INVESTIGADORES
VIRKEL Guillermo Leon
artículos
Título:
Comparative depletion of ivermectin and moxidectin milk residues in dairy sheep after oral and subcutaneous administration
Autor/es:
IMPERIALE, F., LIFSCHITZ, A., SALLOVITZ, J., VIRKEL, G., LANUSSE, C.
Revista:
Journal of Dairy Research
Editorial:
CAMBRIDGE UNIV PRESS
Referencias:
Año: 2004 vol. 71 p. 427 - 433
ISSN:
0022-0299
Resumen:
Ivermectin (IVM) and moxidectin (MXD) are broad-spectrum endectocides
belonging to the avermectin/milbemycin class of antiparasitic drugs not
approved for use in dairy sheep. However, these compounds are widely
used extra-label to control endo- and ecto-parasites in lactating dairy
sheep. Effects of the route of administration on the pattern of IVM and
MXD excretion in milk were comparatively characterized in lactating
dairy sheep. The relationship between the milk and plasma disposition
kinetics after subcutaneous (s.c.) and oral administration at 200 μg/kg
body weight was also evaluated. IVM and MXD concentration profiles were
measured in milk and plasma using a specific HPLC-based methodology. IVM
and MXD were extensively distributed from the bloodstream to the
mammary gland and large quantities, particularly for MXD, were excreted
in milk. Residual concentrations of IVM were recovered in milk up to 11 d
(oral treatment) or 25 d (s.c. treatment) post treatment. However, high
MXD concentrations were detected in milk between 1 h and 35 d after its
oral and subcutaneous administration. MXD concentrations as high as
3.77 ng/ml (oral) and 30.3 ng/ml (s.c.) were measured in milk at day 35
post administration. A higher MXD excretion in milk, compared with that
of IVM, was obtained for both administration routes. An extensive plasma
to milk distribution pattern was observed, being the area under the
concentration-time curve of MXD obtained in milk up to 14-fold higher
than that measured in the bloodstream. The total fraction of the
administered dose excreted in milk for MXD was significantly higher than
that for IVM, which agrees with the well known higher MXD
lipophilicity. The long persistence of milk residual concentrations of
MXD and IVM in lactating dairy sheep should be seriously considered
before their extra-label use is recommended.