Mass spectrometric assay for determination of pancuronium and vecuronium in biological fluids utilizing the moving belt introduction system.

An assay for the determination of the neuromuscular blocking agents pancuronium bromide and vecuronium bromide in plasma or urine has been developed. This method is based on syringe application of sample extracts to the moving belt surface and single metastable transition monitoring of the elimination of acetic acid from the ion of m/z 543 during chemical ionization. The analysis shows good linearity over three orders of magnitude and is capable of analyzing for the compounds below the 5 ng ml-1 level. The assay has been used in preliminary pharmacokinetic studies of the biological fluids of surgical patients. The utility of the method for simultaneous determination of the deacetylated metabolites of these two drugs has also been investigated.