Dose-dependent pharmacokinetics of a new reversible proton pump inhibitor, DBM-819, after intravenous and oral administration to rats: hepatic first-pass effect.

The dose-dependent pharmacokinetic parameters of DBM-819 were evaluated after intravenous (5, 10 and 20 mg/kg) and oral (10, 20 and 50 mg/kg) administrations of the drug to rats. The hepatic first-pass effect was also measured after intravenous and intraportal administrations of the drug, 10 mg/kg, to rats. After intravenous administration, the dose-normalized (based on 5 mg/kg) area under the plasma concentration-time curve from time zero to time infinity, AUC, at 20 mg/kg (27.0 and 45.8 microg min/ml) was significantly greater than that at 5 mg/kg due to saturable metabolism. After oral administration, the dose-normalized (based on 10 mg/kg) AUC(0-12 h) at 50 mg/kg (25.1, 18.3 and 49.2 microg min/ml) was significantly greater than those at 10 and 20 mg/kg again due to saturable metabolism. After oral administration of DBM-819, 10 mg/kg, 2.86% of oral dose was not absorbed and the extent of absolute oral bioavailability (F) was estimated to be 46.7%. After intraportal administration of DBM-819, 10 mg/kg, the AUC was 51.9% of intravenous administration, suggesting that approximately 48.1% was eliminated by liver (hepatic first-pass effect). The considerable hepatic first-pass effect of DBM-819 was also supported by significantly greater AUC of M3 (3.70 and 6.86 microg min/ml), a metabolite of DBM-819, after intraportal administration. The AUCs of DBM-819 were not significantly different (comparable) between intraportal and oral administrations of the drug, 10 mg/kg, suggesting that gastrointestinal first-pass effect of DBM-819 was almost negligible in rats. At 10 mg/kg oral dose of DBM-819, the hepatic first-pass effect was approximately 48.1%, F was approximately 46.7 and 2.86% was not absorbed from gastrointestinal tract in rats.