Spectrofluorometric determination of bufuralol in blood and urine

The benzofuran analog bufuralol, a beta-adrenergic blocker, was determined in blood and urine by a specific and sensitive spectrofluorometric assay. The compound was extracted into ether from blood or urine adjusted to pH 10. The ether extract was separated by TLC to resolve the parent drug from any basic metabolites present, and the spots were eluted off the silica gel and quantitated fluorometrically in 0.1 N HCl. The overall recovery of the assay was 85 +/- 3.0%; the sensitivity limit was 2-4 ng/ml of blood or urine, using a 2.5-ml specimen/analysis. The method was applied to the determination of blood levels in a dog following a single 10-mg/kg oral dose and in two human subjects administered a single 20-mg oral dose.