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Pooled Human Liver Microsomes

Human liver microsomes contain a wide variety of drug metabolizing enzymes and are a recommended test system for assays including metabolite identification (MetID), metabolic stability, enzyme inhibition, reaction phenotyping, and other in vitro drug metabolism and pharmacokinetics (DMPK) studies.

We offer pooled microsomes with representative averages of extensive and wide-ranging inter-individual differences in enzyme activity found in the general North America/USA population, as well as preparations from individual donors that have been genotyped for the presence of a specific single nucleotide polymorphism (SNP). Genotyped human liver microsomes can be used to investigate the influence of allelic variance on the safety and efficacy of new molecular entities.

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Available Human Liver Microsome Products:

Our Approach to High-Activity, Representative Pooling

Our pooled products are engineered to maximize CYP activity levels or to provide a large donor pool that best represents the average North American/US population. We offer 10- and 50-donor pooled human liver microsome products as well as a 200-donor pool (XTreme 200).

Our highly experienced product specialists work hard to make sure our cellular and subcellular test systems meet strict internal standards for optimized performance in your in vitro assays. Features of our pooled human liver microsomes include:

  • Large donor pools to minimize lot-to-lot variation
  • Large lot lot sizes that  increase the long-term availability of each lot
  • Suspended in 250 mM sucrose for long-term stability
  • Sold in several different volume sizes and custom packaging is available upon request
  • Xtreme 200 pool extensively characterized for 10 CYPs, FMO and 5 UGTs
  • CYP activities quantified using validated LC-MS/MS methods
  • Matching S9 and Cytosol available for most donor pools

Reaction Phenotyping Kit

Additionally, we have developed a patented Reaction Phenotyping Kit designed to identify the human liver CYP or UGT enzyme(s) responsible for xenobiotic metabolism. This kit is often used to predict pharmacokinetic variability and provides valuable information on the potential for drug-drug interactions, and samples in the kit are carefully selected to minimize correlations or outliers that can interfere with reliable results. The kit includes:

  • 16 vials of individual donor liver microsomes (4 mg/vial) 
  • 2x vials of mixed gender, pooled liver microsomes (10 mg/vial) 
  • Comprehensive characterization data packet including correlation tables for CYPs, FMO and UGT enzymes
  • Download our guide for best practice when using our kit

Custom Pooling

If your study has specific donor requirements, tailored pooling is available through our designated Custom Products team. Individual human liver subcellular fractions can be selected according to metabolic activity, and demographically-defined pools (age, ethnicity, disease state, etc.) can be ordered by submitting a Custom Preparations request.

Make sure your microsomes are properly activated

For best results from assays using microsomes and S9 fractions, we recommend using NADPH regeneration to support high metabolism levels by ensuring that the NADPH levels are not a limiting factor in your incubations. Our preferred system, RapidStartTM, uses an enzymatic reaction that converts NADP to NADPH, which is then used as a cofactor by CYPs and oxidized back to NADP, and the cycle continues ensuring stable NADPH levels throughout the incubation. RapidStartTM NADPH regeneration is easily activated by simply adding water. Our easy-to-use formula is the most convenient and flexible NADPH regenerating system you’ll find, allowing users to easily tailor the system’s capability by simply varying the amount of water added. RapidStartTM is perfect for long- and short-term incubations and supports the function of recombinant enzymes and subcellular fractions, allowing you to achieve the most accurate and reliable data during your in vitro assay.

Microsomes are the recommended Test System for many In Vitro Metabolism assays

Related Downloadable Scientific Content:

Poster: Evaluation of Chemical Inhibitors for UDP-glucuronosyltransferase (UGT) Reaction Phenotyping Assays in Human Liver Microsomes

Poster: Assessment Under Initial Rate Conditions of the Selectivity and Time Course of Cytochrome P450 Inactivation in Pooled Human Liver Microsomes and Hepatocytes

Poster: Microsomal Cytochrome P450 Enzyme Activities in Nonalcoholic Steatohepatitis Livers.

See our custom preparations capabilities

Find complete list of characterization assays, quality assurance details, typical timeline for preparations, and more

Custom in vitro preclinical products scientist

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Access more details about our capabilities, characterization of subcellular fractions, safety, handling and storage, and more

“Isolation of subcellular fractions: Tissue > Homogenate > S9 > Cytosol > Microsomes