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
    info

    Universidad de Burgos

    Burgos, España

    ROR https://ror.org/049da5t36

  2. 2 Universidad de Valladolid
    info

    Universidad de Valladolid

    Valladolid, España

    ROR https://ror.org/01fvbaw18

Journal:
Bulletin de la Société Chimique de France

ISSN: 0037-8968

Year of publication: 1991

Volume: 128

Pages: 314-318

Type: Article

More publications in: Bulletin de la Société Chimique de France

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  • Web of Science Cited by: 5 (31-12-2022)

Abstract

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.