Abstract: Fully lipid-encapsulated therapeutic agent particles of a charged therapeutic agent are prepared by combining a lipid composition containing preformed lipid vesicles, a charged therapeutic agent, and a destabilizing agent to form a mixture of preformed vesicles and therapeutic agent in a destabilizing solvent. The destabilizing solvent is effective to destabilize the membrane of the preformed lipid vesicles without disrupting the vesicles. The resulting mixture is incubated for a period of time sufficient to allow the encapsulation of the therapeutic agent within the preformed lipid vesicles. The destabilizing agent is then removed to yield fully lipid-encapsulated therapeutic agent particles. The preformed lipid vesicles comprise a charged lipid which has a charge which is opposite to the charge of the charged therapeutic agent and a modified lipid having a steric barrier moiety for control of aggregation.

Abstract: Plasmid-lipid particles which are useful for transfection of cells in vitro or in vivo are described. The particles can be formed using either detergent dialysis methods or methods which utilize organic solvents. The particles are typically 65-85 nm, fully encapsulate the plasmid and are serum-stable.

Abstract: Plasmid-lipid particles which are useful for transfection of cells in vitro or in vivo are described. The particles can be formed using either detergent dialysis methods or methods which utilize organic solvents. The particles are typically 65-85 nm, fully encapsulate the plasmid and are serum-stable.

Abstract: The present invention relates to lipid-based formulations for nucleic acid delivery to cells, methods for the preparation of such formulations and, in particular, to lipid encapsulated plasmids. The compositions are safe and practical for clinical use. In addition, the present invention provides methods for introducing nucleic acids into cells and for inhibiting tumor growth in cells using such lipid-nucleic acid formulations.

Abstract: Plasmid-lipid particles which are useful for transfection of cells in vitro or in vivo are described. The particles can be formed using either detergent dialysis methods or methods which utilize organic solvents. The particles are typically 65-85 nm, fully encapsulate the plasmid and are serum-stable.

Abstract: Plasmid-lipid particles which are useful for transfection of cells in vitro or in vivo are described. The particles can be formed using either detergent dialysis methods or methods which utilize organic solvents. The particles are typically 65-85 nm, fully encapsulate the plasmid and are serum-stable.

Abstract: The present invention relates to new polyamide oligomers. These oligomers can be conjugated to lipids, nucleic acids, peptides, proteins, etc. The oligomer-lipid conjugates can be used to form liposomes, virusomes, micelles, etc., optionally containing drugs or biological agents. The polyamide oligomers are heterobifunctional allowing the attachment of other suitable ligand compounds (e.g., a targeting moiety). In addition, methods of use for the liposomes, virusomes, micelles, etc., are provided.

Abstract: Lipid-therapeutic agent particles are prepared containing a charged therapeutic agent encapsulated in lipid portion containing at least two lipid components including a protonatable or deprotonatable lipid such as an amino lipid and a lipid that prevents particle aggregation during lipid-therapeutic agent particle formation such as a PEG-modified or polyamide oligomer-modified lipid. Other lipid components may also be present and these include a neutral lipid such as DSPC, POPC, DOPE or SM, and a sterol such as Chol. The therapeutic agent is encapsulated by combining a mixture of the lipids with a buffered aqueous solution of a charged therapeutic agent to form an intermediate mixture containing lipid-encapsulated therapeutic agent particles, and changing the pH of the intermediate mixture to neutralize at least some surface charges on the particles. The method permits high ratios of therapeutic agent to lipid and encapsulation efficiencies in excess of 50%.

Abstract: This invention relates to a novel Solvent Extraction and Direct Hydration (SEDH) method for preparing lipid-nucleic acid particles which are useful for the introduction of nucleic acids (e.g., plasmid DNA, antisense molecules, ribozymes, etc.) into cells. The lipid-nucleic acid particles prepared using the methods of the present invention have enhanced circulation characteristics and serum stability and, thus, they are extremely effective as nucleic acid delivery vehicles.

Abstract: Plasmid-lipid particles which are useful for transfection of cells in vitro or in vivo are described. The particles can be formed using either detergent dialysis methods or methods which utilize organic solvents. The particles are typically 65-85 nm, fully encapsulate the plasmid and are serum-stable.

Abstract: Novel lipid-nucleic acid particulate complexes which are useful for in vitro or in vivo gene transfer are described. The particles can be formed using either detergent dialysis methods or methods which utilize organic solvents. Upon removal of a solubilizing component (i.e., detergent or an organic solvent) the lipid-nucleic acid complexes form particles wherein the nucleic acid is serum-stable and is protected from degradation. The particles thus formed have access to extravascular sites and target cell populations and are suitable for the therapeutic delivery of nucleic acids.

Abstract: Methods of forming cationic liposome/nucleic acid complexes in which the complexes have a mean diameter of about 200 to about 300 nm are provided. The complexes are formed by combining a first solution of preformed cationic unilamellar liposomes with a mean diameter of from 100 to 150 nm, with a second solution of nucleic acid. Each of the solutions are equilibrated prior to mixing to temperatures of from 0.degree. C. to about 12.degree. C., preferably about 2.degree. C. to about 7.degree. C. The preformed cationic liposomes are typically prepared from an unsaturated cationic lipid, for example DODAC, DOTAP, DOTMA, DODAP, DMRIE, DORI, DOSPA and combinations thereof, and a neutral lipid, for example DOPE or cholesterol. The combination of the first and second solutions is typically carried out by gentle mixing over ice for a period of time of from about 10 to about 60 minutes.

Abstract: The present invention provides compositions and methods which are useful for the introduction of polyanionic materials into cells. The compositions are mixtures of cationic compounds and neutral lipids which are typically formulated as liposomes. The cationic compounds are quaternary ammonium compounds wherein the nitrogen has two attached long chain alkyl groups, at least one of which is unsaturated. The methods for transfecting cells involve (a) contacting the polyanionic materials with the compositions above to form a polyanionic material-liposome complex, and (b) contacting the complex with the cells to be transfected.

Abstract: Microemulsion compositions for the delivery of hydrophobic compounds are provided. Such compositions have a variety of uses. In one embodiment, the hydrophobic compounds are therapeutic agents including drugs. The present invention also discloses methods for in vitro and in vivo delivery of hydrophobic compounds to cells. Uses of the methods in vitro include the testing of hydrophobic compounds for cytotoxicity. Uses of the methods in vivo include diagnostic and therapeutic purposes.