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    VINCLOZOLIN

    EXPLANATION

         Vinclozolin is a fungicide that is registered for uses on fruits,
    vegetables, and ornamental plants, and is formulated as a solo product
    and as a mixture with other fungicides. It is commonly sold under the
    trade name Ronilan(R). This chemical has not been previously
    evaluated by the WHO Expert Group.

    IDENTITY AND PROPERTIES

    CHEMICAL NAME          3-(3, 5-dichlorophenyl)-5-ethenyl-5-methyl-2,4-
                           oxazolidinedione

    CASE NUMBER:           50471-44-8

    SYNONYMS               Ronilan(R); BAS 352 F; Reg. No. 83 258

    EMPIRICAL FORMULA      C12H9Cl2O3

    STRUCTURAL FORMULA
    CHEMICAL STRUCTURE 6

    MOLECULAR WEIGHT       286.1

    PHYSICAL STATE         Crystalline solid

    COLOUR AND ODOUR       White, odorless

    MELTING POINT          108C

    VAPOUR PRESSURE        < 0.1  10-6mbar at 20C

    SOLUBILITY

                Solvent                g compound/100 g solvent at 20C

                Water                            < 0.1
                ethyl ether                        6.3
                ethyl alcohol                      1.4
                chloroform                        31.9
                lutrol                             2.0   (approx.)
                acetone                           43.5
                ethyl acetate                     25.3
                cyclohexane                        0.9
                benzene                           14.6
                olive oil                          1.5   (approx.)

    OCTANOL/WATER PARTITION COEFFICIENT

                           1000 (approx.)

    SPECIFIC GRAVITY       approx. 1.513 kg/l at 20C

    BULK DENSITY           640 g/l loose (WHO method)
                           900 g/l compact (WHO method)

    COMMERCIAL FORMULATIONS AVAILABLE

                           Too numerous to list; most are available under
                           the trade name Ronilan(R), and are formulated
                           as wettable powders, suspension conentrates, or
                           dust and smoke formulations.

    STABILITY              Stable at temperatures up to 50C; stable in
                           water and dilute acids; half-life in 0.1 N
                           NaOH = 3.8 hours; stable to light.

    EVALUATION FOR ACCEPTABLE INTAKE

    BIOLOGICAL DATA

    Biochemical aspects

    Absorption, distribution and excretion

         Data were not submitted to adequately characterize the absorption
    and excretion of vinclozolin.

         A group of 5 male rats (strain unknown) was administered 5 doses
    by gavage of 40 mg/kg b.w. 14C-vinclozolin (universal label on the
    phenyl ring, s.a. = 8.07 Ci/mg). Excreta were collected daily and
    frozen. Four hours after the last treatment, the rats were sacrificed
    and tissues were collected and frozen. Urine was measured directly for
    radioactivity, whereas samples of faeces, blood and tissues were
    combusted and levels of 14CO2 were determined.

         Data were expressed as the concentration of vinclozolin in
    excreta, blood and tissues. The highest average concentration of
    chemical was found in faeces (1300 g/g), followed by urine
    (450 g/g), kidney (76.4 g/g), liver (75.2 g/g), fat (56.8 g/g),
    muscle (30.8 g/g), and blood (13.3 g/g). Levels of radioactivity in
    urine and faeces appeared to reach a plateau by the second day of
    treatment (Otto et al., 1977).

         In a second study, 14C-vinclozolin was administered orally for
    7 days at a dose of 40 mg/kg b.w./day. Six days after the last dose,
    47% and 54% (mean values) of the total administered dose had been
    eliminated in urine and feaces, respectively, for a total of 101%. No
    radioactivity was detectable in carcasses at this time, nor was any
    radioactivity detected in expired air.

         Cannulation of bile ducts after a single oral dose revealed that
    65% of administered radioactivity was excreted into the bile, whereas
    only 19% and 15% were eliminated in the urine and faeces,
    respectively.

         Peak plasma levels were detected after about 1 hour; the plasma
    half-life was 20 hours. As dosing continued, baseline plasma levels
    tended to increase. After 7 doses, the highest levels of tissue
    radioactivity were detected in the liver, kidneys, gastrointestinal
    tract, fat, adrenals, and ovaries. By 96 hours after the last dose,
    levels of radioactivity in tissues were not different from those of
    plasma. These findings were confirmed by whole-body autoradiography
    (Chasseaud et al., 1976).

