Abstract
1. The pharmacokinetics of rolipram were studied in rat, rabbit, rhesus monkey and cynomolgus monkey using 14C- or 3H-labelIed rolipram and a radioimmunoassay for measurement of unchanged drug.
2. Rolipram was rapidly and completely absorbed after oral doses of up to 50 mg/kg. Bioavailability was 0˙1% in rhesus monkey, 3˙7% in cynomolgus monkey, 3˙6% in rabbit, 35% in rat, and 75% in man.
3. Rolipram was able to pass the blood-brain barrier achieving concentrations in brain twice those in plasma.
4. Plasma levels of the unchanged drug declined with a-similar half-life of 1-3 h in all species investigated. In the rat, there were indications for a different clearance of the two rolipram enantiomers.
5. Labelled rolipram was excreted rapidly and completely. The main route of elimination was via the urine.