title: Metabolites of an orally active antimicrobial prodrug, 2,5-bis(4-amidinophenyl)furan-bis-O-methylamidoxime, identified by liquid chromatography/tandem mass spectrometry.
abstract: DB75 (2,5-bis(4-amidinophenyl)furan) is a promising antimicrobial agent against African trypanosomiasis and Pneumocystis carinii pneumonia. However, it suffers from poor oral activity in rodent models for both infections. In contrast, a novel prodrug of DB75, 2,5-bis(4-amidinophenyl)furan-bis-O-methylamidoxime (DB289), has excellent oral activity. DB289 is currently undergoing clinical investigation as a candidate drug to treat primary stage African trypanosomiasis and Pneumocystis carinii pneumonia. In this study, metabolites of DB289 formed after incubation with freshly isolated rat hepatocytes were characterized using liquid chromatography/ion trap mass spectrometry. Administration of DB289 and octadeuterated DB289 in a 1 : 1 mixture greatly facilitated metabolite identification by providing isotope patterns with twin ions separated by 8 m/z units in the ratio 1 : 1, in the extracted ion chromatograms of molecular ions and in the product ion mass spectra of metabolites. Ten metabolites were identified. Series of O-demethylations and N-dehydroxylations led to the metabolic activation of DB289 to DB75 with the production of four intermediate phase I metabolites. Phase II glucuronidation and sulfation led to the formation of four glucuronide and one sulfate metabolites.
authors.affiliation: Division of Medicinal Chemistry and Natural Products, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Lian
authors.initials: L
authors.lastname: Zhou
authors.forename: Dhiren R
authors.initials: DR
authors.lastname: Thakker
authors.forename: Robert D
authors.initials: RD
authors.lastname: Voyksner
authors.forename: Mariappan
authors.initials: M
authors.lastname: Anbazhagan
authors.forename: David W
authors.initials: DW
authors.lastname: Boykin
authors.forename: James E
authors.initials: JE
authors.lastname: Hall
authors.forename: Richard R
authors.initials: RR
authors.lastname: Tidwell
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001550:Benzamidines / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D022781:Hepatocytes / Q000378:metabolism; D013058:Mass Spectrometry; D015394:Molecular Structure; D011020:Pneumonia, Pneumocystis / Q000188:drug therapy; D011355:Prodrugs / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D014353:Trypanosomiasis, African / Q000188:drug therapy
chemical_list: D001550:Benzamidines; D011355:Prodrugs; C458513:pafuramidine