long chain alkyl thio carbamide metal complex

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

03-Feb-1999 to 14-Apr-1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study, to GLP, on related material

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): NB 6786-35
- Substance type: technical product
- Physical state: black viscous liquid
- Analytical purity: 94% +- 2%
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: Tris (dicocodithiocarbamato) tris (µ-disulphido) (µ3-thio)-triangulotrimolybdenum (IV) dicocodithiocarbamate
- Lot/batch No.: NB 6786-35
- Stability under test conditions: stable for the duration of the study
- Storage condition of test material: ambient temperature in the dark
- Other: Date received: 14-Sep-1998

Test animals

Species:

rat

Strain:

other: Crl:CD(R) BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, UK
- Age at study initiation: ~8 weeks
- Weight at study initiation: males 255-333 g, females 181-243 g
- Fasting period before study: no data
- Housing: 5/cage; suspended cages with wire mesh floors
- Diet (e.g. ad libitum): SDS pelleted Rat and Mouse No.1, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 28 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-25.5
- Humidity (%): 26-67
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: From: 03-Feb-1999 To: 14-Apr-1999

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

peanut oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
- test material administered as a suspension
- suspensions for each dose level prepared independently
- suspensions prepared weight/volume and homogenised
- suspensions prepared daily for the first 7 days then every 2 days, stored in amber glass bottles at 4 ºC

VEHICLE
- Concentration in vehicle: no data, but presumably 3, 30 and 200 mg/ml
- Amount of vehicle (if gavage): 5 ml/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Prior to the commencement of the study, the proposed formulation procedure was checked by chemical analysis to confirm that the method was acceptable and that the stability and homogeniety of the formulation was satisfactory under the conditions of the study. Samples of the formulations prepared for use in weeks I and 3 were also analysed to check the accuracy of preparation. Results reported separately.

Duration of treatment / exposure:

28 days

Frequency of treatment:

Daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 15, 150 and 1000 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

10/sex in 0 and 1000 mg/kg bw/day groups
5/sex in 15 and 150 mg/kg bw/day groups

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: with reference to existing toxicity data, including a 7-day preliminary study with dose levels of 250, 500 and 1000 mg/kg bw/day
- Rationale for animal assignment (if not random): random
- Rationale for selecting satellite groups: random at start of study
- Post-exposure recovery period in satellite groups: 14 days
- Section schedule rationale (if not random): no data

Positive control:

none

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least twice daily
- Cage side observations included: signs of reaction to treatment or ill health

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule:
- detailed physical examination: once weekly
- detailed observations in association with dosing: daily during week 1, twice weekly during weeks 2-4; observations were made pre-dose and four times post-dosing

BODY WEIGHT: Yes
- Time schedule for examinations: study days 1, 8, 15, 22, 28 and recovery days 1, 8 and 14; also at necropsy

FOOD CONSUMPTION: Yes
- food consumption calculated as weekly group mean consumption (g/rat per week) = [(total food given to group - total food left by group) / (number of animal days for the group)] * 7
- quantity of food consumed was recorded weekly for each cage

FOOD EFFICIENCY:
- food conversion (%) = mean food consumption (g) / mean body weight gain (g)
- calculated on a weekly basis

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: main study day 29, recovery animals day 43
- Anaesthetic used for blood collection: Yes, light general anaesthesia
- Animals fasted: Yes
- How many animals: all
- Parameters examined: packed cell volume, haemoglobin, red blood cell count, mean corpuscular haemoglobin and mean corpuscular haemoglobinconcentration, mean corpuscular volume, differential white blood cell count (neutrophils, lymphocytes, eosinophils, basophils, monocytes, large unstained cells), total white blood cell count, platelet count, prothrombin time, activated partial thromboplastin time, bone marrow smear

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: main study day 29, recovery animals day 43
- Animals fasted: Yes
- How many animals: all
- Parameters examined: glucose, total protein, albumin, albumin/globulin ratio, urea nitrogen, creatinine, alkaline phosphatase, glutamic-pyruvic transaminase, glutamic-oxaloacetic transaminase, gamma-glutamyltranspeptidase, bilirubin, sodium, potassium, calcium, inorganic phosphorus, chloride, cholesterol, triglycerides

URINALYSIS: Yes
- Time schedule for collection of urine: main study day 29, recovery animals day 43
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters examined: appearance, volume, pH, specific gravity, protein, glucose, ketones, bile pigments, haem pigments, crystals, epithelial cells, leukocytes, erythrocytes, casts, other abnormal components (including spermatozoa and precursors)

