Volumetric absorptive microsamplingcoupled with hybridization LC–MS/MS forquantitation of antisense oligonucleotides: supplementary materials

Background: Volumetric absorptive microsampling has emerged as a less invasive alternative to venoussampling for small-molecule pharmacokinetic studies, but its application to novel therapeutics such asantisense oligonucleotides (ASOs) is not well-established. Results: A workflow was developed usingMitra microsampling coupled with hybridization LC–MS/MS for accurate determination of fomivirsen,a 21-mer ASO, in human blood. Quantitative recovery was achieved regardless of blood hematocritlevel or microsample age by implementing impact-assisted extraction. A thorough method evaluationconfirmed sensitivity, linearity, precision/accuracy,matrix effect, metabolite interference and four monthsof microsample stability. Conclusion: The combined impact-assisted extraction and hybridization LC–MS/MS workflow demonstrated the successful quantitation of fomivirsen, establishing the validity andapplicability of the approach for ASO drug candidates.