RESUMEN
The degradation kinetics of the antibiotic telithromycin using a stability-indicating high-performance liquid chromatography (HPLC) method is demonstrated. The photodegradation is performed by UVC lamp-254 nm (15W), installed in a chamber internally coated with mirrors, where telithromycin solutions prepared from coated tablets are placed in quartz cells. To promote oxidation, the reaction between the telithromycin solution and 3% hydrogen peroxide solution is carried out. The kinetics parameters of order of reaction and the rate constants of the degradation are determined for both conditions. The degradation process of telithromycin can be described by first-order kinetics under both experimental conditions used in this study. The results reveal the photo and oxidation lability of the drug and confirm the reliability of HPLC method for telithromycin in the presence of its degradation products.
Asunto(s)
Antibacterianos/química , Cromatografía Líquida de Alta Presión/métodos , Cetólidos/química , CinéticaRESUMEN
Foi realizada a dosagem biologica de produtos comerciais de heparina e de amostras do Primeiro Padrao Nacional Argentino de Heparina da mucosa intestinal suina. Os resultados foram comparados com o Quarto Padrao Internacional. Foi empregado o metodo de Reinert e Winterstein, modificado preconizado pelas Farmacopeias Americana e Brasileira. Foram discutidas as metodologias descritas na literatura e indicada a importancia destas para a avaliacao da atividade anticoagulante das heparinas nao-fracionadas e das de baixo peso molecular.
Asunto(s)
Animales , Heparina/farmacología , Sitios de Unión , Bioensayo , Heparina/química , Peso Molecular , Estándares de Referencia , Ovinos/sangre , Relación Estructura-Actividad , PorcinosRESUMEN
Heparin samples from four manufacturers and the First Argentinian Standard Heparin obtained from porcine mucosa were assayed by the Reinert and Winterstein method, modified as suggested by USP and Brazilian Pharmacopeias. Other methods described in the literature and their importance for the evaluation of anticoagulant activity of unfractionated heparins with low molecular weight are discussed.