Developments in the large-scale preparation of oligonucleotides in solution

Despite all the advantages of solid-phase oligonucleotide manufacturing, there are significant drawbacks, such as manufacturing capacity and capital investment. The synthesis of oligonucleotides in solution has been proposed as a potential remedy for the economical and scale-up shortcomings of solid-phase manufacturing. We developed a new oligomerization methodology for manufacturing DNA oligos in solution, which alleviates the limitations inherent in the synthesis on solid supports. Since the majority of potential therapeutic DNA oligonucleotides have a thiophosphate moiety, we have created a novel highly efficient sulfurizing reagent for the formation of the P-S bond during elongation of the oligonucleotide. The new protocols for the synthesis and purification of DNA phosphorothioates oligomers have a significant potential for the economical production of oligonucleotides in solution. The method allows the preparation of high-purity oligonucleotides avoiding expensive chromatography during the early stages of oligomerization. The efficient synthesis, consisting of preparing dimer and tetramer building blocks, represents a critical economic advance for large-scale manufacture of up to 16-mer oligonucleotides. [GRAPHICS] .