[Pharmacokinetic studies on intravenous drip infusion of dibekacin in elderly subjects without apparent renal failure (author's transl)].

The pharmacokinetic behavior of dibekacin was studied in 8 elderly subjects. These subjects had not apparent renal failure, although they were diagnosed as having various diseases such as arteriosclerosis, essential hypertension, etc. Dibekacin, 50 mg/subject, was infused intravenously for 1 hour. Serum and urine concentrations of dibekacin were measured by the bioassay and radioimmunoassay methods. The peak serum concentration of dibekacin ranged from 3.55 to 5.35 micrograms/ml when measured by bioassay, and from 3.19 to 8.9 micrograms/ml by radioimmunoassay. The biological half-life of dibekacin ranged from 2.13 to 3.45 hours, and from 1.57 to 3.55 hours, with these 2 methods. The area under the curve (AUC) ranged from 14.8 to 25.6 micrograms/ml-hr and from 11.3 to 18.0 microgram/ml . hr, respectively. Creatinine clearance showed a positive correlation with the elimination rate constant and a negative correlation with the distribution volume of dibekacin. These relationships were more pronounced when determined by radioimmunoassay. These data suggest that the peak serum concentration of dibekacin decreases with creatinine clearance. The serum and urine concentrations of dibekacin measured by the radioimmunoassay method correlated well with those measured by the bioassay method. Therefore, it was concluded that the radioimmunoassay method is a useful technique for monitoring the serum concentration of dibekacin.