title: Determination of Rhodamine 123 in rat plasma utilizing liquid chromatography-tandem mass spectrometry.
abstract: Rhodamine 123 (R123), as a typical of P-gp substrate, was widely used to quantify P-glycoprotein (P-gp) functional efflux activity in vivo. A new, rapid and sensitive method was developed for quantifying R123 in rat plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). R123 and Rhodamine 6G (R6G, the internal standard, IS) were extracted from aliquots of plasma with ethyl acetate and dichloromethane (4:1) as the solvent and chromatographic separation was performed using a Zorbax Eclipse Plus C18 column. The mobile phase was composed of A: ammonium formate-formic acid buffer containing 5 mM ammonium formate and 0.1% formic acid and B: methanol (A:B, 5:95, v/v). To quantify R123 and IS respectively, multiple reaction monitoring (MRM) transition of m/z 345.2→285.2 and m/z 443.3→415.2 was performed. The analysis time was 4 min in positive mode; the calibration curve was linear in the concentration range of 1-200 ng/ml. The lowest limit of quantification (LLOQ) reached 1 ng/ml. The intra and inter-day precision were less than 9.2% for the low quality control (QC) level, and 3.4% for other QC levels, respectively, while the intra and inter-day relative errors ranged between -7.4% and 9.1% for three QC concentration levels. The LC-MS/MS method proved to be simple, accurate, reliable and with a shorter running time and has been successfully applied to evaluate the functional activity of P-glycoprotein in an absorption experiment in the rat.
authors: Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors: Ya-Bin
authors: YB
authors: Sun
authors: Yu-Guan
authors: YG
authors: Wen
authors: Yuan
authors: Y
authors: Yan
authors: Guo-Feng
authors: GF
authors: Li
mesh_terms: D000042:Absorption; D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D016018:Least-Squares Analysis; D057230:Limit of Detection; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D020112:Rhodamine 123 / Q000097:blood* / Q000493:pharmacokinetics; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D020112:Rhodamine 123