    Biotransformation

         Samples of urine and faeces were analyzed to determine the
    identities of metabolites. Vinclozolin was metabolized extensively, as
    apparently no parent compound was detected in the urine, and about
    8 - 40% of the parent compound was detected in the faeces.
    N-(3,5-Dichlorophenyl)-2-methyl-2,3,4-trihydroxybutanoic acid amide
    (metabolite F) was the major excreted metabolite, which accounted for
    42% of the urinary radioactivity and 60 - 90% of the faecal
    radioactivity. Metabolite F was excreted in urine as either a
    glucuronide or sulfate conjugate, and was excreted in free form in the
    faeces. This metabolite was also the major species found in the blood,
    kidneys, and liver. Other metabolites, resulting from further
    degradation of metabolite F, were formed in insignificant amounts
    (Otto et al., 1977).

         A proposed metabolic pathway is described in Figure 1.

    Toxicological studies

    Special study on carcinogenicity

    Mice

         Groups of NMRI mice (50/sex/dose) were fed diets containing
    0, 162, 486, 1460, or 4370 ppm vinclozolin (purity unspecified) for
    110 weeks. Control or test diet and water were offered ad libitum.
    The dietary concentrations of vinclozolin were equal to 27, 82, 275,
    or 818 mg/kg b.w./day in males and 31, 92, 287, or 912 mg/kg b.w./day
    in females. The results of analyses of the test material or of the
    test diets were not presented. Animals were examined twice daily for
    abnormalities of behaviour or appearance, and were palpated weekly
    beginning at week 26 for evidence of tumours. Eyes, ears, and
    dentition were examined at necropsy. Mice were weighed weekly. The
    schedule and manner of measurement of food consumption were not
    specified.

         Blood was sampled at 0, 6, 13, 26, 52, and 78 weeks, from 10
    mice/sex/dose, for assessment of haematology and clinical chemistry
    parameters. A standard battery of tests/examinations was conducted.
    Urine was collected on a similar schedule for standard urinalysis
    determinations.

    CHEMICAL STRUCTURE 7

         Mice that died on test, moribund animals, and all mice surviving
    to 112 weeks were subjected to complete mecropsies. Mice were
    sacrificed by decapitation. Animals were dissected, and organs were
    weighed. The following tissues were examined for microscopic changes:
    adrenals, aorta, bone and marrow, brain, colon, duodenum, esophagus,
    eye, heart, ileum, jejunum, peripheral nerve, pituitary, prostate,
    rectum, skeletal muscle, skin, spleen, spinal cord, stomach, testes,
    thymus, thyroid, trachea, urinary bladder, uterus, and any tumours.

         No effects of treatment on clinical signs were apparent. Survival
    was somewhat lower in high-dose males than in controls (76% mortality
    vs. 48% in the control group); however, mortality in all female groups
    was about 70%, with no effects of treatment. Mean body weights were
    reduced in males in the 2 highest dose groups; these decreases emerged
    in the second year of treatment and persisted until termination. Food
    intake did not appear to be affected by treatment. No effects of
    treatment oil haematology, clinical chemistry, or urinalysis
    parameters were noted.

         At necropsy, significant increases of 150 - 250% in the absolute
    and relative weights of the liver were noted in females from the 1460
    and 4370 ppm groups. An increase in liver weight of about 40% and an
    increase in testes weight of about 50% were noted in high-dose males.
    Absolute weights of other organs were altered in males; however, these
    changes probably were related to decreases in body weight.

         After microscopic examination, no toxicologically significant
    differences in the incidences of neoplastic or non-neoplastic lesions
    were noted. Vinclozolin was therefore negative for oncogenic potential
    in mice (Leuschner et al., 1977a).

    Special studies on mutagenicity

         Vinclozolin was negative in a number of acceptable mutagenicity
    studies, which included assessments of gene mutations (bacteria and
    mammalian cells), direct DNA damage (bacteria and mammalian cells),
    and clastogenic effects (in vivo mammalian cells).

         Summary results are presnted in Table 1.

