Provided, in part, is a composition comprising one or more chemical entities of formula I, each of which is a compound of formula I:a pharmaceutically acceptable salt thereof, a solvate thereof, or a solvate of a pharmaceutically acceptable salt thereof, the composition characterized in that greater than a first threshold amount of the total amount of chemical entities of formula I in the composition: are chemical entities of formula I.a, wherein the first threshold amount is 50% or are chemical entities of formula I.b.1, wherein the first threshold amount is 25% or are chemical entities of formula I.b.2, wherein the first threshold amount is 25%, wherein the chemical entities of formula I.a, I.b.1, and I.b.2, are described herein, and methods of using such compositions, for example, for the delivery of a polynucleotide in vivo.
