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    TOLYLFLUANID

    EXPLANATION

         Tolylfluanid, a broad spectrum fungicide, is considered for the
    first time by the present Meeting.

    EVALUATION FOR ACCEPTABLE INTAKE

    BIOLOGICAL DATA

    Biochemical aspects

    Absorption, distribution, and excretion

         Single doses of tolylfluanid, 14C-labelled at the
    fluorodichloromethylsulfenyl group, were orally administered to rats.
    In the dose range of 0.1-20 mg/kg, 50-60% and 20-30% of the
    administered activity was eliminated by the urine and the faeces,
    respectively, within 48 hours from administration. Urinary elimination
    took place with a half-life of 2-3 hours during the first 24 hours and
    then more slowly with a half-life of about 40 hours from the third
    day.

         Experiments in rats with biliary fistula showed that, after
    intraduodenal administration of 0.5 mg/kg, about 6% of total
    radioactivity was eliminated via the bile. However, when 5 mg/kg bw of
    tolylfluanid were administered, approximately 16% of the activity was
    exhaled in 48 hours. After oral administration of 5 mg/kg bw, maximal
    plasma concentration (about 1.5 ppm) was attained after two hours.
    While plasma half-life was 2-3 hours during the first 6-8 hours,
    elimination slowed to about 40 hours after 3 days. Of the administered
    activity, 6%, 2%, 1% and 0.5% was retained (excluding gastrointestinal
    tract) 8 hours, 48 hours, 6 and 12 days after administration,
    respectively. The highest concentrations were found in the thyroid
    gland: 5 ppm and 1 ppm, 1 and 10 days after the administration of
    5 mg/kg, respectively. Whole-body autoradiography (after i.v.
    injection of 10 mg/kg bw of tolylfluanid) confirmed this observation
    (Weber et al., 1977).

         In another study, doses of 2 or 20 mg/kg bw of 14C-ring-
    labelled tolylfluanid were orally administered to male and female
    Wistar rats. A group of rats of both sexes were also pretreated
    for 14 days with daily doses of 2 mg/kg bw of non-radioactive
    tolylfluanid before receiving the radioactive compound. Tolylfluanid
    was quickly and almost completely absorbed (>95%). The peak plasma
    concentration was reached within 1.5 hours. Within 48 hours, 75-80% of
    radioactivity was excreted in urine (half-life of 4-8 hours), 14-25%
    with faeces, and 0.06% in expired air. An experiment in animals with
    biliary fistulae showed that biliary secretion accounted for about 14%
    of total elimination. Total residual radioactivity was 0.07-0.20% of
    the total administered dose. Higher concentrations of radioactivity
    were found in liver and kidney (3 to 7 times the mean body
    concentration). Lesser concentrations were found in perirenal fat,
    brain, gonads and thyroid (3 to 9 times less than the mean body
    concentration). Renal clearance was 3.1-4.0 ml/min, which correspond
    to normal renal plasma flow in rats. No influence of dose was observed
    on pharmacokinetics (Abbink & Weber, 1988).

         An autoradiographic study showed a difference between i.v. and
    oral administration. Intravenous injection is characterized by a great
    uniformity of distribution with relatively high concentration in
    almost all body tissues (including highly lipophilic tissues). After
    oral administration, radioactivity in lipophilic tissues was very low.
    It may therefore be assumed that after oral administration
    tolylfluanid is rapidly metabolized prior to or during the absorption
    and distribution process (Weber, 1988).

    Biotransformation

         A single dose of fluorodichloromethyl-14C-labelled tolylfluanid
    was administered orally or intravenously to rats (5 or 10 mg/kg bw).
    The main radioactive metabolite in the urine of treated rats was found
    to be thiazolidine-2-thione-4-carbonic acid (TTC). TTC accounted for
    74% of radioactivity contained in the urine 8 hours after intravenous
    administration and for 50-63% after oral administration. Tolylfluanid
    was not detected in urine (Ecker, 1978).

