Transfer of ceftizoxime surpasses that of cefoperazone by the isolated human placenta perfused in vitro.

The transfer of cefoperazone and ceftizoxime across the human placenta was compared using the in vitro, bidirectionally perfused human placental lobule. The mean (+/- SEM) clearance indices for ceftizoxime and cefoperazone were 0.124 +/- 0.02 and 0.037 +/- 0.01, respectively (P = .0013). Cefoperazone concentration plateaued at a fetal concentration of 4-5 micrograms/mL in a recirculating perfusion system. No evidence of a decreasing slope of ceftizoxime transfer to the fetal compartment was noted after 60 minutes of perfusion. In a closed-closed perfusion system with equal concentrations of ceftizoxime in each compartment, a 1.1:1 fetal gradient was noted. These data indicate that ceftizoxime crosses the placenta significantly better than does cefoperazone and support our in vivo study documenting preferential concentration of ceftizoxime in the fetal compartment.