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    Estabilidade de comprimidos de liberação controlada baseados em hidroxietilcelulose
    (Universidade Federal de São Paulo (UNIFESP), 2016-02-25) Gaiotto, Cristina Aparecida Andrade Raymundo [UNIFESP]; Tada, Dayane Batista [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Cellulose derivatives are polymers commonly used for drug delivery. In this work one of these derivatives, the hydroxiethylcellulose has been applied in the formulation of compressed tablets for controlled release purposes. The tablets were produced by using the same excipients normally used in the commercially available tablets and caffeine was used as model drug. The characterization of raw materials and tablets were performed by using the following techniques: Differential Scanning Calorimetry analysis (DSC), spectroscopic measurements of Raman and UV/VIS, scanning electron microscopy (SEM). The swelling behavior of the polymeric matrix was evaluated by immersion in water and exposition to atmospheric humidity. The drug release profile of the tablets was obtained in ?in vitro? assays in water. The mechanisms of drug release and swelling were characterized by adjusting kinetic data to Higuchi, Korsmeyer and Vergnaud model. Additionally to the establishment of an appropriated formulation for controlled release of caffeine, the present work has identified the effects of compression pressure and storage over the drug release kinetic profile of the tablets. It was observed that the higher compression pressure generates tablets with slower drug release in a anomalous mechanism of release and swelling. The storage under 75/%RH and 30/ºC and 40/ºC increased the rate of drug release in both types of tablets (compressed at higher and at lower pressure). This change has been identified as a consequence of the increased water content of the tablets as well as a result of the relaxation of the polymeric chains due to the increased temperature. Overal, the results obtained, suggested that a criterious planning and combination of raw materials in the design of formulations as well as the set up of the parameters during the production of tablets are critical points to the success of a system for controlled release purposes. Besides, monitoring storage conditions as temperature and humidity is essencial in order to guarantee the controlled release behavior of HEC-based tablets.