Quantitation of locked nucleic acid antisense oligonucleotides in mouse tissue using a liquid-liquid extraction LC-MS/MS analytical approach.

Background: A significant challenge of oligonucleotide bioanalysis is the selective extraction from complex tissue samples, where the molecules that distribute into the intracellular space are extensively protein bound and sit amongst a high concentration of endogenous nucleic acid material. Published analytical methodology currently purports extensive sample preparation requirements that include cell lysis steps, homogenization and dual cleanup with liquid-liquid extraction and solid-phase extraction, prior to injection.

Results: We have developed a simple liquid-liquid extraction approach to rapidly isolate antisense oligonucleotides from biological tissues with high recovery and combined these preparative steps with a robust monolithic column LC-MS/MS setup.