A fully validated method for the simultaneous determination of 11 antihistamines in breast milk by gas chromatography-mass spectrometry

Antihistamines are excreted into breast milk in small amounts; however, there are no adequate published studies or data concerning their effects on newborns and safety during breastfeeding. Thus, the development of sensitive and specific methodologies for the determination of antihistamines in breast milk is critical. A simple and sensitive GC-MS method for the simultaneous determination of 11 antihistamines (diphenhydramine, orphenadrine, chlorpheniramine, dimethindene, meclozine, hydroxyzine, loratadine, desloratadine, cetirizine, rupatadine and ebastine) in breast milk was developed and validated. The antihistamines were solid-phase extracted and derivatized with acetic anhydride and n-propanol. Diazepam-d₅ , hydroxyzine-d₄ and cetirizine-d₈ were used as internal standards. Absolute recovery values for all analytes ranged from 70.5 to 120.0%, while the limits of detection and quantification for all analytes were 1.50 and 5.00 ng/mL, respectively. All calibration curves were linear (R²  ≥ 0.990) within the range 5.00-1000.0 ng/mL. Accuracy (E_r ) ranged between -7.6 and 7.0%, while precision (RSD) was <12% for all antihistamines. The developed method is suitable for the investigation of antihistamine-related clinical cases, as well as for pharmacokinetic and breastfeeding safety studies.