A reversed-phase ion pair chromatography method with liquid-liquid extraction analytical method was developed and validated for the determination of antazoline hydrochloride in plasma and excreta of rat. The aim of our study was to characterize the preclinical pharmacokinetics and excretion profiles of antazoline hydrochloride in rats after intravenous injection at the dose of 10 mg/kg. Plasma and excreta samples were extracted with ethyl acetate, and phenacetin was used as the internal standard. The result showed that the method is suitable for the quantification of antazoline hydrochloride in plasma and excreta samples. Analysis of accuracy (90.89-112.33%), imprecision (<7.1%) and recovery (>82.5%) showed adequate values. After a single intravenous administration at 10 mg/kg to rats, plasma concentration profile showed a relative fast elimination proceeding with a terminal elimination half-life of 3.53 h. Approximately 61.8 and 14.2% of the administered dose were recovered in urine and bile after 72 and 24 h post-dosing respectively; 5.9% of the administered dose was recovered in feces after 72 h post-dosing. The above results show that the major elimination route is urinary excretion.
A visible-light-mediated photocatalytic strategy for the radical–radical cross-coupling of acetenyl ketones with benzyl trifluoroborate has been described.
A highly specific and sensitive liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of ponicidin in dog plasma. The plasma samples were prepared using liquid-liquid extraction with ethyl acetate as the extraction solvent. Chromatographic separation was accomplished on a Waters XTerra MS C18 column. The extracted ponicidin and the internal standard, oridonin, were detected by tandem mass spectrometry in positive electrospray ionization mode with multiple reaction monitoring. The optimized mass transition ion pairs (m/z) for quantitation were 363.08-345.08 for ponicidin and m/z 365.10-347.06 for the internal standard. The lower limit of quantification was 5 ng/mL. The linear range of the method was from 5 to 5,000 ng/mL. The intra-day and inter-day precision measurements were lower than 5.3 and 6.0% in terms of relative standard deviation and the accuracy was within ±8.4% in terms of relative error. Additionally, no significant matrix ionization suppression or enhancement was observed. The validated method was successfully applied in a pharmacokinetic study of ponicidin in dogs. The primary pharmacokinetic parameters in dogs were: terminal elimination half-life, 8.14 ± 1.35 h; mean residence time, 12.30 ± 2.08 h; area under the plasma concentration-time curve from time zero to the last measurable concentration, 14.34 ± 1.37 µg/h/mL; area under the plasma concentration-time curve from time zero to infinity, 15.75 ± 1.44 µg/h/mL; apparent volume of distribution, 4.79± 1.68 L/kg; total body clearance, 0.41 ± 0.08 L/kg/h.
A sensitive and simple liquid chromatography -: electrospray ionization mass spectrometry method has been established and validated for the quantification of Guanfu base G in rats. Phenoprolamine hydrochloride was selected as the internal standard. Sample preparation involved simple liquid-liquid extraction by ethylacetate with high efficiency. The chromatographical separation was performed on a Shimadzu C18 column (150 × 2.0 mm, 5 µm) with a gradient elution of 0.2% acetic acid-acetonitrile (30:70, v/v). The method was sensitive with the lowest limit of detection at 1 ng/mL (S/N ≥ 3) in 100 µL of rat plasma. Good linearity (r = 0.9996) was obtained covering a concentration of 5-2000 ng/mL. The intra- and interday assay precision ranged from 4.3 to 6.1% and 5.4 to 8.3%, respectively. In addition, the stability, extraction recovery and matrix effect involved in the method were also validated. After intravenous dosing, rat plasma Guangfu base G (GFG) concentration declined in a biphasic manner with a terminal elimination half-life of 3.72 h. The total plasma clearance values were 1.15 L/h/kg. After oral dosing, the plasma GFG concentration reached a maximum within 0.5 h. The absolute bioavailability of GFG was 83.06%.
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