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P. MADRIGAL Y COLS. AN. R. ACAD. NAC. FARM.

RESUMEN

Interacción in vivo del Vanadio con Cefotaxima

Anteriormente, en estudios por HPLC, hemos demostrado in vitro, que la pre-
sencia de V (IV) en las disoluciones de penicilinas y cefalosporinas, aumentan la
degradación de éstas en sus correspondientes ácidos penicilóico y cefalosporánico.
Los mecanismos de la catálisis de V (IV) involucran a un complejo ternario. En
este trabajo se estudia las consecuencias de esta degradación, in vivo, de Cefotaxi-
ma, en sangre, hígado, bazo, riñón, pulmón y corazón, para ver las consecuencias
de la intoxicación de vanadio. Las diferencias más importantes en ratas intoxicadas
con vanadio se observaron en hígado, pulmón y riñón.

Palabras clave: Cefotaxima.—Vanadio.—HPLC.—Farmacocinética.—Farmaco-
dinamia.

INTRODUCTION

The transition metal interactions to penicillins (1-5) and
cephalosporins (6) were studied previously by spectrophotometric
and potenciometric methods. In the case of the cefotaxime, as
impurity, also for HPLC (7).

In those studies, it was observed that the effect of V(IV) on the
penicillins and cephalosporins was to promote their degradation to
coordination complexes of V(IV) and the corresponding penicilloic
and cephalosporanic acids (see Figure 1). Other authors have studied
the formation of the complex, in vitro, between V(IV) and penicillins
and cephalosporins, by means of the reaction mechanisms,
evaluating the stability constants for the interaction between V(IV)
and these antibiotics.

This communication presents the way thought which the
formation of the complex between V(IV) and cefotaxime affects on
the concentration, distribution and stability of this cephalosporin.
The importance of the formation of this complex stems from the
lowest concentration of free cefotaxime in blood and organs only
when takes place intoxication. This concentration could be lower
than the concentration of the cephalosporin that is required to kill
the microorganisms that cause the infection.

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