![]() |
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Centre for Applied Pharmacokinetic Research, School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester, United Kingdom
Human liver microsomes have typically resulted in marked underprediction of in vivo human intrinsic clearance (CLint); therefore, the utility of cryopreserved hepatocytes as an alternative in vitro system has become an important issue. In this study, 10 compounds (tolbutamide, diclofenac, S-warfarin, S-mephenytoin, dextromethorphan, bufuralol, quinidine, nifedipine, testosterone, and terfenadine) were selected as substrate probes for CYP2C9, 2C19, 2D6, and 3A4, and the kinetics of metabolite formation (n = 14 pathways) were investigated in three individual lots of cryopreserved hepatocytes and in a pool of human liver microsomes. For the majority of the compounds, lower unbound KM or S50 values were observed in hepatocytes compared with microsomes, on average by 50% over a 200-fold range (0.5140 µM). Expressed on an equivalent liver weight basis, a good correlation between microsomal and hepatocyte Vmax values was observed for most pathways greater than 5 orders of magnitude (0.16216 nmol/min/g liver). Unbound hepatocyte CLint (CLint,u) values, when scaled to the whole liver (range 0.384000 ml/min/kg), were on average 2.5-fold higher than microsomal CLint,u values, with the exception of tolbutamide and diclofenac, for which lower hepatocellular CLint,u values were observed. Hepatocyte predicted CLint values were compared with human in vivo CLint values, and to supplement our data, in vitro data from cryopreserved hepatocytes were collated from four other published sources. These data show that for 37 drugs, there is, on average, a 4.5-fold under-prediction of the in vivo CLint using cryopreserved hepatocytes, representing a significant reduction in prediction bias compared with human microsomes.
This article has been cited by other articles:
![]() |
P. J. Kilford, R. Stringer, B. Sohal, J. B. Houston, and A. Galetin Prediction of Drug Clearance by Glucuronidation from in Vitro Data: Use of Combined Cytochrome P450 and UDP-Glucuronosyltransferase Cofactors in Alamethicin-Activated Human Liver Microsomes Drug Metab. Dispos., January 1, 2009; 37(1): 82 - 89. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. Wei, G. Dai, Z. Liu, H. Cheng, Z. Xie, R. Klisovic, G. Marcucci, and K. K. Chan Enzyme Kinetics of GTI-2040, a Phosphorothioate Oligonucleotide Targeting Ribonucleotide Reductase Drug Metab. Dispos., November 1, 2008; 36(11): 2227 - 2233. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. B. Dennison, M. A. Mohutsky, R. J. Barbuch, S. A. Wrighton, and S. D. Hall Apparent High CYP3A5 Expression Is Required for Significant Metabolism of Vincristine by Human Cryopreserved Hepatocytes J. Pharmacol. Exp. Ther., October 1, 2008; 327(1): 248 - 257. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. J. Kilford, M. Gertz, J. B. Houston, and A. Galetin Hepatocellular Binding of Drugs: Correction for Unbound Fraction in Hepatocyte Incubations Using Microsomal Binding or Drug Lipophilicity Data Drug Metab. Dispos., July 1, 2008; 36(7): 1194 - 1197. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J. Parker and J. B. Houston Rate-Limiting Steps in Hepatic Drug Clearance: Comparison of Hepatocellular Uptake and Metabolism with Microsomal Metabolism of Saquinavir, Nelfinavir, and Ritonavir Drug Metab. Dispos., July 1, 2008; 36(7): 1375 - 1384. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Rowland, D. J. Elliot, K. M. Knights, P. I. Mackenzie, and J. O. Miners The "Albumin Effect" and in Vitro-in Vivo Extrapolation: Sequestration of Long-Chain Unsaturated Fatty Acids Enhances Phenytoin Hydroxylation by Human Liver Microsomal and Recombinant Cytochrome P450 2C9 Drug Metab. Dispos., May 1, 2008; 36(5): 870 - 877. [Abstract] [Full Text] [PDF] |
||||
![]() |
Cheng Li, Tongtong Liu, Xiaoming Cui, A. S. Uss, and K.-C. Cheng Development of In Vitro Pharmacokinetic Screens Using Caco-2, Human Hepatocyte, and Caco-2/Human Hepatocyte Hybrid Systems for the Prediction of Oral Bioavailability in Humans J Biomol Screen, December 1, 2007; 12(8): 1084 - 1091. [Abstract] [PDF] |
||||
![]() |
H. S. Brown, A. Chadwick, and J. B. Houston Use of Isolated Hepatocyte Preparations for Cytochrome P450 Inhibition Studies: Comparison with Microsomes for Ki Determination Drug Metab. Dispos., November 1, 2007; 35(11): 2119 - 2126. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Karanam, M. Madeira, S. Bradley, L. Wenning, R. Desai, E. Soli, D. Schenk, A. Jones, B. Dean, G. Doss, et al. Absorption, Metabolism, and Excretion of [14C]MK-0524, a Prostaglandin D2 Receptor Antagonist, in Humans Drug Metab. Dispos., July 1, 2007; 35(7): 1196 - 1202. [Abstract] [Full Text] [PDF] |
||||