Pharmacokinetics of dibromodulcitol in humans: a phase I study.

A combined clinical and pharmacokinetic phase I study of the substituted hexitol dibromodulcitol (DBD), administered as a single oral monthly dose, has been performed. Twenty-three patients with advanced neoplasms received DBD doses ranging from 600 to 1,800 mg/m2 body surface area (BSA). The dose-limiting toxicity was myelosuppression, with both significant granulocytopenia and thrombocytopenia occurring at dose levels of 1,500 to 1,800 mg/m2. The average pharmacokinetic parameters for DBD, calculated on the basis of a one-compartment model with first-order absorption and elimination, include the elimination constant, .005 +/- .002/min; absorption constant, .012 +/- .009/min; and an apparent volume of distribution, 1.03 +/- .4 L/kg. The area under the drug concentration curve (AUC) and the peak drug level (Cmax) were linearly related to the dose administered (P less than .001). The mean AUC was 18.7 +/- 6.1 mmol/L min, and the mean Cmax was 47.1 +/- 16.8 mumol/L when normalized to a DBD dose of 1 gm/m2. The elimination constant was significantly reduced in patients with abnormal hepatic function (P less than .01). The elimination constant was not correlated with renal function. The half-life of DBD in plasma (158 minutes) was considerably shorter than the four-to eight-hour half-life of total radioactivity in plasma measured by previous investigators following the administration of radiolabeled DBD.