TABLE 2

Equilibrium values of digoxin unbound fractions for albumin and rbc binding

20% rbc-1% Albumin Perfusate
Unbound fractions in plasma perfusate, fp (1 and 2% albumin in perfusate) (for 0.01–100 μM digoxin) 0.64 ± 0.03
Blood to plasma concentration ratio, Cb/Cp (for 0.02–20 μM digoxin) 1.04 ± 0.12
Red blood cell to blood concentration ratio, Crbc/Cb (for 0.02–20 μM digoxin) 1.03 ± 0.12a
f b 0.615b
k′rp (min–1) 1.81 ± 0.12c
kpr (min–1)
0.468 ± 0.021c

  • ↵ a Obtained according to eq. 2

  • ↵ b Equal to fp/(Cb/Cp)

  • ↵ c Obtained from fitting of Crbc and Cp data (eqs. 3 and 4)