A compound of formula I: wherein: R 1 is a lipid; R 2 is selected from -H or a lipid; R 3 is selected from -OH, substituted or unsubstituted -C 1 -C 20 alkyl, substituted or unsubstituted -C 2 -C 20 alkenyl, substituted or unsubstituted -C 1 -C 4 alkylaryl and carbohydrate selected from -(NHCH 2 CH 2) x -Glc, -(NHCH 2 CH 2) x -Gal, -(NHCH 2 CH 2) x -Man, - (NHCH 2 CH 2) x- GlcNAc, -(NHCH 2 CH 2) x -MurNAc, -(NHCH 2 CH 2) x -ManNAc, -(NHCH 2 CH 2) x -GaINAc, -(NHCH 2 CH 2) x -cellbiose and -(NHCH 2 CH 2) x -maltose, where x is 0 or 1; R 4 is selected from -H, substituted or unsubstituted -C 1 -C 20 alkyl, substituted or unsubstituted -C 2 -C 20 alkenyl, substituted or unsubstituted -C 1 -C 4 alkylaryl and carbohydrate selected from -(NHCH 2 CH 2) y -Glc, -(NHCH 2 CH 2) y -Gal, -(NHCH 2 CH 2) y -Man, - (NHCH 2 CH 2) y -GlcNAc, -(NHCH 2 CH 2) y -MurNAc, -(NHCH 2 CH 2) y -ManNac, -(NHCH 2 CH 2) y -GaINAc, -(NHCH 2 CH 2) y -cellbiose and -(NHCH 2 CH 2) y -maltose, where y is 0 or 1; and L 1 is a linker selected from -C 1 -C 20 alkylene-, -C 2 -C 20 alkenylene-, -(C 1 -C 4 alkyl)arylene-, -C 2 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, -C 2 -C 12 alkyl-S-S-C 1 -C 12 alkyl-, -C C 1 -C 20 alkylene-, - C C 2 -C 20 alkenylene-, -C (C 1 -C 4 alkyl)arylene-, -C C 1 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, - C NHC 1 -C 20 alkylene-, -C NHC 2 -C 20 alkenylene-, --C NH(C 1 -C 4 alkyl)arylene-, - C NHC 1 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, -C NHC 1 -C 20 alkylene-, -C NHC 2 -C 20 alkenylene-, -C NH(C 1 -C 4 alkyl)arylene- and -C NHC 1 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, where r is selected from 2 and 3 and s is selected from 0 to 20, or a pharmaceutically acceptable salt, stereoisomer, or solvate thereof, wherein each lipid is a hydrophobic moiety comprising substituted or unsubstituted alkyl, alkenyl, cycloalkyl, bridged cycloalkyl, (alkyl)cycloalkyl, (alkyl) bridged cycloalkyl, (alkyl)cycloalkenyl, and/or alkylaryl groups, wherein, when substituted, any of the above groups are substituted by one or more substituents selected from: -OH, -CN, -NH 2, -NH(C 1 -C 6 alkyl), -N(C 1 -C 4 alkyl) 2, =O, -halo, - C 1 -C 6 alkyl, -C 2 -C 6 alkenyl, -C 1 -C 6 haloalkyl, -C 1 -C 6 haloalkoxy and-C 2 -C 6 haloalkenyl, and - C 1 -C 6 alkylcarboxylic acid. R 1 is a lipid; R 2 is selected from -H or a lipid; R 3 is selected from -OH, substituted or unsubstituted -C 1 -C 20 alkyl, substituted or unsubstituted -C 2 -C 20 alkenyl, substituted or unsubstituted -C 1 -C 4 alkylaryl and carbohydrate selected from -(NHCH 2 CH 2) x -Glc, -(NHCH 2 CH 2) x -Gal, -(NHCH 2 CH 2) x -Man, - (NHCH 2 CH 2) x- GlcNAc, -(NHCH 2 CH 2) x -MurNAc, -(NHCH 2 CH 2) x -ManNAc, -(NHCH 2 CH 2) x -GaINAc, -(NHCH 2 CH 2) x -cellbiose and -(NHCH 2 CH 2) x -maltose, where x is 0 or 1; R 4 is selected from -H, substituted or unsubstituted -C 1 -C 20 alkyl, substituted or unsubstituted -C 2 -C 20 alkenyl, substituted or unsubstituted -C 1 -C 4 alkylaryl and carbohydrate selected from -(NHCH 2 CH 2) y -Glc, -(NHCH 2 CH 2) y -Gal, -(NHCH 2 CH 2) y -Man, - (NHCH 2 CH 2) y -GlcNAc, -(NHCH 2 CH 2) y -MurNAc, -(NHCH 2 CH 2) y -ManNac, -(NHCH 2 CH 2) y -GaINAc, -(NHCH 2 CH 2) y -cellbiose and -(NHCH 2 CH 2) y -maltose, where y is 0 or 1; and L 1 is a linker selected from -C 1 -C 20 alkylene-, -C 2 -C 20 alkenylene-, -(C 1 -C 4 alkyl)arylene-, -C 2 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, -C 2 -C 12 alkyl-S-S-C 1 -C 12 alkyl-, -C C 1 -C 20 alkylene-, - C C 2 -C 20 alkenylene-, -C (C 1 -C 4 alkyl)arylene-, -C C 1 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, - C NHC 1 -C 20 alkylene-, -C NHC 2 -C 20 alkenylene-, --C NH(C 1 -C 4 alkyl)arylene-, - C NHC 1 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, -C NHC 1 -C 20 alkylene-, -C NHC 2 -C 20 alkenylene-, -C NH(C 1 -C 4 alkyl)arylene- and -C NHC 1 -C 4 alkyl-[O(CH 2) r] s -O(CH 2) r -, where r is selected from 2 and 3 and s is selected from 0 to 20, or a pharmaceutically acceptable salt, stereoisomer, or solvate thereof, wherein each lipid is a hydrophobic moiety comprising substituted or unsubstituted alkyl, alkenyl, cycloalkyl, bridged cycloalkyl, (alkyl)cycloalkyl, (alkyl) bridged cycloalkyl, (alkyl)cycloalkenyl, and/or alkylaryl groups, wherein, when substituted, any of the above groups are substituted by one or more substituents selected from: -OH, -CN, -NH 2, -NH(C 1 -C 6 alkyl), -N(C 1 -C 4 alkyl) 2, =O, -halo, - C 1 -C 6 alkyl, -C 2 -C 6 alkenyl, -C 1 -C 6 haloalkyl, -C 1 -C 6 haloalkoxy and-C 2 -C 6 haloalkenyl, and - C 1 -C 6 alkylcarboxylic acid. wherein each lipid is a hydrophobic moiety comprising substituted or unsubstituted alkyl, alkenyl, cycloalkyl, bridged cycloalkyl, (alkyl)cycloalkyl, (alkyl) bridged cycloalkyl, (alkyl)cycloalkenyl, and/or alkylaryl groups, wherein, when substituted, any of the above groups are substituted by one or more substituents selected from: -OH, -CN, -NH 2, -NH(C 1 -C 6 alkyl), -N(C 1 -C 4 alkyl) 2, =O, -halo, - C 1 -C 6 alkyl, -C 2 -C 6 alkenyl, -C 1 -C 6 haloalkyl, -C 1 -C 6 haloalkoxy and-C 2 -C 6 haloalkenyl, and - C 1 -C 6 alkylcarboxylic acid.