A new approach with dried plasma spots: a rapid determination of antidepressants and antipsychotics by fast GC-MS.

Background: The increasing prevalence of poisoning cases related to antidepressants and antipsychotics has raised concerns. Methods: To address this issue, a new adaptation of the dried plasma spot technique was developed using a 24-well plate and fast gas chromatography-mass spectrometry. The method involves the optimization of extraction variables and sample preparation, and was successfully validated. Results: The limits of quantitation ranged from 20 to 60 ng/ml, and accuracy ranged from 87.8% to 112.2%. The technique was applied to 102 human plasma samples from suspected poisoning cases, with positivity of 90.2%. Conclusion: This method provides a cheap, easy to implement and fast approach, making it ideal for toxicological emergency laboratories and promoting valuable support for healthcare professionals managing poisoning cases involving antidepressants and antipsychotics.

Thalidomide measurement in plasma and dried plasma spot by SPE combined with UHPLC-MS/MS for therapeutic drug monitoring.

Aims: To validate an SPE-ultra-HPLC-MS/MS method for thalidomide (THD) measurement in dried plasma spot (DPS). Methods: Extraction included acetonitrile/water clean-up and online SPE. The LOD, LLOQ, linearity, precision, accuracy, recovery, matrix effect, process efficiency, carryover, stability, drug interference and dilution integrity were assessed. Results: The method was linear from 50 to 2000 ng/ml with a LOD of 20 ng/ml and LLOQ of 50 ng/ml. The coefficient of variation for precision was 0.4-7.9% for intra-assay and 1.3-8.9% for interassay, and accuracy was 81.4-97.1%. Adequate matrix effect (100.6-107.0%), recovery (88.7-105.0%) and process efficiency (91.3-109.3%) were registered. DPS was stable for 14 days at room temperature and 45°C ,and for 4 months at -80°C. The method was applied to quantify THD in both wet plasma and DPS from patients with cutaneous lupus receiving THD treatment. The difference between THD wet plasma and DPS concentration was <15%. Conclusion: The method is suitable to quantify THD in DPS.