Experimental pharmacokinetics of niferidil upon intravenous administration

The kinetics of niferidil concentration change in blood serum, organs, and urine of rats was studied after i.v. administration at a dose of 5 mg/kg. The blood concentration profile was shown to be described by a bi-exponential equation corresponding to a two-compartment model. Niferidil disappeared quickly from the blood pool with a distribution half-life of 5.13 min. The elimination half-life from blood was 23.3 min. Niferidil penetrated rapidly into organs such as the liver, kidneys, and heart. The concentration calculated per gram of organ 30 min after i.v. administration was six times greater than that in blood (in 1 mL). Accumulation in these organs was not observed. The elimination half-life from the organs was about 1 h. Niferidil was not detected in brain tissue. Niferidil was excreted after i.v. administration unchanged in urine in small amounts. About 10% of the injected dose was eliminated after 24 h. Niferidil was not found in feces.