         A single oral dose of 20 mg/kg bw of C14-benzene ring-
    tolylfluanid was administered to male Wistar rats. 90% of urine
    radioactivity and 70% of faecal radioactivity was due to one
    metabolite which was found to be 4-dimethylamino-sulphonylamino-
    benzoic acid. A minor metabolite (6% of total radioactivity) could not
    be identified (Ecker & Brauner, 1987).

         The degradation pathway of tolylfluanid in the rat is described
    in Figure 1.

    CHEMICAL STRUCTURE 2

    Toxicological Studies

    Special studies on carcinogenicity

    Mice

         Groups of NMRI mice (50/sex/group) were given tolylfluanid
    technical (99.1% purity in a 90% pre-mix) in the diet (0, 200, 1000,
    5000 ppm) for 104 weeks. In relation to body weight, the males were
    given 32.6, 161.8 or 768.9 mg/kg bw and the females 45.6, 202.4 or
    952.3 mg/kg bw on average. Animals were observed twice a day for
    mortality or adverse physical/behavioural signs. Body weights were
    recorded weekly and food consumption of each animal was determined
    twice a week. Routine haematological and clinical chemistry
    examinations were performed before the start of the study and after 12
    and 24 months. All animals, including those which died or were
    sacrificed before the end of the study, were dissected, their organs
    weighed and tissues prepared for microscopic examination. For
    technical reasons the treated groups started 4 months after the
    control group. This discrepancy in time was considered by the author
    to be the cause of the higher body weight gain (+55% and +10/12% of
    the starting weight in controls and treated males, respectively; +64%
    and +18/24% in control and treated females, respectively) and food
    consumption (about 30% higher) found in control animals and of the
    differences between control and study groups in the haematological and
    clinical laboratory examinations. No dose-related difference in any of
    these parameters was, however, found in animals of the treated groups.

         The mortality rate was higher in female groups but a dose-related
    effect was not evident.

         At necropsy, hepatocellular adenomas and pulmonary adenomas were
    found in all control and treated groups. The incidence of liver
    rumours was higher in male groups, but no treatment-related effect was
    evident (10/51, 7/50, 13/50 and 9/50 in control, 200, 1000 and
    5000 ppm groups, respectively). The incidence of lung adenomas was
    17/51, 17/50, 20/50 and 20/50 in males and 9/49, 6/50, 14/50 and 7/51
    in females of control, 200, 1000 and 5000 ppm groups, respectively.
    Incidence, latency, variety and organ distribution of rumours did not
    indicate any dose-related effect of tolylfluanid (Mohr, 1982).

    Rats

         (See "Long-term studies".)

    Special studies on embryotoxicity and teratogenicity

         Groups (n=22-24) of fertilized female rats (75-95 day-old Long
    Evans FB 30) were given oral daily doses (0, 100, 300, 1000 mg/kg bw)
    of tolylfluanid (99.9% purity) from day 6 through day 15 of gestation.
    Animals were observed routinely for physical appearance, behaviour
    and body weight gain. At day 20 of gestation pups were delivered
    by caesarean section. Foetuses were weighed, sexed, inspected for
    external abnormalities and examined for visceral and bone
    malformations.

         No alteration of physical appearance and behaviour was observed
    in any group. Two dams of the mid-dose group died of effects unrelated
    to treatment. Body weight gains were reduced in a dose-dependent
    manner in the mid- and high-dose groups. However, dams compensated
    after end of treatment. The average foetal weight was reduced by
    treatment of the dams with 300 or 1000 mg/kg bw. The resorption ratio
    in the high-dose group was slightly, not statistically significantly,
    higher than in the control group, because of complete loss of embryos
    by one female. There was no evidence of teratogenicity at any of the
    doses used. The dose of 100 mg/kg bw had no toxic effect to dams and
    foetuses (Machemer, 1976).

    Acute toxicity of metabolites

         4-dimethylamino-sulftoluidine, a metabolite of tolylfluanid, was
    tested for acute toxicity. After single administration, LD50s were
    as follows (Kimmerle & Solmecke, 1971b).

