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阿斯匹林的分解主要是水解生成水杨酸和醋酸。为了抑制水解反应、提高稳定性,一般可以调节pH;和有机溶剂混合而改变介电常数;减少水份;增加粘性;调节离子强度;制成稳定的复合物;添加表面活性剂和控制温度等。低温可使水解反应减慢。作者研究了各种pH值下的水解反应速度常数,发现最稳定的pH是2.5左右。因而液体制剂应尽可
Aspirin decomposition is mainly the hydrolysis of salicylic acid and acetic acid. In order to suppress the hydrolysis reaction and improve the stability, it is generally possible to adjust the pH; to change the dielectric constant by mixing with an organic solvent; to reduce the moisture; to increase the viscosity; to adjust the ionic strength; to make a stable composite; to add a surfactant and to control the temperature . Low temperature can slow down the hydrolysis reaction. The authors studied the rate constants of hydrolysis reactions at various pH values and found that the most stable pH was about 2.5. Thus liquid formulations should be as much as possible