Development of a Plasma Stability Assay of Oligonucleotides

The plasma stability assay plays an important role in drug discovery and development phases. Unstable compounds tend to have rapid clearances and short half-lives, resulting in poor in vivo performances. Oligonucleotides (oligos), including small interference RNAs (siRNAs) and antisense oligonucleotides (ASOs), present unique challenges in plasma stability study design using traditional protocols considering their properties such as relatively high molecular weight, high nonspecific binding, and metabolizing via specific metabolic enzymes compared to small molecule compounds. In order to investigate the effects of anticoagulants, status/sources of plasma, and serum on the metabolism of oligos, we compared the differences between: 1) EDTAK2 and heparin as an anticoagulant, 2) fresh plasma and frozen plasma, 3) frozen plasma and frozen serum, and established the plasma stability assay for siRNAs and ASOs in this presentation.