OBJECTIVETo detect the effect of deltamethrin (DM) on benzyloxyresorufin O-dealkylatase (BROD) activity and the expression of CYP2B1/2B2 in rat brain.

METHODSBROD activity was determined by fluorophotometry under the treatment of DM in vivo and vitro. Western-blot analysis was used to detect the expression of CYP2B1/2B2.

RESULTSIn vivo, DM could markedly inhibit BROD activity in rat brain microsome after rats had been treated with DM (12.5 mg.kg-1.d-1, i.p.) for 5 days. The inhibitory rate in whole brain, cerebral cortex and cerebellum were 26.7%, 23.8% and 33.3% respectively(P < 0.05). However, in vitro, under the concentration of 2 x 10(-8)-2 x 10(-4) mol/L of DM, there was no obvious change of BROD activity in rat brain. Moreover, Western-blot analysis indicated that DM could significantly reduce the expression of CYP2B1/2B2 in vivo, the inhibitory rate of protein synthesis was 42.6%.

CONCLUSIONDM could inhibit BROD activity in rat brain and this effect may be related to the reduction of CYP2B1/2B2 protein synthesis.

Animals ; Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; biosynthesis ; Blotting, Western ; Brain ; drug effects ; enzymology ; Cytochrome P-450 CYP2B1 ; antagonists & inhibitors ; biosynthesis ; Enzyme Inhibitors ; toxicity ; Insecticides ; toxicity ; Nitriles ; toxicity ; Pyrethrins ; toxicity ; Rats ; Steroid Hydroxylases ; antagonists & inhibitors ; biosynthesis

AIMTo study the metabolic kinetics of MN9202 in Beagle dog liver microsome.

METHODSBeagle dog liver microsomes were prepared by using ultracentrifuge method. After incubating 0.4 micromol x L(-1) MN9202 with 1 g x L(-1) microsomes for 30 min at 37 degrees C, the reaction was terminated by adding 0.5 mL alkalization. The RP-HPLC was used to determine the drug in the incubation mixture. The Michaelis-Menten parameters Km, and Vmax in Beagle dog liver microsomes were initially estimated by analyzing Lineweave-Brurk plot. Various selective CYP inhibitors were used to investigate their inhibitory effect on the metabolism of MN9202.

RESULTSThe Km, Vmax and CLint of MN9202 were (22.6 +/- 8.0) micromol x L(-1), (0.54 +/- 0.17) micromol x g(-1) x min(-1) and (0.0242 +/- 0.0009) L x g(-1) x min(-1), respectively. The metabolism of MN9202 was significantly inhibited by ketoconazole (Ket) and troleandomycin (Tro) in Beagle dog liver microsomes. Tranylcypromine (Tra) could inhibit the metabolism of drug as well. While other inhibitors showed little inhibitory effect on the metabolism of MN9202.

CONCLUSIONIt was shown that CYP3A and CYP2C19 were involved in MN9202 metabolism. The inhibitors of human CYP3A and CYP2C19 may have potential interaction with MN9202, and this can reduce the metabolism rate and increase the toxicity of MN9202.

Animals ; Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; Calcium Channel Blockers ; metabolism ; pharmacokinetics ; Cytochrome P-450 CYP2C19 ; Cytochrome P-450 CYP3A Inhibitors ; Dihydropyridines ; metabolism ; pharmacokinetics ; Dogs ; Ketoconazole ; pharmacology ; Microsomes, Liver ; metabolism ; Mixed Function Oxygenases ; antagonists & inhibitors ; Nitrobenzenes ; metabolism ; pharmacokinetics ; Tranylcypromine ; pharmacology ; Troleandomycin ; pharmacology

OBJECTIVEWuji pill is a prescription of traditional Chinese medicine(TCM) and was composed of Rhizoma Coptidis, Fructus Evodiae Rutaecarpae and Radix Paeoniae Alba. The aim of this research is to investigate the effects of Wuji pill compound with different compatibility on the levels of enzymic activity of cytochrome P450 CYP3A1/3A2 in rat liver microsomes in vitro, and to confirm the compatibility mechanism of Wuji pill from the point of relationships between compound prescription of TCM and metabolism.

