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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]

The new breakthrough cystic fibrosis (CF) drug combination of ivacaftor (IVA), tezacaftor (TEZ), and elexacaftor (ELX), namely "caftor" drugs, directly modulates the activity and trafficking of the defective CF transmembrane conductance regulator protein (CFTR) underlying the CF disease. The role of therapeutic drug monitoring (TDM) of caftor drugs in clinical settings has recently been established. The availability of reliable and robust analytical methods for the quantification of IVA, TEZ, and ELX is essential to support dose–concentration–effect studies. We have developed and validated a new liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the rapid and simultaneous quantification of IVA, TEZ, and ELX from the plasma of CF patients. The method was based on a rapid extraction protocol from 50 μL human plasma and separation on a reversed-phase C-18 HPLC column after the addition of deuterated internal standards. Accurate analyte quantification using multiple reaction monitoring (MRM) detection was then obtained using a Thermofisher Quantiva triple-quadrupole MS coupled to an Ultimate 3000 UHPLC. The method has been validated following international (EMA) guidelines for bioanalytical method validation and has been tested on plasma samples from 62 CF patients treated with the three-drug combination IVA/TEZ/ELX, marketed as Kaftrio® or Trikafta®, in steady-state condition. The assay was linear over wide concentration ranges (0.008–12 mg/L) in plasma for IVA, TEZ, and ELX, suitable for a broad range of plasma concentrations, and accurate and reproducible in the absence of matrix effects. The stability of analytes for at least 30 days at room temperature could allow for cost-effective shipment and storage. On the same day of sample collection, a sweat test was evaluated for 26 associated patients' samples, FEV1 (%) for 58, and BMI was calculated for 62. However, Spearman correlation showed no correlation between Cthrough plasma concentrations of analytes (IVA, TEZ, ELX) and sweat test, FEV1 (%), or BMI. Our method proved to be suitable for TDM and could be helpful in assessing dose–concentration–response correlations in larger studies. [ABSTRACT FROM AUTHOR]

Personalization of busulfan (Bu) exposure via therapeutic drug monitoring (TDM) is recommended for patients treated with high-dose conditioning regimens. Several laboratories' developed methods are available in the literature with a lack of standardization. The aim of this study is to develop a new standardized LC-MS/MS method and validate it according to the international ICH M10 (EMA) guidelines. Our method is based on rapid protein precipitation from 50 µL plasma followed by separation on a reversed-phase C-18 UHPLC column after the addition of deuterated internal standard and has been tested on real samples from pediatric patients treated with myeloablative conditioning regimens, including Bu, before autologous or allogeneic hematopoietic stem cell transplantation (HSCT). The validated LC-MS/MS method is linear over wide concentration ranges (125–2000 ng/mL), accurate, and reproducible in the absence of matrix effects, allowing for the specific and rapid quantification of Bu and allowing next-dose recommendations to be made in a timely fashion to answer clinicians' needs. Given the lack of data on the stability of Bu in real clinical samples, stability was assessed both on quality controls and on real samples to set up a robust protocol in real-life conditions. This novel LC-MS/MS method is suitable for application to the TDM-guided personalization of conditioning treatments with high-dose busulfan in pediatric patients undergoing HSCT. [ABSTRACT FROM AUTHOR]

• Ceftobiprole is a 5th generation cephalosporin with antibacterial activity against a large range G+ and G− bacteria • TDM helps to maintain plasma concentrations of antibiotics well above the MIC , thus preventing the resistant strain diffusion • TDM is already recommended for other cephalosporins as it reasonably contributes to the safety and efficacy of these drugs • The set up of a routine HPLC-UV method validated for quantification of ceftobiprole supports its TDM as clinical stardard. Ceftobiprole is a recent 5th generation parenteral cephalosporin with antibacterial activity against a large range Gram+ and Gram− bacteria. Therapeutic drug monitoring (TDM) is an essential tool for maintaining plasma concentrations of antibiotics above the MIC by the end of the dosing interval, thus preventing the resistant strain diffusion. TDM is already recommended for other cephalosporins, and it is a reasonable tool contributing to the safety and efficacy of these drugs. During the treatment of patients in real-life, a number of pharmacokinetic (PK) changes not normally seen in healthy volunteers can occur which can impair the pharmacokinetic/pharmacodynamic target attainment. We aimed to develop simple and rapid HPLC-UV method for determination of ceftobiprole in human serum to implement TDM in clinical practice and support PKs and pharmacokinetic/pharmacodynamic (PK/PD) studies. Samples preparation of calibration standards, QC, and anonymous patients serum samples was performed by protein precipitation by adding 0.01 ml of sulphosalicylic acid at 30 % to 0.1 ml of each sample. Then samples were vortexed and the centrifuged at 12,000 rpm for 10 min at 4 °C. Fifty microlitres of clear supernatant were diluted 1:1 with mobile phase and transferred into HPLC autosampler held at 8 °C. Chromatographic separation was carried out in a gradient mode at 35 °C on an ultra-Biphenyl column using a Thermo Scientific chromatographic system with a Diode array. Data management was performed with Chromeleon 7.4 software. The HPLC-UV method proved to be linear over wide concentration ranges (0.5–50.0 mg/L) and was accurate and reproducible in the absence of matrix effects, allowing for robust, specific, and rapid quantification of ceftobiprole from a low amount of serum (0.1 mL). The mean steady state C trough and C end values measured in the anonymous patients' samples were 6.26 ± 3.81 mg/L and 22.56 ± 15.69 mg/L, respectively. We report a broadened simple and fast HPLC with UV detection method for quantification of ceftobiprole in human serum to implement ceftobiprole TDM as clinical routine, and support future (PK/PD) studies in special patients' population. [ABSTRACT FROM AUTHOR]