Absolute bioavailability, pharmacokinetics, renal and biliary clearance of distigmine after a single oral dose in comparison to i.v. administration of 14C-distigmine-bromide in healthy volunteers

Aim: The aim of the study was to determine the absolute bioavailabilty and pharmacokinetics after a single dose oral administration in comparison to i.v. administration of C-14-labdled distigmine-bromide (C-14-Ubretid) in healthy male volunteers. Results: After the intravenous administration, distigmine is eliminated from the body by renal excretion (85%), and for a small fraction by biliary excretion in the feces (4%). This situation is reversed after an oral administration, where 6.5% of the dose is recovered from the urine and 88% from the feces. This means that distigmine after oral administration is hardly absorbed, the calculated bioavailability is 4.65%. Conclusion: The mean absorption time (MAT) after oral administration was 10 h, influencing the t(1/2 alpha), (1.4 vs 4.5 h) and the t(1/2 beta) (60 vs 70 h) to higher values than after the i.v. administration (p < 0.05).