METHODWith testosterone being a probe, the levels of enzymic activity of CYP3A1/3A2 were detected by HPLC, which were suppressed by Wuji pill with different compatibility in vitro.

RESULTThe IC50 of Rhizoma Coptidis, Fructus Evodiae Rutaecarpae, Radix Paeoniae Alba and 1"-9" of different level Wuji pill is: 38.96, 871.96, 15 519.17, 43.17, 60. 47, 276.12, 133.40, 118.08, 88. 47, 64. 36, 35. 13 and 39. 91 mg x L -', respectively. Rhizoma Coptidis and 1-9" of Wuji pill can suppress the enzymic activity of CYP3A1/3A2 significantly, and the capability of Rhizoma Coptidis in Wuji pill of action on CYP3A1/3A2 can be modified by different composition of Fructus Evodiae Rutaecarpae and Radix Paeoniae in Wuji pill, and there are statistical differences among the IC50 of 1#-9# of Wuji pill. While the ratio of Rhizoma Coptidis raises up in Wuji pill, Wuji pill may suppress the enzymic activity of CYP1A2 largely.

CONCLUSIONThe reason why Wuji pill with different compatibility has different pharmacodynamics and pharmacokinetics characteristics is likely to lie in the difference of the capability of Wuji pill with different compatibility on CYP3A1/3A2. [Key words] Wuji pill; CYP3A1/3A2; testosterone; HPLC; different compatibility prescription of traditional Chinese medi-cine

Animals ; Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; metabolism ; Coptis ; chemistry ; Cytochrome P-450 CYP3A ; Drug Compounding ; Drugs, Chinese Herbal ; adverse effects ; pharmacology ; Enzyme Inhibitors ; adverse effects ; pharmacology ; Evodia ; chemistry ; Inhibitory Concentration 50 ; Male ; Membrane Proteins ; antagonists & inhibitors ; metabolism ; Microsomes, Liver ; drug effects ; enzymology ; Paeonia ; chemistry ; Rats ; Rats, Wistar

The present study utilized LC-MS and HPLC approaches to characterize the metabolites of neferine in rat liver after an oral administration of 20 mg x kg(-1), and investigated the involvement of CYP450 isoforms in the metabolism of neferine by their selective inhibitors in vitro, separately. In positive ionization mode, besides neferine, four metabolites (M1-M4) were detected. M2 (the major metabolite) and M4 were identified as liensinine and isoliensinine by comparison with reference substances. Moreover, according to the analysis of metabolic rule of parent drug (neferine), M1 and M3 may be desmethylliensinine and desmethyl-isoliensinine, respectively. Furthermore, the metabolism of neferine in rat liver microsomes showed that the percentage inhibition of the major metabolism (liensinine) formation was 80.5% by quinidine (10 micromol x L(-1), selective CYP2D1 inhibitor) and 25.7% by ketoconazole (1 micromol x L(-1), selective CYP3A1 inhibitor). Neferine was mainly metabolized by CYP2D1 or CYP3A1 to liensinine, isoliensinine, desmethyl-liensinine and desmethyl-isoliensinine.
Administration, Oral ; Alcohol Oxidoreductases ; antagonists & inhibitors ; Animals ; Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; Benzylisoquinolines ; administration & dosage ; isolation & purification ; metabolism ; Chromatography, High Pressure Liquid ; Cytochrome P-450 CYP3A ; Cytochrome P450 Family 2 ; Isoquinolines ; metabolism ; Ketoconazole ; pharmacology ; Male ; Microsomes, Liver ; metabolism ; Nelumbo ; chemistry ; Phenols ; metabolism ; Plants, Medicinal ; chemistry ; Quinidine ; pharmacology ; Rats ; Seeds ; chemistry ; Spectrometry, Mass, Electrospray Ionization

