title: On-line 2D-LC-ESI/MS/MS determination of rifaximin in rat serum.
abstract: A 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 C(18 )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 (r(2) > 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.
authors.affiliation: Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad 500 607, India. rnrao55@yahoo.com
authors.forename: R Nageswara
authors.initials: RN
authors.lastname: Rao
authors.forename: R Mastan
authors.initials: RM
authors.lastname: Vali
authors.forename: Dhananjay D
authors.initials: DD
authors.lastname: Shinde
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000097:blood* / Q000493:pharmacokinetics; D002138:Calibration; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012294:Rifamycins / Q000097:blood* / Q000493:pharmacokinetics; D000078262:Rifaximin; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000890:Anti-Infective Agents; D012294:Rifamycins; D000078262:Rifaximin