Metabolic Study of Isoproturon in Goats Following a Single Oral Administration: Toxicokinetics and Recovery Sanis Juliet, † Tapan K. Mandal, † Biswanath Mal, † Ashim Chowdhury, ‡ Anjan Bhattacharyya, ‡ and Animesh K. Chakraborty* ,† Department of Pharmacology and Toxicology, West Bengal University of Animal & Fishery Sciences, Mohanpur, Nadia 741235, West Bengal, India, and Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia 741235, West Bengal, India Toxicokinetic behavior and recoveries of isoproturon from feces, urine, and different tissues of goat were determined after 4, 5, 6, and 7 days following single oral administration at 500 mg/kg. Isoproturon was rapidly absorbed and attained blood concentration within 15 min of administration. The kinetic behavior followed a two-compartment open model. The higher t 1/2 () (9.78 ( 0.33 h) and V darea (4.49 ( 0.41 L/kg) associated with lower Cl B (0.32 ( 0.02 L/kg/h) suggested slow elimination from the blood. Approximately 56% of the total administered compound was recovered from feces. The rate of excretion of isoproturon through feces was maximum at 48 h and could not be detected beyond 120 h. The excretion pattern of isoproturon through urine resembled that of feces, and approximately 10-11% was eliminated in urine. A maximum quantity of residue was detected in all tissues of goats slaughtered after 4 days followed by a substantial decline after day 5, and nothing could be detected after day 7. Histopathological study revealed that isoproturon produced moderate cellular changes like fatty degeneration in the liver and kidney and emphysema in the lung after 7 days post administration. Keywords: Toxicokinetics; recovery; isoproturon; goat; histopathology INTRODUCTION Isoproturon, N,N-dimethyl-N′-(4-isopropylphenyl)urea (Figure 1), is a member of the family of substituted ureas. It has been developed as an effective herbicide and is widely used for postemergency application in wheat crops (Anon, 1977). The toxicity of related substituted ureas, viz. linuron, diuron, fenuron, and monuron, has been studied in rats and dogs (Hodge et al., 1968; Geissbiihler et al., 1975) and sheep and cattle (Palmer and Radeleff, 1964) and reported to have a low order of toxicity. Rakha et al. (1983) clinically studied the toxic effects of isoproturon in sheep, goat, cattle, and buffalo after consumption of freshly sprayed fodder and spraying over the body and reported that the herbicide produced identical toxic symptoms like that of fenuron, monuron, and other members of the family. It is expected that necessary data in respect to the rate of absorption, distribution, and retention in tissues of the compound should be generated in an animal system before it is widely used and declared safe to avoid possible health hazards. However, from the above reports, the distribution pattern and as well as the residual retention of isoproturon in animal tissues are not clear and warrant further study in animal systems. Goat is considered as the model animal of study since its meat is popularly consumed by human beings. Therefore, the present experiment studied the toxico- kinetic behavior of isoproturon and its recovery from feces, urine, and in different tissues at different time intervals following single oral administration. EXPERIMENTAL PROCEDURES Chemicals. Isoproturon (Avanon), technical grade, was supplied by M/S Gharda Chemical Ltd., Bandra, Bombay. The purity of the compound was 97.3%. All the chemicals and solvents used in this study was obtained from E. Merck (India), AR grade. Animal Treatment. Clinically healthy adult black Bengal female (nulliparous) and male goats weighing between 9.5 and 12 kg were considered. The goats were acclimated individually in custom made stainless steel metabolism cages (48 in. × 48 in. × 36 in.) for a period of 15 days, and within the period they were dewormed with levamisole at a rate of 7.5 mg/kg. The animal house was provided with artificial lighting and controlled temperature (22 ( 3 °C). The goats were fed with standard feed (two parts wheat husk, one part groundnut cake, one part crushed gram, one part crushed maize, and two parts green) and had free access to fresh water. Each animal was fasted overnight before administration of vehicle and or isoproturon. For ascertaining minimum oral toxic dose level, four differ- ent dose levels of isoproturon after suspension in (carboxy- methyl)cellulose (1% w/v) were administered to four groups of goats separately, each comprising one male and female. For the recovery study of isoproturon, 13 male and 14 female goats were taken, out of which one male and two females were * Author to whom correspondence should be addressed. † West Bengal University of Animal & Fishery Sciences. ‡ Bidhan Chandra Krishi Viswavidyalaya. Figure 1. Structure of isoproturon. 178 J. Agric. Food Chem. 1998, 46, 178-183 S0021-8561(97)00284-7 CCC: $15.00 © 1998 American Chemical Society Published on Web 01/19/1998