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Apixaban, a direct oral anticoagulant drug (DOAC), typically does not require routine therapeutic drug monitoring (TDM), yet recent guidelines propose its use in specific clinical scenarios. While various antifactor Xa (anti‐FXa) chromogenic assays serve as useful proxies for measuring plasma exposure to apixaban in emergencies, they lack specificity compared with chromatographic methods. This research project is intended to the development and validation of a standardized protocol of liquid chromatography–tandem mass spectrometry (LC–MS/MS) in conformity with the ICH guidelines M10 for the measurement of apixaban in both plasma and dried plasma spots (DPSs). Samples preparation included protein precipitation after the addition of a deuterated internal standard (IS), and the chromatographic separation was carried out on a Thermo Scientific™ Accucore™ Polar Premium column (50 mm × 2.1 mm, i.d. 2.6 m). The newly developed LC–MS/MS method for apixaban mesurement from both plasma and DPS resulted linear over a wide concentration range (31.25–500 ng/mL), accurate, and reproducible without matrix effects, allowing for specific and rapid quantification. Stability was assessed on quality controls and a real sample, allowing the setting up of a robust TDM protocol that was applied to five anonymized plasma samples obtained from adult patients undergoing apixaban treatment at steady‐state. In conclusion our novel LC–MS/MS method is adequate for accurate apixaban quantitation from both plasma and DPS matrixes, and may thus facilitate the guidelines suggested implementation of apixaban TDM, even in peripheral hospitals through shipment of DPS at reference laboratories. [ABSTRACT FROM AUTHOR]

Background: Iron-chelation therapy is life-saving in patients on a chronic transfusion regimen as it reduces organ damage related to iron deposition in the tissues. Deferasirox, an iron-chelator, is characterized by pharmacokinetics variability, and some patients may discontinue the treatment due to toxicities., Objective: Understanding whether deferasirox plasma levels are related to patients' specific characteristics could help to optimize DFX dosage., Methods: We analyzed deferasirox plasma concentration in 57 transfusion-dependent anemic patients using the HPLC method in this prospective-retrospective cohort study. All outpatients (3 to 98 years) were treated with deferasirox (film-coated tablet) for at least one year (median dose, 16.5 mg/Kg once a day). Deferasirox plasma concentration was normalized for dose/Kg (C/dose) and corrected with a linear regression model that relates C/dose and the time of blood sampling (C ref /dose)., Results: No significant differences in C ref /dose were found between males and females, either between different types of hemoglobinopathies or depending on the presence of the UGT1A1*28 polymorphism. C ref /dose has a positive and significant correlation with age, creatinine, and direct bilirubin. C ref /dose, instead, has a negative and significant correlation with Liver Iron Concentration (LIC), ferritin, and eGFR. C ref /dose was significantly different between three age categories <18yrs, 18-50yrs, and >50yrs, with C ref /dose median values of 1.0, 1.2, and 1.5, respectively., Conclusion: The study evidenced that to ensure the efficacy of deferasirox in terms of control over LIC and, at the same time, a lesser influence on renal function, the dose of the drug to be administered to an elderly patient could be reduced., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)