SDBR

Endpoint summary

Description of key information

A 28-day repeated dose toxicity study with SDBR is available. 

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6 June - 4 July 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Remarks:

Crl:(WI)WU BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females nulliparous and non-pregnant: yes
- Age at study initiation: about 5 weeks
- Weight at study initiation: 96.2 -119.9 g (males), 84.7 - 97.7 g (females)
- Fasting period before study: No (but fasted o/n before necropsy)
- Housing: housed in groups of 5 in Macrolon cages (type 3), with sterilized wood shavings
- Diet: Rat&Mouse No 3 Breeding diet RM 3 (SDS Special Diets Services, Witham, England), ad libitum)
- Water: tap-water, ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.3 - 23.1
- Humidity (%): 30-70
- Air changes (per hr): about 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 6 June To: 4 July 2000

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Fresh suspensions of SDBR in corn oil were made once weekly by weighing the appropriate amount of SDBR (after grinding with a coffee mill) in volumetric flasks and making up with corn oil. The samples for dosing were taken during vigorous stirring using a magnetic stirrer, The test suspensions and corn oil were stored in glass jars in refrigerator (2-10ºC).

VEHICLE
- Concentration in vehicle: 0, 3, 30 or 200 mg SDBR/ 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:

The stability, homogeneity and concentration of SDBR in corn oil was determined using a validated HPLC method.

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily

Dose / conc.:

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

Remarks:

Low dose group

Dose / conc.:

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

Remarks:

Mid dose group

Dose / conc.:

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

Remarks:

High dose animals received 250 mg/kg bw/day during first 3 days of the study

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At least once daily (animals were handled if necessary to detect signs of toxicity)
- Clinical observations were performed outside the home cage prior to treatment and on a weekly basis during the treatment period.

BODY WEIGHT: Yes
- Time schedule for examinations: on days 0, 3, 7, 10, 14, 17, 21, 24, 27 and 28

FOOD CONSUMPTION: Yes
- Food consumption was measured per cage over successive periods of 7 days (weeks 1-2) or 6 days (last week)

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necropsy
- Anaesthetic used for blood collection: No
- Animals fasted: Yes
- How many animals: All
- Parameters: heamoglobin, packed cell volume, red blood cell count, reticulocytes (control and high dose rats only), total white blood cell count, prothrombin time, thrombocyte count (mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular heamoglobin concentration were calculated).

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at necropsy
- Animals fasted: Yes
- Anaesthesia: CO2/ CO
- How many animals: All
- Parameters: Alkaline phosphatase activity, aspartate aminotransferase activity, alanine aminotransferase activity, gamma glutamyl transferase activity, total protein, albumin, ratio albumin/globulin, urea, creatinine, fasting glucose, bilirubin (total), cholesterol, triglycerides, phospholipids, calcium, sodium, potassium, chloride, inorganic phosphate

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: during last week of treatment
- Dose groups that were examined: All
- Battery of functions tested: sensorimotor reflex testing, grip strength measurement and motor activity assessment

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Organs weighed: adrenals, brain, epididymides, heart, kidneys, liver, ovaries, seminal vesicles with coagulation glands, spleen, testes, thymus

HISTOPATHOLOGY: Yes (all organs specified above except seminal vesicles, and axillary lymph node, bone marrow (femur), caecum, colon, eyes, lungs, mammary gland, mesenteric lymph node, parathyroids, Peyer's patches, pituitary, prostate, rectum, sciatic nerve, spinal cord, small intestines (duodenum, jejunum, ileum), stomach, thyroid, trachea/bronchi, urinary bladder, uterus, vagina and all gross lesions)
Histopathological examinations was performed on all control and high dose rats, and on all gross lesions.

Statistics:

- Body weight: one-way analysis of covariance (covariate: bw on day 0) followed by Dunnett’s multiple comparison tests;
- Haematological parameters and clinical chemistry values: one-way ANOVA followed by Dunnett’s multiple comparison tests, or Kruskal-Wallis non-parametric ANOVA followed by Mann-Whithey U-tests;
- Parameters assessed during functional observations: continuous measures were analysed by post-hoc group comparisons in case of a significant result. Rank order data were analysed by Kruskal-Wallis analysis of variance at each test time point, followed by planned multiple comparisons between dose groups in case of a significant result. Categorical data were analysed by Pearson chi-square analysis.
- Motor activity data were analysed using one-way analysis of variance at each test time point.
All tests were two-sided. Group mean differences with an associated probability of less than 0.05 were considered to be statistically significant.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

The final body weight of high dose males was lower than control males (around -7%). This effect was observed throughout the study. The other males and all dosed females were comparable to the controls.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food consumption (-6% compared to controls) was slightly decreased in high dose males compared to the control males. No effects were observed in females.

