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Diss Factsheets

Administrative data

short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
22 July 2019 - 9 June 2020
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guidelineopen allclose all
according to guideline
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
according to guideline
other: The United States Environmental Protection Agency (EPA) Health Effects Test Guidelines, OPPTS 870.3650, Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test.
GLP compliance:
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
4-benzoylbenzene-1,2,3-triyl tris(6-diazo-5,6-dihydro-5-oxonaphthalene-1-sulphonate)
EC Number:
EC Name:
4-benzoylbenzene-1,2,3-triyl tris(6-diazo-5,6-dihydro-5-oxonaphthalene-1-sulphonate)
Cas Number:
Molecular formula:
4-benzoylbenzene-1,2,3-triyl tris(6-diazo-5,6-dihydro-5-oxonaphthalene-1-sulphonate)
Test material form:
Specific details on test material used for the study:
- Storage condition of test material: Ambient condition, protected from light
- Stability: The stability of the bulk test item was not determined during the course of this study. Stability analyses performed previously in conjunction with study 20190830 demonstrated that the test item is stable in the vehicle when prepared and stored under the same conditions at concentrations bracketing those used in the present study.

Test animals

other: CRL:WI (Han)
Details on test animals or test system and environmental conditions:
- Source: Charles River UK, Margate, Kent, UK
- Age at study initiation: 11 to 12 weeks
- Weight at study initiation: 249 - 392 g (males); 174 - 247 g (females)
- Housing: Animals were initially housed 2 or 3 per cage by sex (unless reduced by mortality) in appropriately sized suspended polycarbonate cages with stainless steel grid tops and solid bottoms. Bedding material was sterilised white wood shavings. A few days prior to mating, males were transferred to individual cages with solid bottoms. Mated females were transferred to individual solid bottomed cages. White paper tissue was supplied as nesting material from Gestation Day (GD) 20. Females with litters were retained in this type of cage until termination. After mating, the males were re-housed with their original cages mates.
- Diet: SDS VRF-1 breeder diet, ad libitum (except during designated procedures)
- Water: tap water, ad libitum
- Acclimation period: 5 weeks

- Temperature: 18 to 26°C (actual range)
- Humidity (%): 28 to 89% (actual range)
- Air changes: Ten or greater air changes per hour
- Photoperiod: 12-hour light/12-hour dark cycle

IN-LIFE DATES: From: 22 July 2019 To: 29 September 2019

Deviations: The protocol stated that the target environmental conditions would be 19 to 23°C for temperature and 40 to 70% for humidity. The actual ranges were 18 to 26°C and 28 to 90%, respectively. Animal welfare checks (morning and afternoon) were performed on all the study animals during these dates and all animals appeared unaffected from the transient change in environmental conditions. Therefore, this deviation had no impact on the outcome of the study.

Administration / exposure

Route of administration:
oral: gavage
Details on route of administration:
The oral route of administration was selected for this study as this route has been defined by the Sponsor as a possible route of human exposure. Doses were administered using plastic tube.
other: 0.25% Methocel KM4 premium in water
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS: Test item dosing formulations were prepared based on a method established at the Test Facility at appropriate concentrations to meet dose level requirements. The dosing formulations were prepared at least weekly, stored in a refrigerator set to maintain 4˚C, protected from light, or transferred to animal unit immediately and dispensed daily.

