High quality services for screening metabolism-related toxicity
1 June 2012
We at admescope are proud to be undisputed leader in the field of reactive drug metabolites and metabolism related CYP inhibition. Due to our extensive R&D work in this field we can offer unique and/or hard-to-find services, including high quality assays for screening reactive metabolites, evaluating reactivity of acyl-glucuronide metabolites, or estimation of time-dependent inhibition. We provide supreme quality in data as well as in data interpretation. Note also our various scientific publications related to reactive metabolites and CYP interactions.
Reactive metabolites have a short lifespan and therefore for identification they need to be trapped to form more stable conjugates. Our service, Reactivescreen, is conducted in liver microsomes or S9 fraction in the presence of cofactors and two stable isotope-labelled agents; GHS and KCN, to trap both soft and hard electrophiles. To guarantee supreme quality in data, highly sensitive UPLC/Q-TOF-MS is employed to obtain accurate mass data for identification of formed GSH or CN adducts.
Glucuronide-conjugation is most commonly considered a detoxification route, but in the presence of carboxylic acid moiety in a parent or a metabolite, reactive acyl-glucuronide conjugates (AGs) can be formed. These conjugates can readily react with plasma and tissue proteins, and their chemical stability in various conditions is shown to correlate well with their toxicity. Acylstab is an assay to assess stability and reactivity of acyl-glucuronide metabolites in liver microsomes. Use of UPLC/TOF-MS analysis results in very high quality separations between isomeric AGs formed via acyl migration reaction, that leads to clear advantages in interpretation of the results.
Our service for analyzing time-dependent inhibition, TDIscreen, will reveal if NCE or its metabolites inhibit CYP enzymes over time, using a IC50-shift approach between 30 min preincubation with and without NADPH in human liver microsomes. The assay contains comprehensive cocktail of 9 substrates for all major drug metabolizing CYP enzymes. LC/MS/MS is utilized to determine the level of metabolites formed in the presence or absence of a drug candidate. This assay can also be extended to include more detailed experiments to reveal kinetic inactivation parameters (kinact and KI), and/or dialysis-including inhibition experiments to confirm the covalent nature of interaction.