                                                 

    Species             Route          mg/kg bw
                                                 

    Rat (male)          p.o.           >2500
    Mouse (male)        p.o.           >1000
    Rabbit (male)       p.o.           >1000
    Rat (male)          i.p.             551
                                                 

    Special studies on mutagenicity

         Tolylfluanid was variably active in a range of in vitro
    assays. In vivo, however, tolylfluanid was inactive. Results are
    summarized in Table 1.

        Table 1.  Results of Mutagenicity assays on tolylfluanid
                                                                                                                                              

    Test system              Test Object           Concentration of tolylfluanid        Purity       Results           References
                                                                                                                                              

    Ames test (with and      S. typhimurium        3.15-1000 µg/plate                   100%         weakly            Oesch, 1977
    without activation)      TA-98,100,1537        dissolved in DMSO                                 positive 1/

    Ames test (with and      S. typhimurium        4-2500 µg/plate                      100%         weakly            Herbold, 1979
    without activation)      TA-98,100,1535,       dissolved in DMSO                                 positive 2/
                             1537

    Reverse mutation         Saccharomyces         Nonactivated:  1-200 µg/ml           99.1%        negative          Hoorn, 1984
    in vitro                 cervisiae             Activated:     1-100 µg/ml
                             (S138, S211alfa)

    Gene mutation            Somatic               Nonactivated:  4-40 µg/ml            98.5%        negative 3/       Heidemann,1987
    (HGPRT-test)             mammalian cells       Activated: 300-3000 µg/ml
    in vitro                 (V79)

    Gene mutation            Chinese hamster       Nonactivated: 0.5-6 µg/ml            98.5%        negative 4/       den Boer, 1987
    (HGPRT-test)             ovary cells           Activated:     3-30 µg/ml
    in vitro

    Forward mutation         Mouse lymphoma        Nonactivated: 25-300 µg/ml           99.1%        positive          Hoorn, 1985
    in vitro                 cells (L5178Y)        Activated:  500-7500 µg/ml

    Cytogenetic assay        Human lymphocytes     0.1-10 µg/ml (activated              99.2%        positive 5/       Herbold, 1984b
    in vitro                                       and nonactivated)

    Micronucleus test        Mice (NMRI strain)    2x250 and 2x500 mg/kg                98.8%        negative 6/       Herbold, 1980
                                                   (p.o. 24 h apart)
                                                                                                                                              

    Table 1. (cont'd)
                                                                                                                                              

    Test system              Test object           Concentration of tolylfluanid        Purity       Results           References
                                                                                                                                              

    Dominant lethal test     Mice (NMRI strain)    4000 mg/kg p.o.(mortality:5/50)      98.8%        negative          Herbold, 1986
                                                   8000 mg/kg p.o.(mortality:12/50)

    Cytogenetic assay        Chinese hamster       4000 mg/kg p.o.                      99.7%        negative 6/       Herbold, 1983
    in vivo                  bone marrow

    Cytogenetic assay        Chinese hamster       2x250 and 2x500 mg/kg                93.1%        inconclusive      Herbold, 1984a
    in vivo                  spermatogonia         (p.o. 24 h apart)                                 7/

    Cytogenetic assay        Mice (NMRI strain)    500-5000 mg/kg bw p.o.               97.9%        negative 8/       Voelkner,1988b
    in vivo                  germ cells

    Sister chromatide        Mice (NMRI strain)    500-5000 mg/kg bw p.o.               97.9%        negative 7/       Voelkner,1988a
    exchange                 bone marrow

    Mammalian                Mice C5781/6JxT       1750-7000 mg/kg bw p.o.              98.4%        negative 9/       Herbold, 1988
    Spot test
                                                                                                                                              

    1/   With S-9 mix only; positive controls (benzo(a)pyrene 4,5-oxide, N-methyl-N'-nitro-N-nitrosoguanidine,
         3,methylcholanthrene, 2-aminoanthracene) yielded expected positive results.
    2/   TA-100 only; positive controls (endoxan, trypaflavin) yielded expected positive results.
    3/   Positive controls (ethyl-methane sulfonate (EMS), 9,10-dimethyl-1,2-benzanthracene (DMBA) yielded expected positive
         results.
    4/   Positive controls (5-bromodeoxyuridine and 3-methylcholanthrene) yielded expected positive results.
    5/   At cytotoxic concentrations; positive controls (mitomycin c, endoxan) yielded expected positive results.
    6/   Positive controls (endoxan) yielded expected positive results.
    7/   Positive controls (doxorubicin) yielded expected positive results.
    8/   Positive controls (cyclophosphamide) yielded expected positive results.
    9/   Positive controls (1-ethyl-1-nitrosourea) yielded expected positive results.
        Special study on potentiating effects

