A high-throughput flow injection inductively coupled plasma mass spectrometry method for quantification of oligonucleotides

Development of an ICP-MS/MS approach for absolute quantification and determination of phosphodiester to phosphorothioate ratio in therapeutic oligonucleotides

A new analytical method based on ICP-MS/MS is proposed for the characterization of synthetic phosphorothioate oligonucleotides. Absolute quantification of oligonucleotides is challenging, as well as the determination of phosphodiester to phosphorothioate ratio for phosphorothioate oligonucleotides. Both are considered as critical quality attributes and should be determined using robust validated methods. The method we developed was designed to be easy to apply, fast, and robust. It allows simultaneous absolute quantification of an oligonucleotide (based on the quantification of phosphorus), determination of the phosphodiester to phosphorothioate ratio (based on the quantification of phosphorus and sulfur) and optionally determination of sodium (or any other metal) as a counter ion. The performance of the method was demonstrated on O,O-diethyl thiophosphate potassium salt, a well characterized model substance that possesses similar composition to phosphorothioate oligonucleotides. Method was also tested on different synthetic phophorothioate oligonucleotides, showing excellent accuracy and precision.

Review on investigations of antisense oligonucleotides with the use of mass spectrometry

Antisense oligonucleotides have been investigated as potential drugs for years. They inhibit target gene or protein expression. The present review summarizes their modifications, modes of action, and applications of liquid chromatography coupled with mass spectrometry for qualitative and quantitative analysis of these compounds. The most recent reports on a given topic were given prominence, while some early studies were reviewed in order to provide a theoretical background. The present review covers the issues of using ion-exchange chromatography, ion-pair reversed-phase high performance liquid chromatography and hydrophilic interaction chromatography for the separation of antisense oligonucleotides. The application of mass spectrometry was described with regard to the ionization type used for the determination of these potential therapeutics. Moreover, the current approaches and applications of mass spectrometry for quantitative analysis of antisense oligonucleotides and their metabolites as well as their impurities during in vitro and in vivo studies were discussed. Finally, certain conclusions and perspectives on the determination of therapeutic oligonucleotides in various samples were briefly described.