Media type: E-Article Title: On‐line 2D‐LC‐ESI/MS/MS determination of rifaximin in rat serum Contributor: Rao, R. Nageswara; Vali, R. Mastan; Shinde, Dhananjay D. Published: Wiley, 2009 Published in: Biomedical Chromatography, 23 (2009) 11, Seite 1145-1150 Language: English DOI: 10.1002/bmc.1236 ISSN: 1099-0801; 0269-3879 Origination: Footnote: Description: AbstractA highly sensitive and selective on‐line two‐dimensional reversed‐phase liquid chromatography/electrospray ionization–tandem mass spectrometry (2D‐LC‐ESI/MS/MS) method was developed and validated to determine rifaximin in rat serum by direct injection. The 2D‐LC‐ESI/MS/MS system consisted of a restricted access media column for trapping proteins as the first dimension and a Waters C18 column as second dimension using 0.1% aqueous acetic acid:acetonitrile as mobile phase in a gradient elution mode. Rifampacin was used as an internal standard. The linear dynamic range was 0.5–10 ng/mL (r2 > 0.998). Acceptable precision and accuracy were obtained over the calibration range. The assay was successfully used in analysis of rat serum to support pharmacokinetic studies. Copyright © 2009 John Wiley & Sons, Ltd.