         Equitoxic doses of tolylfluanid (purity not reported) and
    triadimefon (89.5% purity) were given in combination to rats. No
    potentiating effect was noted (Flucke & Kimmerle, 1978).

    Special study on reproduction

         Groups of Long Evans FB30 rats (30 animals/dose, 10 males and 20
    females) were fed diets containing tolylfluanid (technical grade,
    98.8% purity in a 90% pre-mix) at levels of of 0, 300, 1500 or
    7500 ppm. After 70 days of treatment F0 animals were mated on a
    2-female-to-1-male basis. After delivery (F1a) and a 4-week
    lactation and a 2-week waiting period, F0 rats were mated again.
    After delivery (F1b) lactation lasted for 4 weeks and then F0
    animals were sacrificed. F1b animals (20 females-10 males/dose) were
    then mated and F1a and F1b generations were obtained. The study
    was ended when F1b generation reached 4 weeks of age.

         Rats were weighed weekly and pups were weighed at birth, 5 and 7
    days after birth, and weekly thereafter. Pups were also observed
    immediately after birth and during lactation.

    F0 generation:

         Appearance and behaviour of all treated animals did not differ
    from controls throughout the study. Body weight was reduced in a
    dose-related manner in male rats treated with 1500 or 7500 ppm; only
    the dose of 7500 ppm was associated with reduced body weight in female
    rats. Fertility indices and litter sizes of first and second matings
    were not reduced by any of the treatments. Survival rate was slightly
    reduced in F1b generation of the high-dose group. Lactation index (%
    of pups surviving 4 weeks) was reduced in the F1a generation of the
    7500 ppm group, but in the F1b generation of the same group was
    significantly higher than controls. Body weight of pups at birth and
    body weight gain were significantly lower in both F1a and F1b
    generations of the 7500 ppm group. None of the pups showed
    malformations.

    F1b generation:

         Appearance and behaviour of all treated animals did not differ
    from controls throughout the study. Body weight was reduced in the
    7500 ppm group. Fertility indices and litter sizes of first and second
    matings were not reduced by any of the treatments. Survival rate was
    reduced in F2b generation of the high-dose group. Lactation index
    (% of pups surviving 4 weeks) was reduced in F2a and F2b
    generations of the 7500 ppm group and in the F2b generation of the
    1500 ppm group. In the latter group, however, the number of pups

    surviving four weeks was the same as in the control group and the
    lower lactation index was due to a higher number of pups at 5 days
    when all litters were reduced to a maximum of 10 pups rearing. Body
    weight of pups at birth and body weight gain was lower in both F2a
    and F2b generations of the 7500 ppm group. None of the pups showed
    malformations.

         In summary, this study shows that tolylfluanid at doses up to
    1500 ppm did not affect the reproduction of rats. The NOAEL in this
    study was found to be 300 ppm (Loser, 1980).

    Special study on skin and eye irritation

         A 90% pre-mix with 99.2% active ingredient was applied to rabbit
    skin for 24 hours under semi-occlusive conditions. Tolylfluanid did
    not show skin irritant properties. The test compound dust (0.1 g),
    however, when placed on the conjuntival sac of rabbit eyes, displayed
    a strong irritant potential (redness and swelling of the conjuntivae).
    The effect was reversible within 14 days (Helmann & Pauluhn, 1983).

         A further study was conducted on irritant and corrosive effects
    on the skin and eyes. Tolylfluanid (99.1% purity) did not show
    irritant effect on the skin (4 hours' exposure). However, 70 mg of
    a.i. placed in the conjuntival sac produced redness and swelling of
    the conjuntivae which were completely reversible within 21 days. No
    cornea or iris lesions were found at any time (Pauluhn, 1984).

