Abstract: New emulsion and micelle formulations are described as are complexes of these formulations with biologically active substances. The novel formulations are different from cationic lipid vectors such as cationic liposomes in that the complexes formed between biologically active substances and the emulsion and micellar formulations of this invention are physically stable and their transfection activity is resistant to the presence of serum. These novel formulations are disclosed to be useful in areas such as gene therapy or vaccine delivery.

Abstract: Novel stable, concentrated, biologically active and ready-to-use lipid-comprising drug delivery complexes and methods for their production are described. The biological activity of the complexes produced are comparable to the formulations prepared according to the prior art admixture method and upon purification, the complexes produced by the method of this invention are 50 to 500 fold more concentrated than the complexes formed by admixture. The method described herein provides for the large scale production of lipid-comprising drug delivery systems useful for gene therapy and other applications.

Abstract: A simple, rapid method for creating a lipidic vector for delivery of a therapeutic molecule entails bringing the molecule into contact with a polycation, thereby forming a complex, and then mixing the complex with an anionic lipidic preparation. Tissue-specific targeting peptides, fusogenic peptides and nucleus-targeting peptides also can be added to the lipid preparation. The result is a stable lipidic vector of reduced immunogenicity and cytotoxicity. The vector also displays enhanced transfection activity.

Abstract: Novel stable, concentrated, biologically active and ready-to-use lipid-comprising drug delivery complexes and methods for their production are described. The biological activity of the complexes produced are comparable to the formulations prepared according to the prior art admixture method and upon purification, the complexes produced by the method of this invention are 50 to 500 fold more concentrated than the components of the complexes formed by admixture. The method described herein provides for the large scale production of lipid-comprising drug delivery systems useful for gene therapy and other applications.

Abstract: Liposome carrier systems, methods and pharmaceutical compositions that target an organ preferentially with high concentrations of at least one therapeutic agent utilize a liposome carrier having a lipid membrane and an aqueous space to deliver pharmacologically active agents, such as free radical scavengers and antioxidants, to a target organ such as the liver. At least one free radical scavenger and/or antioxidant and a liposome carrier may be provided to a liver donor prior to harvesting to preserve the liver for transplantation.

Abstract: Liposomes containing phosphatidylethanolamine, palmitoyl homocysteine or oleic acid or palmitic acid, fuse rapidly when the pH of the medium is reduced below 7. Liposome fusion was measured by (a) mixing of the liposomal lipids as shown by resonance energy transfer, (b) gel filtration and (c) electron microscopy. The presence of phosphatidylethanolamine or acid addition esters thereof in the liposomes greatly enhances fusion; whereas the presence of phosphatidylcholine inhibits fusion. During fusion of liposomes containing phosphatidylethanolamine:palmitoyl homocysteine (8:2), almost all of the encapsulated calcein is released. Inclusion of cholesterol (40%) in the liposomes substantially decreases leakage without impairing fusion. Those pH sensitive liposomes are fused to deliver biologically active molecules such as DNA, into living cells.

Abstract: A method for facilitating the transfer of nucleic acids into cells comprising preparing a mixed lipid dispersion of a cationic lipid with a co-lipid in a suitable carrier solvent. The lipid has a structure which includes a lipophilic group derived from cholesterol, a linker bond, a spacer arm including from about 1 to about 20 carbon atoms in a branched or unbranched linear alkyl chain, and a cationic amino group selected from the group consisting of primary, secondary, tertiary and quaternary amino groups. The method further comprises adding the nucleic acids to the dispersion to form a complex. The cells are then treated with the complex. There is also disclosed a novel cationic amphiphile useful for this purpose.

Abstract: Small unilamellar liposomes (d<600 nm) comprising an unsaturated phosphatidylethanolamine (PE) such as dioleoyl PE (DOPE) and a fatty acid such as oleic acid (OA) are stabilized by adding to a freshly prepared liposome suspension, an amphipile which has a high tendency to form micelles. Examples are shown for the following micelle-forming amphiphiles: lysophospholipide, gangliosides (GM.sub.1 and GTlb), sulfatide, synthetic glycopholipids such as sialo-lactosyl phosphatidylethanolamine, liopohilic drugs such as cytosine arabinoside diphosphate diacyglycerol, and proteins such as cytochrome b.sub.5, human high density lipoprotein (HDL), and human glycophorin A. The stabilized liposomes are resistant to the lytic action of albumin, the major blood component which causes the lysis of this type of liposome. Prior to the present invention, liposomes comprising PE and OA were typically stabilized by the incorporation of cholesterol.

