Kinetic Studies from Different Tablets of Furosemide for DTA and TG Isothermal

摘要

The data obtained by DTA and TG were possible to determine the thermal and kineticrnparameters of the furosemide drug, tablets A, B, C and D. The drug furosemide and tablet Brnwere obtained in LTF/UFPB, while the other tablets were acquired in the local drugstores. ThernDTA curves were obtained in Shimadzu DTA, model DTA-50, in temperature range of 25 -rn300℃ and nitrogen atmosphere. The TG curves were obtained in Shimadzu termobalance, modelrnTGA-50H, air and nitrogen flows of 20 and 50 ml/min., respectively, up to 900℃. Furosemiderndrug presented a exothermic process characteristic of decomposition, whereas tablets A, B, Crnand D presented a endothermic process with temperature between 206-209℃. The TGdynamicalrncurves for the tablets and the raw material presented initial temperature ofrndecomposition between 180 - 230℃. The TG-Isothermal curves were obtained in quintuplicatesrnin pre-established temperatures of 180 - 230℃. The rate constants of decomposition (k) andrnactivation energy (Ea) were calculated using the classical Arrhenius' equations, while the shelfrnlife estimate was obtained by the linear modeling and non-linear methods. The data obtainedrnfrom the rate constants of decomposition and the shelf life values revealed that the furosemiderndrug has presented larger stability in relation to tablets. The furosemide tablets has shown thernfollowing order of stability C>B>A>D.