The present study reports the stability profile of an antithrombotic drug: dabigatran etexilate (DAB). The drug was subjected to thermal degradation at 60 ºC and products formed were investigated by liquid chromatography-UV (LC-UV) and liquid chromatography-mass spectrometry (LC-ESI-MS). Chromatographic separation of the degradation products was performed on a GL Sciences Inc. Inertsil ODS-2 column (250 mm × 4.6 mm i.d., with a particle size of 5 µm and pore size of 110 Å) with mobile phase consisting of acetonitrile and ammonium acetate buffer (pH 5.5; 10 mmol L−1) (65:35, v/v) pumped at 1.0 mL min−1 flow rate. Column temperature was set at 30 ºC and detection at 225 nm using a UV detector. LC-UV method previously validated was extended to LC-ESI-MS for the characterization of the degradation products (DP-01 and DP-02) formed, without complicated isolation or purification processes, based on retention times and confirmation of molecular weight. Degradation kinetics of DAB was also evaluated and could be described as a first-order process (R2= 0.9900). Furthermore, no evidence of cytotoxicity in human mononuclear cells was observed for DAB degraded samples.

A stability-indicating method using MEKC was validated for the analysis of olmesartan medoxomil in tablets. Successful separation was achieved using a fused silica capillary (40 cm x 50 µm i.d.); background electrolyte consisted of a combination of 10 mmol L-1 borate buffer and 5 mmol L-1 anionic detergent sodium dodecyl sulfate (95:5; v/v) pH 6.5; hydrodynamic mode at 50 mBar for 5 s; 25 kV separation voltage at 25 ºC; and column temperature 25 ºC with detection at 257 nm. The proposed method, validated following ICH guidelines, was applied to the determination of this antihypertensive with good results compared with an LC method.

OBJETIVO: Determinar a concentração plasmática de zinco em crianças e adolescentes cirróticos e investigar a associação entre esses resultados e a ingestão dietética de zinco, os dados antropométricos e a gravidade da doença hepática. MÉTODOS: As concentrações plasmáticas de zinco foram avaliadas por espectrofotometria de absorção atômica em 30 crianças e adolescentes com cirrose (105,0±60,0 meses; 22 meninas) e 27 hígidas e sem doença hepática (122,3±47,3 meses, 14 meninas). Os dados relacionados ao zinco dietético foram avaliados por registro de ingestão alimentar de 3 dias. A antropometria incluiu peso, altura, espessura da dobra cutânea, circunferência braquial e área muscular do braço. A gravidade da doença hepática foi classificada de acordo com os critérios de Child-Pugh, MELD e PELD. RESULTADOS: As concentrações plasmáticas de zinco dos indivíduos controles e dos pacientes foram 105,69±19,46 e 75,44±24,45 μg/dL, respectivamente (p < 0,001). Nenhuma associação foi encontrada entre os índices antropométricos, a ingestão dietética e o zinco plasmático. Houve diferença estatística nas concentrações de zinco plasmático entre pacientes Child-Pugh B+C e controles (p < 0,001), e com relação ao PELD, entre pacientes abaixo e acima do ponto de corte 15 (p = 0,002). CONCLUSÃO: A prevalência de hipozincemia foi de 43% para pacientes com cirrose. A baixa concentração plasmática de zinco foi associada com a doença hepática grave; entretanto, a hipozincemia esteve presente mesmo em pacientes Child-Pugh A. Portanto, a suplementação de zinco deve ser considerada para os pacientes pediátricos cirróticos.

OBJECTIVE: To determine plasma zinc concentrations in children and adolescents with cirrhosis and to investigate the association between these results and dietary zinc intake, anthropometric data, and severity of liver disease. METHODS: Plasma zinc concentration was assessed by atomic absorption spectrophotometry in 30 children and adolescents with cirrhosis (105.0±60.0 months; 22 girls) and 27 without liver disease (122.3±47.3 months, 14 girls). Dietary zinc data were evaluated by 3-day food intake records. Anthropometry measures included height, weight, skinfold thickness, brachial circumference, and upper arm muscle size. Severity of liver disease was classified according to the Child-Pugh, MELD, and PELD criteria. RESULTS: The mean (± standard deviation) plasma zinc concentrations in control subjects and patients were 105.69±19.46 and 75.44±24.45 μg/dL, respectively (p < 0.001). No associations were found between anthropometric measures, dietary zinc intake, and plasma zinc concentration. There was statistical difference related to plasma zinc concentrations between Child-Pugh B + C patients and control subjects (p < 0.001), and concerning PELD, between patients below the cutoff score of 15 and those above (p = 0.002). CONCLUSION: The prevalence of hypozincemia was 43% for patients with cirrhosis. Although low plasma zinc concentration was associated with more severe liver disease, it was present even in some Child-Pugh A patients. Therefore, zinc supplementation should be considered for cirrhotic children.