- Concentration in vehicle: 10.7 mg/L; 32.1 mg/mL; 107 mg/mL
- Amount of vehicle: 10 mL/kg
Analytical verification of doses or concentrations:
Details on analytical verification of doses or concentrations:
Analyses were performed by ultra-performance liquid chromatography-ultra violet (UPLC-UV) using a validated analytical procedure (study 20190830).
Duplicate top, middle and bottom (middle only for control) samples for each sampling time point were sent to the analytical laboratory. Triplicate top, middle and bottom (middle only for control) samples were collected for each sampling occasion as backup. Week 2 and 5 backup samples were shipped to the analytical laboratory for analysis and Week 1 back up samples were retained at the Test Facility. Sample volumes were 1 mL for Day 1 and Week 5 collections and 0.5 mL for Week 2 collections. Concentration results were considered acceptable if sample concentration results were within or equal to ±10% of theoretical concentration. Each individual sample concentration result was considered acceptable if it was within or equal to ± 15%. Homogeneity results were considered acceptable if the relative standard deviation (RSD) of the mean value at each sampling location was ≤ 5%.
Duration of treatment / exposure:
The males were dosed for at least 4 weeks overall, starting from 2 weeks prior to mating. The females were dosed from 2 weeks prior to mating, then continuing until the day prior to termination.
Frequency of treatment:
Once daily
Doses / concentrationsopen allclose all
Dose / conc.:
100 mg/kg bw/day (actual dose received)
Group 2
Dose / conc.:
300 mg/kg bw/day (actual dose received)
Group 3
Dose / conc.:
1 000 mg/kg bw/day (actual dose received)
Group 4
No. of animals per sex per dose:
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The dose levels were selected based on information provided from the previous dose range finding study (490089) where the administration of the substance by once daily for 14 days was well tolerated in Han Wistar rats at dose levels up to 1000 mg/kg bw/day with no effects on clinical observations, body weights, body weight gains or food consumption.
- Fasting period before blood sampling for clinical biochemistry: No


Observations and examinations performed and frequency:
- Time schedule: twice daily

- Time schedule: at least weekly beginning Week -1

- Time schedule for examinations: Animals were weighed weekly from Week -1 and mated females were weighed on Gestation Day (GD) 0, 4, 7, 11, 14, 17 and 20 and on Lactation Day (LD) 0 (when possible for dosing purposes), 1, 4, 7, 10 and 13

- Time schedule: Food consumption was quantitively measured weekly for both sexes from Week -1 until pairing for mating, and on GD 0 to 4, 4 to 7, 7 to 11, 11 to 14, 14 to 17, and 17 to 20 and LD 1 to 4, 4 to 7, 7 to 10, and 10 to 13 for the mated females, where possible. Weekly food consumption resumed for the males following mating.

- Time schedule for examinations: Water consumption was monitored on a regular basis throughout the study by visual inspection of the water bottles.

- Time schedule for collection of blood: Week 4 (males); Lactation day 11/12 (females)
- How many animals: 5 selected animals/sex/group
- Anaesthetic used for blood collection: Not specified
- Parameters checked: Red blood cell count, Haemoglobin, Haematocrit, Mean cell volume, Mean cell haemoglobin concentration, Mean cell haemoglobin Reticulocytes, Reticulocyte count (absolute), Red blood cell distribution width, Platelets, White blood cell count, Neutrophils count (absolute), Lymphocytes count (absolute), Monocytes count (absolute), Eosinophils count (absolute), Basophils count (absolute), Large unstained cells (absolute)

- Time schedule for collection of blood: Week 4 (males); Lactation day 11/12 (females)
- Animals fasted: Not specified
- How many animals: Five males and 5 females per group
- Parameters checked: Urea, Glucose, Aspartate aminotransferase, Alanine aminotransferase, Alkaline phosphatase, Creatine phosphokinase, Lactate dehydrogenase, Sodium, Potassium, Chloride, Total protein, Albumin, Globulin, Albumin/globulin ratio, Cholesterol, Creatinine, Total bilirubin, Calcium Inorganic phosphate, Triglycerides, Total bile acids

TSH, T4 and T3: Yes
- Time schedule for collection of blood: Prior to necropsy
- Animals fasted: No
- How many animals: all males and females
- Parameters checked: TSH, T4 and T3

- Time schedule for examinations: for 5 selected males per group (prior to blood sampling) once during Week 4 and for the first 5 females per group which reared their litter to at least LD 10 to 12 (prior to blood sampling) during lactation
- Battery of functions tested: functional observation battery included homecage observations (posture, temperature), handling observations, air righting, extensor thrust, observations in a standardized arena (2 minute observation), functional test including: reaction to sudden sound, reaction to touch, grip strength, pain perception, landing foot splay, motor activity.

