The present invention provides compositions and methods for the delivery of therapeutic agents to cells. In particular, these include novel, trialkyl, cationic lipids and nucleic acid-lipid particles that provide efficient encapsulation of nucleic acids and efficient delivery of the encapsulated nucleic acid to cells in vivo. The compositions of the present invention are highly potent, thereby allowing effective knock-down of a specific target protein at relatively low doses.

The present invention provides compositions and methods for the delivery of therapeutic agents to cells. In particular, these include novel, trialkyl, cationic lipids and nucleic acid-lipid particles that provide efficient encapsulation of nucleic acids and efficient delivery of the encapsulated nucleic acid to cells in vivo. The compositions of the present invention are highly potent, thereby allowing effective knock-down of a specific target protein at relatively low doses.

The present application discloses a polyhydroxy aromatic intermediate, preparation thereof and use thereof in a polycondensate water-reducer with branched side chains. The polycondensate water-reducer with branched side chains has a branched side chain structure which provides a stronger steric hindrance. The synergistic effect of the branched side chains and the rigid skeleton of the aromatic ring greatly improves the water-reducing ability. Especially under a condition of low water/cement ratio, the improvement in water-reducing ability is more obvious. The branched polyether side chain is more conducive to the formation of a thicker water film layer, which has an obvious viscosity reduction effect. The conformation of the branched polyether side chain is less affected by different ionic environments in the pore solution in cement, and thus has a stronger adaptability to various raw materials. The water-reducer is suitable for the preparation of high-strength concrete, self-compacting concrete and concrete with low water-to-binder ratio and high volume of mineral admixtures, especially for the preparation of concrete containing machine-made sand.

The present invention provides a cationic lipid, which allow nucleic acids to be easily introduced into cells, represented by formula (I) (wherein: R.sup.1 and R.sup.2 are, the same or different, alkenyl, etc, and X.sup.1 and X.sup.3 are hydrogen atoms, or are combined together to form a single bond or alkylene, and X.sup.3 is absent or is alkyl, etc, Y is absent or anion, a and b are, the same or different, 0 to 3, and L.sup.3 is a single bond, etc, R.sup.3 is alkyl, etc, L.sup.1 and L.sup.2 are —O—, —CO—O— or —O—CO—), a composition comprising the cationic lipid and a nucleic acid, and a method for introducing a nucleic acid into a cell by using the composition comprising the cationic lipid and the nucleic acid, and the like. ##STR00001##

The present invention provides a cationic lipid, which allow nucleic acids to be easily introduced into cells, represented by formula (I) (wherein: R.sup.1 and R.sup.2 are, the same or different, alkenyl, etc, and X.sup.1 and X.sup.3 are hydrogen atoms, or are combined together to form a single bond or alkylene, and X.sup.3 is absent or is alkyl, etc, Y is absent or anion, a and b are, the same or different, 0 to 3, and L.sup.3 is a single bond, etc, R.sup.3 is alkyl, etc, L.sup.1 and L.sup.2 are —O—, —CO—O— or —O—CO—), a composition comprising the cationic lipid and a nucleic acid, and a method for introducing a nucleic acid into a cell by using the composition comprising the cationic lipid and the nucleic acid, and the like. ##STR00001##

The present invention relates to a cationic lipid having one or more biodegradable groups located in a lipidic moiety (e.g., a hydrophobic chain) of the cationic lipid. These cationic lipids may be incorporated into a lipid particle for delivering an active agent, such as a nucleic acid. The invention also relates to lipid particles comprising a neutral lipid, a lipid capable of reducing aggregation, a cationic lipid of the present invention, and optionally, a sterol. The lipid particle may further include a therapeutic agent such as a nucleic acid.

The present invention relates to a cationic lipid having one or more biodegradable groups located in a lipidic moiety (e.g., a hydrophobic chain) of the cationic lipid. These cationic lipids may be incorporated into a lipid particle for delivering an active agent, such as a nucleic acid. The invention also relates to lipid particles comprising a neutral lipid, a lipid capable of reducing aggregation, a cationic lipid of the present invention, and optionally, a sterol. The lipid particle may further include a therapeutic agent such as a nucleic acid.

The present invention provides a cationic lipid, which allow nucleic acids to be easily introduced into cells, represented by formula (I) (wherein: R.sup.1 and R.sup.2 are, the same or different, alkenyl, etc, and X.sup.1 and X.sup.2 are hydrogen atoms, or are combined together to form a single bond or alkylene, and X.sup.3 is absent or is alkyl, etc, Y is absent or anion, a and b are, the same or different, 0 to 3, and L.sup.3 is a single bond, etc, R.sup.3 is alkyl, etc, L.sup.1 and L.sup.2 are —O—, —CO—O— or —O—CO—), a composition comprising the cationic lipid and a nucleic acid, and a method for introducing a nucleic acid into a cell by using the composition comprising the cationic lipid and the nucleic acid, and the like.

##STR00001##

The present invention provides a cationic lipid, which allow nucleic acids to be easily introduced into cells, represented by formula (I) (wherein: R.sup.1 and R.sup.2 are, the same or different, alkenyl, etc, and X.sup.1 and X.sup.2 are hydrogen atoms, or are combined together to form a single bond or alkylene, and X.sup.3 is absent or is alkyl, etc, Y is absent or anion, a and b are, the same or different, 0 to 3, and L.sup.3 is a single bond, etc, R.sup.3 is alkyl, etc, L.sup.1 and L.sup.2 are —O—, —CO—O— or —O—CO—), a composition comprising the cationic lipid and a nucleic acid, and a method for introducing a nucleic acid into a cell by using the composition comprising the cationic lipid and the nucleic acid, and the like.

##STR00001##

An ammonium salt having a saccharin anion, which is represented by formula (1), exhibits excellent thermal stability even though no halogen atom is contained therein. ##STR00001##
(In the formula, each of R.sup.1-R.sup.4 independently represents an alkyl group having 1-4 carbon atoms or an alkoxyalkyl group that is represented by —(CH.sub.2).sub.n—OR (wherein R represents an alkyl group having 1-4 carbon atoms, and n represents an integer of 1 or 2). Incidentally, any two of the R.sup.1-R.sup.4 may combine with each other to form a ring together with a nitrogen atom.