Amido-bridged nucleic acids with small hydrophobic residues enhance hepatic tropism of antisense oligonucleotides in vivo.

High scalability of a novel bicyclic nucleoside building block, amido-bridged nucleic acid (AmNA), to diversify pharmacokinetic properties of therapeutic antisense oligonucleotides is described. N2'-functionalization of AmNA with a variety of hydrophobic groups is straightforward. Combinations of these modules display similar antisense knockdown effects and improve cellular uptake, relative to sequence-matched conventional 2',4'-bridged nucleic acid (2',4'-BNA) in vivo.