5.
Composition of isomeric population of purified E2, E4, and E6. The percent of the E2 and E6 isomers were determined from reversed-phase HPLC data using Equations 1 and 2, respectively. The percent of E4A was determined from capillary electrophoresis data using Equation 3 and then the percent of E4B and E4C were determined from reversed-phase HPLC data using Equations 4 and 5. For each drug loading level, the sum of the isomers is equal to 100%.