title: A novel trapping system for the detection of reactive drug metabolites using the fungus Cunninghamella elegans and high resolution mass spectrometry.
abstract: A new model is presented that can be used to screen for bioactivation of drugs. The evaluation of toxicity is an important step in the development of new drugs. One way to detect possible toxic metabolites is to use trapping agents such as glutathione. Often human liver microsomes are used as a metabolic model in initial studies. However, there is a need for alternatives that are easy to handle, cheap, and can produce large amounts of metabolites. In the presented study, paracetamol, mefenamic acid, and diclofenac, all known to form reactive metabolites in humans, were incubated with the fungus Cunninghamella elegans and the metabolites formed were characterized with ultra high performance liquid chromatography coupled to a quadrupole time of flight mass spectrometer. Interestingly, glutathione conjugates formed by the fungus were observed for all three drugs and their retention times and MS/MS spectra matched those obtained in a comparative experiment with human liver microsomes. These findings clearly demonstrated that the fungus is a suitable trapping model for toxic biotransformation products. Cysteine conjugates of all three test drugs were also observed with high signal intensities in the fungal incubates, giving the model a further indicator of drug bioactivation. To our knowledge, this is the first demonstration of the use of a fungal model for the formation and trapping of reactive drug metabolites. The investigated model is cheap, easy to handle, it does not involve experimental animals and it can be scaled up to produce large amounts of metabolites.
authors.affiliation: Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123, Uppsala, Sweden.
authors.forename: Axel
authors.initials: A
authors.lastname: Rydevik
authors.affiliation: Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123, Uppsala, Sweden.
authors.forename: Annelie
authors.initials: A
authors.lastname: Hansson
authors.affiliation: Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123, Uppsala, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Hellqvist
authors.affiliation: Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123, Uppsala, Sweden.|National Veterinary Institute (SVA), Department of Chemistry, Environment and Feed Hygiene, SE-75651, Uppsala, Sweden.
authors.forename: Ulf
authors.initials: U
authors.lastname: Bondesson
authors.affiliation: Division of Analytical Pharmaceutical Chemistry, Department of Medicinal Chemistry, Uppsala University, Box 574, SE-75123, Uppsala, Sweden.|National Veterinary Institute (SVA), Department of Chemistry, Environment and Feed Hygiene, SE-75651, Uppsala, Sweden.
authors.forename: Mikael
authors.initials: M
authors.lastname: Hedeland
mesh_terms: D000082:Acetaminophen / Q000032:analysis / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D020093:Cunninghamella / Q000737:chemistry / Q000378:metabolism*; D004008:Diclofenac / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D008528:Mefenamic Acid / Q000032:analysis / Q000378:metabolism*; D008862:Microsomes, Liver / Q000737:chemistry / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D004008:Diclofenac; D000082:Acetaminophen; D008528:Mefenamic Acid
keywords: Q-ToF; cysteine; diclofenac; glutathione; mefenamic acid; paracetamol; toxic metabolites; trapping