| abstract |
In some embodiments, a composition is provided comprising a compound having a structural formula according to Formula (A) or Formula (B), or a pharmaceutically acceptable salt, tautomer or hydrate thereof. In addition, in some embodiments, methods of making and using the compounds and compositions are also provided: In this formula, X 2 is a bond or a linkage group, X 3 is a bond or —PO 4 —, and X 1 , R 1 , R 2 , R 3 , and n are as described herein. |