Abstract: Novel target-sensitive immunoliposomes were prepared and characterized. In this invention, target specific binding of antibody-coated liposomes was sufficient to induce bilayer destabilization, resulting in a site-specific release of liposome contents.Unilamellar liposomes were prepared by using a small quantity of palmitoyl IgG (pIgG) to stabilize the bilayer phase of the unsaturated phosphatidylethanol amine (PE) which by itself does not form stable liposomes. A mouse monoclonal IgG antibody to the glycoprotein D (gD) of Herpes Simplex Virus (HSV) and dioleoyl PE were used in one preferred embodiment.In another preferred embodiment, potentially cytotoxic antiviral drugs were entrapped in target sensitive (TS) immunoliposomes and delivered to HSV infected cells. Potency was as much as 1000 times superior to the free drug and cytotoxicity was decreased by as much as 3000 fold.

Abstract: The A fragment of the diphtheria toxin (DTA) was encapsulated in pH-sensitive liposomes. This novel reagent is extremely cytotoxic to cells expressing surface antigen which is recognized by the immunoliposome. The reagent is not toxic to cells which do not express the antigen. Thus, this reagent, or others similarly prepared represent potential anticancer reagents.

Abstract: Preferred solid core liposomes were prepared through four major steps:(1) Preparation of prevesicles with encapsulated solid cores of agarose-gelatin by emulsification of agarose-gelatin sol in organic solvent containing emulsifiers followed by cooling;(2) Extraction of lipophilic components from prevesicles to obtain microspherules of agarose-gelatin;(3) In an optional step, colloidal gold particles were introduced into the microspherules, which were then coated with a protein or peptide molecule layer;(4) Encapsulation of the microspherules was conducted using a modified organic solvent spherule evaporation method for the formation of the liposomes.Electron micrographs indicate that if liposomes were prepared by using a lipid mixture containing dioleoyl phosphatidyl choline, cholesterol, dioleoylphosphatidylglycerol, and triolein (molar ratio 4.5:4.5:1:1), there was only a single continuous bilayer membrane for each solid core liposome.

Abstract: Liposomes containing phosphatidylethanolamine, palmitoyl homocysteine or oleic acid or palmitic acid, fuse rapidly when the pH of the medium is reduced below 7. Liposome fusion was measured by (a) mixing of the liposomal lipids as shown by resonance energy transfer, (b) gel filtration and (c) electron microscopy. The presence of phosphatidylethanolamine or acid addition esters thereof in the liposomes greatly enhances fusion; whereas the presence of phosphatidylcholine inhibits fusion. During fusion of liposomes containing phosphatidylethanolamine:palmitoyl homocysteine (8:2), almost all of the encapsulate calcein is released. Inclusion of cholesterol (40%) in the liposomes substantially decreases leakage without impairing fusion. Those pH sensitive liposomes are fused to deliver biologically active molecules such as DNA, into living cells.

Abstract: This invention is directed to a new membrane lytic immunoassay. In one embodiment of this assay, an antigen is first covalently coupled with lipids and this antigen-lipid complex is mixed with a hexagonal phase forming lipid to form bilayer liposome vesicles additionally containing a self-quenching fluorescent dye. When this antigen-containing liposome is brought into contact with a solid surface coated with antibody molecules, binding occurs between the antigen and the antibody, disrupting the liposome and releasing the dye. To assay a biological fluid for free antigen the fluid is first contacted with the solid surface-antibody complex, to saturate the bound antibody. Binding by the liposomes is thereby inhibited, leading to reduced dye release. Comparing dye release against a standardized curve of dye release versus known antigen concentrations allows for rapid determination of the unknown antigen concentration in the biological fluid. Similarly, antibodies and other entities, e.g., enzymes, drugs, etc.