    Special study on reproduction

    Rats

         Groups of male and female Sprague-Dawley rats (20/sex/dose) were
    fed diets containing 0, 162, 486, or 1485 ppm vinclozolin (purity
    unspecified) over 3 generations. Control or test diet and water were
    offered ad libitum. The dietary concentrations of vinclozolin were
    equal to 12, 37, or 113 mg/kg b.w./day in males and 17, 51, or
    152 mg/kg b.w./day in females. The results of analyses of the test
    material or of the test diets were not presented.

        Table 1:  Results of mutagenicity studies on vinclozolin
                                                                                                                                              

    Test system        Test object             Concentration of     Purity              Results       Reference
                                               vinclozolin
                                                                                                                                              

    Ames test1         S. typhimurium          0, 100, 500          98.1%               Negative2     Gelbke & Engelhardt, 1983
                       TA98, TA100, TA1535,    2500, 5000,
                       10,000, TA1537,         7500, and
                       and TA1538.             g/plate

    CHO/HGPRT gene     Chinese hamster         0,0.32,1.0,          > 99.5%             Negative3     Gelbke & Jckh, 1985
    mutation           ovary cells,            3.2, or 10.0
    assay1             CHO-K1                  mg/ml

    Unscheduled        Primary hepatocytes     0, 5, 10,            > 99.5%             Negative4     Cifone & Myhr, 1984
    DNA                from male Fischer       25, 50, 100,
    synthesis          344 rats                250, 500, &
                                               1000 g/ml

    Mouse lymphoma     L5178Y mouse            Nonactivated:        Technical           Negative3     Witterland & Hoorn, 1984
    forward            lymphoma                0 - 1000 g/ml
    mutation           cells (TK+/-)           (8 dose levels)
    assay1                                     Activated:
                                               0 - 600 g/ml
                                               (13 dose levels)

    DNA repair         B. subtilis             0, 1, 10,            Technical           Negative5     Hoorn, 1983
    assay1             H17 and M45             100, 500,
                       (rec +/-)               1000, 2500,
                                               5000 & 10,000
                                               g/plate
                                                                                                                                              

    Table 1:  (cont'd).
                                                                                                                                              

    Test system        Test object             Concentration of     Purity              Results       Reference
                                               vinclozolin
                                                                                                                                              

    In vivo sister     Chinese hamster         0, 3830, &           98.1%               Negative6     Gelbke, et al., 1982
    chromatid          bone marrow             5620 mg/kg
    exchange assay

    Mouse dominant     NMRI mice               0 & 2000             Technical           Negative7     Hofmann & Peh, 1975a
    lethal assay                               mg/kg
                                                                                                                                              

    1    With and without activation.
    2    The positive controls gave the expected positive results.
    3    The positive controls, EMS and MCA, gave the expected positive results.
    4    The positive control, 0.05 g/ml 2-AAF, gave the expected positive result.
    5    The positive controls, MMS and sterigmatocystin, gave the expected positive results.
    6    The positive control, cyclophosphamide, gave the expected positive response.
    7    This study is not acceptable. A positive control was not included; therefore, the sensitivity of the test system was not
         established.
             Two litters were obtained from each generation. Rats from the
    parental generation (F0) were bred after 8 and 16 weeks of treatment
    (1:1 male to female) to form the F1a and F1b litters, respectively.
    Twenty rats/sex/dose were selected from the F1b litters to become
    parents of the F2a and F2b litters. This process was repeated
    through the F3 generation. Twenty rats of the F3b generation were
    maintained on test diets for 9 weeks, at which time they were
    sacrificed and histopathological evaluations were conducted on 10
    rats/sex/dose.

         Animals were examined daily for abnormalities of behaviour or
    appearance, and food consumption was measured daily. Rats were weighed
    weekly. Fertility, litter size, pup growth, and pup survival for each
    litter were determined. At weaning, selected pups were evaluated for
    consciousness, emotional behaviour, activity and reactivity,
    coordination, and reflexes. Parental rats of each generation were
    sacrificed after completion of the second litter and subjected to
    gross necropsies. Pups not selected for breeding of the next
    generation were sacrificed at weaning with the exception of 10 F3b
    pups/sex/dose, which were maintained for 9 weeks on test diets and
    then subjected to complete histopathological evaluation.

