The thermal stability of raw material and tablet of acetaminophen

The weight loss curves(TG) of raw materials and tablets of acetaminophen(PAPA) were measured by thermal analysis.The result indicated that initial weight loss temperature of acetaminophen tablet is higher than that of acetaminophen raw material.For example,initial weight loss temperature was 504 K for tablet,while 464 K for raw material,when the heating rate was 10 K·min-1.In this paper,the apparent activation energy and pre-exponential factor for raw material and tablet of acetaminophen were obtained by Kissinger method.And the apparent activation energy and pre-exponential factor are 56.73 kJ·mol-1 and 1.100×105(for raw material),103.0 kJ·mol-1and 8.340×108(for tablet),respectively.According to Arrhenius equation,the thermal degradation rate constant k is calculated as 1.27×10-5(for raw material) and 7.587×10-10(for tablet),respectively.Therefore,the thermal analysis results show that the thermal stability of acetaminophen tablet is higher than that of raw material.The thermodynamic parameters in fusion process of raw material and tablet of acetaminophen were obtained by DSC.