Measurement of haloperidol in human breast milk by high-performance liquid chromatography

A high-performance liquid chromatographic method was developed for the assay of haloperidol in human breast milk. The method involves rapid extraction of haloperidol and chromatography with a reversed-phase C18 column and a mobile phase of phosphate buffer (pH 4.0):acetonitrile (70:30, v/v). Moperone was used as the internal standard. Haloperidol and moperone were detected with ultraviolet detection at 254 nm. The sensitivity was 5 ng/mL of milk, and the standard curve was linear in the concentration range 5-250 ng/mL. The average interassay coefficient of variation for samples with drug in the concentration range 25-125 ng/mL was less than 8.8%. The absolute recovery of haloperidol by the method was greater than 94.4%. No interference with endogenous substances in human milk was observed. The method was used to determine haloperidol levels in breast milk from patients undergoing chronic haloperidol treatment.