Effects of Bis(2,4,5-Trichlorophenol) Piperazine Salt against Intestinal Nematodes in Laboratory Animals

Field: Pharmacology, Toxicology and Pharmaceutics (Life Sciences)

The potentialities of bis(2,4,5-trichlorophenol) piperazine salt (CI-416) were assessed as a vermifuge by examining its effects against nine types of intestinal nematodes distributed among 478 mice, 29 rats, and 29 dogs. Hexylresorcinol was studied in several instances as a reference drug. CI-416 was active by gavage (single dose) in mice against Nematospiroides dubius, Syphacia obvelata, and Aspiculuris tetraptera. The efficacy of either CI-416 or hexylresorcinol against N. dubius varied according to the drug vehicle. Comparisons of the two drugs as aqueous suspensions showed CI-416 to be twoto fourfold more potent against N. dubius. S. obvelata was about equally susceptible to both drugs but hexylresorcinol was not appreciably effective against A. tetraptera. In rats, S. muris was susceptible to CI-416 treatment but Nippostrongylus muris was not. In dogs, ascarids usually were removed by a single 100 mg/kg dose of CI-416, hookworms usually were removed by three 200 mg/kg doses, and whipworms occasionally were removed by several doses. Limited comparisons in dogs suggested a similar order of effect by CI-416 and hexylresorcinol against ascarids and hookworms but apparently CI-416 was more effective than hexylresorcinol against whipworms. The need persists for a substance effective in a simple treatment regimen against the intestinal nematodes of greatest medical importance-ascarids and hookworms. This study deals with the potential value of a new salt of two anthelmintic moieties (CI-416) (v.i.) as reflected by vermifugal activity in laboratory animals. Hexylresorcinol was used as a reference drug owing to the primarily phenolic nature of the new substance. MATERIALS AND METHODS CI-416 (fig. 1), first synthesized by Short and Elslager (1962), is a white crystalline salt of 2,4,5trichlorophenol (82.2%) and piperazine (17.8%). It is soluble in water to the extent of approximately 0.25%. Bulk hexylresorcinol was used as the reference drug. Natural or experimentally induced helminthic infections in mice, rats, and dogs were used as in earlier work (Thompson and Reinertson, 1952; Weston et al., 1953; Sheffield et al., 1959). The mice were albinos of either sex, procured from several suppliers. The mice of a particular testhomogeneous with respect to sex, supplier, and roughly as to size-were randomly subdivided, usually without prior examination for worms, into treated and control groups. The drug was given by gavage in vehicle volumes of 10 or 20 ml/kg; control groups were sham-dosed with the vehicle. Results were determined by autopsy. Syphacia obvelata, Aspiculuris tetraptera, and Nematospiroides dubius were recorded on an all-or-none basis, and in certain instances as actual numbers. Perianal examinations for eggs in adhesive Scotch Received for publication 15 February 1962. tape preparations were used in the selection of certain mice for S. obvelata. When expedient, the significance of differences in the prevalence of infection and in worm burdens was estimated by t e respective methods of Mainland et al. (1956) and Duncan (1955) as modified by Kramer (1956). The rats were albino males of the Yale strain, purchased locally. Nippostrongylus muris infections were induced by the intraperitoneal injection of 450 inf ctive larvae. Syphacia muris (Hussey, 1957) infections occurred naturally. Anthelmintic effects were assayed, respectively, as against N. dubius and oxyurids in mice. The dogs were of various types. They were housed in grid-bottom cages. Intestinal helminthiases, diagnosed by brine flotation tests for eggs in th feces, were predominantly Toxocara canis, Ancylosto a caninum, and Trichuris vulpis. Drugs were given in gelatin capsule on an empty stomach, except when there were two doses on the same ay. In such cases the second dose was given approximately 3 hours after the animals had been fed. Ca ned salmon was fed to produce soft stools and facilitate stool examination. The animals were fasted during the 2 days between the end of treatment and autopsy. Feces passed during and after treatment were searched for worms. Upon autopsy, the opened stomach and entire intestinal tract were examined for worms and gross evidence of irritation. In vitro effects upon pig ascarids were observed by a modification of the methods used by Lamson and Brown (1936). Washed living adult worms, equal numbers of each sex, were immersed in agitated 1% preparations of the test substance at 37 C. Subgroups were removed after varying intervals of exposure, washed, and stored at 37 C in physiologic saline. Deaths were recorded the