Purification of DMT-On Oligonucleotide by Simulated Moving-Bed (SMB) Chromatography

Recent clinical advances in the development of oligonucleotides as therapeutics have triggered a significant demand for these molecules in large quantities. To facilitate their development, purification of full-length oligonucleotide from various synthesis related byproducts is an important endeavour. Herein, we report for the first time an application of simulated moving-bed (SMB) chromatography as a purification tool for DMT-protected oligonucleotides. An efficient separation has been accomplished with polystyrene/divinyl benzene copolymer as the stationary phase and 0.05 M NH₄HCO₃ buffer (pH 8)/MeOH (6:4, v/v) as the mobile phase. A DMT-protected product purity of >99% with 77% yield for a 20-mer phosphorothioate oligonucleotide is reported.