Title:  Biodegradable mixed polymeric micelles for gene delivery

United States Patent:  6,210,717

Assignee:  Samyang Corporation (Seoul, KR)

Filed:  December 11, 1998

A biodegradable, mixed polymeric micelle used to deliver a selected nucleic acid into a targeted host cell contains an amphiphilic polyester-polycation copolymer and an amphiphilic polyester-sugar copolymer. The polyester-polycation copolymer forms an electrostatic interaction with polyanionic nucleic acids, and the polyester-sugar copolymer directs the micelle-nucleic acid complex to cells in vivo. Additional copolymers with similar properties may also be included. The composition improves delivery efficiency by providing a particulate gene carrier for which particle size and charge density are easily controlled by multivariate means. Various kinds of ligands and other functional compounds may be also be introduced using the composition. The composition may be used in a method for transforming a targeted host cell with a selected nucleic acid.

BREF SUMMARY OF THE INVENTION

It is an object of the present invention to provide a composition and method for delivering nucleic acids into cells.

It is also an object of the invention to improve delivery efficiency by providing a particulate gene carrier wherein particle size and charge density are easily controlled by multivariate means.

It is another object of the invention to provide a composition and a method for gene delivery wherein the gene carrier is biodegradable and biocompatible.

These and other objects are addressed by providing a carrier for delivery of a selected nucleic acid into a host cell, the carrier comprising a mixture of an amphiphilic polyester-polycation copolymer and an amphiphilic polyester-sugar copolymer. In a preferred embodiment of the invention, the polyester-polycation copolymer comprises about 5 to 95% by weight of the carrier. The polyester-sugar copolymer also preferably comprises about 5 to 95% by weight of the carrier. The polyester polycation copolymer can be either a diblock copolymer comprising a hydrophobic polyester block bonded to a hydrophilic polycation block by an amide linkage or a graft copolymer comprising a hydrophobic polyester portion and a hydrophilic cation portion. The polyester is preferably a member selected from the group consisting of poly(L-lactic acid), poly(D-lactic acid), poly(D-,L-lactic acid), poly(glycolic acid), poly(L-lactic-co-glycolic acid), poly(D-lactic-co-glycolic acid), poly(.epsilon.-caprolactone), polybutyrolactone, and polypropiolactone. More preferably, the polyester is poly(L-lactic acid). In a preferred embodiment of the invention the polyester has a molecular weight of about 500 to 10,000. The polycation is preferably a member selected from the group consisting of poly(L-serine ester), poly(D-serine ester), poly(L-lysine), poly(D-lysine), polyornithine, and polyarginine, and more preferably is poly(L-serine ester). In a preferred embodiment of the invention the polycation has a molecular weight of about 500 to 10,000.

The polyester-sugar copolymer comprises a hydrophobic polyester segment and a hydrophilic sugar segment. The polyester segment is preferably a member selected from the group consisting of poly(L-lactic acid), poly(D-lactic acid), poly(D-,L-lactic acid), poly(glycolic acid), poly(L-lactic-co-glycolic acid), poly(D-lactic-co-glycolic acid), poly(.epsilon.-caprolactone), polybutyrolactone, and polypropiolactone, and more preferably is poly(L-lactic acid). In a preferred embodiment of the invention the polyester segment has a molecular weight of about 500 to 10,000. The sugar segment can comprise either a polysaccharide or a glycosylated polymer. Such a glycosylated polymer preferably comprises at least one sugar moiety selected from the group consisting of galactose, glucose, fucose, fructose, lactose, sucrose, mannose, cellobiose, nytrose, triose, dextrose, trehalose, maltose, galactosamine, glucosamine, galacturonic acid, glucuronic acid, gluconic acid, and lactobionic acid, and more preferably is lactobionic acid. The polymer moiety of the glycosylated polymer is preferably selected from the group consisting of poly(L-serine ester), poly(D-serine ester), poly(L-lysine), poly(D-lysine), polyornithine, and polyarginine and more preferably is poly(L-serine ester), and more preferably is poly(L-lysine).

The carrier can optionally further comprise a copolymer comprising (a) a hydrophobic portion, (b) a hydrophilic portion bonded to the hydrophobic portion, and (c) a functional moiety coupled to the hydrophilic portion, wherein the functional moiety is a member selected from the group consisting of ligands, fusogenic agents, lysosomotrophic agents, nucleus localizing signals, and mixtures thereof. Such a ligand is preferably selected from the group consisting of transferrin, epidermal growth factor, insulin, asialoorosomucoid, inannose-6-phosphate, mannose, LewisX, sialyl LewisX, N-acetyllactosamine, galactose, glucose, and thrombomodulin; the fusogenic agent is preferably selected from the group consisting of polymixin B and hemaglutinin H2; and the nucleus localization signal is preferably T-antigen.

A composition for delivery of a selected nucleic acid into a host cell comprises a mixed-polymeric-micelle/nucleic-acid complex in an aqueous medium, wherein the mixed-polymeric-micelle/nucleic-acid complex comprises (a) a mixture of an amphiphilic polyester-polycation copolymer and an amphiphilic polyester-sugar copolymer, and (b) an effective amount of the selected nucleic acid.

A method for delivering a selected nucleic acid into a host cell comprises administering an effective amount of a mixed-polymeric-micelle/nucleic-acid complex in an aqueous medium, wherein the mixed-polymeric-micelle/nucleic-acid complex comprises (a) a mixture of an amphiphilic polyester-polycation copolymer and an amphiphilic polyester-sugar copolymer comprising a sugar moiety, and (b) an effective amount of said selected nucleic acid, such that the complex contacts the host cell and the sugar moiety triggers receptor mediated endocytosis of the mixed-polymeric-micelle/nucleic-acid complex, thus delivering the nucleic acid into the host cell.

Claim 1 of 50 Claims

We claim:

1. A carrier for delivery of a nucleic acid into a host cell comprising a mixture of an amphiphilic polyester-polycation copolymer and an amphiphilic polyester-sugar copolymer.

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