Bioavailability of ifosfamide in patients with bronchial carcinoma

The pharmacokinetics of ifosfamide (I) were determined in ten patients with bronchogenic carcinoma. In seven patients, doses of 1 and 2 g (I) were given both as a bolus orally and later intravenously and were well tolerated. A further three patients received 5 g (I) as a single oral dose but in two this produced reversible CNS toxicity and severe vomiting. The area under the curve (AUC, microgram . h . l-1) for the 1-g dose was the same following oral and i.v. treatment and this was also true for the 2-g doses. There was a proportionate increase in the AUC for the 5-g oral dose, indicating 100% bioavailability at all three dose levels. We conclude that doses up to 2 g by mouth represent a well-tolerated alternative route of administration.