BACKGROUND: Clopidogrel has been widely used to prevent recurrent ischemia in patients with acute coronary syndrome (ACS). However, inter-individual variability in response to clopidogrel has been a problem in the clinical setting. The aim of the present study was to investigate the frequency of clopidogrel resistance and to determine the clinical, pharmacokinetic, and pharmacogenetic factors for clopidogrel resistance in Korean patients with ACS. METHODS: Clinical information, such as the underlying diseases and concurrent medications, of 114 patients with ACS who received clopidogrel therapy was studied. The degree of inhibition of platelets was assessed using the VerifyNow assay (Accumetrics, USA). The patients who showed less than 20% inhibition of platelets were defined as non-responders to clopidogrel treatment. Steady state plasma concentrations of clopidogrel were measured using HPLC/tandem mass spectrometry. CYP2C19 genotyping was also performed. RESULTS: A wide inter-individual variability was observed in platelet inhibition (0-76%); 56 patients (49%) showed less than 20% inhibition. There were no differences between the patients' history of diabetes mellitus and concurrent medications as well as the plasma concentrations of clopidogrel of the responders and non-responders. CYP2C19 variants, including CYP2C19*2 and CYP2C19*3, were more commonly observed in the non-responders than in the responders (P value<0.0001). CONCLUSIONS: The response to clopidogrel was highly variable in Korean patients with ACS. The results of the present study confirmed that the genetic polymorphism of CYP2C19 could be important in clopidogrel response. However, further studies are required to investigate other likely factors involved in clopidogrel resistance.
Acute Coronary Syndrome/complications/*drug therapy/genetics ; Adult ; Aged ; Aged, 80 and over ; Aryl Hydrocarbon Hydroxylases/antagonists & inhibitors/genetics/metabolism ; Asian Continental Ancestry Group/*genetics ; Diabetes Complications ; Drug Resistance ; Female ; Genotype ; Humans ; Male ; Middle Aged ; Platelet Aggregation Inhibitors/blood/pharmacokinetics/*therapeutic use ; Polymorphism, Genetic ; Republic of Korea ; Ticlopidine/*analogs & derivatives/blood/pharmacokinetics/therapeutic use

Rotundine (1 micromol L(-1)) was incubated with a panel of rCYP enzymes (1A2, 2C9, 2C19, 2D6 and 3A4) in vitro. The remained parent drug in incubates was quantitatively analyzed by an Agilent LC-MS. CYP2C19, 3A4 and 2D6 were identified to be the isoenzymes involved in the metabolism of rotundine. The individual contributions of CYP2C19, 3A4 and 2D6 to the rotundine metabolism were assessed using the method of total normalized rate to be 31.46%, 60.37% and 8.17%, respectively. The metabolites of rotundine in incubates were screened with ESI-MS at selected ion mode, and were further identified using MS2 spectra and precise molecular mass obtained from an Agilent LC/Q-TOF-MSMS, as well as MS(n) spectra of LC-iTrap-MS(n). The predominant metabolic pathway of rotundine in rCYP incubates was O-demethylation. A total 5 metabolites were identified including 4 isomerides of mono demethylated rotundine and one di-demethylated metabolite. The results also showed that CYP2C19, 2D6 and 3A4 mediated O-demethylation of methoxyl groups at different positions of rotundine. Furthermore, the ESI-MS cleavage patterns of rotundine and its metabolites were explored by using LC/Q-TOF-MSMS and LC/iTrap-MS(n) techniques.
Analgesics, Non-Narcotic ; metabolism ; Aryl Hydrocarbon Hydroxylases ; metabolism ; Berberine Alkaloids ; metabolism ; Chromatography, Liquid ; Cytochrome P-450 CYP1A2 ; metabolism ; Cytochrome P-450 CYP2C19 ; Cytochrome P-450 CYP2C9 ; Cytochrome P-450 CYP2D6 ; metabolism ; Cytochrome P-450 CYP3A ; metabolism ; Cytochrome P-450 Enzyme System ; metabolism ; Dopamine Antagonists ; metabolism ; Humans ; Isoenzymes ; metabolism ; Methylation ; Recombinant Proteins ; metabolism ; Spectrometry, Mass, Electrospray Ionization

