TABLE 7.

Comparison SIs in terms or receptor binding (SI₁), receptor occupancy (SI₂), and pharmacological response (SI₃) for bisoprolol, NDD-713, and -825

β-Blocker	SI1a (in vitro binding)a	SI1b (in vitro inhibition of functional response)b	SI2 (in vivo receptor occupancy)c	SI3 (in vivo pharmacologic response)d
NDD-713	589	1202	67	67
NDD-825	1023	1738	115	81
Bisoprolol	43	69	6	4

^aSI_1a = K_d,β2/K_d,β1 (K_d values from ³H-CGP12177 whole-cell binding; Table 1). ^bSI_1b = K_d,β2/K_d,β1 (K_d values from antagonism of cimaterol-induced ³H-cAMP accumulation; Table 2). ^cSI₂ = Φ_β1/Φ_β2 = (K_d,β2 + C_ssf)/(K_d,β1 + C_ssf), where Φ is the receptor occupancy at the βARs, and C_ssf values refer to unbound drug levels in plasma at steady state upon once-daily oral dosing (K_d values from Table 1). ^dSI₃ = E_β1/E_β2, where E_β1 and E_β2 refer to effects on exercise HR and on FEV1 under steady-state conditions after drug administration, respectively.