GLC determination of ethinamate and its hydroxy derivative in biological fluids.
A sensitive, specific GLC assay was developed for the determination of ethinamate in plasma and its major metabolite, trans-4-hydroxyethinamate, in urine. The assay uses a mass internal standard of dimethylethinamate. Ethinamate is extracted from alkalinized plasma with dichloromethane. Urine samples require beta-glucuronidase hydrolysis prior to extraction of hydroxyethinamate. The dichloromethane is removed by evaporation, and the compounds are measured by GLC using a flame-ionization detector. By using GLC-chemical-ionization mass spectrometry, the compounds measured were identified as the intact ethinamates. Plasma and urine data are presented from a bioavailability study to demonstrate the utility of this method. From these data, the ethinamate plasma half-life was calculated as 1.9 +/- 0.3 hr.
D001682:Biological Availability; D002214:Capsules; D002219:Carbamates / Q000031:analogs & derivatives / Q000032:analysis* / Q000378:metabolism; D002849:Chromatography, Gas; D006801:Humans; D013058:Mass Spectrometry; D012995:Solubility; D013607:Tablets
D002214:Capsules; D002219:Carbamates; D013607:Tablets