对乙酰氨基酚原料及其片剂的热稳定性研究

The thermal stability of raw material and tablet of acetaminophen

用热分析方法测量了对乙酰氨基酚原料及其片剂的热失重曲线,从其热失重曲线可知:片剂的起始失重温度高于原料药.以升温速率为10K.min-1为例,片剂的起始失重温度为504K,而原料药的起始失重温度为464K.本文采用Kissinger法对所获得的热失重曲线进行解析,分别得到他们的表观活化能和指前因子;对乙酰氨基酚原料的表观活化能和指前因子分别为56.73kJ.mol-1和1.100×105;对乙酰氨基酚片剂的表观活化能和指前因子分别为103.0kJ.mol-1和8.340×108.由阿伦尼乌斯公式得到对乙酰氨基酚原料和片剂在298.15K下的热降解速率常数分别为1.27×10-5和7.50×10-10.热分析实验结果表明:对乙酰氨基酚片剂的稳定性高于原料的稳定性.同时,采用DSC测量了对乙酰氨基酚的原料与片剂的熔化过程,得到其相关的热力学参数.

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.