Transplacental pharmacokinetics of cocaine (C) and benzoylecgonine (BZE) in plasma and hair of rhesus monkeys

In utero exposure to C results in variable physical and neurobehavioural outcome suggesting substantial variability in transplacental transport of C. In order to study the relationship between maternal dose and C/BZE pharmacokinetics and maternal/infant C and BZE hair concentrations [hair], ten female rhesus monkeys were administered C before and during pregnancy to simulate maternal addiction. C and BZE pharmacokinetics were determined at the end of pregnancy. After birth, C and BZE [hair] were determined and correlated with AUC_0-∞ and C_max. There were significant correlations between maternal C [hair] and either maternal C AUC_0-∞ (r=0.73 p=0.02) or C C_max (r=0.74 p=0.02). Although there was a correlation between the infant's C [hair] and maternal C C_max (r=0.82 p=0.007), no correlation was found with C AUC_0-∞ (r=0.45 p=0.22). There were significant correlations between maternal BZE [hair] and either maternal BZE AUC_0-∞ (r=0.92 p=0.0001) or BZE C_max (r=0.88 p=0.0008). No such correlations were found with the infant's [hair] (r=0.52 p=0.15 and r=0.49 p=0.18). The absence of correlation of the infant's C [hair] with maternal C AUC_0-∞ suggests that the placenta modulates the amounts of C reachina the fetus.