[The metabolism of pancuronium in man]

The metabolic disposition of pancuronium was investigated in man under clinical condition. Pancuronium and its desacetylated derivatives were determined in body fluids using the previously described bromophenol blue method (3). The metabolites were isolated by thin layer chromatography. One minute after the intravenous injection of a mg of pancuronium the drug reaches a serum concentration of 2,2 plus or minus 0,2mug/ml. As an exponential function the concentration curve then falls to half of the initial value during the first 30 to 60 min. The end of the neuromuscular block conincides with a concentration of 0,1 to 0,3 mug/ml serum which is reached about 2 hours after the injection. After 3 to 4 hours no more pancuronium can be detected in the serum. The renal elimination of pancuronium can be folowed up for 12 hours. On average half of the injected dose is recovered in the urine. 80% of this proportion is unchanged pancuronium and 20% desacetylated metabolites. The monodesacetylated derivatives of pancuronium are still pharmacologically active. The biliary excretion 24 hours after the administration of pancuronium accounts for 5 to 10% of the injected dose...