Influence of light and heat on the stability of rotundine sulfate injection

✍ Scribed by Linli Li; Xiancheng Zhan; Kailan Li; Xiucen Yang

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 160 KB
• Volume: 90
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.1100

✦ Synopsis

The in¯uence of both light and heat on the stability of rotundine sulfate injection was studied. Results show that in experiments with either isothermal heating or exposure to light at high temperatures, the drug coloration rate obeys zero-order kinetics. The total rate constant, k total , caused by both light and heat can be divided into two parts: k total k dark k light , where k dark and k light are the rate constants caused by heat and light, respectively. The k light can be expressed as k light A light exp(ÀE a,light /RT)E, where E is the illuminance of light, A light is an experimental constant related to light sources, and E a,light is an experiment constant. Because the form of k light is similar to the Arrhenius equation, it is suggested that E a,light might be the observed activation energy of the rate-determining step of the subsequent processes of the photochemical reaction. This viewpoint is supported by the fact that E a,light is independent of light sources.