Experimental pharmacokinetics of fenozan acid and fenoxan in rabbits

The experimental pharmacokinetics of the new antioxidant preparations - fenozan acid and fenoxan (potassium salt of fenozan acid) - were studied in rabbits by monitoring the concentration profiles of the drugs in the blood plasma. Upon peroral administration in a single dose of 100 mg/kg, both fenozan acid and fenoxan are rapidly absorbed into the blood, their maximum concentrations peaking within 12 min after administration. The dynamics of the fenozan acid concentration in the blood plasma upon peroral administration was described by a one-compartment pharmacokinetic model, and that upon the intravenous injection, by a two-compartment model. The pharmacokinetic parameters characterizing the distribution and elimination of fenozan acid and fenoxan were close for both peroral administration and intravenous injections. Fenozan acid was slowly eliminated from the rabbit organism, the mean retention times being 11.3 and 11.8 h; the half-elimination times, 8.28 h and 7.68 h; and the stationary distribution volume, 20.8 and 37.5 liter/kg (i.v. versus p.o., respectively), which is indicative of intracell penetration of the drug and its trapping by organs and tissues. The relatively low value (F = 57.8%) of the bioavailability of fenozan acid upon peroral administration is related to a presystemic metabolism of this drug. © 2006 Springer Science+Business Media, Inc.