High-performance liquid chromatographic assay for etomidate in human plasma: results of preliminary clinical studies using etomidate for hypnosis in total intravenous anesthesia.

A sensitive and specific high-performance liquid chromatographic assay was developed for the measurement of etomidate in human plasma following extraction of the drug and the internal standard. Using 0.5-ml aliquots of plasma, the assay was linear in the concentration range of 20-2000 ng of etomidate/ml of plasma. This method was used to evaluate a preliminary clinical study of an etomidate infusion regimen for hypnosis in a total intravenous anesthesia protocol in 23 patients. The average duration of the infusion was 30 min, and awakening and alertness occurred 20 and 36 min after the termination of the infusion, respectively, at the respective plasma concentrations of 297 and 214 ng/ml. These results and this assay will be used to design and evaluate an improved etomidate infusion regimen.