Measurement of tulobuterol in human plasma by capillary gas chromatography and selected ion monitoring detection.
A method is described for the quantification of tulobuterol in human plasma, based upon selective extraction and high resolution capillary gas chromatography-mass spectrometry. The mass spectrometric determination is based on selected ion monitoring of two fragment ions derived from the N,O-heptafluorobutyryl derivatives of tulobuterol and its internal standard, deschlorotulobuterol. The plasma work-up procedure consists of extraction of 1.0 ml alkalinised plasma with dichloromethane, back-extraction into an acidified aqueous phase, followed by a final extraction with dichloromethane after realkalinisation. The method gave interference-free and linear results. The between-assay variability is 4.7% CV at the 3.0 micrograms l-1 plasma concentration level. The assay permitted quantitative measurements down to 170 ng tulobuterol per litre of plasma and hence provided sufficient sensitivity for quantification of plasma levels after therapeutic doses.
D001993:Bronchodilator Agents / Q000097:blood*; D002986:Clinical Trials as Topic; D004311:Double-Blind Method; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D013726:Terbutaline / Q000031:analogs & derivatives* / Q000097:blood
D001993:Bronchodilator Agents; C010809:tulobuterol; D013726:Terbutaline