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: prior to the start of treatment, during week 4 and during week 2 of recovery
- Dose groups that were examined: all
- Battery of functions tested: full functional observational battery and quantitative assessment of locomotor activity
- Other: examinations in the hand and standard arena were also performed on all main study rats during weeks 2 and 3

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

adrenals# w
alimentary tract (oesophagus, stomach*, duodenum*, jejunum*, ileum*, caecum*, colon*, rectum *)
aorta (thoracic)
brain* w
epididymides# w
eyes
femur#
gross abnormalities#
harderian glands*
heart* w
kidneys# w
lachrymal gland
liver# w
lungs (including bronchi)*
lymph nodes (mandibular, mesenteric)*
mammary area (caudal)
marrow smear
optic nerves
ovaries* w
pancreas
pituitary
prostate* w
salivary gland
sciatic nerve
seminal vesicles* w
skeletal muscle (thigh)
skin (overlying mammary area)
spinal cord*
spleen# w
sternum
testes# w
thymus*
thyroids (with parathyroids)*
tongue
trachea*
urinary bladder*
uterus (with cervix)*
vagina*

w - indicates organ weighed
* - indicates tissues examined for all main study animals
# - indicates tissues examined for main study animals in control and top dose groups

Other examinations:

no data

Statistics:

Fisher's Exact Test and Mantel's test for data where the relative frequency of the mode exceeded 75%
Bartlett's test for heterogeneity of variance; if significant, logarithmic transformation tried
One-way analysis of variance if non-significant Bartlett's; Kruskal-Wallis analysis if significant Bartlett's
Student's t-test and Williams test or non-parametric equivalents where appropriate

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

no effects observed

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY
- there were no clinical signs associated with a toxic response to the test material.
- clear or brown coloured saliva was observed immediately after dosing in some animals from all treated groups. This was considered to be associated with oral gavage administration of a bolus dose of the test material formulated in peanut oil.
- incidental hairloss from various regions of the body (with or without scabbing) was observed in some animals from all groups

BODY WEIGHT AND WEIGHT GAIN
- during the 4-week dosing period, body weight gain in top-dose males, mid-dose males and females and low-dose males was statistically significantly reduced. The differences, particularly for the males, were more marked at the lower doses than at the high dose, and were considered to reflect lower food consumption noted for these groups. Furthermore, there was some evidence of similar differences in growth rates prior to the start of treatment. As such, the body weight differences recorded during the dosing period were considered to be unrelated to treatment.
- during the 2-week recovery period, body weight gain for top-dose males was slightly reduced but the difference was not statistically significant.

FOOD CONSUMPTION
- Cumulative food consumption in the top-dose groups were similar to control during the dosing and recovery periods. Reduced food consumption was seen in low-dose males and mid-dose females during the 4-week dosing period, and differences between control and treated groups in cumulative food consumption were considered not to be treatment-related

FOOD EFFICIENCY
- food conversion ratios were variable with no evidence of a treatment-related effect

HAEMATOLOGY
- week 5, prothrombin time, mid- and high-dose males, statistically significantly increased. These differences were minimal, did not show a relationship to dose, were present only in one sex and, therefore, were considered unrelated to treatment.
- week 5, neutrophil and platelet counts, top-dose females, statistically significantly increased. A slight numerical dose relationship was evident for the neutrophils, however all values were within the range of background data for rats of the age and strain used. These findings are therefore considered to be unrelated to treatment.
- week 7, all parameters were within accepted limits and there were no statistically significant differences between top-dose groups and vehicle control.
- remaining parameters measured, but not mentioned above, were within accepted limits and showed no evidence of a response to treatment.

CLINICAL CHEMISTRY
- week 5 in the main study, urea nitrogen, top-dose females, statistically significantly increased. However, this difference was minimal, present only in one sex, did not show a relationship to dose and was considered unrelated to treatment. Furthermore, the same group mean (17 mg/dl) value was recorded for both top-dose and vehicle control groups at week 7.
- week 7 in the main study, creatinine and calcium level, top-dose males, statistically significantly reduced; glucose and triglyceride levels, top-dose females, statistically significantly reduced; albumin/globulin ratio, top-dose males, statistically significantly increased. However, these differences were minimal and were present only in one sex. In addition these differences were only evident 2 weeks after the cessation of treatment. Therefore, they were considered incidental and unrelated to treatment.
- remaining parameters measured, but not mentioned above, were within accepted limits and showed no evidence of a response to treatment.

URINALYSIS
- week 5 in the main study, pH in the top-dose males was statistically significantly reduced. A mild dose relationship was evident, however the change was small, confined to one sex and all values were within the range of background data for rats of the age and strain used. For these reasons the observed differences were considered to be unrelated to treatment.
- remaining parameters measured, but not mentioned above, were within accepted limits and showed no evidence of a response to treatment.

