Developments in the large-scale preparation of oligonucleotides in solution

GRAPHICAL ABSTRACT

ABSTRACT

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.

KEYWORDS:

• DNA oligonucleotides
• large-scale preparation in solution phase
• novel sulfurizing reagent

Acknowledgments

The authors appreciate the contribution to the process development provided by Dr. Yigang He, Dr. Victor Sorokin, and Dr. Angelina Georgieva, Girindus America Inc., Cincinnati, OH, USA.