Effect of route of administration on the relative efficacy and potency of 2-aminoethyl-4-(1,1-dimethylethyl)-6-iodophenol HCl (MK447) and furosemide.

2-Aminoethyl-4-(1,1-dimethylethyl)-6-iodophenol hydrochloride (MK447) is a chemically novel diuretic that has oral efficacy and potency greater than furosemide (FUR). In this study, the relative efficacy and potency of MK447 and FUR were assessed following oral, i.v. bolus and i.v. infusion administration in rats and dogs. MK447 was more potent than furosemide but the two were equally efficacious when administered orally to rats and dogs. The relative potency remained unchanged when administered as an i.v. bolus to rats (1 mg/kg). However, when infused continuously there was no difference in potency or efficacy between the two compounds. These observations lead to the conclusion that pharmacokinetic differences between the two compounds play a major role in determining their relative oral potency. Comparative studies of the effects of compounds given by different routes of administration are useful in providing insight into the role of pharmacokinetics in overall response to different compounds.