Kinetics of the degradation of indomethacin and acemethacin in basic medium

  1. J. Arcos 1
  2. J. López-Palacios 2
  3. J.M. Leal 1
  4. P. Sánchez Batanero 2
  5. F. Mata 2
  1. 1 Universidad de Burgos

    Universidad de Burgos

    Burgos, España


  2. 2 Universidad de Valladolid

    Universidad de Valladolid

    Valladolid, España


Bulletin de la Société Chimique de France

ISSN: 0037-8968 1878-7126

Any de publicació: 1991

Volum: 128

Pàgines: 314-318

Tipus: Article

Altres publicacions en: Bulletin de la Société Chimique de France


The kinetics of degradation of indomethacin and acemethacin was investigated in basic aqueous media at several temperatures between 20 and 50-degrees-C. Fast polarography, linear sweep voltammetry and UV-VIS spectroscopy were used to obtain the observed first-order rate constants. The rate constant / hydroxide-ion concentration profile was linear with a slope equal to unity, suggesting the relationship: k(obs) = k2 [OH-]. Activation energies and other related parameters were calculated from Arrhenius-type plots. An acceptable scheme for the decomposition of both substances is proposed. The kinetic data obtained from both techniques are in very good agreement and point to the same conclusions. From the half-life times, acemethacin is inferred to be the most stable of the two drugs.