title: Heat-accelerated degradation of solid-state andrographolide.
abstract: The stability of andrographolide, the major active diterpene lactone from Andrographis paniculata (BURM. f.) WALL. ex NEES., was determined to show that, while crystalline andrographolide was highly stable even at 70 degrees C (75% relative humidity) over a period of 3 months, its amorphous phase degraded promptly. Heat-accelerated conditions revealed second-order kinetics of the decomposition with the rate constant at 25 degrees C (k(25 degrees C)) predicted from the Arrhenius plot of 3.8 x 10(-6) x d(-1). The major decomposed product under elevated temperature (70 degrees C, 75% relative humidity) is 14-deoxy-11,12-didehydroandrographolide.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Thailand.
authors.forename: Luelak
authors.initials: L
authors.lastname: Lomlim
authors.forename: Noppong
authors.initials: N
authors.lastname: Jirayupong
authors.forename: Anuchit
authors.initials: A
authors.lastname: Plubrukarn
mesh_terms: D004224:Diterpenes / Q000737:chemistry / Q000378:metabolism*; D006358:Hot Temperature
chemical_list: D004224:Diterpenes; C030419:andrographolide