Dae Y. Lee

Pharmacokinetics of ipriflavone and its two metabolites, M1 and M5, after the intravenous and oral administration of ipriflavone to rat model of diabetes mellitus induced by streptozotocin.

Ipriflavone was reported to be primarily metabolized via hepatic cytochrome P450 (CYP) 1A1/2 and 2C11 in male Sprague-Dawley rats. The protein expression and/or mRNA levels of hepatic CYP1A subfamily and 2C11 was reported to be increased and decreased, respectively, in diabetic rats induced by streptozotocin (DMIS rats). Thus, the pharmacokinetic parameters of ipriflavone and its two metabolites, M1 and M5, were compared after the i.v. (20mg/kg) and p.o. (200mg/kg) administration of ipriflavone to control and DMIS rats. After both i.v. and p.o. administration of ipriflavone to DMIS rats, the AUCs of ipriflavone were significantly smaller (by 31.7% and 34.2% for i.v. and p.o. administration, respectively) than controls. The faster Cl(nr) (smaller AUC) of i.v. ipriflavone could have been due to the faster hepatic Cl(int) (because of an increase in the protein expression and/or mRNA level of hepatic CYP1A subfamily) and the faster hepatic blood flow rate than controls. The smaller AUC of p.o. ipriflavone in DMIS rats could have mainly been due to the faster intestinal Cl(int) (because of an increase in the intestinal CYP1A subfamily) than controls.

Faster clearance of omeprazole in mutant Nagase analbuminemic rats: possible roles of increased protein expression of hepatic CYP1A2 and lower plasma protein binding

It is well known that there are various changes in the expression of hepatic and intestinal CYPs in mutant Nagase analbuminemic rats (NARs). It has been reported that the protein expression of hepatic CYP1A2 was increased, whereas that of hepatic CYP3A1 was not altered, and it was also found that the protein expression of the intestinal CYP1A subfamily significantly increased in NARs from our other study. In addition, in this study additional information about CYP changes in NARs was obtained; the protein expression of the hepatic CYP2D subfamily was not altered, but that of the intestinal CYP3A subfamily increased in NARs. Because omeprazole is metabolized via hepatic CYP1A1/2, 2D1, 3A1/2 in rats, it could be expected that the pharmacokinetics of omeprazole would be altered in NARs. After intravenous administration of omeprazole to NARs, the Clnr was significantly faster than in the controls (110 versus 46.6 ml/min/kg), and this could be due to an increase in hepatic metabolism caused by a greater hepatic CYP1A2 level in addition to greater free fractions of the drug in NARs. After oral administration of omeprazole to NARs, the AUC was also significantly smaller (80.1% decrease) and F was decreased in NARs. This could be primarily due to increased hepatic and intestinal metabolism caused by greater hepatic CYP1A2 and intestinal CYP1A and 3A levels. In particular, the smaller F could mainly result from greater hepatic and intestinal first‐pass effect in NARs than in the controls. Copyright

Effects of morin on the pharmacokinetics of docetaxel in rats with 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors.

Docetaxel is a P-glycoprotein (P-gp) substrate and metabolized via cytochrome P450 (CYP) 3A subfamily in rats. Morin is an inhibitor of both CYPs and P-gp. Hence, the effects of morin on the intravenous and oral pharmacokinetics of docetaxel were investigated using 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumor rats (DMBA rats) as an animal model of human breast cancer. Docetaxel was administered intravenously (4 mg/kg) and orally (20 mg/kg) without and with morin (15 mg/kg) in DMBA rats. After the intravenous administration of docetaxel in control and DMBA rats with and without morin, the values of non-renal clearance and area under the plasma concentration-time (AUC) for docetaxel were comparable. Morin did not increase AUC or the absolute oral bioavailability (F) for docetaxel after the oral administration of docetaxel in control and DMBA rats with and without morin. The inhibition of hepatic and intestinal metabolism of docetaxel by morin and/or DMBA and the effect of intestinal P-gp inhibition by morin on the pharmacokinetics of docetaxel did not seem to be considerable in DMBA-induced mammary tumor rats.

Effects of Cysteine on the Pharmacokinetic Parameters of Omeprazole in Rats With Protein-Calorie Malnutrition: Partial Restoration of Some Parameters to Control Levels by Oral Cysteine Supplementation

BACKGROUND It has been reported that omeprazole is mainly metabolized via the hepatic cytochrome (CYP) 1A1/2, 3A1/2, and 2D1, and the expressions and mRNA levels of CYP1A2, 2C11, and 3A1/2 decreased in protein-calorie malnutrition (PCM) rats compared with controls. Interestingly, the decreased CYP1A2, 2C11, and 3A1/2 in PCM rats returned fully or partially to control levels by oral cysteine supplementation (PCMC rats). Hence, it could be expected that some pharmacokinetic parameters of omeprazole might change in PCM rats and partially restore to control levels in PCMC rats. The purpose of this study is to investigate the pharmacokinetic changes of omeprazole in PCM rats and restoration of the parameters in PCMC rats to control levels. METHODS Omeprazole was administered intravenously (20 mg/kg) and orally (40 mg/kg) to control, PCM, and PCMC rats. RESULTS The following pharmacokinetic parameters were changed in PCM rats and partially returned to control levels in PCMC rats: the area under the plasma concentration-time curve (AUC; 387, 762, and 539 microg min/mL for control, PCM, and PCMC rats, respectively, after intravenous [IV] administration, and the corresponding values after oral administration: 115, 304, and 201 microg min/mL), total body clearance (51.7, 25.5, and 37.1 mL/min/kg, respectively), nonrenal clearance (51.5, 25.4, and 36.1 mL/min/kg, respectively), and in vitro intrinsic clearance (0.158, 0.118, and 0.138 mL/min/mg protein). CONCLUSIONS PCM was associated with significant changes in some omeprazole pharmacokinetics and the pharmacokinetic parameters restored to control levels by oral cysteine.

Faster clearance of omeprazole in rats with acute renal failure induced by uranyl nitrate: contribution of increased expression of hepatic cytochrome P450 (CYP) 3A1 and intestinal CYP1A and 3A subfamilies

It has been reported that omeprazole is mainly metabolized via hepatic cytochrome P450 (CYP) 1A1/2, CYP2D1 and CYP3A1/2 in male Sprague‐Dawley rats, and the expression of hepatic CYP3A1 is increased in male Sprague‐Dawley rats with acute renal failure induced by uranyl nitrate (U‐ARF rats). Thus, the metabolism of omeprazole would be expected to increase in U‐ARF rats. After intravenous administration of omeprazole (20 mgkg−1) to U‐ARF rats, the area under the plasma concentration‐time curve from time zero to infinity (AUC) was significantly reduced (371 vs 494 μg min mL−1), possibly due to the significantly faster non‐renal clearance (56.6 vs 41.2 mL min−1 kg−1) compared with control rats. This could have been due to increased expression of hepatic CYP3A1 in U‐ARF rats. After oral administration of omeprazole (40 mg kg−1) to U‐ARF rats, the AUC was also significantly reduced (89.3 vs 235 μg min mL−1) compared with control rats. The AUC difference after oral administration (62.0% decrease) was greater than that after intravenous administration (24.9% decrease). This may have been primarily due to increased intestinal metabolism of omeprazole caused by increased expression of intestinal CYP1A and 3A subfamilies in U‐ARF rats, in addition to increased hepatic metabolism.