What is described is a compound of formula I

##STR00001##

wherein R.sub.1 is a linear alkyl, alkenyl, or alkynyl of 2 to 12 carbons, or a branched alkyl with 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, or 7 carbons, R.sub.2 is a branched alkyl with 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, or 7 carbons, L.sub.1 and L.sub.2 are independently a linear alkylene with 1-18 carbons or alkenylene with 2-18 carbons, X is S or O, L.sub.3 is a bond or an alkylene with 1 to 6 carbons, R.sub.3 is an alkylene with 1 to 6 carbons, and R.sub.4 and R.sub.5 are the same or different, each a linear or branched alkyl with 1 to 6 carbons; or a pharmaceutically acceptable salt thereof.

What is described is a compound of formula I

##STR00001##

consisting of a compound in which R.sub.1 is a branched chain alkyl consisting of 10 to 31 carbons; R.sub.2 is a linear alkyl, alkenyl, or alkynyl consisting of 2 to 20 carbons; L.sub.1 and L.sub.2 are the same or different, each a linear alkylene of 1 to 20 carbons or a linear alkenylene of 2 to 20 carbons; X.sub.1 is S or O; R.sub.3 is a linear or branched alkylene consisting of 1 to 6 carbons; and R.sub.4 and R.sub.5 are the same or different, each a hydrogen or a linear or branched alkyl consisting of 1 to 6 carbons; or a pharmaceutically acceptable salt thereof.

What is described is a compound of formula I

##STR00001##

consisting of a compound in which R.sub.1 is a branched chain alkyl consisting of 10 to 31 carbons; R.sub.2 is a linear alkyl, alkenyl, or alkynyl consisting of 2 to 20 carbons; L.sub.1 and L.sub.2 are the same or different, each a linear alkylene of 1 to 20 carbons or a linear alkenylene of 2 to 20 carbons; X.sub.1 is S or O; R.sub.3 is a linear or branched alkylene consisting of 1 to 6 carbons; and R.sub.4 and R.sub.5 are the same or different, each a hydrogen or a linear or branched alkyl consisting of 1 to 6 carbons; or a pharmaceutically acceptable salt thereof.

What is described is a compound of formula I

##STR00001##

consisting of a compound in which R.sub.1 is a branched chain alkyl consisting of 10 to 31 carbons; R.sub.2 is a linear alkyl, alkenyl, or alkynyl consisting of 2 to 20 carbons, or a branched chain alkyl consisting of 10 to 31 carbons; L.sub.1 and L.sub.2 are the same or different, each a linear alkane of 1 to 20 carbons or a linear alkene of 2 to 20 carbons; X.sub.1 is S or O; R.sub.3 is a linear or branched alkylene consisting of 1 to 6 carbons; and R.sub.4 and R.sub.5 are the same or different, each a hydrogen or a linear or branched alkyl consisting of 1 to 6 carbons; or
a pharmaceutically acceptable salt thereof.

What is described is a compound of formula I

##STR00001##

consisting of a compound in which R.sub.1 is a branched chain alkyl consisting of 10 to 31 carbons; R.sub.2 is a linear alkyl, alkenyl, or alkynyl consisting of 2 to 20 carbons, or a branched chain alkyl consisting of 10 to 31 carbons; L.sub.1 and L.sub.2 are the same or different, each a linear alkane of 1 to 20 carbons or a linear alkene of 2 to 20 carbons; X.sub.1 is S or O; R.sub.3 is a linear or branched alkylene consisting of 1 to 6 carbons; and R.sub.4 and R.sub.5 are the same or different, each a hydrogen or a linear or branched alkyl consisting of 1 to 6 carbons; or
a pharmaceutically acceptable salt thereof.

Here described are compounds of formula I: ##STR00001##
wherein R.sub.1 and R.sub.2 are independently selected from C.sub.10 to C.sub.18 alkyl, C.sub.12 to C.sub.18 alkenyl, and oleoyl; R.sub.3 and R.sub.4 are independently selected from C.sub.1 to C.sub.6 alkyl and C.sub.2 to C.sub.6 alkanol; X is selected from CH.sub.2, S, and O, or X is absent; Y is selected from (CH.sub.2).sub.n, S(CH.sub.2).sub.n, O(CH.sub.2).sub.n, -thiophene-, SO.sub.2(CH.sub.2).sub.n, and ester; n=1-4; a=1-4; b=1-4; c=1-4; and Z.sup. is a counterion. Also described herein are compositions and pharmaceutical formulations including compounds of formula I which are useful for the delivery of therapeutic agents, and methods of using these compositions and formulations.

Here described are compounds of formula I: ##STR00001##
wherein R.sub.1 and R.sub.2 are independently selected from C.sub.10 to C.sub.18 alkyl, C.sub.12 to C.sub.18 alkenyl, and oleoyl; R.sub.3 and R.sub.4 are independently selected from C.sub.1 to C.sub.6 alkyl and C.sub.2 to C.sub.6 alkanol; X is selected from CH.sub.2, S, and O, or X is absent; Y is selected from (CH.sub.2).sub.n, S(CH.sub.2).sub.n, O(CH.sub.2).sub.n, -thiophene-, SO.sub.2(CH.sub.2).sub.n, and ester; n=1-4; a=1-4; b=1-4; c=1-4; and Z.sup. is a counterion. Also described herein are compositions and pharmaceutical formulations including compounds of formula I which are useful for the delivery of therapeutic agents, and methods of using these compositions and formulations.

What is described is a compound having the formula ##STR00001##
wherein R.sub.1 is branched alkyl of the structure (CH.sub.3(CH.sub.2).sub.m).sub.2CH, wherein m is 2 or 3; R.sub.2 is a linear alkyl of 1, 2, 3, 4, 5, 6, 7, 8, or 9 carbons, a branched alkyl of 3, 4, 5, 6, 7, 8, or 9 carbons, or an alkenyl or alkynyl of 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11 carbons; R.sub.3 is (CH.sub.2).sub.p, wherein p is 2, 3, 4, 5 or 6; R.sub.4 and R.sub.5 are the same or different, each a hydrogen, or a linear or branched alkyl of 1, 2, 3, 4, 5 or 6 carbons; L.sub.1 and L.sub.2 are the same or different, of the structure (CH.sub.2).sub.n, wherein n is 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18; L.sub.3 is a bond; X.sub.1 is COO whereby -L.sub.2-COOR.sub.2 is formed; X.sub.2 is S or O; and X.sub.3 is COO whereby -L.sub.1-COOR.sub.1 is formed; and
wherein m+n+p is 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, or 27;
or a pharmaceutically acceptable salt thereof.

The present disclosure describes compounds of Formula (I) and pharmaceutically acceptable salts thereof:

##STR00001##

The present disclosure describes compounds of Formula (I) and pharmaceutically acceptable salts thereof:

##STR00001##