ABSTRACT
The present work evaluated a microwave-assisted wet digestion method using diluted HNO3 with in situ UV radiation for the digestion of starch and skimmed milk powder for further metals determination by spectrometric plasma-based techniques. The sample digestion was conducted using an in situ UV lamp (electrodeless discharge lamp), and the digestion efficiency was improved by employing O2 (20 bar) and 2 mL 30 % H2O2 as auxiliary reagents. The accuracy of the proposed digestion method was evaluated by metals determination (Ca, Cd, Cu, Fe, K, Mg, Mo, Mn, Na, Pb, and Zn) in certificated reference material, which agreed with certified values (Student t-test <0,05). With the use of a UV lamp an environmentally friendly protocol was developed for starch and skimmed milk powder digestion using 0.1 mol L-1 HNO3 with auxiliary reagents (H2O2 or O2). The RCC value ranged from 0.9 to 1.2 % (starch and skimmed milk powder, respectively). The simultaneous cooling approach further improved the digestion efficiency (RCC <0,3 % for both samples), allowing to use milder digestion conditions, or even just water, being environmentally friendly, reducing the waste generation and reagents consumption, allowing food quality control through a greener approach.
Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Trace Elements , Humans , Animals , Milk/chemistry , Powders/analysis , Hydrogen Peroxide/analysis , Microwaves , Starch/analysis , Ultraviolet Rays , Metals/analysis , Indicators and Reagents , Digestion , Trace Elements/analysisABSTRACT
Vildagliptin (VLG) corresponds to a drug used for the treatment of diabetes mellitus. This disease requires continuous treatment, and so the control of impurities present in it is important to assure the quality of this drug. Thus, it is necessary to use sensitive and selective detection techniques and the ultra-performance liquid chromatography is a better option compared with high-performance liquid chromatography because it enhances the separation efficiency with a shorter analysis time and an increased resolution. This research analysis was accomplished by using liquid chromatography/tandem mass spectrometry, and the quantification was performed by using an extracted ion from the VLG drug and its main organic impurities of synthesis. During the validation process, following international standards, the method proved to be linear for the tree substances (R2 = 0.997-0.998) and the analysis of variance showed a non-significant linearity deviation (P > 0.05). Three critical factors were selected to evaluate method robustness with a full factorial experimental design, and the changes in the parameters were found to be not significant for the quantification of VLG and its impurities. The ultra-performance liquid chromatography-tandem mass spectrometry for the determination of impurities in VLG was precise, accurate and robust proving to be effective for analysis in the pharmaceutical industry and to improve the quality, safety and effectiveness of the new drug developed.
Subject(s)
Chromatography, High Pressure Liquid/methods , Drug Contamination , Tandem Mass Spectrometry/methods , Vildagliptin/analysis , Vildagliptin/chemistry , Limit of Detection , Linear Models , Reproducibility of ResultsABSTRACT
BACKGROUND/AIMS: to examine the relationship between the antioxidant potential and severity parameters of cirrhosis in humans. METHODS: fifteen patients with hepatic cirrhosis (nine subjects - Child group B, and six subjects - Child group C) and nine control subjects were enrolled in the study. The main criteria taken into account to characterize the diagnosis of cirrhosis and its complications were the AST: ALT ratio, AST to platelet ratio index, Bonacini score, Meld score and Child classification. Those parameters were determined based on laboratory results and patient's clinical records. Se, Zn, ascorbic acid (AA) levels and oxidative stress parameters were measured in blood samples of cirrhotic patients. RESULTS: the analysis of plasma levels of Se and AA showed low concentrations in cirrhotic patients compared with control subjects (P < 0.05). Though, there was a positive correlation between plasma of Se and severity parameters of cirrhosis in patients of Child group B and C. In the activity of the antioxidant enzymes only catalase was lower in patients of Child group C compared with control group. CONCLUSION: we found low plasma levels of Se and AA among cirrhotic patients. However, is not clear why selenium levels tend to increase with the severity of liver cirrhosis.
Introducción/Objetivos: examinar la relación entre los potenciales antioxidantes y los parámetros de gravedad de la cirrosis en los seres humanos. Métodos: quince pacientes con cirrosis hepática (nueve sujetos - grupo Child B, y seis sujetos - grupo Child C) y nueve sujetos control fueron incluidos en el estudio. Los principales criterios que se tuvieron en cuenta para caracterizar el diagnóstico de la cirrosis y sus complicaciones fueron la AST: relación de ALT, AST índice de la relación de plaquetas, clasificación Bonacini, clasificación MELD y clasificación de Child. Estos parámetros fueron determinados con base en los resultados de laboratorio y los registros clínicos del paciente. Se midieron los niveles de Zn, ácido ascórbico (AA) y los parámetros de estrés oxidativo en muestras de sangre de pacientes cirróticos. Resultados: el análisis de los niveles plasmáticos de Se y AA mostraron bajas concentraciones en los pacientes cirróticos en comparación con los sujetos control (P < 0,05); sin embargo, hubo una correlación positiva entre el plasma de Se y los parámetros de gravedad de la cirrosis en pacientes del grupo Child B y C. En la actividad de las enzimas antioxidantes catalasa solamente fue menor en los pacientes del grupo Child C, en comparación con el grupo control. Conclusión: se encontraron niveles bajos en plasma de Se y AA en pacientes cirróticos. Sin embargo, no está claro por qué los niveles de selenio tienden a aumentar con la gravedad de la cirrosis hepática.
