Assuntos
Aorta Abdominal/lesões , Tratamento de Emergência/métodos , Cintos de Segurança/efeitos adversos , Ferimentos não Penetrantes/diagnóstico por imagem , Adulto , Fenômenos Biomecânicos , Colostomia , Endarterectomia , Humanos , Masculino , Radiografia , Retalhos Cirúrgicos , Síndrome , Ferimentos não Penetrantes/cirurgiaRESUMO
The use of precision-cut liver slices constitutes a new in vitro metabolism technique for the study of coupled phase I and phase II biotransformations. This technique has the advantage of being easily amenable to studies with human tissue. As a means of characterizing the metabolic viability of diverse liver samples, a standard substrate capable of undergoing oxidative and conjugative pathways of metabolism would be desirable. An assay based on 7-ethoxycoumarin was developed whereby the metabolites--7-hydroxycoumarin, 7-hydroxycoumarin sulfate, and 7-hydroxycoumarin glucuronide--could be quantitated using a single HPLC analytical method. This required the synthesis of metabolite standards. 7-Hydroxycoumarin glucuronide was prepared by coupling 7-hydroxycoumarin with methyl 2,3,4-tri-O-acetyl-1-bromo-1-alpha-D- glucopyranuronate, under phase transfer conditions, to give the protected conjugate that was then hydrolyzed to give the glucuronide as the sodium salt. Assignment of configuration at the anomeric center was based on analysis of the simulated 1H and gated 13C NMR spectra, in addition to enzymatic hydrolysis. The sulfate conjugate was prepared by treatment of 7-hydroxycoumarin with Bu4N+ HSO4-/dicyclohexylcarbodiimide/pyridine. 7-Ethoxycoumarin, 7-hydroxycoumarin, and the glucuronide and sulfate conjugates were resolved by HPLC on a C8 Hypersil BDS column using ion-pairing conditions. Incubation of 7-ethoxycoumarin with rat or human liver slices in Krebs-Henseleit buffer resulted in the formation of these metabolites that were readily quantitated in the media with UV detection at 320 nm, using external standard curves. Although the sulfate was seen as the major metabolite in rats, the glucuronide predominated in human tissue. Two different human livers were examined.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Cumarínicos , Fígado/metabolismo , Adulto , Animais , Biotransformação , Cromatografia Líquida de Alta Pressão , Cumarínicos/síntese química , Cumarínicos/farmacocinética , Glucuronatos/síntese química , Glucuronatos/farmacocinética , Humanos , Hidrólise , Técnicas In Vitro , Fígado/química , Espectroscopia de Ressonância Magnética , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Conformação Molecular , Ratos , Ratos Sprague-Dawley , Espectrofotometria Ultravioleta , Sulfatos/síntese química , Sulfatos/farmacocinética , Umbeliferonas/síntese química , Umbeliferonas/farmacocinéticaRESUMO
A capillary gas chromatographic-mass spectrometric method for the determination of ibuprofen and tetra-deuterated ibuprofen in serum is described. Ibuprofen, [ar-2H4]ibuprofen and the internal standard, [ar-2H4,3,3,3-2H3]ibuprofen, are extracted (after acidification) from serum onto a cross-linked styrene divinyl benzene resin by an automated sample processor. After elution and evaporation of the organic phase, samples are reconstituted with solvent and analyzed without derivatization by capillary gas chromatography-mass spectrometry. This methodology was used to evaluate possible kinetic isotope effects after the coadministration of an equimolar mixture of ibuprofen and the deuterium-labeled covariant in the beagle. No significant differences in absorption or elimination were observed.
