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Compound feed is particularly vulnerable to multi-mycotoxin contamination. A method for the determination of 12 mycotoxins; enniatins A, A1, B, B1; aflatoxins B1, B2, G1, G2; OTA; ZEA; T-2 and HT-2 by liquid chromatography-tandem mass spectrometry has been developed and applied for the analysis of laboratory rat commercial feeds. The method trueness was checked by recovery assays at three different spiked levels (n = 9). Recoveries ranged from 73% to 112%, and the intra-day and inter-day precision were lower than 9% and 13%, respectively. Limits of quantitation were lower than 15 μg/kg. Twenty-seven laboratory rats feed samples showed multi-contamination by at least three up to six different mycotoxins. ENNs B and B1, followed by ZEA were the most prevalent mycotoxins. T-2, HT-2, and OTA were not detected. ZEA showed the highest concentration levels reaching 492 μg/kg. The results underline the importance of implementing mycotoxin regular surveillance programs for laboratory animal feeds. [ABSTRACT FROM PUBLISHER]

□A rapid and sensitive analytical method of liquid chromatography combined with tandem mass spectrometry (LC–MS/MS) was established for simultaneous quantitative analysis of hydrazine, methylhydrazine, and 1,1-dimethylhydrazine in rat plasma. Plasma samples were pretreated with protein precipitation and optimized derivatization procedure. Separation was achieved using acetonitrile and water containing 5 mM ammonium acetate as gradient elution. The optimized mass transition ion-pairs (m/z) monitored for three hydrazine derivatives werem/z299.1→m/z151.1,m/z180.2→m/z78.1, andm/z194.2→m/z59.1, respectively. The lower limit of quantitation (LLOQ) of hydrazine was 1 ng/mL and those of other compounds were 10 ng/mL. Intra- and inter-day precision were within 14.00%. Meanwhile, the relative error was within the acceptable range. The recovery of three analytes and (IS) were between 57.78 ± 4.73%and 107.04 ± 7.46%.Target derivatives were stable under the conditions tested. The dilution test showed that this method is not only suitable for samples in the detection limit but also applicable for high concentration samples that exceed the upper limit of detection. The performance of the method was successfully verified for real rat plasmas and would be useful for routine analysis in cases of suspected hydrazine poisoning. [ABSTRACT FROM AUTHOR]

A highly selective and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of scicinib, a novel thiosemicarbazone analogue and anticancer agent in rat plasma. Protein precipitation with saturated EDTA solution and methanol was selected for sample preparation, and brodimoprim was employed as the internal standard (IS). The analytes were separated on a Symmetry C18column (200 × 4.6 mm i.d., 5 µm) by isocratic elution with a mobile phase consisting of methanol and 0.2 mM EDTA (75:25, v/v) at a flow rate of 0.4 mL/min. After electrospray ionization, the analyte and IS were recorded under selected reaction monitoring (SRM) mode. The chosen transition wasm/z313.0 → 267.9 for scicinib andm/z339.0 → 280.9 for IS, respectively. The validated linearity range is 5–5000 ng/mL, with the lower limit of quantitation of 5 ng/mL. The developed method was successfully applied to a pharmacokinetic study of scicinib in rats after a single intravenous administration of 5 mg/kg. [ABSTRACT FROM AUTHOR]

A simple and rapid liquid chromatography-tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the quantitation of indirubin-5-nitro-3′-monoxime (5-NIO) in rat plasma using 5-chloro-5′-chloro-indirubinoxime as the internal standard. The sample preparation involved protein precipitation using acetonitrile. Separation was achieved on an Xterra column C18 (2.1 mm × 50 mm, i.d. 5 µm) using a mixture of 0.1% formic acid-water/acetonitrile (18:82, v/v) as the mobile phase at a flow rate of 300 µL/min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization and multiple reaction monitoring (MRM) in negative ion mode. The total chromatographic run time was 2.5 min, and the calibration curves of 5-NIO were linear (correlation coefficient range: 0.9989–0.9999) over the concentration range of 0.2–2000 ng/mL in rat plasma. Also, the detection limit of the method was 0.05 ng/mL and it showed good accuracy and precision within the concentration range of 0.45–376 ng/mL. This validated method was successfully applied to estimating the pharmacokinetic parameters of 5-NIO following intravenous administration of 5-NIO to rats. [ABSTRACT FROM AUTHOR]

A simple and specific LC-MS/MS method for the determination of FK506 in blood was developed, validated, and successfully applied in pharmacokinetic studies of the effect of silymarin on FK506 in rats. Blood samples were extracted by liquid-liguid extraction with methyl tert-butyl ether and separated on an Eclipse plus-C18 column (150 × 2.1 mm, 3.5 µm) with the mobile phase of acetonitrile-10 mM ammonium acetate buffer solution (80:20, v/v). FK506 was detected without interference in the multiple-reaction monitoring mode with positive electrospray ionization. Good linearity was achieved over a range of 2.0–200 ng mL−1. The intra- and inter-day precisions were less than 13.5 % for all concentrations of quality control samples. The recoveries of FK506 were 74.2–85.3 %. Although the mean Cmax and AUC0 − ∞ of FK506 were increased to some extent, there was no significant difference in the pharmacokinetic profile of FK506 after oral administration to rats in the presence and absence of silymarin (200 mg kg−1, 2 times/d for 14 d). [ABSTRACT FROM AUTHOR]