INVESTIGADORES
VIRKEL Guillermo Leon
artículos
Título:
A detailed assessment of the pattern of moxidectin tissue distribution after pour-on treatment in calves
Autor/es:
SALLOVITZ JM, LIFSCHITZ A, IMPERIALE F, VIRKEL G, LANUSSE C.
Revista:
JOURNAL OF VETERINARY PHARMACOLOGY AND THERAPEUTICS
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 2003 vol. 26 p. 95 - 103
ISSN:
0140-7783
Resumen:
The use of topical (pour-on) administration of endectocide drugs in
cattle has reached world-wide acceptance. However, only limited
information is available on the kinetic behaviour for topically
administered moxidectin (MXD). To improve our understanding of the
relationship between pharmacokinetics and efficacy for pour-on
preparations, MXD concentration profiles were measured in tissues of
endo- and ectoparasites location over 35 days postadministration. MXD
distribution to the fluid content and mucosal tissue of the abomasum and
different intestinal sections (duodenum, ileum, caecum and colon) was
assessed. The comparative patterns of MXD distribution to skin and
hypodermic tissue from different anatomical sites (backline, rib cage,
thigh and face) were also investigated following the pour-on
administration. Wide tissue distribution and long residence time
characterized the kinetics of topically administered MXD. MXD was
recovered between 1 and 35 days post-treatment in all the tissues
investigated. The highest MXD availabilities were observed in the skin
layers at the site of administration (backline) and in the fat tissue.
The fluid contents of different intestinal sections showed MXD
concentrations higher than those measured in their respective mucosal
tissues, particularly at day 1 post-treatment. MXD concentrations in the
skin (epidermis + dermis) were higher than those measured in the
hypodermic tissue. Large differences in the availability of MXD in skin
from different anatomical regions (backline > rib cage > thigh
> face) were observed. The low plasma and the high skin availability
indicate the formation of a skin depot of the drug, being released
slowly to the plasma and reaching concentrations in systemic tissues
(abomasal mucosa, lungs, etc.) similar to those measured after
subcutaneous administration. These findings demonstrate that target
parasites may be exposed to markedly different drug concentrations
according to their location sites, which is particularly relevant for
ectoparasites located in different anatomical regions. Knowledge of the
tissue distribution of topically administered endectocides contributes
to understand the differences observed in efficacy and/or persistence of
activity and to optimize their use in cattle.