| abstract |
Compounds are provided having the following structure (I) or a pharmaceutically acceptable salt, tautomer or stereoisomer thereof, wherein X, Y, L 1 , L 2 , L 3 , G 1 , G 2 and G 3 are as defined herein. Use of the compounds as a component of lipid nanoparticle formulations for delivery of a therapeutic agent, compositions comprising the compounds and methods for their use and preparation are also provided. |