Combinatorial approach of LC-MS/MS and LC-TOF-MS for uncovering in vivo kinetics and biotransformation of ochratoxin A in rat

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• 作者：Zheng Han^a ; ^e ; Zhiyong Zhao^a ; Jianxin Shi^b ; Yucai Liao^c ; Zhihui Zhao^a ; Dabing Zhang^b ; Yongning Wu^d ; Sarah De Saeger^e ; Aibo Wu^a ; ^{wuaibo2007@yahoo.com.cn} ; ^{wuaibo@saas.sh.cn}
• 关键词：Ochratoxin A ; Liquid chromatography&ndash ; tandem mass spectrometry ; Liquid chromatography coupled with time of flight mass spectrometry ; Kinetics ; Biotransformation
• 刊名：Journal of Chromatography B, Analytical Technologies in the Biomedical and Life Sciences
• 出版年：2013
• 出版时间：15 April, 2013
• 年：2013
• 卷：925
• 期：Complete
• 页码：46-53
• 全文大小：667 K

文摘

A combinatorial platform of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography coupled with time of flight mass spectrometry (LC-TOF-MS) has been developed to investigate the in vivo kinetics and biotransformation of ochratoxin A (OTA) in rats. The stable isotope dilution LC-MS/MS method was first validated by determining the linearity (R² ¡Ý 0.9990), sensitivity (lower limit of quantitation of 0.05 ng mL^?1), accuracy (83.3-108.3), precision (RSD ¡Ü 15.6 % ) and stability (¡Ý75.0 % ), and was approved for the determination OTA in plasma, heart, liver, spleen, lung, kidney and brain with a run time of 7.0 min. Simultaneously, an LC-TOF-MS method could unambiguously identify the metabolites of OTA in a total run time of 14 min. The subsequent studies on kinetics and distribution after oral administration of 0.2 mg/kg b.w. OTA in rat indicated that OTA could reach a maximum value of 1932.4 ¡À 124.9 ng mL^?1 within 5 h due to its fast absorption, and then was slowly eliminated in plasma with a half-life time (t_1/2) of 75.6 ¡À 29.0 h. Results of tissue accumulation after a daily oral administration of 0.1 mg/kg b.w. OTA during 20 days showed that the highest concentration of OTA was observed in lung (95.9 ¡À 13.7 ng g^?1), followed by liver (76.0 ¡À 9.7 ng g^?1), heart (62.0 ¡À 4.2 ng g^?1) and kidney (55.7 ¡À 4.7 ng g^?1). Furthermore, three less toxic metabolites of OTA were clearly identified: Ochratoxin ¦Â (OT¦Â) and ochratoxin B (OTB) methyl ester were found in kidney and spleen, respectively, while phenylalanine was detected in heart and kidney. Thus, a possible metabolic pathway of OTA was proposed. The above achieved results justified that the application of combinatorial LC-MS/MS and LC-TOF-MS methods are valuable tools to uncover the kinetics and metabolism of OTA for the interpretation of toxicological findings in animals and extrapolation of the resulting data as reference to humans.