Studies on the pharmacokinetics and the metabolism of gitoxin in the guinea-pig: II. the enteral absorption and the enterohepatic recirculation.

Absorption of 3H-gitoxin and enterohepatic recirculation of the metabolites excreted in the bile were studied in the guinea-pig. Samples were assayed either by RIA or by selective counting of the radioactivity due to tritium. When administered as hydroalcoholic solutions into the stomach or into the duodenum, gitoxin is nearly completely absorbed (94.5%). But the availability of the drug in the systemic circulation is of only 35% (RIA) or 52% (CH2C12-soluble radioactivity). Only 3-5% of the metabolites excreted in the bile enter the enterohepatic cycle.