NEUROBEHAVIOUR
- no changes considered to be indicative of neurotoxicity

ORGAN WEIGHTS
- week 5 in the main study, relative liver weight, top-dose females, statistically significantly increased. However, this difference was present only in one sex and all individual values were within the normal background range for rats of the age and strain used. This finding is therefore considered to be unrelated to treatment
- week 5 in the main study, relative spleen weight, top-dose females, were also statistically significantly increased. There was some overlap of the individual data between this test group and the controls, and in the absence of a statistically significant result for absolute organ weights the observed differences were considered to be unrelated to treatment
- week 7 in the main study, relative kidney weight, top-dose males, statistically significantly increased; relative heart weight, top-dose females, statistically significantly increased. Since these differences were only evident 2 weeks after the cessation of treatment, they were considered incidental and unrelated to treatment
- remaining organs weighed, but not mentioned above, were within accepted limits and showed no evidence of a response to treatment.

GROSS PATHOLOGY
- forestomach, brown staining on the epithelial aspect, 3/5 males and 4/5 females in the top-dose group and 1/5 females in the mid-dose group
- large intestine, dark contents, all animals in top-dose group
- these findings are considered to be pigmentation associated with the coloured nature of the test material
- recovery animals, no changes attributable to treatment
- incidence and distribution of all other findings were considered to fall within the background range of macroscopic changes.

HISTOPATHOLOGY: NON-NEOPLASTIC
- mesenteric lymph nodes, eosinophilic/vacuolated macrophages were seen in top-dose males (5/5) and females (5/5), p<0.01, at the end of the 4-week treatment period and after a 2-week recovery period. This change showed partial reversibility in rats allowed a 2-week recovery period. This finding is not considered an adverse response but indicates that some material was absorbed through the gastro-intestinal tract and taken up in the mesenteric lymph nodes.
- all other microscopic findings seen in rats at the end of the treatment period were considered to be incidental and of no toxicological importance
- no microscopic findings were detected which might be associated with the statistically higher relative liver weights for top-dose females; therefore this finding was considered to be incidental.
- no microscopic findings were seen in the gastrointestinal tract of any animals in this study.

HISTOPATHOLOGY: NEOPLASTIC:
- No data

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: overall effects

2

Dose descriptor:

NOEL

Effect level:

150 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In a GLP study conducted according to OECD guideline 407, no treatment-related adverse effects were seen in rats administered NB 6786-35 by gavage at up to 1000 mg/kg bw/day (the highest tested dose) for 28-days, and this dose is considered the NOAEL for this study.

Executive summary:

In a GLP study conducted according to OECD guideline 407, groups of 5 male and 5 female Crl:CD(R) BR rats were administered NB 6786-35 (tris (dicocodithiocarbamato) tris (µ-disulphido) (µ3-thio)-triangulotrimolybdenum (IV) dicocodithiocarbamate) at 0, 15, 150 or 1000 mg/kg bw/day by oral gavage (in peanut oil) for 28 days. Additional groups of 5 rats/sex, administered 0 or 1000 mg/kg bw/day, were retained for a further 2-week recovery period.

There were no deaths reported. Clear or brown coloured saliva was seen immediately after dosing in some animals from all treated groups; this was considered to be associated with the method of dosing. Relative liver weight was statistically significantly increased in females administered 1000 mg/kg bw/day. However, this difference was present only in one sex, all individual values were within the normal background range for rats of the age and strain used, and no associated microscopic findings were detected; it is therefore considered to be unrelated to treatment.

At necropsy, brown staining was observed on the epithelial aspect of the forestomach in 3/5 males and 4/5 females treated with 1000 mg/kg bw/day and 1/5 females treated with 150 mg/kg bw/day, and dark contents were seen in the large intestine of all rats treated with 1000 mg/kg bw/day. These findings were considered to be pigmentation associated with the coloured nature of the test material. Histopathological examination revealed eosinophilic/vacuolated macrophages in the mesenteric lymph nodes of all main study rats treated with 1000 mg/kg bw/day and, to a lesser extent, in recovery rats treated similarly indicating partial reversibility. This finding is not considered an adverse response but indicates that some test material was absorbed through the gastrointestinal tract and taken up in the mesenteric lymph nodes.

In conclusion, the 28-day oral no-observed-adverse-effect level (NOAEL) for NB 6786-35 in rats was 1000 mg/kg bw/day (the highest tested dose). [In view of the structural and chemical similarities, it is considered that the results of this study can be used for read-across to EC# 457-320-2.]