Absorption of the beta-adrenergic-blocking agent, nadolol, by mice, rats, hamsters, rabbits, dogs, monkeys, and man: an unusual species difference.

1. Dogs absorbed [14C]nadolol almost completely (88--104%) after oral administration of 10--75 mg/kg. In contrast, mice, rats, hamsters, and rabbits, given oral doses of 20 mg/kg, absorbed, at most, 25%. After administration of oral doses of 2--75 mg/kg, monkeys absorbed no more than an average of 30%. Six monkeys given oral doses of 10 mg/kg absorbed 12--44%. 2. In rats, [14C]nadolol was orally absorbed to an average of 13.7--17.5%, whether given in suspension or in solution, indicating that absorption was not limited by rate of dissolution nor by solubility. 3. Mildly hypertensive humans given single doses of [14C]nadolol (2 or 80 mg, orally) and normal subjects given single doses (10 mg, orally) absorbed an average of 20.4--33.3%.