Modified-12-28-04 Link to in vitro ADME
Metabolism Assays
In vitro Assays for Human Drug Metabolism
Using human tissue in vitro metabolism and absorption studies as key features of the drug
discovery and development process. Our project managers are available to assist with
development of study designs and data interpretation. We conduct your studies in a GLP
environment, while applying our experience and knowledge to your particular ADME problem to
move your drug or vaccine efficiently through the development process.
In Vitro Absorption and Metabolism Models
In vitro models to predict drug absorption and metabolism are valuable techniques for both
screening new drug candidates, and later evaluations of potential drug-drug interactions. MDS
offers the following services
o Predict gastrointestinal absorption, using Caco2 cells.
o Rapid screening in multi well plates to detection, to quickly identify those compounds
that can cross the GI tract into the blood stream.
o Mechanism studies, evaluating flux rate and permeability constants from the apical to
basolateral, and basolateral to apical directions
o Evaluate drug metabolism and drug interactions, using human and animal tissue
models, such as primary hepatocytes.
o Determine the metabolite profile of drug candidates using hepatocytes, liver and
small intestine microsomes and S9, microsomes containing a single enzyme.
o Predict drug interactions due to inhibition or induction of drug metabolizing enzymes.
o Identify pharmacogenetic effects on human drug metabolism
o Study the transport properties of your drug, using bile canalicular membrane vesicles
from animals and humans.
Comparative Metabolism and In Vitro Toxicity Studies
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Incubation with In Vitro Preparations
Liver, kidney, small intestine from humans, dogs, monkeys, or rodents
Isolated cells, tissue slices, or subcellular fractions (S9, microsomes, or cytosol, with
cofactors)
Two test chemical concentrations, 3 time points
Protein assay for standardization
Cytochrome P450 activity and isozyme profile available
Drug-Drug Interaction Studies
MDS-Z303
MDS-Z404
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Determination of Cytochrome P450 Form-Specific Metabolism · Measure
metabolism of form-specific substrate · Correlation assay with six form-specific
activities · Confirmation with microsomes from cells expressing single form of
human P450
Cytochrome P450 Inhibition · Three drug concentrations · Pooled human
liver microsomes from six donors · Six P450 form-specific assays for CYP1A, 2A6,
2C9, 2C19, 2D6, and 2E1
Cytochrome P450 Induction
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Hepatocytes in primary culture
Preliminary range finding experiment
Definitive experiment with 5 concentrations
Measurement of marker enzyme activities, confirmed by Western blotting · Available in
rat or human hepatocytes
Peroxisome Proliferation Studies: Palmitoyl CoA-Oxidation
MDS-Z 201 Rat Hepatocytes
MDS-Z 202 Human Hepatocytes
o Hepatocytes in primary culture ·
o Preliminary cytotoxicity experiment ·
o Definitive experiment with 5 concentrations of the test agent and solvent and
positive controls ·
o Palmitoyl CoA-oxidation as endpoint ·
o Four independent cultures per concentration in each experiment ·
o Concurrent measurement of DNA or protein levels in each culture
Cytotoxicity Assays In Primary Cultures:
MDS-Z 200 Screening Assays ·
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Hepatocytes or renal proximal tubules ·
Two experiments with 6 concentrations tested with positive, solvent, and media controls
Four replicate samples
Three time points (conducted in 96-well dishes)
FIVE COMPOUNDS MINIMUM.
MDS-Z101 Enzyme Release (lactate dehydrogenase)
MDS-Z102 MTT Conversion (Mitochondrial Function)
Available Species · Human · Rat · Dog · Rabbit · Mouse · Guinea pig · Hamster ·
Nonhuman primates
Specific functional assays · Available for determining chemical mechanism of action and
include urea synthesis, protein synthesis, lipid peroxidation, and oxygen consumption, among
others.
Hemolytic Potential and Compatibility Assays
M108 Hemolytic Potential in Rat or Dog Blood · Whole rat or dog blood is exposed to
the test article and the amount of hemoglobin released from lysed cells is determined
spectrophotometrically · Untreated controls, vehicle controls, and positive controls are
included · Known volumes of whole blood are used to generate a standard curve
representing 0% to 100% hemolysis
M108-A Hemolytic Potential in Human Blood · Same as M108 but using human blood
M108-B Hemolytic Potential in Rat, Dog, and Human Blood · Same as M108 but using blood
from all three species
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M108-C Optional Plasma and Serum Compatibility:
Concurrent with M108, M108-A, & M108-B, compatibility is determined by adding the test
article to plasma and serum, individually, and then assessing the occurrence or nonoccurrence of precipitation or coagulation of plasma or serum protein
Comparative Metabolism and In Vitro Toxicity Studies
Incubation with In Vitro Preparations: Liver, kidney, small intestine from humans, dogs,
monkeys, or rodents.Isolated cells, tissue slices, or subcellular fractions (S9, microsomes, or
cytosol, with cofactors)
 Two test chemical concentrations, 3 time points
 Protein assay for standardization
 Cytochrome P450 activity and isozyme profile available
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