Disposition of FK037 (3) : Transfer into the Fetus and Milk in Rats after Single Intravenous Dosing

Abstract

The ¹⁴C-labelled compound of FK037, a new antibiotics, was administered intravenously at a dose of 20 mg/kg to pregnant and lactating rats to study its transfer into the fetus and milk, respectively.
1. The radioactivity levels in the fetus was only 1% of that in the maternal plasma at 5 min after intravenous dosing to rats on day 13 of gestation and was not detected at 24 hr after dosing. The radioactivity in the fetus was less than 1% of that in the maternal plasma at 5 min after intravenous dosing to rats on day 18 of gestation and declined to 19% of the maximum concentration at 24 hr after dosing. The whole body autoradiograms showed no radioactivity in the fetus after intravenous dosing to rats on day 13 and 18 of gestation.
2. The radioactivity in milk attained the maximum concentration of 0.93μg eq./ml at one hour after intravenous dosing to lactating rats, then declined with a half life of 5.6 hr until 8 hr after dosing, and was not detected at 24 hr after dosing.