Novel methodology to perform incurred sample reanalysis on dried blood spot cards: Experimental data using darolutamide and filgotinib

Abstract Different options on performing incurred sample reanalysis (ISR) on dried blood spot (DBS) cards were investigated using drugs belonging to various therapeutic areas: (a) darolutamide (to treat prostate cancer) and (b) filgotinib (to treat rheumatoid arthritis). The proposed novel methodology included the generation of half‐DBS and quarter‐DBS discs after initial blood collection using the full‐DBS discs. Accordingly, blood collection via DBS was performed in male BALB/c mice following intravenous and oral dosing of darolutamide; in male Sprague Dawley rats following intravenous and oral dosing of filgotinib. The ISR data generated from the full‐DBS disc, half‐DBS disc and quarter‐DBS disc were compared for the assessment of the proposed methodology. Quantification of darolutamide and filgotinib was accomplished using liquid chromatography‐electrospray ionization/tandem mass spectrometry methods. Darolutamide and filgotinib ISR samples, which were collected and prepared using full‐, half‐ and quarter‐DBS discs, met the acceptance criteria for ISR analysis. In conclusion, this is the first report showing a viable tool for the performance of ISR on DBS cards. The use of quarter‐ or half‐DBS discs would aid in not only ISR but also in long‐term storage experiments of analytes because it would avoid the need for additional blood sampling in patients.