TABLE 1

Compound, mode of action, doses, study period, molecular weight, and unbound fraction in rats

Unbound fractions from in-house data and FDA approval documentation (www.pharmapendium.com).

CompoundMode of ActionDosesStudy PeriodMolecular Weightfu
mg kg-1hg mol−1
IvabradineBlocks If and HCN channels in SAN0, 3, 10, 3024468.60.25
SildenafilPDE5-inhibitor0, 3, 10, 307474.60.05
DofetilideIKr-channel blocker0, 1, 3, 107441.60.2
PimobendanCa2+ sensitizer, PDE3-inhibitor0, 1, 3, 1024334.40.05
  • fu, unbound fraction of test compounds in rats; HCN, hyperpolarization-activated cyclic nucleotide–gated channels; If, funny current; SAN, sinoatrial node.