Intrinsic Clearance and Metabolism Pathway of Fosthiazate in Rat and Cock Liver Microsomes: From Chiral Assessment View

2021 ◽  
Author(s):  
Lianshan Li ◽  
Haiyan Shi ◽  
Xiude Hua ◽  
Minghua Wang ◽  
Hongjie Wang
Keyword(s):  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
Metabolism Pathway

In Vitro Metabolism of E2, G2: Novel Bile Acid-Coupling Camptothecin Analogues, in Rat Liver Microsomes

2021 ◽  
Vol 16 ◽  
Author(s):  
Xiangli Zhang ◽  
Qin Shen ◽  
Yi Wang ◽  
Leilei Zhou ◽  
Qi Weng ◽  
...  
Keyword(s):  
Bile Acid ◽  
Phase I ◽  
Rat Liver ◽  
Deoxycholic Acid ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
Rat Liver Microsomes ◽  
Camptothecin Analogues

Background: E2 (Camptothecin - 20 (S) - O- glycine - deoxycholic acid), and G2 (Camptothecin - 20 (S) - O - acetate - deoxycholic acid) are two novel bile acid-derived camptothecin analogues by introducing deoxycholic acid in 20-position of CPT(camptothecin) with greater anticancer activity and lower systematic toxicity in vivo. Objective: We aimed to investigate the metabolism of E2 and G2 by Rat Liver Microsomes (RLM). Methods: Phase Ⅰ and Phase Ⅱ metabolism of E2 and G2 in rat liver microsomes were performed respectively, and the mixed incubation of phase I and phase Ⅱ metabolism of E2 and G2 was also processed. Metabolites were identified by liquid chromatographic/mass spectrometry. Results: The results showed that phase I metabolism was the major biotransformation route for both E2 and G2. The isoenzyme involved in their metabolism had some difference. The intrinsic clearance of G2 was 174.7mL/min. mg protein, more than three times of that of E2 (51.3 mL/min . mg protein), indicating a greater metabolism stability of E2. 10 metabolites of E2 and 14 metabolites of G2 were detected, including phase I metabolites (mainly via hydroxylations and hydrolysis) and their further glucuronidation products. Conclusion: These findings suggested that E2 and G2 have similar biotransformation pathways except some difference in the hydrolysis ability of the ester bond and amino bond from the parent compounds, which may result in the diversity of their metabolism stability and responsible CYPs(Cytochrome P450 proteins).

scholarly journals In vitro and in vivo evaluation of hypothermia on pharmacokinetics and pharmacodynamics of nimodipine in rabbits

2017 ◽  
Vol 46 (1) ◽  
pp. 335-347 ◽  
Author(s):  
Yu-xing Fei ◽  
Tian-hong Zhang ◽  
Jing Zhao ◽  
He Ren ◽  
Ya-nan Du ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Protein Binding ◽  
Plasma Concentrations ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
Pharmacokinetics And Pharmacodynamics ◽  
In Vivo Evaluation

Objective To investigate the effect of hypothermia on the pharmacokinetics and pharmacodynamics of nimodipine in rabbits using in vivo and in vitro methods. Methods Five healthy New Zealand rabbits received a single dose of nimodipine (0.5 mg/kg) intravenously under normothermic and hypothermic conditions. Doppler ultrasound was used to monitor cerebral blood flow, vascular resistance, and heart rate. In vitro evaluations of protein binding, hepatocyte uptake and intrinsic clearance of liver microsomes at different temperatures were also conducted. Results Plasma concentrations of nimodipine were significantly higher in hypothermia than in normothermia. Nimodipine improved cerebral blood flow under both conditions, but had a longer effective duration during the hypothermic period. Low temperature decreased the intrinsic clearance of liver microsomes, with no change in protein binding or hepatocyte uptake of nimodipine. Conclusion Nimodipine is eliminated at a slower rate during hypothermia than during normothermia, mainly due to the decreased activity of cytochrome P450 enzymes. This results in elevated system exposure with little enhancement in pharmacological effect.

scholarly journals Interspecies Variation in NCMN-O-Demethylation in Liver Microsomes from Various Species