The present study was to evaluate feasibility of a limited sampling strategy (LSS) in the prediction of inhibited hepatic CYP3A activity with systemic clearance of midazolam (MDZ), a hepatic CYP3A activity phenotyping probe. Rats were pretreated with a serial doses of ketoconazole, a selective inhibitor on CYP3A. Blood samples were collected and detected for MDZ at specified time points after intravenous injection of MDZ. Stepwise regression analysis and a Jack-knife validation procedures were performed in one group of rats as training set to establish the most informative LSS model for accurately estimating the clearance of MDZ. Another group of rats with same treatment was used as validation set to estimate the individual clearance based on predictive equations derived from the training set. Bland-Altman plots showed a good agreement between the systemic clearance calculated from DAS (CLobs) and corresponding parameter that was derived from three LSS models (CLest). LSS models derived from two or three sampling time points, including 60, 90 min, 30, 60, 90 min and 30, 60, 120 min, exhibited a good accuracy and acceptable error for estimating the CLobs of MDZ to evaluate hepatic CYP3A activity, especially the 60, 90 min LSS model is most accurate and convenient. The results supported that limited plasma sampling to predict the systemic clearance of MDZ is easier than the usual method for estimating CYP3A phenotyping when the hepatic activity of CYP3A is reduced in the rat. The present study provided theoretical basis and laboratory evidence for LSS to clinically evaluate metabolizing function of liver and
Animals ; Area Under Curve ; Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; genetics ; metabolism ; Cytochrome P-450 CYP3A ; genetics ; metabolism ; Cytochrome P-450 CYP3A Inhibitors ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; pharmacology ; Injections, Intravenous ; Ketoconazole ; administration & dosage ; pharmacology ; Male ; Metabolic Clearance Rate ; Midazolam ; blood ; pharmacokinetics ; Phenotype ; Random Allocation ; Rats ; Rats, Wistar

Licorice root has been frequently used as antitode in traditional Chinese medicine. As the main active component of Licorice root, glycyrrhetic acid (GA) is mainly metabolized in liver. This study was designed to investigate the in vitro metabolism of GA by human liver microsomes (HLM) and human recombinant cytochrome P450 (CYP) isoforms. The results indicated that GA was metabolized mainly by CYP3A4. The K(m), V(max) and CL(int) of GA in HLM were 18.6 micromol x L(-1), 4.4 nmol x mg(-1) (protein) x min(-1) and 0.237 mL x mg(-1) (protein) x min(-1), respectively. At concentration up to 50 micromol x L(-1), GA inhibited CYP2C19, CYP2C9 and CYP3A4 enzyme activities with the inhibitory potencies up to 50%.
Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; metabolism ; Cytochrome P-450 CYP2C19 ; Cytochrome P-450 CYP2C9 ; Cytochrome P-450 CYP3A ; metabolism ; Cytochrome P-450 CYP3A Inhibitors ; Enzyme Inhibitors ; pharmacology ; Glycyrrhetinic Acid ; isolation & purification ; pharmacokinetics ; pharmacology ; Glycyrrhiza ; chemistry ; Humans ; Isoenzymes ; metabolism ; Microsomes, Liver ; enzymology ; metabolism ; Plant Roots ; chemistry ; Plants, Medicinal ; chemistry

AIMTo investigate the variation of CYP2C9 isoenzyme activity in the microbial model in response to inhibitors of CYP2C9.

METHODSUsing C. blakesleeana AS 3. 910 as a model strain, the impact of CYP2C9 inhibitors on the metabolites yields of CYP2C9 substrates was determined and the drug-drug interactions among CYP2C9 substrates were evaluated. Liquid chromatography-mass spectrometry was used to analyze biotransformation products.

