A RIA combined with SPE for the determination of a dual D2-receptor and beta2-adrenoceptor agonist, AR-C68397XX, in human plasma

Quantification of trantinterol, its two metabolites and their primary conjugated metabolites in human plasma by ultra-high-performance liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study

A highly rapid, selective and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously determine trantinterol, its major phase-I metabolites and their primary conjugated metabolites in human plasma. Waters Oasis HLB C18 solid phase extraction cartridges were used in the sample preparation. The separation was carried out on an ACQUITY UPLC™ BEH C18 column with methanol/0.2% formic acid (30:70, v/v) as the mobile phase at a flow rate of 0.25 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in selective reaction monitoring (SRM) mode with the use of an electrospray ionization (ESI) source. The linear calibration curves for trantinterol, tert-butyl hydroxylated trantinterol (tert-OH-trantinterol) and 1-carbonyl trantinterol (trantinterol-COOH) were obtained in the concentration ranges of 0.200-250, 0.108-4.00 and 0.0840-5.02 ng/mL, respectively (r(2)≥0.99). The intra- and inter-day precision (relative standard deviation, RSD) values were less than 13%, and the accuracy (relative error, RE) was within ±9.9%, as determined from quality control (QC) samples for the analytes. The concentrations of conjugated forms of trantinterol and tert-OH- trantinterol in plasma were determined using selective enzyme hydrolysis. The method described herein was fully validated and successfully applied for the pharmacokinetic study of trantinterol in healthy volunteers after oral administration.

A time-resolved fluorescence immunoassay for the determination of a novel respiratory therapeutic agent, AR-C68397XX (Viozan) in human plasma

A dissociation-enhanced lathanide fluorescence immunoassay (DELFIA) method has been developed for the determination of AR-C68397XX, a novel respiratory therapeutic agent, in human plasma. The method is a 'direct' immunoassay and provides an alternative to the solid phase extraction RIA described in a previous publication, which employs the same specific antiserum. The DELFIA method is suitable for the determination of the analyte at pg ml(-1) concentrations. The non-isotopic label was prepared by complexation of a DTPA derivative of AR-C68397XX with free europium cation (Eu3+). Plasma samples were diluted at least 5-fold prior to analysis to eliminate matrix interference. The calibration range is 10-2000 pg ml(-1), and the LOQ of the method is 50 pg ml(-1) using 50 microl of diluted human plasma sample.