Liposomal compositions for enhanced retention of bioactive agents
AssigneesInex Pharmaceuticals Corporation, The University of British Columbia
InventorsMarcel B. Bally, Nancy L. Boman, Pieter R. Cullis, Lawrence D. Mayer
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Abstract
Liposomal compositions encapsulating bioactive agents and having improved circulation longevity of the agents are disclosed. Such liposomes combine a low pH of the solution in which a bioactive agent is entrapped and a sugar-modified lipid or an amine-bearing lipid, the combination of which enhances the retention of the encapsulated bioactive agent and thereby promotes circulation longevity. The present invention also discloses methods of making and using such compositions.
Claims10
A composition comprising liposomes having encapsulated therein both a bioactive agent and a buffered solution having a pH of 2 to 3, said liposomes containing a sugar-modified lipid which is a ganglioside and cerebroside in an amount of about 10 mol percent.
A composition comprising liposomes produced by
- (a) hydrating a lipid film in a buffered first solution having a pH of 2 to 3 to yield liposomes, said lipid film containing a sugar-modified lipid which is a ganglioside and cerebroside in an amount of about 10 mol percent;
- (b) contacting said liposomes with a second solution, said second solution containing a bioactive agent to provide a liposomal bioactive agent mixture;
- (c) increasing the pH of said mixture in step (b) to a pH not above the pK.sub.a of the bioactive agent to provide a liposomal mixture having a pH differential;
- and
- (d) incubating said mixture having a pH differential under conditions and for a time sufficient to promote entrapping of said bioactive agent by said liposomes, thereby producing liposomes that encapsulate a bioactive agent and that contain a sugar-modified lipid ganglioside and cerebroside in an amount of about 10 mol percent.
Dependencies are inferred from the claim text.