Over a 14 day period prior to test item administration, then continuing through pre-mating test item administration and mating period, vaginal lavages were taken early each morning and the stages of oestrous observed was recorded. Vaginal smears were examined on the morning of necropsy to determine the stage of oestrus cycle to allow correlation with histopathology of ovaries.
Sacrifice and pathology:

- Organs were collected, processed and evaluated in accordance with the applicable guideline.
- Full tissues of unscheduled deaths from all groups.
- Full tissues of the 5 male and 5 female Group 1 and Group 4 animals used for laboratory investigations.
- The reproductive organs (cervix, clitoral gland, coagulation gland, epididymides, ovaries, preputial gland, prostate gland, seminal vesicles, testes, uterus, and vagina) of all Group 1 and Group 4 animals
- Testes of all Group 1 and Group 4 males, examined for staging of spermatogenesis (qualitative evaluation).
- Gross lesions of all animals (all groups).
All statistical tests were conducted at the 5% significance level. All pairwise comparisons were conducted using two sided tests and are reported at the 1% and 5% levels, unless otherwise noted.
The pairwise comparisons of interest are listed below:
- Group 2 vs. Group 1
- Group 3 vs. Group 1
- Group 4 vs. Group 1

Levene’s test was used to assess the homogeneity of group variances.
The groups were compared using an overall one-way ANOVA F-test if Levene’s test was not significant or the Kruskal-Wallis test if it was significant. If the overall F-test or Kruskal-Wallis test was found to be significant, then pairwise comparisons were conducted using Dunnett’s or Dunn’s test, respectively.

Results and discussion

Results of examinations

mortality observed, non-treatment-related
Description (incidence):
Two control females were euthanised unscheduled on Gestation Day 11 (Day 27 of the study) due to clinical signs of decreased muscle tone in both forelimbs and swollen abdomen resulting in an abnormal gait. One animal was also noted to have increased vocalisation. There appeared to be no effects on body weights or food consumption. In one animal, dark red discoloration of the thymus was observed during gross necropsy examination. This finding correlated microscopically with agonal haemorrhage. Moderate axonal degeneration was also noted microscopically in the lumbar spinal nerves attached to the lumbar spinal cord segment and this was associated with mild, regionally extensive myofiber atrophy and replacement by adipose tissue in skeletal muscle from the hindlimb. In the second control animal that was euthanised there were no gross necropsy findings, however, mild axonal degeneration was also noted microscopically in the lumbar spinal nerves accompanied by mild, regionally extensive hindlimb skeletal muscle myofiber atrophy and replacement by adipose tissue, similar to that seen in the first control animals that was euthanised. Although lumbar spinal nerve degeneration and secondary skeletal muscle myofiber atrophy would be expected to be associated with clinical signs in the hindlimbs (e.g. abnormal gait and decreased muscle tone), given the nature of these microscopic changes it is considered likely that this may be indicative of a more generalised/multifocal condition which could account for the gait/forelimb changes described clinically in these animals. Irrespective, as both animals were in Group 1 (Control) and had not received any test item, these findings cannot be associated with the treatment.
Body weight and weight changes:
effects observed, non-treatment-related
Description (incidence and severity):
There were minor changes that occasionally achieved statistical significance such as Day 8 to 15, Group 4 males at 1000 mg/kg bw/day body weight gain was noted to be 48% lower in comparison to the Control male group with an overall 18% lower body weight gain from Day 1 to 42. In addition, on Day 15 to 22 Group 2 males at 100 mg/kg bw/day body weight gain was 62% lower in comparison to the Control male group. However, due to the low incidence and lack of a dose related pattern, these findings were considered sporadic and unrelated to treatment.
Haematological findings:
effects observed, non-treatment-related
Description (incidence and severity):
There were minor changes that achieved statistical significance however, noted changes were considered to be within normal biological variation and/or due to a small magnitude of difference. They were therefore considered incidental and unrelated to treatment.
Clinical biochemistry findings:
effects observed, non-treatment-related
Description (incidence and severity):
There were minor changes that were considered to be within normal biological variation and/or due to a small magnitude of difference. They were therefore considered incidental and unrelated to treatment.
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, non-treatment-related
Description (incidence and severity):
Compared to controls, absolute and relative (to both body weight and brain weight) thymus weights were slightly lower in Group 2, 3 and 4 females (although these differences were not statistically significant). In two animals of group 4 this correlated microscopically with minimal decreased cellularity in the cortex. However, this microscopic finding was also present in one control animal, with an individual absolute thymus weight lower than that of one group 4 animal. Absolute thymus weights were also slightly lower in Group 2, 3 and 4 males but again the difference was not statistically significant and there was no microscopic correlate. As these differences were small, not statistically significant and lacked any compatible gross finding (e.g. small thymus) and given that a correlating microscopic finding occurred in only one sex (females) and was also present in a control animal, they were considered not to be related to the treatment and were considered
most likely to be a spontaneous occurrence or related to pregnancy/lactation. At least in males, the lower absolute thymus weights were considered most likely to be a reflection of the lower terminal body weights in these groups. There were individual organ weight values that were different from their respective controls. There were, however, no patterns or correlating data to suggest these values were related to treatment.
Gross pathological findings:
no effects observed
Description (incidence and severity):
All gross findings observed were considered incidental, of the nature commonly observed in this strain and age of rat or occurred at a similar incidence in control and treated animals, and therefore, were considered not to be related to treatment.
Neuropathological findings:
no effects observed
Other effects:
no effects observed
Description (incidence and severity):
At dose levels up to and including 1000 mg/kg bw/day, there were no treatment related changes in the mating performance and in the duration or pattern of the oestrus cycle.
At dose levels up to and including 1000 mg/kg bw/day, there were no treatment related changes in the thyroid hormone parameters noted in the F0 animals.

