title: Quantification of naturally occurring benzodiazepine-like substances in human breast milk.
abstract: The possible occurrence of benzodiazepine-like substances in human breast milk was investigated in 35 healthy, newly delivered women who were known not to be taking benzodiazepines. Maternal blood samples and a sample of breast milk were obtained on the fifth post partum day. A radioreceptor technique (lower limit of detection 1.5 ng/ml; difference between duplicates at various concentrations less than 7%) was used for measuring benzodiazepine-like substances in blood and breast milk (with and without prior extraction). No benzodiazepine-like substances could be demonstrated in any of the blood samples taken from the 35 women. Measurable concentrations of benzodiazepine-like substances were demonstrated in all but 1 of the 35 breast milk samples. The mean concentration of benzodiazepine-like substances for all 35 women was 4.3 +/- 2.3 ng/ml (range 0-9.3 ng/ml) expressed as lorazepam. The corresponding value for extracted breast milk was 2.6 +/- 1.5 ng/ml (range 0-7.0 ng/ml). There was no association between concentrations of benzodiazepine-like substances in breast milk and maternal age, weight, height and body mass or parity, or the sex of the infant and infant birth weight. We suggest that non-detectable amounts of benzodiazepine-like substances in serum are concentrated in the mammillary glands and excreted in a higher concentration in breast milk. It is less likely that the relevant benzodiazepines are produced in the mammillary glands.
authors.affiliation: Department II of Psychiatry, Lillhagen Hospital, Hisings Backa, Sweden.
authors.forename: S J
authors.initials: SJ
authors.lastname: Dencker
authors.forename: G
authors.initials: G
authors.lastname: Johansson
authors.forename: I
authors.initials: I
authors.lastname: Milsom
mesh_terms: D000328:Adult; D001569:Benzodiazepines / Q000032:analysis* / Q000097:blood; D005260:Female; D006801:Humans; D008895:Milk, Human / Q000737:chemistry*; D011869:Radioligand Assay; D012044:Regression Analysis
chemical_list: D001569:Benzodiazepines