Compounds for targeted drug delivery and enhance the activity of siRNA

The compounds described herein of Formula I: wherein R1 and R2 are independently selected from C10 to C18 alkyl group, C12 to C18 alkenyl group, and oleyl; wherein R3 and R4 are independently selected from C1 to C6 alkyl, and C2 to C6 alkanol; wherein X is selected from -CH2 -, - S-, and -O- or absent; wherein Y is selected from - (CH2) n, -S (CH2) n, -O (CH2) n-, thiophene, -SO2 (CH2) n-, and esters, wherein n = 1-4; where a = 1-4; where b = 1-4; where c = 1-4; and wherein Z is a counterion; compound of the following molecular structures :( orientation) m- linker - (molecular orientation) n, wherein said molecule is oriented retinoid or a fat-soluble vitamin, with specific receptors on the target cell; wherein m and n are independently is 0, 1, and 3; wherein the linker comprises polyethylene glycol (PEG) or PEG-based molecules, as well as compositions and pharmaceutical formulations comprising one or both of these compounds, the compound useful for delivery of therapeutic agents ; and methods for using these compositions and pharmaceutical preparations.