Inhibition Express

Assay SelectionTest SystemIncubation ConditionsAutomation and AnalysisResultsOptional ServicesRelated Information

XenoTech's Inhibition Express is more than just a screening service. Our 96-well plate format combines both direct and time-dependent inhibition information and offers the flexibility of compound and CYP/UGT enzyme combinations to provide accurate and reliable data. Inhibition Express is a non-GLP service that provides our customers with a data summary of results in about a week. This service is best utilized for compounds that are in the early discovery phase/early development phase. For compounds that will be submitted for regulatory agency approval, please visit our standard inhibition services site here.

Download XenoTech's Inhibition Express Informational Flyer Here!

Assay Selection

Option #1 (IC₅₀ determinations)

XenoTech also offers the ability to perform IC₅₀ experiments based on values that are calculated from area ratios in either single or duplicate determination with the flexibility to evaluate direct inhibition, time-dependent inhibition, or both. 

Option #2 (% inhibition)

XenoTech offers the flexibility for our customers to combine assays and compounds on a single inhibition express plate.  Each plate can consist of 12 enzymatic assays/1 compound, 1 enzymatic assay/12 compounds, or any other combination of 12 samples per plate as desired. Data are presented as % inhibition based on a solvent control and calculated from area ratios.

We recommend the following assays:

• CYP1A2    Phenacetin O-dealkylation
• CYP2B6    Efavirenz 8-hydroxylation
• CYP2C8    Amodiaquine N-dealkylation
• CYP2C9    Diclofenac 4´-hydroxylation
• CYP2C19    S-Mephenytoin 4´-hydroxylation
• CYP2D6    Dextromethorphan O-demethylation
• CYP3A4/5    Midazolam 1´-hydroxylation
• CYP3A4/5    Testosterone 6β-hydroxylation

Additional validated assays available:

• CYP2A6    Coumarin 7-hydroxylation
• CYP2B6    Bupropion hydroxylation
• CYP2C8    Paclitaxel 6α-hydroxylation
• CYP2E1    Chlorzoxazone 6-hydroxylation
• CYP3A4/5    Nifedipine oxidation
• CYP3A4/5    Atorvastatin ortho-hydroxylation
• CYP4A11    Lauric acid 12-hydroxylation
• UGT1A1    17β-Estradiol 3-glucuronidation
• UGT1A6    Naphthol glucuronidation
• UGT1A9    Propofol glucuronidation
• UGT2B7    Morphine 3-glucuronidation

Test System

Pool of 16 individuals, mixed gender, human liver microsomes

Incubation Conditions

Protein concentration:  ≤ 0.1 mg/mL
Incubation time:  5 minutes
Time-dependent pre-incubation (includes NADPH):  30 minutes

Automation and Analysis

Tecan liquid-handling system
Validated LC/MS/MS methods
High-throughput Shimadzu autosamplers
Deuterated internal standards for most reactions

Results

Option #1 (% inhibition)

- Direct inhibition measured over four concentrations
- Time-dependent inhibition (with NADPH) measured over two concentrations
- Data summary in about a week 

Option #2 (IC₅₀ determinations)

- Direct and time-dependent (with NADPH) inhibition measured over seven concentrations
- IC₅₀ curves in about a week

Optional Services

Assessment of solubility
Consultation on results

Related Information

FDA’S latest guidance document (PDF)

XenoTech Products: Human Liver Microsomes