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2765
Author(s):  
Ziru Dai ◽  
Guibo Sun ◽  
Jiada Yang ◽  
Jie Hou ◽  
Ping Zhou ◽  
...  
Keyword(s):  
Cynomolgus Monkey ◽  
Liver Microsomes ◽  
Specific Inhibitor ◽  
Intrinsic Clearance ◽  
Beagle Dog ◽  
Interspecies Variation ◽  
Human Cytochrome ◽  
Practical Tool ◽  
Cytochrome P450 1A

NCMN (N-(3-carboxy propyl)-4-methoxy-1,8-naphthalimide), a newly developed ratiometric two-photon fluorescent probe for human Cytochrome P450 1A (CYP1A), shows the best combination of specificity and reactivity for real-time detection of the enzymatic activities of CYP1A in complex biological systems. This study aimed to investigate the interspecies variation in NCMN-O-demethylation in commercially available liver microsomes from human, mouse, rat, beagle dog, minipig and cynomolgus monkey. Metabolite profiling demonstrated that NCMN could be O-demethylated in liver microsomes from all species but the reaction rate varied considerably. CYP1A was the major isoform involved in NCMN-O-demethylation in all examined liver microsomes based on the chemical inhibition assays. Furafylline, a specific inhibitor of mammalian CYP1A, displayed differential inhibitory effects on NCMN-O-demethylation in all tested species. Kinetic analyses demonstrated that NCMN-O-demethylation in liver microsomes form rat, minipig and cynomolgus monkey followed biphasic kinetics, while in liver microsomes form human, mouse and beagle dog obeyed Michaelis-Menten kinetics, the kinetic parameters from various species are much varied, while NCMN-O-demethylation in MLM exhibited the highest similarity of specificity, kinetic behavior and intrinsic clearance as that in HLM. These findings will be very helpful for the rational use of NCMN as a practical tool to decipher the functions of mammalian CYP1A or to study CYP1A associated drug-drug interactions in vivo.

Predicting drug pharmacokinetics in humans from in vitro metabolism studies

2001 ◽  
Vol 29 (2) ◽  
pp. 135-139 ◽  
Author(s):  
D. F. McGinnity ◽  
R. J. Riley
Keyword(s):  
Specific Binding ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
In Vitro Assays ◽  
Recombinant Enzymes ◽  
Pharmacokinetic Properties ◽  
Ic50 Values ◽  
Drug Oxidation ◽  
Cyp Inhibition

The pharmaceutical industry is committed to market safer drugs with fewer side effects, predictable pharmacokinetic properties and quantifiable drug-drug interactions. There is an increasing need to develop robust, enhanced-throughput in vitro assays, which accurately extrapolate to humans. The major drug metabolizing human hepatic cytochrome P450s (CYPs; CYP1A2, 2C9, 2C19, 2D6 and 3A4) have been co-expressed functionally in Escherichia coli with human NADPH-cytochrome P450 reductase and validated as surrogates to their counterparts in human liver microsomes (HLM) with respect to their kinetic and inhibition properties. Using these recombinant enzymes, fully automated in vitro assays to assess CYP inhibition and determine the enzymology of drug oxidation have been developed and validated. IC50 values determined for a series of test compounds in HLM and recombinant CYPs were similar (r2 = 0.9, P < 0.001). There was a good correlation between the sum of individual CYP intrinsic clearance (Clint) and HLM CIint (r2 = 0.8, P< 0.001) for ten prototypic substrates for which clearance was CYP-dependent. Several in vitro incubation milieu (e.g. CYPs, HLM, human hepatocytes) are routinely used and the level of non-specific binding was investigated with respect to effects on Km and Ki determinations. There were clear correlations between binding and lipophilicity (logD7.4) for a selection of bases (r2 = 0.98, P < 0.001) and acids (r2 = 0.79, P < 0.001) that may allow prediction of this property. Our laboratory has shown that recombinant enzymes are suitable for ‘frontline’ predictive human metabolism studies in early drug discovery.

scholarly journals CYP-Dependent Metabolism of PF9601N, A New Monoamine Oxidase-B Inhibitor, by C57BL / 6 Mouse and Human Liver Microsomes

