title: Chemiluminescence and LC-MS/MS analyses for the study of nitric oxide release and distribution following oral administration of nitroaspirin (NCX 4016) in healthy volunteers.
abstract: The metabolic fate of nitric oxide (NO) released from nitroaspirin, benzoic acid, 2-(acetyloxy)-3-[(nitrooxy)methyl]phenyl ester (NCX 4016), the lead compound of a new class of NO-releasing non-steroidal anti-inflammatory drugs (NO-NSAIDs) has been studied in eight healthy male Caucasian subjects following p.o. administration of 1600 mg (single dose), by monitoring at different times in plasma the bioactive storage forms of NO, S-nitrosothiols (RSNO) and its oxidation products (NOx). Plasma levels of NOx and RSNO and urinary levels of NOx were determined by an ozone-based chemiluminescent assay using a sensitive Nitric Oxide Analyzer (LOQ: 10 pmol NO injected). In parallel plasma samples were analyzed by a newly developed LC-MS/MS method for analysis of NCX 4015, the metabolite bearing the nitrate ester function. Using MS/MS with multiple reaction monitoring (MRM) in negative ion mode for NCX 4015 and the internal standard (NCX 4015- 13C-D2) it was possible to detect with sufficient accuracy and precision the metabolite in plasma with a quantification limit of 78.1 ng ml(-1). Concentration versus time profile of plasma NCX 4015 gave a Cmax value of 161.94 +/- 47.4 ng ml(-1) and a tmax 4.5 +/- 1 h. The results indicate that both NOx and RSNO (these last for the first time determined in vivo in man following oral administration of a NO-donor drug) are effective plasma markers of NO release in vivo, the latter being an earlier indicator of NO distribution (tmax 2.0 +/- 0.6 h versus 5.4 +/- 1.2 h).
authors.affiliation: Istituto Chimico Farmaceutico Tossicologico, University of Milan, Viale Abruzzi 42, 20131 Milan, Italy. marina.carini@unimi.it
authors.forename: Marina
authors.initials: M
authors.lastname: Carini
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Aldini
authors.forename: Marica
authors.initials: M
authors.lastname: Orioli
authors.forename: Angela
authors.initials: A
authors.lastname: Piccoli
authors.forename: Paola
authors.initials: P
authors.lastname: Tocchetti
authors.forename: Roberto Maffei
authors.initials: RM
authors.lastname: Facino
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001241:Aspirin / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid; D006801:Humans; D008163:Luminescent Measurements; D008297:Male; D013058:Mass Spectrometry; D009569:Nitric Oxide / Q000032:analysis* / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide; C102148:nitroaspirin; D001241:Aspirin