    Special study on subacute cutaneous toxicity in rabbits

         Rabbits (5 males and 5 females) received daily dermal doses of
    500 mg/kg bw of tolylfluanid (98.9% purity) for fourteen days. Each
    exposure lasted 24 hours. Before and immediately after the end of
    treatment, and 2 weeks later, clinical-chemical tests were performed,
    including blood tests (erythrocyte, leucocyte and thrombocyte count,
    haemoglobin determination, etc.), liver function tests, serum
    transaminases, sorbitol dehydrogenase, bilirubin and albumin) and
    kidney function tests (urinanalysis and serum urea concentration). No
    variation was found between control and treated animals (Kimmerle &
    Solmecke, 1971a).

    Acute toxicity

         Table 2 reports the LD50 values for tolylfluanid and
    metabolites as determined in different studies and animal species.

         In rats, signs of toxicity observed after oral administration
    were altered behaviour, disturbed motility and dyspnoea. In mice,
    guinea pigs, rabbits and cats tolylfluanid caused deterioration of
    general conditions and (in cats only) vomiting. In sheep,
    tolylfluanid, orally administered, caused anorexia, weakness of
    extremities and loose faeces.

         Intraperitoneal injection to rats caused disturbed motility,
    staggering, spastic gait, distention of abdomen, narrowed eyelids, a
    specific disturbed behaviour. Irritation of abdominal organs was found
    at autopsy.

         The dermal application of tolylfluanid at doses up to
    5000 mg/kg bw was tolerated without signs of toxicity or skin
    alterations.

         The skin-sensitising potential of tolylfluanid was assessed by
    the Magnusson and Klingman's maximization test on guinea pigs (n=15).
    The concentration of tolylfluanid (99.2% purity in a 90% pre-mix) used
    were 1% for the intradermal induction, 0.6% for the topical induction,
    and 0.3% for the topical challenge. The results indicate that
    tolylfluanid has a skin-sensitising potential (Heimann, 1983).

    Short-term studies

    Rats

         0, 150, 500, 1500 or 4500 ppm of tolylfluanid (99% purity) were
    given to rats (15 males and 15 females) in the diet for 3 months. All
    dose-regimens were tolerated without alteration of behaviour, weight,
    mortality or clinical chemistry tests. Morphological examination of
    organs and tissues did not reveal any treatment-induced alterations
    (Bomhard and Schilde, 1976).

    Dogs

         Beagle dogs (4 males and 4 females/group) were administered
    0, 330, 1000 or 3000 ppm of tolylfluanid (99.7% purity) in diet for 3
    months. Animals of the high-dose group showed poor general condition
    and 6/8 animals had a reduced food intake and weight gain. In this
    group an increased serum alkaline phosphatase activity and a
    retardation of its age-related decrease as compared to controls was
    found. Increased liver relative weight and increased PAS histological
    reaction were also found in these animals. Doses up to 1000 ppm did
    not induce any detectable adverse effect (Hoffmann & Mirea, 1974).

        Table 2.  Acute toxicity of tolylfluanid (mg/kg bw)
                                                                                                             

    Species            Sex          Route              LD50            LC50       Reference
                                                                                                             

    Mouse              M            oral               >1000 1/        -          Kimmerle, 1968
    Rat                M            oral               >2500 2/        -          Kimmerle & Lorke, 1967.
    Rat                M            inhalation*        -               265 2/     Kimmerle & Lorke, 1967
                                    (4-hr exp.)
    Rat                M            i.p.               20.2 1/         -          Kimmerle, 1968
    Rat                F            i.p.               25.6 1/         -          Kimmerle, 1968
    Rat                F            oral               >5000 3/        -          Heimann & Pauluhn, 1983
    Rat                M            i.p.               14.7 3/         -          "
    Rat                F            i.p.               15.9 3/         -          "
    Rat                M&F          dermal             >5000 3/        -          "
                                    (24-hr exp.)

