Toltrazuril is a symmetrical tiazinetrione compound. It is active against all intracellular developmental stages including those of schizogony and gametogony. In this study the disposition kinetics of toltrazuril (TZR) and its major metabolites (TZR-SO and TZR-SO 2 ) in broiler chickens after single oral administrations of 10 or 20 mg/kg were investigated. Mean plasma concentrations of TZR peaked at 16.4 and 25.2 μg/mL at 5.0 and 4.7 h after dosing, respectively. TZR was converted to the short-lived intermediary metabolite toltrazuril sulfoxide (TZR-SO), and then further metabolized to the reactive toltrazuril sulfone (TZR-SO 2 ) being actually more slow eliminated with 80.3 and 82. 9 h than TZR (10. 6 and 10. 7 h) or TZR-SO (14. 8 and 15. 3 h) in low and high dosing groups, respectively. Prolonged elimination half-life of TZR-SO 2 could be interpreted as the persistent clinical efficacy of TZR in the treatment of protozoal parasites infection.Key words: broiler, pharmacokinetics, toltrazuril, toltrazuril sulfone, toltrazuril sulfoxide J. Poult. Sci., 50: 257-261, 2013 Introduction Coccidiosis is a particularly dangerous disease in the poultry industry where chickens are maintained on the floor (Greif, 2000). Anticoccidial drugs of many different chemical types have been the dominant means to prevent and control the coccidiosis (Polozowski, 1993;Greif et al., 2001). However, the massive and uncontrolled use of anticoccidial drugs has resulted in the emergence of drug-resistant parasites (Suo X et al., 2006)., 5-triazinane-2, 4, 6-trione, is a symmetrical triazinetrione compound. It has coccidiocidal action against all intracellular developmental stages including those of schizogony and gametogony (Mehlhorn et al., 1984;Haberkorn and Stoltefuss, 1987). It has been reported to be effective against all coccidial species in most animal species, such as chickens (Mehlhorn et al., 1984), ducks (Chauve et al., 1994), dogs (Daugschies et al., 2000), mice (Haberkorn et al., 1983), pigeons (Van Reeth and Vercruysse, 1993), piglets (Mundt et al., 2007) and rabbits (Peeters and Geeroms, 1986).TZR undergoes extensive metabolism to toltrazuril sulfoxide (TZR-SO) and then to TZR-SO 2 , which appears to have anticoccidial activity (Benoit et al., 1993;Lang et al., 1996;Bach et al., 2003;Mundt et al., 2007) (Fig. 1). Generally, triazines produced the same types of metabolites in most species, but the ratios of the metabolites showed the species differences (Furr and Kennedy, 2000;MacKay, 2006;Kim et al., 2010;Lim et al., 2010). Also, TZR is almost exclusively metabolized to TZR-SO 2 , also known as ponazuril (PZR), which has been recognized as the marker metabolite in a number of tissues. Although TZR is commonly used for the prevention and treatment of coccidosis in broilers, the pharmacokinetic and metabolic profiles of TZR in broilers have received minimal investigation. There must be assessed not only in terms of good clinical efficacy but also considering the pharmacokinetics and metabolism of TZR in broilers for the rat...

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This paper shows a way to obtain contact parameters for multi-body dynamics simulation (MBDS) of a wheelless snake robot, KAEROT-snake V. We developed a simulation model of the snake robot in a commercial MBDS software RecurDyn(V8). RecurDyn provides a convenient way to model contact geometries directly from CAD models, which are very close to the actual shape. Contact parameters such as spring, damping and friction coefficient are very important in MBDS so that we obtained the contact parameters through experiments of falling and sliding test. The contact parameters were obtained by analyzing the images of the test and the MBDS simulation of the test. Some locomotion simulation results for the snake robot were experimentally verified.Index Terms-contact parameters, image processing, MBDS, snake robot.