         No effects of treatment on clinical signs, food consumption, or
    body weight of parental rats were noted. Similarly, no alterations in
    fertility, gestation length, litter size, sex ratio of pups, fetal
    birth weight, weight gain of pups, or survival of pups during
    lactation were noted in any of the litter intervals. No treatment-
    related malformations or developmental defects were noted. No
    treatment-related pathological findings were noted in either parental
    rats or pups at necropsy. The NOEL for reproductive effects was
    determined to be greater than the highest dose tested (Leuschner
    et al., 1977b).

    Special studies on teratology

    Mice

         Groups of female NMRI [SPF] mice (24-30/dose) with vaginal plugs
    were fed diets containing technical vinclozolin (purity unspecified)
    from days 0 - 18 of presumed gestation. Two studies were conducted, 1
    with test diets containing 0 and 60,000 ppm vinclozolin, and a second
    study with test diets containing 0, 600, and 6000 ppm vinclozolin.
    Identical protocols were followed in both studies. Mice were examined
    daily for clinical signs of toxicity, and food consumption and body
    weights were determined periodically. On day 18 of gestation, the mice
    were sacrificed and the number of implantation and resorption sites
    and the number of live and dead fetuses were determined. Body weights,
    lengths, and the sex of live fetuses were determined, and placentas
    were weighed. Fetuses were examined for external abnormalities, and
    one-third of the fetuses were examined for visceral abnormalities, and
    the remaining two-thirds were examined for skeletal defects.

         The appearance and behaviour of mice from the low-dose (600 ppm)
    and mid-dose (6000 ppm) groups were not affected by treatment. In
    contrast, all mice from the high-dose (60,000 ppm) group died during
    the treatment interval. Since these mice also refused food and lost
    considerable body weight, it was not clear whether death was the
    result of toxicity or of starvation due to food avoidance. Mice fed
    600 ppm vinclozolin had a mean body-weight gain during gestation that
    was similar to that of mice in the control groups, whereas animals fed
    6000 ppm ate about 25% less food than control or low-dose mice, and
    gained significantly less body weight. Mice offered the 60,000 ppm
    diets refused food, and lost body weight until death.

         At necropsy, it was found that none of the mice from the 6000
    or 60,000 ppm dose groups had any implantations. The number of
    implantations and resorptions, fetal weights and lengths, and
    placental weights were similar in control and low-dose mice. Visceral
    and skeletal examinations of control and low-dose fetuses revealed
    no treatment-related abnormalities. The NOEL for maternal and
    developmental toxicity in mice in this study therefore was 600 ppm
    (equal to 110 mg/kg b.w./day) (Hofmann & Peh, 1975b).

    Rabbits

         Groups of female New Zealand white rabbits (15/dose) were
    administered doses of 0, 20, 80, or 300 mg/kg b.w./day of technical
    vinclozolin (98.1% purity) by gavage from days 6 - 18 of presumed
    gestation. Doses were based on a preliminary range-finding assay which
    demonstrated that a dose of 900 mg/kg b.w./day was not well tolerated,
    while a dose of 300 mg/kg b.w./day produced moderate signs of
    toxicity. Rabbits were observed daily for clinical signs of toxicity,
    and were weighed periodically during gestation. On day 29 of
    gestation, the rabbits were sacrificed by cervical dislocation, and
    uteri and the ovaries were examined to determine the number of corpora
    lutea and resorptions, live and dead fetuses, gravid uterine weights,
    and fetal body weights and lengths. Live fetuses were examined for
    external abnormalities, then sacrificed by injection of pheno-
    barbitone. Fetuses were weighed, then dissected and examined for
    visceral abnormalities. Fetuses were then processed and stained for
    skeletal examinations.

         No signs of toxicity were observed in does during gestation (the
    findings observed in the range-finding study were not reproduced), and
    the 4 recorded deaths were considered unrelated to treatment. No
    effects of treatment on maternal body weights were apparent. At
    necropsy, no effects of treatment on gravid uterine weight or on
    litter size or frequency were noted. An approximately 3-fold increase
    in the number of resorptions was noted in the high-dose group
    (compared to the control group); however, this increase was not

    statistically significant. Mean fetal weight was decreased in the
    high-dose group by about 6%; this change was not statistically
    significant. No effects of treatment on the incidences of visceral or
    skeletal abnormalities were apparent. The authors concluded that the
    highest dose tested of 300 mg/kg b.w./day had no statistically-
    significant effects on litter parameters, nor on maternal health
    (Cozens et al., 1981).

