title: Microbial oxidative metabolism of diclofenac: production of 4'-hydroxydiclofenac using Epiccocum nigrum IMI354292.
abstract: The 4'-hydroxylated metabolite of diclofenac was produced by biocatalysis for probing specific human drug-metabolising enzymes (CYP2C9). An initial screen of 11 microorganisms was carried out (50 ml scale) to identify the organism best suited to the regioselective conversion of diclofenac to its 4'-hydroxylated metabolite. From this screen, the fungus Epicoccum nigrum IMI354292 was selected as the most suitable microorganism. Scale-up was carried out in a 30-l fermenter to which 2 g diclofenac was added. After 48 h, 50% of the diclofenac had been converted to it 4'-hydroxylated metabolite. The broth was then extracted with ethyl acetate and purified by chromatography and crystallisation. This yielded 0.3 g 4'-hydroxydiclofenac with a purity of at least 99%. The 4'-hydroxydiclofenac produced by E. nigrum was characterised by HPLC, mass spectrometry and NMR.
authors.affiliation: Department of Drug Metabolism, Pfizer Central Research, Sandwich, Kent, UK.
authors.forename: R
authors.initials: R
authors.lastname: Webster
authors.forename: M
authors.initials: M
authors.lastname: Pacey
authors.forename: T
authors.initials: T
authors.lastname: Winchester
authors.forename: P
authors.initials: P
authors.lastname: Johnson
authors.forename: S
authors.initials: S
authors.lastname: Jezequel
mesh_terms: D001711:Biotransformation; D002851:Chromatography, High Pressure Liquid; D004008:Diclofenac / Q000378:metabolism*; D005658:Fungi / Q000201:enzymology*; D006801:Humans; D006900:Hydroxylation; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010084:Oxidation-Reduction
chemical_list: D004008:Diclofenac