Abstract: Reagents for use in preparing a therapeutic liposome composition sensitized to a target cell are described. The reagents include a liposomal composition composed of pre-formed liposomes having an entrapped therapeutic agent and a plurality of targeting conjugates composed of a lipid, a hydrophilic polymer and a targeting ligand. The therapeutic, target-cell sensitized liposome composition is formed by incubating the liposomal composition with a selected conjugate.

Abstract: Reagents for use in preparing a therapeutic liposome composition sensitized to a target cell are described. The reagents include a liposomal composition composed of pre-formed liposomes having an entrapped therapeutic agent and a plurality of targeting conjugates composed of a lipid, a hydrophilic polymer and a targeting ligand. The therapeutic, target-cell sensitized liposome composition is formed by incubating the liposomal composition with a selected conjugate.

Abstract: A liposome composition comprising small, surface-bound effector molecules is disclosed. The liposomes have a surface layer of hydrophilic polymer chains, for enhanced circulation time in the bloodstream. The effector molecules are attached to the distal ends of the polymer chains. In one embodiment, the effector is polymyxin B, for treatment of septic shock.

Abstract: Reagents for use in preparing a therapeutic liposome composition sensitized to a target cell are described. The reagents include a liposomal composition composed of pre-formed liposomes having an entrapped therapeutic agent and a plurality of targeting conjugates composed of a lipid, a hydrophilic polymer and a targeting ligand. The therapeutic, target-cell sensitized liposome composition is formed by incubating the liposomal composition with a selected conjugate.

Abstract: A fusogenic liposome composition for delivering a liposome-entrapped compound into the cytoplasm of a target cell is described. The liposomes have an outer surface coating of chemically releasable hydrophilic polymer chains which shield hydrophobic polymers on the liposome outer surface. Release of the hydrophilic polymer chains exposes the hydrophobic polymers for interaction with outer cell membranes of the target cells to promote fusion of the liposome with the target cells. Also disclosed is a polymer-lipid conjugate for use in promoting fusion between target membranes. The conjugate is composed of a first segment composed of a hydrophilic polymer and a second hydrophobic polymer segment. The second segment is joined to the first segment by a bond effective to release the first segment in response to an existing or an induced physiologic condition. Attached to the second segment is a vesicle-forming lipid member.

Abstract: A liposome composition comprising small, surface-bound effector molecules is disclosed. The liposomes have a surface layer of hydrophilic polymer chains, for enhanced circulation time in the bloodstream. The effector molecules are attached to the distal ends of the polymer chains. In one embodiment, the effector is polymyxin B, for treatment of septic shock.

Abstract: A plasmid-liposome composition for transfection of a cell is described. The composition includes plasmid molecules condensed with a polycationic condensing agent and cationic liposomes. Also disclosed is a method for preparing the plasmid-liposome complexes.

Abstract: A liposome composition containing an entrapped cisplatin compound is described. The liposomes have a surface coating of hydrophilic polymer chains on inner and outer surfaces and an entrapped cisplatin compound. The compound is entrapped with substantially greater retention in the liposomes, when compared to liposomes lacking the polymer coating. A method of preparing the composition is also described.

Abstract: Reagents for use in preparing a therapeutic liposome composition sensitized to a target cell are described. The reagents include a liposomal composition composed of pre-formed liposomes having an entrapped therapeutic agent and a plurality of targeting conjugates composed of a lipid, a hydrophilic polymer and a targeting ligand. The therapeutic, target-cell sensitized liposome composition is formed by incubating the liposomal composition with a selected conjugate.

Abstract: A method of liposome-based therapy for a mammalian subject is disclosed. The method uses liposomes with outer surfaces that contain an affinity moiety effective to bind specifically to a biological surface at which the therapy is aimed, and a hydrophilic polymer coating effective to shield the affinity moiety from interaction with the target surface. The hydrophilic polymer coating is made up of polymer chains covalently linked to surface lipid components in the liposomes through releasable linkages. After a desired liposome biodistribution is achieved, a releasing agent is administered to cause cleaving of a substantial portion of the releasable linkages in the liposomes, to expose the affinity agent to the target surface.

Abstract: A liposome composition for treating a bacterial infection is described. The composition includes liposomes having a surface coating of hydrophilic polymer chains and an entrapped drug-conjugate composed of ciprofloxacin conjugated to an amino acid.

Abstract: A liposome composition containing an entrapped cisplatin compound is described. The liposomes have a surface coating of hydrophilic polymer chains on inner and outer surfaces and an entrapped cisplatin compound. The compound is entrapped with substantially greater retention in the liposomes, when compared to liposomes lacking the polymer coating. A method of preparing the composition is also described.

Abstract: A fusogenic liposome composition for delivering a liposome-entrapped compound into the cytoplasm of a target cell is described. The liposomes have an outer surface coating of chemically releasable hydrophilic polymer chains which shield hydrophobic polymers on the liposome outer surface. Release of the hydrophilic polymer chains exposes the hydrophobic polymers for interaction with outer cell membranes of the target cells to promote fusion of the liposome with the target cells. Also disclosed is a method for using the composition to deliver a compound to target cells, and a method for selecting suitable hydrophobic polymers for use in the composition.

Abstract: An improvement in a method of preparing plasmid-liposome complexes for in vivo transfection is described. The improvement includes selecting a condensing agent to condense the plasmid prior to contact with the liposomes, selecting a working medium and selecting a ratio of liposome lipid to plasmid. Also disclosed are DNA plasmid-liposome complexes formed by the method.

Abstract: A method of treating a site of systemic infection which includes administering a therapeutic compound entrapped in liposomes. Also included is a liposomal composition and a method of preparing a liposomal composition for use in concentrating a therapeutic compound to an infected region via the bloodstream. The liposomes, which contain the agent in entrapped form, are composed of vesicle-forming lipids, a vesicle-forming lipid derivatized with hydrophilic biocompatible polymer, and have sizes in a selected size range between 0.07 and 0.2 microns. After parenteral administration, the liposomes are selectively taken up by the infected region within 24-48 hours, for release of entrapped compound into the infected region.

Abstract: A lipid-polymer conjugate for use in forming long-circulating liposomes is disclosed. The conjugate includes a vesicle-forming lipid having covalently attached to its polar head group, one of the polymers: polyvinylpyrrolidone, polyvinylmethylether, polyhydroxypropyl methacrylate, polyhydroxypropylmethacrylamide, polyhydroxyethyl acrylate, polymethacrylamide, polydimethylacrylamide, polymethyloxazoline, polyethyloxazoline, polyhydroxyethyloxazoline, polyhydroxypropyloxazoline, or polyaspartamide. A method for preparing liposomes containing the lipid-polymer conjugate is also disclosed.

Abstract: A method of administering an anti-tumor compound to a subject is disclosed. The method includes administering to a subject liposomes having sizes predominantly in the range 0.05 to 0.12 microns, and containing an anti-tumor compound in liposome-entrapped form, a surface coating of polyethylene glycol chains, at a surface concentration thereof sufficient to extend the blood circulation time of the liposomes severalfold over that of liposomes in the absence of such coating, and surface-attached antibody molecules effective to bind specifically to tumor-associated antigens present at the tumor site. One liposome composition includes doxorubicin in entrapped form, and, on the liposome surface, a monoclonal antibody against highly proliferating cells in a lung squamous cell carcinoma.