    Acute toxicity

         Vinclozolin possesses a low order of acute toxicity. The results
    of acute toxicity studies are summarized in Table 1.

        Table 2.  Acute toxicity of vinclozolin1
                                                                                              

                                           LD50             LD50
    Species       Route           Sex      (mg/kg b.w.)     (mg/l)     Reference
                                                                                              

    Mouse         oral            M        > 15,000           -        Shirasu et al.,
                                  F        > 15,000                    1978a

                  s.c.            M        > 15,000           -        Shirasu et al.,
                                  F        > 15,000                    1978a

                  i.p.            M           1570             -       Shirasu et al.,
                                  F           1640                     1978a

    Rats          oral            M        > 15,000           -        Shirasu et al., 
                                  F        > 15,000                    1978b

                  i.p.            M           8300             -       Shirasu et al., 
                                  F           4220                     1978a

                  dermal          M        >  5000            -        Shirasu et al., 
                                  F        >  5000                     1978b

                  inhalation      M           -             > 29.1     Leuschner, 1979
                  (4 hr. exp.)    F                         > 29.1

    Guinea-pig    oral            M/F         8000             -       Hofmann, 1973
                                                                                              

    1    Technical vinclozolin was tested in these studies.
    
         Technical vinclozolin was shown to cause mild reversible
    irritation to the conjunctivae of the eye (Hildebrand, 1977a) and skin
    (Hildebrand, 1977b).

    Short-term studies

    Rats

         Groups of male and female Sprague-Dawley [SPF] rats (16
    rats/sex/dose) were fed diets containing 0, 100, 300, 1000, or
    2000 ppm technical vinclozolin for 3 months. Six rats from each group
    were further maintained on control diets for a post-observation period
    of 6 weeks at the end of the study. Rats were examined daily for
    mortality, abnormalities of appearance or behaviour, and food
    consumption. Body weights were determined weekly. Rats were palpated
    at weekly weighings, and the eyes were examined. Blood was sampled for
    haematology and clinical chemistry examinations prior to initiation,
    after 6 and 12 weeks of treatment, at termination, and at the end of
    the post-observation period. Urine was collected on a similar
    schedule. At termination, rats were sacrificed by CO2 asphyxiation
    and decapitated. Animals were dissected and examined for gross
    pathological changes. Absolute and relative weights of major organs
    were determined, and a complete set of tissues from each animal was
    saved for future histopathological examinations. The results of
    microscopic examinations of tissues were not reported in this study,
    with the exception of eyes, which were examined in serial sections.

         A single death was noted on day 42 in the female high-dose
    treatment group; all other rats survived to scheduled termination. No
    disturbances of appearance or behaviour were noted, and eyes appeared
    normal at all examinations. Body weights of rats in all treatment
    groups were comparable to those of controls throughout the study
    period. Food consumption was not affected in males, although
    occasional statistically-significant increases were noted in the
    female treatment groups. Changes in haematology consistent with
    decreased red cell mass (decreased numbers of erythrocytes, heama-
    tocrits, and haemoglobin, with increased MCH and MCHC) were noted
    at the 6-week sampling time in males and females fed diets of 300 ppm
    and higher; however, these changes were apparent at termination only
    in the female 1000 and 2000 ppm groups. Clinical chemistry parameters
    were not altered in a toxicologically-significant manner.

         At necropsy, no effects of treatment on the gross appearance of
    tissues were apparent. Statistically-significant dose-related
    increases in the mean absolute and relative weights of the liver and
    adrenals were noted in males and females from the 1000 and 2000 ppm
    groups. Increased relative weights of kidneys were noted in 2000 ppm
    males and females, and increased relative spleen weight was noted in
    2000 ppm females. These organ-weight effects were apparently
    reversible, as they were not observed in treated rats that were
    continued on control diets for an additional 6 weeks. Microscopic
    examinations of eyes did not reveal any treatment-related
    abnormalities. The results of microscopic examinations of the
    remaining tissues were not included in the study report (Hofmann,
    1974).

