INVESTIGADORES
VIRKEL Guillermo Leon
artículos
Título:
Comparative distribution of ivermectin and doramectin to parasite location tissues in cattle
Autor/es:
LIFSCHITZ, A., VIRKEL, G., SALLOVITZ, J., SUTRA, J.F., GALTIER, P., ALVINERIE, M., LANUSSE, C.
Revista:
VETERINARY PARASITOLOGY
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2000 vol. 87 p. 327 - 338
ISSN:
0304-4017
Resumen:
Pharmacokinetic studies have been used traditionally to characterize
drug concentration profiles achieved in the bloodstream. However,
endectocide molecules exert their persistent and broad spectrum activity
against parasites localized in many different tissues. The aim of this
study was to compare the distribution of ivermectin (IVM) and doramectin
(DRM) to different tissues in which parasites are found following
subcutaneous administration to calves. Holstein calves weighing 120-140
kg were injected in the shoulder area with commercially available
formulations of IVM (Ivomec 1% MSD AGVET, NJ, USA) (Group A) or DRM
(Dectomax 1%, Pfizer, NY, USA) (Group B). Two treated calves were
sacrificed at 1, 4, 8, 18, 28, 38, 48 or 58 days post-treatment. Plasma,
abomasal and small intestinal fluids and mucosal tissues, bile, faeces,
lung and skin samples were collected, extracted, derivatized and
analyzed by high performance liquid chromatography (HPLC) with
fluorescence detection to determine IVM and DRM concentrations. IVM and
DRM were distributed to all the tissues and fluids analyzed.
Concentrations >0.1 ng/ml (ng/g) were detected between 1 and 48 days
post-treatment in all the tissues and fluids investigated. At 58 days
post-treatment, IVM and DRM were detected only in bile and faeces, where
large concentrations were excreted. Delayed Tmax values for DRM (4 days
post-administration) compared to those for IVM (1 day) were observed in
the different tissues and fluids. High IVM and DRM concentrations were
measured in the most important target tissues, including skin. The
highest IVM and DRM concentrations were measured in abomasal mucosa and
lung tissue. Enhanced availabilities of both IVM (between 45 and 244%)
and DRM (20-147%) were obtained in tissues compared to plasma. There was
good correlation between concentration profiles of both compounds in
plasma and target tissues (mucosal tissue, skin, and lung). Drug
concentrations in target tissues remained above 1 ng/g for either 18
(IVM) or 38 (DRM) days post-treatment. The characterization of tissue
distribution patterns contributes to our understanding of the basis for
the broad-spectrum endectocide activity of avermectin-type compounds.