Determinação da Energia de Ativação e Pureza de Formulações Farmacêuticas Contendo Paracetamol Utilizando Técnicas Termoanalíticas

Paracetamol ( acetaminophen , N -acetyl- p- aminophenol ) is an antipyretic analgesic that has anti -inflammatory effect and is widely used in Brazil . This work was made use of Thermogravimetry ( TG ) and differential scanning calorimetry ( DSC ) to determine the activation energy and purity of pharmaceutical commercial forms of reference, generic and similar containing the active principle paracetamol . The Ozawa method was applied for the activation energy using thermogravimetric curves in three heating rates ( 5 , 10 and 20 ° C min - 1 ) . The results showed an average activation energy for the thermal decomposition evaluated between 87.2 and 103.7 kJ mol -1 . The Van't Hoff equation applied to the paracetamol fusion event observed in the DSC curves showed 99.5 , 99.3 and 99.6 % purity for the reference samples , and like generic , respectively.