Tissue disposition and plasma concentrations of idarubicin after intravesical therapy in patients with bladder tumors.

We studied single doses of intravesical idarubicin (IDA) given as 1-h instillations to 33 patients with bladder tumors. The dose was escalated from 5 to 30 mg and the concentration, from 0.25 to 1.5 mg/ml for evaluation of the importance of both the total amount of drug and the drug concentration on the levels of IDA found in different tissues (tumor, mucosa and muscle). Additionally, plasma uptake over 24 h was studied. The results demonstrated that (1) the levels of IDA in extracts of bladder tumors were significantly higher than those in normal bladder tissue, (2) the incorporation of IDA into tumors depended on the total amount of drug instilled and on the concentration of drug in the instillation fluid, (3) cytotoxic concentrations of IDA were noted in all tumors when the total amount of drug instilled was greater than 15 mg and the drug concentration in the instillation fluid was greater than 0.33 mg/ml, and (4) plasma levels of IDA were negligible.