         Another 3-month feeding study in rats has been performed, but it
    was not reviewed, because the study report was incomplete. In the
    study narrative the authors concluded that 300 ppm (equal to
    21.3 mg/kg b.w./day in males and 24.1 mg/kg b.w./day in females) was
    the NOEL based on decreased body-weight gain and altered haematology
    and clinical chemistry parameters at 1500 ppm and 7500 ppm, and on
    altered organ weights and histopathological findings in the liver,
    kidneys, ovaries, and pancreas at 7500 ppm (Takehara et al., 1978).

    Rabbits

         Groups of New Zealand white rabbits (6/sex/dose, 3 of each group
    with intact skin, 3 with abraded skin) were treated by dermal
    application for 21 consecutive days (8 hours/day) with doses of 111,
    333, or 1000 mg/kg b.w. vinclozolin. All animals survived the
    treatment period without effects on appearance, behaviour, body
    weight, food or water intake, haematology, clinical chemistry, or
    necropsy parameters. The highest dose was considered to be the NOEL in
    this study (Leuschner et al., 1977c).

    Dogs

         Groups of purebred beagle dogs (6/sex/dose) were fed diets
    containing 0, 100, 300, 600, or 2000 ppm technical vinclozolin
    (98.1% purity) for 6 months. Dogs were offered a total of 700 grams of
    food for 3 hours/day, and consumption was measured daily. Daily
    dosages were equal to 0, 7.0, 20, 41, or 135 mg/kg b.w./day in males
    and 0, 7.4, 21, 41, or 141 mg/kg b.w./day in females. Dogs were
    examined daily for clinical signs of toxicity, and body weights were
    determined weekly. Eyes were examined at 3-month intervals for changes
    in refracting media or the fundus. Blood was sampled at approximately
    monthly intervals for measurement of haematology and clinical
    chemistry parameters. Urine was collected approximately every 2 months
    for urinalysis determinations.

         At termination, dogs were anaesthetized and sacrificed by
    exsanguination. Standard necropsy techniques were followed. The
    following tissues were examined (those indicated by an asterisk * were
    also weighed) for gross and microscopic changes: abnormalities,
    adrenals*, aorta, bone (sternum & marrow), brain*, colon, duodenum,
    esophagus, eye (with optic nerve), gall, bladder, heart*, ileum,
    jejunum, kidneys*, liver*, lungs (with mainstem bronchi), lymph nodes
    (axillary & mesenteric), mammary glands, ovaries*, pancreas, parotid,
    pituitary*, prostate, sciatic nerve, skeletal muscle, skin, spleen*,
    spinal cord (thoracic, lumbar), stomach, testes* (with epididymides),
    thymus, thyroid* (with parathyroid), trachea, urinary bladder, and
    uterus (corpus, cervix, and cornu).

         No effects of treatment on clinical signs, survival, food
    consumption or body-weight gain were apparent. Ophthalmoscopic
    examinations did not reveal any treatment-related abnormalities.

         Evidence of haemolytic anaemia was noted in high-dose males and
    females in the form of increased MCHC, increased numbers of
    reticulocytes and red cells containing Howell-Jolly bodies, and
    increased serum bilirubin, lactate dehydrogenase, and urea levels.
    However, decreases in erythrocyte counts or haematocrits were not
    observed, apparently due to compensatory phenomena. Increased numbers
    of platelets noted in these dogs also suggested a compensatory
    response to anaemia. These effects were more profound in males than in
    females. Other clinical chemistry parameters were not affected.
    Statistically-significant decreases in SGPT, which were observed in
    females, are of questionable toxicological significance. Urinalysis
    parameters were not affected by treatment.

         At necropsy, statistically-significant dose-related increases in
    absolute and relative weights of adrenals were noted in males and
    females fed 300 ppm or more vinclozolin. Other changes in organ
    weights included decreases in absolute weights of kidneys in males at
    300 ppm and above, decreases in absolute brain weights, and increases
    in relative spleen weights in high-dose males. Other changes noted in
    females included decreased relative pituitary weights at 300 ppm and
    higher.

         Potential treatment-related gross findings were restricted to
    reduced size of the prostate in high-dose males. Upon microscopic
    examination, the following potential treatment-related findings were
    observed in males (numbers and incidences in control, 100, 300, 600,
    and 2000 ppm groups, respectively, of 6 dogs examined): increased
    erythropoiesis of bone marrow (0, 0, 0, 1, 4); sinusoidal dilatation/
    accumulation of erythrocytes in the spleen (1, 2, 2, 2, 4);
    atrophy/stromal proliferation of the prostate (0, 0, 2, 4, 6); and
    vacuolization of the zona fasciculata of the adrenals (0, 0, 1, 1, 4).

