Publication: A Novel Hybridization LC-MS/MS Methodology for Quantification of siRNA in Plasma, CSF and Tissue Samples

Long Yuan, a former colleague of mine, and a few current colleagues recently published a method for double-stranded siRNA using hybridization extraction and LC-MS/MS. Long reports the first hybridization method for double stranded siRNA using conventional DNA capture probes, as well as, a peptide nucleic acid (PNA) capture probe. The PNA has a higher affinity for the siRNA and therefore, has greater recovery efficiency (and was proven experimentally). To optimize the LC-MS/MS conditions, they used the active antisense siRNA strand.  However for the calibration curve and QCs the double-stranded siSNA was used. A typical BMV validation was used. The calibration curve was 2-1000 ng/ML and the s/n at the LLOQ appeared to be >10. They tested monkey plasma, CSF and 8 different tissues. Using the PNA probe, they achieved around 90% recovery - demonstrating the viability of the approach for this and other double-stranded siRNA therapies. More details are in the article.