Pharmacokinetic study of clarithromycin in human breast milk by UPLC–MS/MS

•This is the first method for pharmacokinetic study of clarithromycin in human breast milk by UPLC-MS/MS in the literature.•The method allows determination of clarithromycin in human breast milk.•According to the data obtained, it was found that the method is reliable. This study aimed to develop a validated UPLC-MS/MS method for pharmacokinetic analysis of clarithromycin in human breast milk. For sample preparation, proteins precipitated with methanol and azithromycin were used as internal standards. Clarithromycin and azithromycin detection was achieved using electrospray ionization in positive mode. The chromatographic separation time was 5 min. The lower limit of quantification was 50 ng/mL. The calibration curve of clarithromycin was 50–4000 ng/mL, with a correlation coefficient> 0.99. The method was successfully applied to determine clarithromycin levels in breast milk obtained from a lactating mother after oral administration of a single tablet containing 500 mg of clarithromycin. The maximum human breast milk concentration (Cmax) was 3660 ng/mL, the time to reach the maximum concentration (tmax) was 2.5 h, and the area under curve (AUC0–24) was 18450 ng h/mL. The present study provides a novel UPLC–MS/MS method for pharmacokinetic analysis of clarithromycin in breast milk.