【摘要】 目的　探讨呋喃西林水溶液对光和热的稳定性 ,并考察在高温光照试验中用变温法代替恒温法的可能性。方法　用恒温加速试验和变温加速试验的方法。结果　该药物在恒温避光加速试验和恒温光照加速试验中的降解均遵从零级动力学规律。在高温和光照同时作用下的降解速率常数k由两部分构成 :k =kdark+klight,kdark 和klight分别为避光时热反应的降解速率常数及光化反应的降解速率常数 ,且klight=Alight·exp(-Ea ,light RT)·E。其中E为光源的照度 ,Alight和Ea ,light为试验常数。变温法所求得的参数值与恒温法一致。结论　在研究光和热对药物稳定性影响的试验中 ,可以采用变温法代替恒温法 ,以节省时间和样品 ,减少工作量更多还原

【Abstract】 AIM To study the effect of both light and heat on the stability of furacilin aqueous solution and the probability of substituting for isothermal accelerated tests by nonisothermal accelerated tests upon exposure to light at high temperatures. METHODS The isothermal and nonisothermal accelerated tests were employed. The accelerated tests were proceeded in the dark and exposed to light at high temperature. Tungsten, ultraviolet and fluorescent lamps were employed in exposure tests. RESULTS The degradation of furacilin aqueous solution in isothermal heating experiments or the exposure experiments to light at high temperatures obeys zero order kinetics. The total degradation rate constant k caused by both light and heat can be divided into two parts: k = k dark + k light , where k dark and k light are the degradation rate constant caused by heat and light, respectively. The k light can be expressed as k light = A light ·exp(- E a,light / RT)·E , where E is the illuminance of light; A light and E a,light are both experimental constants. The parameters obtained in nonisothermal accelerated tests were comparable to those obtained in classic isothermal accelerated tests. CONCLUSION Nonisothermal accelerated tests may substitute for isothermal accelerated tests during the study of the effects of both light and heat on the stability of drugs, in order to save time, labor and drugs.更多还原