    Guinea pig         F            oral               250-500 1/      -          Kimmerle, 1968
    Rabbit             M            oral               250-500 1/      -          Kimmerle, 1968
    Cat                M&F          oral               >500 1/         -          Kimmerle, 1968
    Sheep              M&F          oral               625-1250 3/     -          Hoffmann, 1983
                                                                                                             

    1/   99.6% purity
    2/   98.7% purity
    3/   99.2% purity in a 90% pre-mix
    *    Dynamic spraying with Lutrol/ethanol. In static spraying experiments, mice, guinea
         pigs and rabbits were found to be more sensitive than rats to tolylfluanid.
    
         In another study, groups (4 male/4 female) of beagle dogs were
    orally treated for 12 months with tolylfluanid (99.2% purity in a 90%
    pre-mix) 0, 2.5, 12.5 or 62.5 (let to 33rd week) and 125 (34th to 52nd
    week) mg/kg bw. The test compound was administered in gelatin
    capsules. All animals survived the study and did not show any
    treatment-related effect on appearance or behaviour. Body weight
    development in male control animals (+4.4 kg in 12 months) was above
    the average of the historical controls (+2.8 kg in 12 months), while
    it was significantly reduced in the animals of the high-dose group.
    The females in the high-dose group also had lower body weight gain.
    Animals of the high-dose group vomited quite frequently after
    administration of the compound. They also had a significant increase
    of serum alanine aminotransferase (ALT) and glutamate dehydrogenase
    (GLDH), and a retarding of the physiological age-related decrease of
    the alkaline phosphatase activity. No liver alteration was found,
    however, at histology.

         An effect on renal function was also evident in the high-dose
    group. Urea and creatinine concentrations were significantly increased
    and in two dogs glycosuria and proteinuria were found. Histology
    revealed slight alterations of cortical tubules (dilation, epithelial
    flattening, focal hypertrophy and/or desquamation of the epithelia) in
    all dogs of the high-dose group. Slightly lower serum potassium
    concentrations were found in the high-dose group animals as compared
    to control values, possibly as a result of the frequent vomiting.

         No treatment-related effect was evident on blood, blood
    coagulation and transparent media and fundus of the eye.

         Oral doses of tolylfluanid up to 12.5 mg/kg bw were therefore
    tolerated by dogs for 12 months without detectable adverse effects
    (von Keutz & Nash, 1986).

    Long-term studies

    Rats

         Wistar rats (50 males and 50 females/group; 100 male and 100
    females, controls) were fed for 2 years with tolylfluanid (98.9%
    purity in 90% pre-mix) at concentrations of 0, 300, 1500, 7500 ppm.
    Toxicity following chronic administration and carcinogenic potential
    of tolylfluanid were evaluated.

         The animals in the high-dose group had a reduced food consumption
    (-10%) and a reduced (about 10%) body weight gain; appearance,
    behaviour and mortality were not affected by the treatment. Clinical
    laboratory tests showed random alteration of some blood parameters
    (mean corpuscular volume, mean corpuscular haemoglobin, reticulocyte
    count, polymorphonuclear cells and lymphocytes). Plasma alkaline

    phosphatase (AP), transaminases (ALT and AST), bilirubin and total
    protein were measured as indices of liver function. No dose-related
    alteration of these parameters was found. Gross pathological and
    histological examinations did not detect any indication of liver
    damage. Urinanalysis did not indicate any dose-related kidney
    alteration. Blood sugar and cholesterol were within normal range in
    all groups. On autopsy, bone alterations (diffuse hyperostosis of the
    rib bones, hardened cranial bones, focal hyperostosis of the skull
    caps) in both sexes, and a faster growth of the incisors of the upper
    jaw in males only, were found in the 1500 and 7500 ppm groups. These
    effects were presumably due to an increased fluorine intake from the
    active ingredient.

         Tumours of endocrine and reproductive system accounted for about
    80% of the rumours seen in the study. Only malignant uterine tumours
    appeared higher in all treated groups as compared to controls. The
    incidence was 3/50, 8/50, 12/50 and 13/50 in the 0, 300, 1500 and
    7500 ppm groups, respectively. An unusually low incidence of these
    fairly con, non tumours was found in control animals. Therefore, a
    second, concurrent group of 50 controls was studied in which the
    incidence of malignant uterine rumours was similar (9/50) to that of
    the treated groups. The test, therefore, did not provide indications
    of carcinogenic potential for tolylfluanid.

