ABSTRACT
Enantioselective separations on chiral stationary phases with or without derivatization were developed and compared for the HPLC analysis of (+)-(R)- and (-)-(S)-metoprolol acidic metabolite in human plasma and urine. The enantiomers were analysed in plasma and urine without derivatization on a Chiralcel OD-R column, and in urine after derivatization using methanol in acidic medium on a Chiralcel OD-H column. The quantitation limits were 17 ng of each enantiomer/ml plasma and 0.5 microgram of each enantiomer/ml urine using both methods. The confident limits show that the methods are compatible with pharmacokinetic investigations of the enantioselective metabolism of metoprolol. The methods were employed in a metabolism study of racemic metoprolol administered to a patient phenotyped as an extensive metabolizer of debrisoquine. The enantiomeric ratio (+)-(R)/(-)-(S)-acid metabolite was 1.1 for plasma and 1.2 for urine. Clearances were 0.41 and 0.25 l/h/kg, respectively, for the (+)-(R)- and (-)-(S)-enantiomers. The correlation coefficients between the urine concentrations of the acid metabolite enantiomers obtained by the two methods were >0.99. The two methods demonstrated interchangeable application to pharmacokinetics.
Subject(s)
Adrenergic beta-Antagonists/pharmacokinetics , Chromatography, High Pressure Liquid/instrumentation , Metoprolol/pharmacokinetics , Adrenergic beta-Antagonists/blood , Adrenergic beta-Antagonists/urine , Area Under Curve , Chromatography, High Pressure Liquid/methods , Humans , Metoprolol/blood , Metoprolol/urine , Reference Standards , Reproducibility of Results , Sensitivity and Specificity , Spectrometry, Fluorescence , StereoisomerismABSTRACT
Os autores analisaram qualitativamente os pós de alguns cimentos obturadores de canais radiculares (Endométhasone, endométhasone Ivory, Fillcanal e N- Rickert) na tentativa de identificar os componentes químicos presentes nesses pós. Os testes realizados foram de microanálise espectrográfica a laser, espectrofotometria de absorção atômica e espectrofotometria de infravermelho. Os resultados dos testes demonstraram que os cimentos estudados apresentaram contaminação por diversos íons metálicos, inclusive o chumbo.
Subject(s)
Dental Cements/chemistry , Evaluation Studies as Topic , Spectrophotometry, Atomic/methods , Lead/toxicity , Spectrography , Spectrophotometry, InfraredABSTRACT
No presente estudo, analisou-se o efeito da adiçäo de diferentes tipos de breus e resinas hidrogenadas ao pó do cimento de GROSSMAN sobre o tempo de endurecimento. Os experimentos foram realizados de acordo com a Especificaçäo 57 para materiais obturadores de canais radiculares da American Dental Association (ADA). Para análise, foram aviados pós do cimento de GROSSMAN com diferentes tipos de breu (X, WW e WG) e resinas hidrogenadas (Stabylite e Stabylite éster 10). Os estudos das propriedades físico-químicas dos cimentos tipo GROSSMAN obtidos de diferentes tipos de breus e resinas hidrogenadas interferem no tempo de endurecimento do cimento. A resina hidrogenada, obtida do processo de hidrogenaçäo tem o pH mais alto, provocando um aumento do tempo de endurecimento do cimento em relaçäo aos breus tipo X, WW e WG, que têm pH mais ácido
