In veterinary medicine amitraz has been used as an insecticide to eliminates mites, lice, and ticks in dogs, cats, goats, swine and cattle. The objective of present study was to developed an analytical method using one-step extraction and determination of the amitraz in veterinary drugs by liquid chromatography (LC). The amitraz was analyzed by LC equipped with Waters XTerra RP18 (4.8×250 mm; 5 ㎛; Waters, USA) analytical column, using 75% acetonitrile (acetonitrile/D.W; 75/25) at 1.0 ml/min. The UV-VIS detection of amitraz was made at 290 nm. Calibration graphs were linear with very good correlation coefficients (r² greater than 0.9999) from 80~120 ㎍/ml. The limit of detection was 0.09 ㎍/ml and limit of quantification was 0.27 ㎍/ml. The method showed good intra-day precision (CV 0.05~0.09%) and inter-day precision (CV 0.06~0.18%).

This study investigated the potential effects of amitraz on the pre- and postnatal development, behavior, and reproductive performance of offspring of parent rats given amitraz during pre-mating, gestation, and lactation. The test chemical was administered via the drinking water containing 0, 40, 120, and 360 ppm to male rats from 2 weeks before mating to the end of 14-day mating period and to females from 2 weeks before mating, throughout mating, gestation and lactation up to weaning. Based on fluid consumption, the male rats received an average of 0, 5.7 ± 1.33, 13.2 ± 2.08, and 35.8 ± 3.42 mg/kg/day amitraz, and the female rats received an average of 0, 8.7 ± 4.42, 20.1 ± 9.60, and 47.6 ± 22.38 mg/kg/day amitraz, respectively. At 360 ppm, an increase in the incidence of abnormal clinical signs, a suppression in the body weight gain, a decrease in the food consumption and litter size, an increase in the post-implantation loss, and a decrease in the seminal vesicle weight were observed in the parent animals. In addition, a suppression in the body weight gain, a decrease in the grip strength, a delay in the negative geotaxis, an increase in the pre- and post-implantation loss, and a decrease in the number of live embryos were observed in the offspring. At 120 ppm, suppressed body weight gain and reduced food consumption were observed in the parent rats. Suppressed body weight gain and decreased grip strength were also observed in the offspring. There were no signs of either reproductive or developmental toxicity at 40 ppm. Under these experimental conditions, the no-observed-adverse-effect level of amitraz for parent rats and their offspring was estimated to be 40 ppm in rats.

A 3-year-old female Thoroughbred racehorse was presented following the accidental oral and skin administration of amitraz. This case report describes the clinical signs and the treatment of this horse. Clinical signs of amitraz toxicosis are associated with the stimulation of alpha2-adrenergic receptors. Amitraz is seldom fatal because the effects can be reversed by alpha2-adrenergic antagonists. The horse displayed typical clinical signs of colic, including pawing, small hard drops, tranquillisation, depression, ataxia, muscular incoordination and impaction colic lasting up to 7 days. The syndrome was accompanied by mild dehydration. The horse survived after persistent symptomatic treatment, including the giving of intravenous fluids, antibiotics, multiple doses of mineral oil per os, nonsteroidal anti-inflammatory drugs and dexamethasone intramuscularly and intravenously.

The present study was carried out to investigate the potential adverse effects of amitraz on pregnant dams after maternal exposure during the gestational days (GD) 1 through 19 in Sprague-Dawley rats. The test chemical was administered orally to pregnant rats at dose levels of 0, 3, 10, or 30 mg/kg/day. During the test period, clinical signs, mortality, body weights, food consumption, serum biochemistry, gross findings, organ weights and reproductive findings on GD 20 were examined. In the 30 mg/kg group, an increase in the incidence of abnormal clinical signs and death, a suppression in the body weight gain, and a decrease in the food consumption were observed.