RESULTSBenzbromarone decreased the yield of 4'-hydroxytolbutamide from 100% to 14.5%; sulfaphenazole decreased the yield of O-demethylindomethacin from 75.2% to 9.9%; valproic acid decreased the yield of 4'-hydroxydiclofenac from 98.6% to 2.7%, separately. Tolbutamide, indomethacin and diclofenac interacted with each other, resulting in the decreased formation of metabolites catalyzed by CYP2C9.

CONCLUSIONThree CYP2C9 inhibitors inhibit the activity of CYP2C9 isoenzyme in C. blakesleeana AS 3. 910 differently, and there are drug-drug interactions among CYP2C9 substrates.

Aryl Hydrocarbon Hydroxylases ; antagonists & inhibitors ; metabolism ; Benzbromarone ; pharmacology ; Biotransformation ; drug effects ; Catalysis ; drug effects ; Chromatography, High Pressure Liquid ; methods ; Cunninghamella ; enzymology ; metabolism ; Cytochrome P-450 CYP2C9 ; Diclofenac ; analogs & derivatives ; metabolism ; pharmacology ; Dose-Response Relationship, Drug ; Drug Interactions ; Fungal Proteins ; antagonists & inhibitors ; metabolism ; Indomethacin ; pharmacology ; Isoenzymes ; antagonists & inhibitors ; metabolism ; Spectrometry, Mass, Electrospray Ionization ; methods ; Substrate Specificity ; Sulfaphenazole ; pharmacology ; Tolbutamide ; analogs & derivatives ; metabolism ; pharmacology ; Valproic Acid ; pharmacology

BACKGROUND/AIMS: Genetic polymorphism of cytochrome P450 CYP2C19 influences the efficacy of proton pump inhibitor (PPI) in Helicobacter pylori (H. pylori) eradication therapy. We investigated the difference in the cure rates of H. pylori infection by triple (rabeprazole plus amoxacillin and clarithromycin) therapy in relation to CYP2C19 genotype status. METHODS: One hundred and sixteen H. pylori infected patients with gastric ulcer and duodenal ulcer completed the triple therapy with 10 mg of rabeprazole b.i.d., 1,000 mg amoxacillin b.i.d. and 500 mg of clarithromycin b.i.d. for one week. The genotype of CYP2C19 was determined by a PCR-restriction fragment length polymorphism method. RESULTS: According to the univariate analysis, heterozygous extensive metabolizers (hetero EMs) and poor metabolizers (PMs) showed the highest (87.0%) and the lowest (80.0%) eradication rates, respectively. The difference in the therapeutic efficacy of rabeprazole among the different CYP2C19 genotypes was insignificant. With regard to gender, age and smoking history in relation to eradication rate, a statistical significance was noted only with age with odds ratio of 1.063 and p-value of 0.0202. CONCLUSIONS: In the eradication therapy of H. pylori, no statistically significant difference in therapeutic efficacy of rabeprazole was found among different CYP2C19 genotypes.
2-Pyridinylmethylsulfinylbenzimidazoles ; Adult ; Aged ; Amoxicillin/administration & dosage ; Anti-Bacterial Agents/administration & dosage ; Anti-Ulcer Agents/*administration & dosage ; Aryl Hydrocarbon Hydroxylases/*genetics ; Benzimidazoles/*administration & dosage ; Clarithromycin/administration & dosage ; Drug Therapy, Combination ; Duodenal Ulcer/drug therapy/*genetics/microbiology ; Female ; Genotype ; Helicobacter Infections/*drug therapy ; *Helicobacter pylori ; Humans ; Male ; Middle Aged ; Mixed Function Oxygenases/*genetics ; Omeprazole/analogs & derivatives ; Proton Pumps/*antagonists & inhibitors ; Stomach Ulcer/drug therapy/*genetics/microbiology