Patent ID: 6426086
Filing Date: 2002-07-30
Classification: A61K,Y10T

Abstract:
A pH-sensitive, serum-stable liposome loaded with an agent and having a lipid bilayer, complexed with a molecule comprising(a) a thermally-sensitive polymer showing lower critical solution temperature behavior in aqueous solutions, (b) a hydrophobic substituent of less than 10 kD covalently bound to said thermally-sensitive polymer, and (c) a pH sensitive substituent covalently bound to said thermally-sensitive polymer, which pH sensitive substituent remains ionizable following said covalent bonding to said thermally-sensitive polymer, and whose pH sensitivity does not depend on cleavage of the covalent bond to said thermally-sensitive polymer, wherein said liposome and said molecule are complexed by the insertion of said hydrophobic substituent into the lipid bilayer of the liposome, and further wherein the liposome, when complexed to said molecule and in an aqueous solution, releases at least 20% of the agent when the pH of the solution is changed from pH 7.4 to pH 3.5.