Studies on the thermal decomposition process and kinetics of purine drugs.
OBJECTIVE
To study the thermal stability, decomposition process and kinetics of such purine pharmaceuticals as aciclovir (Acv), penciclovir (Pcv), and their parent substance, guanine.


METHODS
Using infrared technique, accelerating test method and thermogravimetry to investigate the thermal decomposition processes and using Coast-Redfern method, MKN method and Ozawa method to deal with the data to get kinetic functions.


RESULTS
The decomposition process and the formed products were derived, the kinetic model function was suggested by comparison of the kinetic parameters.


CONCLUSIONS
Pcv and Acv's degrading product for the first step is guanine. The sequences of their thermal stabilities is: Pcv > Acv. The two drugs' kinetic equation of thermal decomposition is expressed as: da/dt = Ae-Ea/RT2(1-alpha)3/2.
Zhang
Jian
J
College of Chemistry and Life Sciences, South-central University for Nationalities, Wuhan 430074, China.
Sheng
Rui-long
RL
Mai
Wen-peng
WP
D000212:Acyclovir / Q000031:analogs & derivatives* / Q000737:chemistry*; D004355:Drug Stability; D006147:Guanine / Q000737:chemistry; D006358:Hot Temperature; D007700:Kinetics; D013816:Thermodynamics; D013818:Thermogravimetry
C053539:penciclovir; D006147:Guanine; D000212:Acyclovir