title: Isolation and identification of seven metabolites of a water-soluble platelet aggregation inhibitor in rat urine.
abstract: 1. Seven metabolites of 7-piperidino-1,2,3,4,5-tetrahydroimidazo[2,1- b]quinazolin-2-one dihydrochloride monohydrate (DN-9693) were isolated from rat urine by extraction with Amberlite XAD-2 and purification by silica gel and Sephadex LH-20 open-column chromatography and preparative high-performance liquid chromatography (hplc). The structure assignment of the metabolites was performed by field desorption mass spectrometry and 200-MHz Fourier transform nmr spectroscopic analysis and comparison with authentic standards when available. 2. DN-9693 underwent metabolism mainly at the piperidine ring to give the 4-hydroxypiperidine derivative (III) and 2-hydroxy-piperidine derivative, which is further metabolized to lactam (II) or delta-aminovaleric acid (V). The acyl side chain of V was shortened by beta-oxidation to form the 3-aminopropionic acid derivative (VII). V and/or VII underwent oxidative dealkylation to give the 7-amino derivative, which was conjugated with acetic acid to form the 7-acetylamino derivative (IV). DN-9693 also underwent hydrolysis of its lactam moiety to give VI. 3. The urinary excretion of III, V and VII was determined by liquid chromatography/electrochemistry (LC/EC) and V proved to be the major metabolite in rat urine. 4. A procedure is also presented for the identification of DN-9693 metabolites using LC/EC.
authors.affiliation: Drug Metabolism and Analytical Chemistry Research Center, Daiichi Pharmaceutical Co. Ltd, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: F
authors.initials: F
authors.lastname: Ishikawa
authors.forename: H
authors.initials: H
authors.lastname: Hakusui
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005583:Fourier Analysis; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry; D015394:Molecular Structure; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000652:urine*; D011799:Quinazolines / Q000652:urine*; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility; D014867:Water
chemical_list: D010975:Platelet Aggregation Inhibitors; D011799:Quinazolines; D014867:Water; C049662:1,5-dihydro-7-(1-piperidinyl)-imidazo(2,1-b)quinazolin-2(3H)-one