The capacity factors of ephedrine and pseudoephedrine at 37 °C.

Notes: k′e and k′p represent the capacity factors of ephedrine and pseudoephedrine respectively. k′e is determined when ephedrine serves both injecting solute and competitive agents with the concentrations of 4, 8, 12, 20, 24, 30 and 34 µM. While k′p is obtained by direct competitive study for which pseudoephedrine is used as an injection and ephedrine acts as competitive agents with the concentrations of 2, 4, 8, 12, 16, 24 and 30 µM.