METHODS FOR PREPARING POLYNUCLEOTIDES USING MULTIVALENT CATIONIC SALT COMPOSITIONS

Abstract

Aspects of the description include processes for the preparation of a polynucleotide. In some embodiments, the process includes contacting a first polynucleotide composition comprising: a polynucleotide having a sequence of 7 or more nucleoside subunits and at least two of the nucleoside subunits joined by an n3'→p5' thiophosphoramidate inter-subunit bond; and non-targeted synthetic products and reagents; with a multivalent cation salt to precipitate a polynucleotide salt comprising at least one multivalent cation counterion; and separating the polynucleotide salt from the first contacted polynucleotide composition to produce a second polynucleotide composition comprising the polynucleotide salt.In some embodiments, the process further comprises contacting the polynucleotide salt with a reversed-phase chromatography support and eluting a third polynucleotide composition comprising the polynucleotide from the chromatography support. The invention also relates to compositions comprising a polynucleotide salt including at least one multivalent cation counterion.