Purification of a highly modified RNA-aptamer - Effect of complete denaturation during chromatography on product recovery and specific activity

To evaluate RNA-aptamers as potential drug candidates, efficient and scalea ble purification protocols are needed. Because aptamers are highly structur ed and rigid molecules, denaturation during the purification process is a c ritical aspect to obtain a pure and active product. A two-step chromatograp hic procedure was developed to purify a synthetic anti-VEGF aptamer at the preparative scale. A reversed-phase chromatographic step was optimized with a highly hydrophobic ion pairing reagent, followed by ion-exchange chromat ography in which heat and a chaotropic salt were used. Because of the prese nce of 2'-modified ribose, denaturation conditions had to be optimized in b oth chromatographic steps to achieve a fully active molecule. (C) 1999 Else vier Science B.V. All rights reserved.