Patent ID: 8137695

Claim:
A conjugate delivery system for delivering an RNA interference polynucleotide to a liver cell in vivo comprising: wherein, P is a membrane active polyamine, L 2 is a disubstituted maleamate linkage, M 1 is a masking agent containing a galactose derivative, M 2 is a masking agent containing a polyethyleneglycol, N is an RNA interference polynucleotide, L 1 is a physiologically labile covalent linkage that is orthogonal to L 2 , y and z are integers greater than 1 wherein the value of y and z together is greater than 50% on amines of P, positive charge of P is neutralized and membrane activity of P is reversibly inhibited by modification of greater than 50% of P amines by attachment of M 1 and M 2 through the physiologically pH-labile linkages L 2 , and cleavage of L 2 restores membrane activity of P.