title: Studies on the thermal decomposition process and kinetics of purine drugs.
abstract: 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.
authors.affiliation: College of Chemistry and Life Sciences, South-central University for Nationalities, Wuhan 430074, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Rui-long
authors.initials: RL
authors.lastname: Sheng
authors.forename: Wen-peng
authors.initials: WP
authors.lastname: Mai
mesh_terms: D000212:Acyclovir / Q000031:analogs & derivatives* / Q000737:chemistry*; D004355:Drug Stability; D006147:Guanine / Q000737:chemistry; D006358:Hot Temperature; D007700:Kinetics; D013816:Thermodynamics; D013818:Thermogravimetry
chemical_list: C053539:penciclovir; D006147:Guanine; D000212:Acyclovir