Modified fluorometric quantitation of pancuronium bromide and metabolites in human maternal and umbilical serums

The procedure for pancuronium bromid ion-pair extraction into chloroform using rose bengal and subsequent fluorometric measurement was modified by changing the extraction pH and eliminating phenol, ethanol, and acetone to give easier operation and enhanced fluorescence stability. Precision, accuracy, and sensitivty were evaluated over 0.14-0.82 microgram/ml (CV = 14; relative error = 9%) and 0.05-0.17 microgram/ml (CV = 19; relative error = 21%). Following a dose of 0.1 ml/kg for cesarean section in humans, the mean maternal arterial and umbilical venous serum concentrations of pancuronium bromide and metabolites were 0.52 and 0.12 microgram/ml, respectively, at delivery (mean of 13 min after injection).