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 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 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.

Abstract: A method for selectively controlling the rate of release of a liposome-entrapped compound from an intramuscular or subcutaneous injection site. The method includes selecting the average size, amount, and lipid composition of liposomes injected into the site to produce a desired half-life of release of the compound. A preferred composition used in practicing the invention includes an aqueous suspension of liposomes containing the compound in entrapped form, and having average particle sizes less than about 0.2 microns, and large amount of larger empty lipsomes present in an amount effective to increase the half-life of release of the compound from the injection site to a desired half-life between about 1-14 days.

Abstract: A liposome composition which contains between 1-20 mole percent of an amphipathic lipid derivatized with a polyalkylether, as exemplified by phosphatidylethanolamine derivatized with polyethyleneglycol. The derivatized lipid enchances the circulation time of the liposomes severalfold, and this enhancement is achieved with either fluid or membrane-rigidifying liposome components. Also disclosed are methods for delivering a drug for slow release from the bloodstream, and for targeting a selected tissue or cells with liposomes, via the bloodstream.

Abstract: A method of selectively enhancing efficacy of gentamicin, when used in the treatment of Mycobacterium avium Complex (MAC), by intravenous administration of the drug in liposomal form. Gentamicin-liposomes are comparable to amikacinliposomes in activity against MAC infection in the bloodstream and substantially more effective against MAC infection residing in liver and spleen.

Abstract: A liposome composition designed for enhanced binding to mucosal tissue, The liposomes contain about 10-40 mole percent of an amine-derivatized lipid component in which a charged amine group is spaced from a lipid polar head region by a carbon-containing spacer arm at least 3 atoms in length. The liposomes preferably have a close packed lipid structure produced by inclusion of between 20-50 mole percent of cholesterol or an amine-derivatized cholesterol, and/or phospholipids with predominantly saturated acyl chain moieties. For ophthalmic use, the liposomes may be suspended in an aqueous medium containing a high-viscosity polymer, to enhance further the retention of liposomes on a corneal surface.