[Studies on the absorption and excretion of rokitamycin in infant beagle dogs. Comparison with adult beagle dogs].

Absorption and excretion of rokitamycin (RKM) were studied after oral administration of 50 mg/kg to fasted infant and adult Beagle dogs. In infant Beagle dogs, the mean plasma level of RKM reached its peak of 6.53 micrograms/ml in 15 minutes after administration. The area under the curve (AUC) value was 11.04 micrograms.hr/ml. In adult Beagle dogs, the mean plasma level of RKM reached its peak of 8.62 micrograms/ml in 30 minutes after administration. The AUC value was 18.25 micrograms.hr/ml. Ratios of Cmax and AUC value in infant Beagle dogs to those in adults were about 75% and 60%, respectively. In infant Beagle dogs, urinary excretion of RKM was 2.55% of the dose within 24 hours. In adult Beagle dogs, urinary excretion of RKM was 3.03% of the dose within the same period. The excretion ratio of RKM in infant Beagle dogs was about 85% of the adults' value.