First validated liquid chromatography–tandem mass spectrometry method for simultaneous quantification of propranolol and 4-hydroxypropranolol in pig plasma and dried blood spots and its application to a pharmacokinetic study

This study reports the first validated LC-MS/MS assay for propranolol and 4-hydroxypropranolol in pigs and demonstrates its successful application in a PK study. The method's simplicity, short runtime, and compatibility with DBS microsampling make it ideal for preclinical and veterinary research, minimizing animal stress and sampling volume. Absence of 4-hydroxypropranolol highlights interspecies metabolic variability and warrants further investigation into propranolol biotransformation pathways in swine and other translational models.