         No gross findings were evident in females. Incidences of
    microscopic lesions (as described above) were: increased erythro-
    poiesis of bone marrow (1, 0, 2, 2, 5), sideropexia of the bone
    marrow (1, 0, 4, 5, 6); sinusoidal dilatation/accumulation of
    erythrocytes in the spleen (0, 1, 3, 4, 5); and vacuolization of zona
    fasciculata of the adrenals (0, 0, 0, 3, 6).

         The authors concluded that the no adverse-effect level in this
    study was between 300 and 600 ppm vinclozolin in the diet (Kirsch
    et al., 1982).

    Long-term studies

    Rats

         Groups of male and female Sprague-Dawley [SPF] rats (50/sex/dose)
    were fed diets containing 0, 162, 486, 1460, or 4370 ppm vinclozolin
    (purity unspecified) for 130 weeks. Control or test diet and water
    were offered ad libitum. The dietary concentrations were equal to
    9.4, 27, 83, or 257 mg/kg b.w./day in males and 9.1, 28, 84, or
    278 mg/kg b.w./day in females. The results of analyses of the test
    material or of test diets were not presented. Animals were examined
    twice/day for abnormalities of behaviour or appearance, and were
    palpated weekly beginning at week 26 for evidence of rumours. Eyes,
    ears, and dentition were examined "regularly". Rats were weighed
    weekly. The schedule and manner of measurement of food consumption
    were not specified.

         Blood was sampled at 0, 4, 8, 13, 26, 52, and 104 weeks from 10
    rats/sex/dose for assessment of haematology and clinical chemistry
    parameters. A standard battery of tests/examinations was conducted,
    and in addition, at week 104, glycogen in heart, liver, and skeletal
    muscle, total lipids in liver, and ascorbic acid in the adrenals were
    measured. Urine was collected on a similar schedule for standard
    urinalysis determinations.

         Rats that died on test, moribund animals, and all rats surviving
    to 130 weeks were subjected to complete necropsies. Rats were
    sacrificed by decapitation. Animals were dissected, and organs were
    weighed. The following tissues were examined for microscopic changes:
    adrenals, aorta, bone and marrow, brain, colon, duodenum, esophagus,
    eye, heart, ileum, jejunum, kidneys, liver, lungs, lymph node,
    ovaries, pancreas, parotid, peripheral nerve, pituitary, prostate,
    rectum, skeletal muscle, skin, spleen, spinal cord, stomach, testes,
    thymus, thyroid, trachea, urinary bladder, uterus, and any tumours.

         No effects of treatment on clinical signs or mortality were
    apparent. Eye, hearing, and dentition parameters were within normal
    limits. The study was terminated at week 130 when combined male and
    female mortality in the control group reached 70%. Survival in test
    groups was inversely related to dose, as the lowest mortality was
    noted in the high-dose group. Body weights were decreased by about 10%
    in males and females fed the 1460 ppm diet, and by about 40 and 25%,
    respectively, in males and females fed the 4370 ppm diet. These
    changes emerged within the first month of treatment and persisted
    until study termination. Food consumption was decreased in a similar
    manner in the 2 highest-dose groups.

         No effects of treatment on haematology or clinical chemistry
    parameters were apparent. A decrease of about 20% total bilirubin in
    high-dose females is of doubtful toxicological significance.
    Occasional increases in the urinary excretion of 17 ketosteroids and
    of ascorbic acid were noted in high-dose females in the first year of
    treatment; however, these changes were not evident in the final year
    of treatment.

         At necropsy, organ weights were altered in a manner related to
    the body-weight changes. Absolute weights of several organs were
    decreased in males and females from the 1460 ppm and 4370 ppm groups,
    whereas relative organ weights tended to increase in these groups.
    Other necropsy parameters were not affected by treatment. The
    incidences of macroscopic and microscopic findings were randomly
    distributed among all test groups, and did not appear to be related to
    treatment with the test material. The total number of rumours, as well
    as the distribution of specific rumour types, was random throughout
    the test groups, and not affected by treatment. Therefore, vinclozolin
    was determined not to be oncogenic in the rat. The NOEL for chronic
    toxicity was 486 ppm, equal to 27 and 28 mg/kg b.w./day in males and
    females, respectively, based on decreases in food consumption and
    body-weight gain (Leuschner et al., 1977d).

