounds were ascertained in comparison with that prepared by an untreated-fiber as the stationary phase. Furthermore, it was indicated that the perfluoroalkyl group introduced fibrous stationary phase showed a specific retention behavior with respect to halogenated benzenes. These results demonstrated that the derivatization of the surfaces of PPTA fibers was successfully carried out. Selectivity differences between the modified-fiber packed columns were also confirmed through the use of some sample probes.
A capillary chromatography called the tube radial distribution chromatography (TRDC) system has been developed using an open capillary tube and a water-hydrophilic/hydrophobic organic solvent mixture carrier solution. In this study, we examined the effects of the analyte injection volume (injection time) and concentration on the chromatograms in the TRDC system using a fused-silica capillary tube (50 µm i.d. and 100 cm effective length) and a water-acetonitrile-ethyl acetate mixture carrier solution (volume ratio, 3: 8: 4). Analyte solutions of 1-naphthol and 2,6-naphthalenedisulfonic acid (1 mM each) were injected into the system with various injection times of 10-1500 s from a height of 20 cm by gravity. They were separated and detected in this order with good reproducibility up to an injection time of 150 s. The analyte solutions (0.075-3.0 mM) were analyzed with the definite injection time of 30 s from a height of 20 cm by gravity. They were separated and detected with a baseline separation and their calibration curves showed linearity up to 1.5 mM. It was confirmed that the TRDC system worked well as a quantitative analysis.