Enprofylline kinetics in healthy subjects after single doses

Abstract

The kinetics of enprofylline, a novel antiasthmatic xanthine derivative, were studied. Eight healthy subjects received 3 different single enprofylline doses i.e., 0.5, 1 and 1.5 mg/kg, injected as an infusion over 10 min. Plasma and urine levels of unchanged enprofylline were observed 3-7 and 21-24 h after dosing. Plasma t1/2 [half-life] varied among individuals from 1.2-1.9 h. Volume of distribution (V.beta. or area) and volume of distribution at steady state (Vss) averaged 0.57 and 0.511/kg. Total clearance averaged 0.25 l/h per kg. Renal clearance ranged from 200-400 ml/min, indicating a large contribution by active tubular secretion. The mean recovery of unchanged drug in the urine was 89%. Unlike theophylline, enprofylline was eliminated mainly by the kidney.