Materno-fetal transfer of azlocillin

We studied 20 patients to assess transfer of azlocillin to the fetus at parturition. The elimination half-life of approximately 1.3 h in these mothers was similar to that reported for normal subjects. Azlocillin quickly reached umbilical cord blood, amniotic fluid, the placenta and the urine of the neonate, achieving substantial concentrations. Azlocillin then disappeared from umbilical cord blood with an elimination half-life of 2.3 h, i.e., similar to that of the mother. At 6 h, concentrations of azlocillin were still increasing in amniotic fluid and placenta. In addition, in two stillborn infants, azlocillin was found to reach substantial concentrations in all tissues analysed except brain. Concentrations of azlocillin achieved in fetal tissues are sufficient to have important therapeutic effects.