Potential of moxalactam and other new antimicrobial agents for bilirubin-albumin displacement in neonates.

The effects of several novel antibiotics on in vitro binding of bilirubin to human serum albumin were investigated. At physiologic bilirubin-albumin ratios and pH values, aztreonam, imipenem, azlocillin, enoxacin and ciprofloxacin did not compete with bilirubin at drug concentrations less than 900 micrograms/mL. Cefoperazone caused an apparent increase in unbound bilirubin only at concentrations greater than 35 microM (330 micrograms/mL). Moxalactam, however, caused a linear increase in unbound bilirubin, greater than that seen with sulfisoxazole, over the entire range of antibiotic concentrations. These results may have implications for the use of these newer antimicrobial agents in neonatal infections.