| abstract |
Provided in some embodiments are compositions comprising a compound having a structure according to Formula A or Formula B: n n n n n n n n n n or a pharmaceutically acceptable salt, tautomer or hydrate thereof, where X 2 is a bond or linker, X 3 is bond or —PO 4 —, and X 1 , R 1 , R 2 , R 3 , and n are described herein. Also provided in some embodiments are methods for making and using such compounds and compositions. |