    Observations in humans

         No information available.

    COMMENTS

         Data were not submitted to completely characterize the rates of
    absorption or elimination of vinclozolin. In studies that were
    submitted, all of the administered dose was eliminated, and no
    potential for bioaccumulation was apparent. The plasma half-life was
    about 20 hours.

         Vinclozolin is extensively metabolized, and its major metabolite
    (metabolite F) is excreted as a glucuronide or sulfate conjugate.
    Specific interaction with enzymes is not known.

         A plant metabolite has been identified that is not formed in rats
    (metabolite T). Additional testing is necessary to evaluate the
    toxicity of this compound.

         Vinclozolin has a low order of acute toxicity.

         Special studies on carcinogenicity were negative for oncogenic
    potential in rats and mice. Similarly, this chemical has no known
    specific potential for mutagenicity, teratogenicity, or reproductive
    toxicity.

         A sub-chronic feeding study in rats suggested possible anaemia
    after treatment with diets containing 1000 or 2000 ppm vinclozolin.
    However, this finding was not reproduced in a 2-year feeding study in
    rats. Chronic effects noted in the long-term rat study were restricted
    to decreases in food consumption and body-weight gain of rats fed
    1460 ppm and higher (equal to 83 mg/kg b.w./day), with a NOEL for this
    effect of 486 ppm (equal to 27 and 28 mg/kg b.w./day in males and
    females, respectively).

         A feeding study in dogs demonstrated evidence of haemolytic
    anaemia in animals fed 2000 ppm vinclozolin for 6 months (equal to 135
    and 141 mg/kg b.w./day in males and females, respectively). Other
    relevant findings included significant increases in relative and
    absolute adrenal weights in males and females at doses of 300 ppm and
    higher (equal to 20 and 21 mg/kg b.w./day in males and females,
    respectively). A clear dose-related trend for vacuolization of the
    zona fasciculata of the adrenals was noted in males and females at
    doses of 600 and 2000 ppm. Thus, the changes in adrenal weights
    observed at the lower doses can be related to pathology at higher
    doses. Other dose-related histopathological findings noted in the
    300 ppm groups included accumulation of erythrocytes in the spleen,
    atrophy of the prostate, and sideropexia of the bone marrow
    (accumulation of haemosiderin within reticuloendothelial elements of
    the bone marrow). On the basis of these findings, the NOEL in this
    study was 100 ppm, equal to 7.0 mg/kg b.w./day in males and 7.4 mg/kg
    b.w./day in females.

    TOXICOLOGICAL EVALUATION

    LEVEL CAUSING NO TOXICOLOGICAL EFFECTS

         Averages for males and females:

         Mice:     486 ppm, equal to 87 /kg b.w./day.
         Rats:     486 ppm, equal to 27 /kg b.w./day.
         Dogs:     100 ppm, equal to 7.2 /kg b.w./day.

    ESTIMATE OF TEMPORARY ACCEPTABLE DALLY INTAKE FOR MAN

         0 - 0.04 mg/kg b.w.

    STUDIES WITHOUT WHICH THE DETERMINATION OF AN ADI IS IMPRACTICABLE, TO
    BE SUBMITTED TO WHO BY 1987:

         Additional studies to evaluate the toxicity of the plant
    metabolite, metabolite T.

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

         1.   Data to demonstrate the rate of absorption and elimination
              after a single oral dose of vinclozolin.

         2.   Data on the potential effects to humans of exposure to
              vinclozolin.

    REFERENCES

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              rats. Not submitted for review.

    Cifone, M.A. & Myhr, B.C. Report on the evaluation of Vinclozolin in
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    1981      Effect of vinclozolin on pregnancy of the the New Zealand
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              Aktiengelsellschaft, Limburgerhof, FRG.
    


    See Also:
       Toxicological Abbreviations
       Vinclozolin (Pesticide residues in food: 1988 evaluations Part II Toxicology)
       Vinclozolin (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)