LAUSR

Direct oral anticoagulants (DOACs) are first-line drugs used for the treatment of venous thromboembolism and prevention of stroke in patients with atrial fibrillation. These drugs do not require the regular biochemical monitoring that is mandatory for warfarin, and they exhibit shorter half-lives and have a faster onset of action. Since recent real-world studies evidence a higher prevalence of adverse side effects than what was anticipated in clinical trials, monitoring the plasma concentrations of DOACs is being used to personalize their pharmacotherapy, in accordance to the characteristics of the patient, and to evaluate the adherence to therapy. In order to fulfill the aforementioned clinical unmet needs, there are specific coagulation assays that indirectly assess the plasma concentrations of DOACs. Nevertheless, these assays are not sufficiently accurate or sensitive. For this reason, liquid chromatography techniques coupled to mass spectrometry detection, are considered the gold standard method to accurately determine plasma concentrations of DOACs. Therefore, the present paper provides the first comprehensive review of the current analytical methods that were developed and validated for the quantitative determination of apixaban, dabigatran, rivaroxaban and/or edoxaban and their main metabolites in biological samples. The chromatographic methods will be particularly highlighted and an emphasis will be placed on the major difficulties faced during optimization and development steps. In addition, the physicochemical, pharmacokinetic and pharmacodynamic characteristics of each drug will be critically related to chromatographic conditions. Their influence on the pre-treatment procedures and storage conditions of DOACs will be examined, suggesting strategies that should be applied to accurately quantify DOACs in biological samples.