Pharmacokinetics of gallium nitrate in man.

Gallium nitrate is a new antineoplastic agent that has shown activity in a number of in vitro tumor systems. During a Phase I clinical trial, the pharmacokinetics of two methods of administration of gallium nitrate were studied: a seven-day continuous intravenous infusion, and a weekly rapid intravenous infusion. During the continuous infusion of 200 mg/M2 of gallium nitrate, plasma gallium concentrations of 0.9 +/- 0.2 microgram/ml in one patient, and 1.9 +/- 0.4 microgram/ml in a second were noted. Urine excretion of gallium approximated the daily administered dose by day 2-3. Overall, 68-107% of the total administered dose was recovered in the urine. Following a rapid intravenous infusion, a biphasic curve was generated. The T1/2 alpha ranged from 8.3-26 minutes; the T1/2 beta from 6.3-196 hours. From 69-91% of the administered dose was recovered in the urine. The effects of gallium nitrate on tissue localization and body retention of 67Ga are also presented.