[Absorption, distribution, metabolism and excretion of bacmecillinam. II. The placental transfer and transition into milk of 14C-bacmecillinam].

The placental transfer and transition into milk of bacmecillinam (KW-1100), a new semisynthetic penicillin, have been studied with 14C-KW-1100 administered orally in the pregnant and lactating rats, respectively. The level of 14C-KW-1100 in the umbilical cord blood was 7.2% of the peak maternal blood level and the radioactivity was eliminated slowly. At the peak fetus level (4 hours after administration), the radioactivity transferred into the fetuses was found to be 0.01% of the dose. 14C-KW-1100 was distributed into the uterus, ovary, placenta and consistently into the fetal membrane. 14C-KW-1100 was excreted into milk slightly, and the concentration of radioactivity in milk did not exceed the maternal peak blood level.