Effect levels

Key result
Dose descriptor:
Effect level:
1 000 mg/kg bw/day (actual dose received)
Basis for effect level:
other: based on the absence of adverse effects up to and including the highest dose levels tested.

Target system / organ toxicity

Key result
Critical effects observed:

Any other information on results incl. tables

Dose Formulation Analyses

No test item was detected in the Group 1 control samples.

Formulation analysis demonstrated that Week 1 samples did not meet the specified acceptance criteria. Out of specification investigation concluded that samples were out of specification due to being unprotected from light. As a result, an additional sampling occasion was performed (Week 2) on samples protected from light.

Formulation analysis demonstrated that the Week 2 and 5 prepared formulation samples were accurate and homogenous. Initial analysis of Group 2 and Group 3 samples failed to meet the criterion, therefore back up samples were analysed and were within the specified acceptance criteria:

- Mean sample concentration results within or equal to ± 10% of theoretical concentration (week 2: 91-98%; week 5: 88-95%)

- Each individual sample concentration result within or equal to ± 15% (week 2: 88-106%; week 5: 85-96%)

- A relative standard deviation (RSD) of concentrations of ≤ 5% for each group (week 2: 1.0-4.2; week 5: 1.5-2.1).

Applicant's summary and conclusion

A combined repeated dose toxicity study with reproduction/developtmental toxicity screening test was performed according to OECD 422 and in accordance with GLP principles. Administration of Diazo PW 980 by once daily oral gavage was well tolerated in rats at levels of 1000 mg/kg bw/day without in-life observations of toxicity or histopathological findings in the F0 or F1 generation. There was no evidence of test item related changes to the mating and fertility, maternal behaviour or pre-weaning viability. Mean litter weights and pre-weaning physical development were similar in all dose groups. Based on these results, the no-observed-effect level (NOEL) of parental, reproduction (up to and including implantation) and developmental (from implantation onwards) was considered to be 1000 mg/kg bw/day.