TOXICOKINETICS OF AMITRAZ FOLLOWING SINGLE DERMAL APPLICATION IN GOATS
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Date
2014-05-26
Authors
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Journal ISSN
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD
Abstract
Amitraz is a formamidine derivative widely used for the control of ticks and
mange mites in animals. The work reported here describes the toxicokinetics of
amitraz in Malabari goats after single dermal application at 0.25 per cent. Blood
samples were collected at predetermined time intervals up to 168 h and milk samples
were collected every morning and evening up to eight days post dermal application.
Analysis of amitraz was done by High Performance Liquid Chromatography. Amitraz
was detected in blood within 0.5 h attaining a peak concentration of 7.24 ± 0.79 at 6 h
followed by a decline and persisted till 168 h. The various kinetic parameters were
calculated using a two compartment open model. The absorption rate constant (Ka),
apparent volume of distribution (V / F), elimination half-life (t1/2β), ratio of k12 and
K21, tissue-blood ratio and mean residence time (MRT) were 0.58 h
-1
, 33.29 µl / mg,
172.59 h, 0.63, 0.71 and 240.10 h respectively. Amitraz was rapidly absorbed from
the site of application, widely distributed and slowly eliminated from the body. The
lower tissue-blood ratio suggested its minimum affinity for accumulation in the
tissues. The concentration of amitraz detected in milk ranged from 0.37-0.44 mg / L
until the duration of the study period. Absorption of the retained drug from the
application site contributed to the persistent concentration detected in the blood and
milk till 168 h.