Pharmacokinetics of proterguride in rat and cynomolgus monkey

1. The pharmacokinetics of proterguride were studied in rat and cynomolgus monkey using 3H- and 14C-labelled drug and a radioimmunoassay for concentration measurements of unchanged drug. 2. Proterguride was rapidly and completely absorbed at low doses but not completely at higher dose levels, especially in rat. 3. Bioavailability was 18% in the monkey (low and high doses) and 79% (low doses) and 38% (high dose), respectively, in the rat. 4. Proterguride was able to pass the blood-brain barrier achieving concentrations in brain similar to those in plasma. 5. Excretion of labelled compounds was mainly in the faeces in rat, but in monkey elimination was equal in faeces and urine.