Olanzapine transfer by human placenta.

1. The present study assessed the human transplacental transport of olanzapine, a new antipsychotic drug effective in the treatment of schizophrenia. 2. Using the normal-term placenta perfused single cotyledon system, we show that: (i) 5-14% of labelled olanzapine crosses from the maternal to foetal compartments in 4 h; (ii) transport depends significantly on binding characteristics, especially of albumin; (iii) no oxidative metabolites of olanzapine appear in the placental perfusate over 4 h; and (iv) approximately 17% of olanzapine, on average, is converted to the glucuronide, which is transferred by the placenta at a rate slightly slower than the parent drug.