Background: We report here an evaluation of a novel experimental system- cofactorsupplemented
permeabilized cryopreserved human enterocytes (MetMax™ cryopreserved human enterocytes
(MMHE), patent pending) for applications in the evaluation of enteric drug metabolism. A
major advantage of MMHE over Conventional Cryopreserved Human Enterocytes (CCHE) is the simplification
of the use procedures including storage at -80°C instead of in liquid nitrogen, and use of the
cells immediately after thawing without a need for centrifugation and microscopic evaluation of cell
density and viability and cell density adjustment.
Methods: In this study, we compared MMHE and CCHE in key phase 1 oxidation and phase 2 conjugation
Drug Metabolism Enzyme (DME) activities that we recently reported for cryopreserved human
enterocytes: CYP2C9 (diclofenac 4’- hydroxylation), CYP2C19 (s-mephenytoin hydroxylation),
CYP3A4 (midazolam 1’-hydroxylation), CYP2J2 (astemizole O-demethylation), uridine 5'-diphosphoglucuronosyltransferase
(UGT; 7-hydroxycoumarin glucuronidation), sulfotransferase (SULT; 7-
hydroxycoumarin sulfation), N-acetyl transferase-1 (NAT-1; p-benzoic acid N-acetylation), and carboxyesterase-
2 (CES-2; hydrolysis of irinotecan to SN38). Both CCHE and MMHE were active in all
the DME pathways evaluated, with specific activities of MMHE ranged from 142% (CYP2C9) to
1713% (UGT) of that for CCHE. β-hydroxylation and testosterone 6.
Result and Conclusion: Our results suggest that the MMHE system represents a convenient and robust
in vitro experimental system for the evaluation of enteric drug metabolism.