2007 ◽  
Vol 10 (4) ◽  
pp. 473 ◽  
Author(s):  
Stefania Dragoni ◽  
Giada Materozzi ◽  
Federica Pessina ◽  
Maria Frosini ◽  
José Luis Marco ◽  
...  
Keyword(s):  
Monoamine Oxidase ◽  
Human Liver ◽  
Formation Rate ◽  
Antioxidant Properties ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
Human Liver Microsomes ◽  
Monoamine Oxidase B ◽  
Mao B

Purpose. The selective monoamine oxidase-B (MAO-B) inhibitor, l-deprenyl, is still used for treating Parkinson's patients, however, a disadvantage of its use lies in the formation of l-amphetamine and l-methamphetamine. Subsequently, this has promoted the design of a novel, more potent, MAO-B inhibitor PF9601N, which also has neuroprotective and antioxidant properties. The aim of this work was to investigate the effect of treatment with PF9601N on its own phase I hepatic metabolism. Kinetic parameters of PF9601N CYP-dependent N-dealkylation reaction was also studied and compared with those of l-deprenyl. Methods. C57BL/6 mice were treated with PF9601N for 4 days. After CYP content and related monooxygenase activities were assayed in liver microsomes of control and treated animals. Results. CYP activities, cytochrome b5 content, NADPH-cytochrome P450 reductase and various monooxygenase activities were unaffected by in vivo PF9601N treatment. With microsomes from both control and treated mice, the PF9601N-dealkylation product, FA72, was the only detected metabolite with its formation rate following an hyperbolic, Michaelis-Menten curve. Among various inhibitors, only ketoconazole inhibited the FA72 formation rate, indicating a major involvement for CYP3A. Apparent Km and Vmax values generated by human liver microsomes were similar to those found with mouse microsomes. Ketoconazole inhibition indicates that CYP3A is one of the major enzymes involved in PF9601N metabolism also by human liver microsomes. In mouse liver microsomes, the intrinsic clearance of PF9601N was significantly lower than that of l-deprenyl suggestive of an improved bioavailability for the former. Conclusion. The observed favourable metabolic profile may suggest suitability of PF9601N for clinical use.

Mechanistic insights from comparing intrinsic clearance values between human liver microsomes and hepatocytes to guide drug design

2012 ◽  
Vol 57 ◽  
pp. 441-448 ◽  
Author(s):  
Li Di ◽  
Christopher Keefer ◽  
Dennis O. Scott ◽  
Timothy J. Strelevitz ◽  
George Chang ◽  
...  
Keyword(s):  
Drug Design ◽  
Human Liver ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
Human Liver Microsomes

scholarly journals Utilization of Liver Microsomes to Estimate Hepatic Intrinsic Clearance of Monoamine Oxidase Substrate Drugs in Humans

2017 ◽  
Vol 34 (6) ◽  
pp. 1233-1243 ◽  
Author(s):  
Yusuke Masuo ◽  
Shushi Nagamori ◽  
Aoi Hasegawa ◽  
Kazuki Hayashi ◽  
Noriyoshi Isozumi ◽  
...  
Keyword(s):  
Monoamine Oxidase ◽  
Liver Microsomes ◽  
Intrinsic Clearance

scholarly journals Development of SGC-GAK-1 as an orally active in vivo probe for cyclin G associated kinase through cytochrome P450 inhibition

2019 ◽  
Author(s):  
Christopher R. M. Asquith ◽  
James M. Bennett ◽  
Lianyong Su ◽  
Tuomo Laitinen ◽  
Jonathan M. Elkins ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Liver Microsomes ◽  
Intrinsic Clearance ◽  
In Vivo Studies ◽  
Chemical Probe ◽  
Active Chemical ◽  
Rapid Clearance ◽  
Cyclin G ◽  
Orally Active

AbstractSGC-GAK-1 (1), a potent, selective, cell-active chemical probe for cyclin G associated kinase (GAK), was rapidly metabolized in mouse liver microsomes by P450 mediated oxidation. 1 displayed rapid clearance in mice, limiting its utility for in vivo studies. All chemical modifications of 1 that improved metabolic stability led to a loss in GAK activity. However, pretreatment of liver microsomes with the irreversible cytochrome P450 inhibitor 1-aminobenzotriazole (ABT) decreased intrinsic clearance of 1. Coadministration of ABT also greatly improved plasma exposure of 1 in mice, supporting its use as a chemical probe to study the in vivo biology of GAK inhibition.

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