INVESTIGADORES
VIRKEL Guillermo Leon
artículos
Título:
Comparative disposition of ricobendazole enantiomers after intravenous and subcutaneous administration of a racemic formulation to calves
Autor/es:
CRISTOFOL, C., VIRKEL, G., ALVAREZ, L., ARBOIX, M., LANUSSE, C.E.
Revista:
Biopharmaceutics and Drug Disposition
Editorial:
John Wiley & Sons, Inc.
Referencias:
Año: 2000 vol. 21 p. 303 - 311
ISSN:
1099-081X
Resumen:
The enantioselective disposition kinetics of the benzimidazole
anthelmintic, ricobendazole (RBZ), have been characterized after its
intravenous (iv) and subcutaneous (sc) administration as a racemic
formulation to cattle. The (+) and (-) RBZ enantiomeric forms were
recovered in plasma after iv and sc administration of the racemic RBZ
formulation, using a chiral phase based HPLC method. A biexponential
plasma concentration versus time curve was observed for both RBZ
enantiomers following the iv treatment. Total body clearance was higher
for (-) RBZ (150.4 mL/h. kg) compared with that obtained for the (+) RBZ
antipode (78.1 mL/h. kg). The elimination half-life of the (-) RBZ
enantiomer was shorter (T1/2beta: 2.67 h) compared with the (+)
enantiomer (T1/2beta: 5.41 h). The plasma availability (expressed as
AUC) was significantly higher for (+) RBZ compared with that obtained
for the (-) antipode following both treatments. The enantiomeric ratio
in plasma at T(0) was close to unity (50% of each enantiomer); the
analysis of the concentration ratios (+) RBZ/(-) RBZ, demonstrated an
increase in the proportion of (+) RBZ during the time course of the
kinetics after both iv and sc treatments. The results presented herein
show the enantioselective disposition kinetics of RBZ in cattle and are a
further contribution to the understanding of the kinetic behaviour of
these sulphoxide-containing benzimidazole anthelmintics in ruminants.