Abstract: The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

Abstract: The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

Abstract: The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

Abstract: The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

Abstract: The present invention relates to lipid assemblies, compositions, and liposomal delivery systems comprising single chain anionic lipids, and the use thereof in diagnosis and therapy. It involves the use of anionic lysolipids for modifying the surface charge of a cationic lipid composition consisting at least one type of cationic lipid, optionally in combination with one or more neutral lipids and/or one or more anionic lipids.

Abstract: The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

Abstract: An amphoteric liposome composed of a mixture of lipids, said mixture comprising a cationic amphiphile, an anionic amphiphile and optionally one or more neutral amphiphiles, at least one of said cationic and anionic amphiphiles being chargeable and the respective amounts of said cationic and anionic amphiphiles being selected such there is a stoichiometric excess of positively charged cationic amphiphile at a first lower pH, a stoichiometric excess of negatively charged anionic amphiphile at a second higher pH and said mixture has an isoelectric point intermediate said first and second pHs; characterised in that said positively charged cationic and negatively charged anionic amphiphiles are adapted to form a lipid salt with one another at said isoelectric point. Also disclosed are methods of predicting the fusogenicity of an amphoteric liposome at a given pH, formulating an amphoteric liposome and loading an amphoteric liposome with a cargo moiety.

Abstract: An amphoteric liposome composed of a mixture of lipids, said mixture comprising a cationic amphiphile, an anionic amphiphile and optionally one or more neutral amphiphiles, at least one of said cationic and anionic amphiphiles being chargeable and the respective amounts of said cationic and anionic amphiphiles being selected such there is a stoichiometric excess of positively charged cationic amphiphile at a first lower pH, a stoichiometric excess of negatively charged anionic amphiphile at a second higher pH and said mixture has an isoelectric point intermediate said first and second pHs; characterised in that said positively charged cationic and negatively charged anionic amphiphiles are adapted to form a lipid salt with one another at said isoelectric point. Also disclosed are methods of predicting the fusogenicity of an amphoteric liposome at a given pH, formulating an amphoteric liposome and loading an amphoteric liposome with a cargo moiety.

Abstract: The present invention relates to lipid assemblies, compositions, and liposomal delivery systems comprising single chain anionic lipids, and the use thereof in diagnosis and therapy. It involves the use of anionic lysolipids for modifying the surface charge of a cationic lipid composition consisting at least one type of cationic lipid, optionally in combination with one or more neutral lipids and/or one or more anionic lipids.

Abstract: An amphoteric liposome comprising neutral lipids wherein said neutral lipids are selected from the group comprising cholesterol or mixtures of cholesterol and at least one neutral or zwitterionic lipid and wherein K (neutral) of said mixtures is 0.3 or less. Said amphoteric liposome may encapsulate an active agent, such as nucleic acid therapeutics. Also disclosed are pharmaceutical compositions comprising said amphoteric liposomes as a carrier for the delivery or targeted delivery of active agents or ingredients.

Abstract: The invention concerns lipid assemblies, liposomes having an outer surface comprising a mixture of anionic and cationic moieties; wherein at least a portion of the cationic moieties are imino moieties that are essentially charged under physiological conditions, and their use for serum resistant transfection of cells.

Abstract: Lipid assemblies, such as liposomes, comprising transfection enhancer elements (TEE's), which are complexed with the lipid assemblies by means of ionic interactions, or lipids incorporating such TEE's are disclosed for enhancing the fusogenicity of the lipid assemblies. The TEE's have the formula: hydrophobic moiety-pH sensitive hydrophilic moiety??(II) The pH sensitive hydrophilic moiety of each TEE is a weak acid having a pka of between 2 and 6 or a zwitterionic structure comprising a combination of acidic groups with weak bases having a pKa of between 3 and 8. Lipids incorporating one or more such TEEs have the formula (I): Lipid moiety-[Hydrophobic moiety-pH sensitive hydrophilic moiety]??(I).

Abstract: An amphoteric liposome composed of a mixture of lipids, said mixture comprising a cationic amphiphile, an anionic amphiphile and optionally one or more neutral amphiphiles, at least one of said cationic and anionic amphiphiles being chargeable and the respective amounts of said cationic and anionic amphiphiles being selected such there is a stoichiometric excess of positively charged cationic amphiphile at a first lower pH, a stoichiometric excess of negatively charged anionic amphiphile at a second higher pH and said mixture has an isoelectric point intermediate said first and second pHs; characterised in that said positively charged cationic and negatively charged anionic amphiphiles are adapted to form a lipid salt with one another at said isoelectric point. Also disclosed are methods of predicting the fusogenicity of an amphoteric liposome at a given pH, formulating an amphoteric liposome and loading an amphoteric liposome with a cargo moiety.

Abstract: An amphoteric liposome comprising neutral lipids wherein said neutral lipids are selected from the group comprising cholesterol or mixtures of cholesterol and at least one neutral or zwitterionic lipid and wherein K (neutral) of said mixtures is 0.3 or less. Said amphoteric liposome may encapsulate an active agent, such as nucleic acid therapeutics. Also disclosed are pharmaceutical compositions comprising said amphoteric liposomes as a carrier for the delivery or targeted delivery of active agents or ingredients.

Abstract: Lipid assemblies, such as liposomes, comprising transfection enhancer elements (TEE's), which are complexed with the lipid assemblies by means of ionic interactions, or lipids incorporating such TEE's are disclosed for enhancing the fusogenicity of the lipid assemblies. The TEE's have the formula: hydrophobic moiety-pH sensitive hydrophilic moiety??(II) The pH sensitive hydrophilic moiety of each TEE is a weak acid having a pka of between 2 and 6 or a zwitterionic structure comprising a combination of acidic groups with weak bases having a pKa of between 3 and 8.

Abstract: This disclosure describes structural elements that enhance fusogenicity of lipids and lipid assemblies (e.g. liposomes) with biological membranes, in particular cell membranes, and use of such structures. The elements are pH sensitive in terms of charge and hydrophilicity and undergo a polar—apolar transition when exposed to low pH.

Abstract: An amphoteric liposome composed of a mixture of lipids, said mixture comprising a cationic amphiphile, an anionic amphiphile and optionally one or more neutral amphiphiles, at least one of said cationic and anionic amphiphiles being chargeable and the respective amounts of said cationic and anionic amphiphiles being selected such there is a stoichiometric excess of positively charged cationic amphiphile at a first lower pH, a stoichiometric excess of negatively charged anionic amphiphile at a second higher pH and said mixture has an isoelectric point intermediate said first and second pHs; characterised in that said positively charged cationic and negatively charged anionic amphiphiles are adapted to form a lipid salt with one another at said isoelectric point. Also disclosed are methods of predicting the fusogenicity of an amphoteric liposome at a given pH, formulating an amphoteric liposome and loading an amphoteric liposome with a cargo moiety.