Dose-dependent pharmacokinetics of itraconazole after intravenous or oral administration to rats: intestinal first-pass effect.
The dose-dependent pharmacokinetics of itraconazole after intravenous (10, 20, or 30 mg/kg) and oral (10, 30, or 50 mg/kg) administration and the first-pass effects of itraconazole after intravenous, intraportal, intragastric, and intraduodenal administration at a dose of 10 mg/kg were evaluated in rats. After intravenous administration at a dose of 30 mg/kg, the area under the plasma concentration-time curve from time zero to infinity (AUC(0- infinity )) was significantly greater than those at 10 and 20 mg/kg (1,090, 1,270, and 1,760 micro g. min/ml for 10, 20, and 30 mg/kg, dose-normalized at 10 mg/kg). After oral administration, the AUC(0- infinity ) was significantly different for three oral doses (380, 687, and 934 micro g. min/ml for 10, 30, and 50 mg/kg, respectively, dose-normalized at 10 mg/kg). The extent of absolute oral bioavailability (F) was 34.9% after an oral dose at 10 mg/kg. The AUC(0- infinity ) (or AUC(0-8 h)) values were comparable between intravenous and intraportal administration and between intragastric and intraduodenal administration, suggesting that the hepatic and gastric first-pass effects were almost negligible in rats. However, the AUC(0-8 h) values after intraduodenal and intragastric administration were significantly smaller than that after intraportal administration, approximately 30%, suggesting that the intestinal first-pass effect was approximately 70% of that of an oral dose of 10 mg/kg. The low F after oral administration of itraconazole at a dose of 10 mg/kg could be mainly due to the considerable intestinal first-pass effect.
Shin
Jee H
JH
College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, San 56-1, Shinlim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
Choi
Ka Y
KY
Kim
Yu C
YC
Lee
Myung G
MG
D000284:Administration, Oral; D000818:Animals; D000935:Antifungal Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001646:Bile / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000378:metabolism; D005750:Gastric Juice / Q000378:metabolism; D006207:Half-Life; D007275:Injections, Intravenous; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism*; D007441:Intubation, Gastrointestinal; D017964:Itraconazole / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D011169:Portal Vein; D051381:Rats; D017207:Rats, Sprague-Dawley
D000935:Antifungal Agents; D017964:Itraconazole