Purification of a synthetic oligonucleotide by anion exchange chromatography: method optimisation and scale-up.

A single-step chromatographic method for purification of a synthetic 20-mer oligonucleotide is described. Method optimisation was conducted at laboratory scale where 30 mg crude sample was purified per run with a yield of 17 mg pure oligonucleotide. The protocol was scaled-up in steps to achieve 5-, 58- and a final 230-fold scale-up. At the final scale, 7.0 g of crude material was purified with a yield of 4.1 g product. The purity of the oligonucleotide was in all scales higher than 97%. The cycle time was 110 min, which corresponds to a purification capacity of about 90 g crude oligonucleotide material per 24 h.