         The concentration of tolylfluanid without detectable adverse
    effect was 300 ppm (equivalent to 15 mg/kg bw) (Krötlinger &
    Loser, 1982).

    Observations in humans

         Small cottonwool pads on which an unknown concentration of
    tolylfluanid was applied, were placed on the forearm of 10 male
    volunteers for 24 hours. Subjects were observed for 10 days; no
    skin-irritant effects were noted (Kimmerle, 1968).

    COMMENTS

         Following oral administration to rats, tolylfluanid was rapidly
    absorbed, metabolized and eliminated in urine and faeces. When using
    14C-ring-labelled tolylfluanid (2 or 20 mg/kg bw), less than 0.2% of
    the administered radioactivity was detectable in the body 2 days after
    administration. The highest concentrations were found in liver and
    kidney.

         When using 14C-tolylfluanid (0.1-20 mg/kg bw) labelled at the
    fluorodichloronenthyl group instead, accumulation of radioactivity was
    evident in the thyroid. The major urinary metabolites were thiazolidine-
    2-thione-4-carboxylic acid and 4-dimethylaminosulphonyl-amino-benzoic
    acid.

         The oral LD50 is greater than 5000 mg/kg bw in rats and
    250-500 mg/kg bw in guinea pigs and rabbits. The oral LD50 of a
    major plant metabolite, DMST (N,N-dimethyl-N'-p-tolylsulphamide),
    exceeds 2500 mg/kg in rats and 1000 mg/kg in mice and rabbits.

         In one study in rats, tolylfluanid was found to be maternally
    toxic and embryotoxic at doses above 100 mg/kg bw/day but not
    teratogenic at doses up to and including 1000 mg/kg bw/day. In a
    two-generation two-litter-per-generation reproduction study, dietary
    levels up to and including 1500 ppm did not affect rat reproduction.
    No malformations were observed at dietary levels up to and including
    7500 ppm.

         In a short-term toxicity study with beagle dogs, tolylfluanid did
    not cause adverse effects for 12 months at doses up to and including
    12.5 mg/kg bw/day.

         Tolylfluanid was mutagenic in prokaryotes and eukaryotes in four
    of seven in vitro assays. In vivo tests, however, did not indicate
    a mutagenic potential.

         In a long-term study in Wistar rats, a higher incidence of
    malignant uterine tumours was found in the treated groups as compared
    to controls, but no statistically significant dose-related pattern was
    evident. Moreover in a second, concurrent, group of controls the
    incidence was comparable to that in treated groups. In animals treated
    with 1500 or 7500 ppm tolylfluanid, bone alterations were also found
    which were suggested to be due to the fluorine constituent of
    tolylfluanid. No alterations were found in the thyroid or in other
    organs.

         The Meeting noted that in the NMRI mouse study, the control
    animals were four months older than the treated groups, thus
    compromising the design of the study. Lung and liver adenomas occurred
    at similar frequency in all treated groups, but because of their known
    occurrence in mice they were not considered to be biologically
    relevant. The Meeting therefore concluded that the results of this
    study did not indicate an oncogenic potential.

         The Meeting did not request a special study on thyroid function
    because the dichlorofluorometylthio group is common to dichlofluanid,
    for which a NOAEL for the thyroid has been demonstrated to be greater
    than 1500 ppm.

    TOXICOLOGICAL EVALUATION

    LEVEL CAUSING NO TOXICOLOGICAL EFFECT

         Rat:      300 ppm in the diet, equal to 15 mg/kg bw/day
         Dog:      12.5 mg/kg bw/day

    ESTIMATE OF ACCEPTABLE DAILY INTAKE FOR MAN

         0-0.1 mg/kg bw

    STUDIES WHICH WILL PROVIDE INFORMATION VALUABLE FOR THE CONTINUED
    EVALUATION OF THE COMPOUND

         Observations in man.

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    See Also:
       Toxicological Abbreviations