m-Hydroxy benzoylecgonine recovery in fetal guinea pigs

Recently, meta-hydroxybenzoylecgonine (m-OH BE) was identified by gas chrom atography-mass spectroscopy during quantitative analysis for cocaine. Ident ification of m-OH BE in addition to the routinely identified benzoylecgonin e by gas chromatography-mass spectroscopy confirmatory assays may increase detection of cocaine-exposed infants and decrease false negative results. H owever, it is not known whether m-OH BE is derived directly from benzoylecg onine or from hydroxylated cocaine, or whether this metabolite is produced in the fetus or transferred across the placenta from the maternal circulati on. We quantitated the recovery of cocaine, benzoylecgonine, and m-OH BE fr om amniotic fluid, fetal meconium, fetal intestine, and maternal urine for up to 4 days after single dose administration of either cocaine or benzoyle cgonine to pregnant time-bred guinea pigs. m-OH BE was recovered from mecon ium after maternal injections of cocaine and benzoylecgonine. There was no significant detection of m-OH BE from amniotic fluid or intestine and minim al recovery from maternal urine after either cocaine or benzoylecgonine adm inistration. Detection of m-OH BE in meconium increased the identification of in utero exposed guinea pigs, and the greatest yield of m-OH BE from mec onium occurred later than that observed for cocaine or benzoylecgonine.