Abstract: A liposome composition for localizing an anti-tumor compound to a solid tumor via the bloodstream. The liposomes, which contain the agent in entrapped form, are composed of vesicle-forming lipids and between 1-20 mole percent of a vesicle-forming lipid derivatized with hydrophilic biocompatible polymer, and have sizes in a selected size range between 0.07 and 0.12 microns. After intravenous administration, the liposomes are taken up by the tumor within 24-48 hours, for site-specific release of entrapped compound into the tumor. In one composition for use in treating a solid tumor, the compound is an anthracycline antibiotic drug which is entrapped in the liposomes at a concentration of greater than about 50 &mgr;g agent/&mgr;mole liposome lipid. The method results in regression of solid colon and breast carcinomas which are refractory to anthracycline antibiotic drugs administered in free form or entrapped in conventional liposomes.

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 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: 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: 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 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: 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 treating a subject having a disorder characterized by a neoplasm of B-lymphocyte or T-lymphocyte lineage cells is described. The method includes administering a suspension of liposomes having a surface coating of polyethylene glycol chains. Attached to the distal ends of the chains are antibodies or antibody fragments effective to bind to an antigen specific to the affected cells. In one embodiment, anti-CD19 antibodies are attached to the liposome-bound chains, for treatment of multiple myeloma.

Abstract: A composition of polymer-coated particles, and a polymer compound used in forming the particles are disclosed. The polymer compound is composed of a hydrophilic polymer attached to a lipophilic moiety through a linking segment which contains chemical groups through which the compound can be crosslinked to other such compounds. The particles in the composition are prepared by forming lipid structures containing ordered arrays of the polymer compounds, and crosslinking the compounds through their chemical groups. The particles are used for parenteral administration of a pharmaceutical compound which is entrapped in the particles.

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.

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 and composition for concentrating a therapeutic agent in an inflamed dermal region are disclosed. The composition, which is also used in the method, is a liposomal composition. The liposomes contain the therapeutic agent in entrapped form and are composed of vesicle-forming lipids including a vesicle-forming lipid derivatized with hydrophilic biocompatible polymer. After intravenous administration, the liposomes are taken up by the inflamed region within 24-48 hours, for site-specific release of entrapped compound into the inflamed region.

Abstract: A liposome composition for extended release of a therapeutic compound into the bloodstream. The liposomes are composed of vesicle-forming lipids and between 1-20 mole percent of a vesicle-forming lipid derivatized with hydrophilic polymer, have sizes in a selected size range between 0.1 and 0.4 microns, and contain the therapeutic compound in liposome-entrapped form. The dosage form of the composition contains at least about three times the dose of the compound required for intravenous injection in free form. Also disclosed in a method for extending to at least 24 hours the period in which an intravenously administered therapeutic compound is therapeutically active in the bloodstream, and novel liposomes compositions for practicing the method.

Abstract: A liposome composition for localizing an anti-tumor compound to a solid tumor via the bloodstream. The liposomes, which contain the agent in entrapped form, are composed of vesicle-forming lipids and between 1-20 mole percent of a vesicle-forming lipid derivatized with hydrophilic biocompatible polymer, and have sizes in a selected size range between 0.07 and 0.12 microns. After intravenous administration, the liposomes are taken up by the tumor within 24-48 hours, for site-specific release of entrapped compound into the tumor. In one composition for use in treating a solid tumor, the compound is an anthracycline antibiotic drug which is entrapped in the liposomes at a concentration of greater than about 50 .mu.g agent/.mu.mole liposome lipid. The method results in regression of solid colon and breast carcinomas which are refractory to anthracycline antibiotic drugs administered in free form or entrapped in conventional liposomes.