Development of innovative and highly performing diagnostic techniques in the field of veterinary pharmacology and toxicology and in support of internal medicine

Liquid chromatography–tandem mass spectrometry (LC-MS/MS) has become a cornerstone analytical technique in human medicine, widely employed in both clinical diagnostics and biomedical research. Its exceptional sensitivity, specificity, and versatility have also established it as a key tool in areas such as food safety and environmental monitoring. However, its adoption in veterinary medicine remains comparatively limited. This doctoral thesis aims to bridge this gap by developing innovative LC-MS/MS-based diagnostic methods tailored for veterinary applications in pharmacology, toxicology, and internal medicine. The work begins with an overview of LC-MS/MS technology, tracing its evolution and transformative impact in human healthcare and related scientific disciplines. Building on this foundation, the thesis advocates for the broader integration of LC-MS/MS into veterinary diagnostics and research through a multidisciplinary, collaborative approach. The research focuses on three major areas where LC-MS/MS can substantially enhance diagnostic accuracy, therapeutic monitoring, and animal welfare. The core section presents results from extensive experimental work and international collaborations, culminating in twelve scientific papers at various stages of publication. Novel quantitative methods were developed for antibiotic determination in animals, enabling advanced pharmacokinetic modelling and therapeutic drug monitoring (TDM). The implementation of dried blood spot (DBS) microsampling further improved diagnostic feasibility while minimizing invasiveness. In parallel, validated LC-MS/MS protocols were established for detecting per- and polyfluoroalkyl substances (PFAS) in biological samples from companion animals, contributing to a One Health understanding of environmental exposure. Additionally, assays for 25-hydroxyvitamin D₃ and purine metabolites were developed, supporting metabolic profiling and biomarker discovery, with preliminary studies in dairy cows. The concluding discussion emphasizes the analytical, clinical, and ethical benefits of LC-MS/MS in veterinary medicine, highlighting its potential to advance sustainable, animal-centred diagnostics and proposing strategic directions for its long-term integration into veterinary practice.