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

Food conversion efficiency was slightly decreased in high dose males compared to the control males. No effects were observed in females.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

The prothrombin time was slightly decreased on male rats in the mid and high dose group (36.7s for controls and 36.8s, 34.2s and 34.5s in the low, mid and high dose males). Mean corpuscular volume was increased in high dose males compared to controls (-4.5%). Based on the small effects and as no similar effects were observed in females, these were not considered toxicologically relevant.
Increased red blood cell count and haemoglobin concentration was observed in high dose females (both around 10% compared to controls). Furthermore high dose females had increased neutrophil counts (0.6*10E9/L vs 0.2*10E9/L in controls).

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Glucose values were decreased in high dose males, which was considered to be related to the decreased food intake of this group. Glucose values were also decreased in females in the low and the high dose group (around -18%).
Total bilirubin was increased in high dose females (1.5 vs 1.0 µmol/L in controls). No effect on total bilirubin was found in males.
An increase in albumin/ globulin ration was observed in females of the low-dose group, which was considered an incidental finding.

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

The results of neurobehavioural observations and motor activity assessment did not indicate any neurotoxic potential of SDBR.

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No treatment-related findings were observed on absolute and relative organ weights.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No gross macroscopical findings.

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No SDBR-related effects observed (details included below).

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical biochemistry

haematology

Critical effects observed:

no

Formulation analysis

The formulations were concluded to be homogeneous (RSD 7.6%, 0.4% and 1.8% for the low, mid and high dose formulations, respectively).

SDBR formulations in corn oil were found to be stable when stored for one week in the refrigerator (rel. difference to upon storage max. +/- 5.5%).

The concentrations of the formulations were confirmed analytcially (difference from nominal no more than 9%). 

Conclusions:

In a 28-day repeated dose toxicity study, the NOAEL was concluded to be at least 150 mg/ kg bw/day based on a slightly slower growth and food intake of the males dosed at 1000 mg/kg bw/day and slight changes in some haematology and clinical chemistry parameters in females dosed at 1000 mg/kg bw/day.

Executive summary:

A 28-day repeated dose toxicity study was performed in male and female rats at dose levels of 0, 15, 150 and 1000 mg/kg bw/day. No mortality occurred, no clinical signs were noted during the study. Food consumption, food conversion efficiency and growth were slightly decreased in high dose males (<10%). Haematalogy revealed statistically significant increased in haemoglobin concentration, number of red blood cells and neutrophil counts in high dose females. No treatment-related changes were seen for organ weights (absolute and relative), neurobehaviour (including motor activity), and in macroscopic and microscopic observations. Based on the slightly slower growth and food intake of the high dose males and the slight changes in some haematology and clinical chemistry parameters in high dose females, 1000 mg/kg bw/day was considered a minimal effect level, and the NOAEL of SDBR in the this study was conservatively placed at 150 mg/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

150 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The available study is reliable (Klimisch 1 study).

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

A 28-day repeated dose toxicity study was performed in male and female rats at dose levels of 0, 15, 150 and 1000 mg/kg bw/day. No mortality occurred, no clinical signs were noted during the study. Food consumption, food conversion efficiency and growth were slightly decreased in high dose males (<10%). Haematalogy revealed statistically significant increased in haemoglobin concentration, number of red blood cells and neutrophil counts in high dose females. No treatment-related changes were seen for organ weights (absolute and relative), neurobehaviour (including motor activity), and in macroscopic and microscopic observations. Based on the slightly slower growth and food intake of the high dose males and the slight changes in some haematology and clinical chemistry parameters in high dose females, 1000 mg/kg bw/day was considered a minimal effect level, and the NOAEL of SDBR in the this study was conservatively placed at 150 mg/kg bw/day.

Justification for classification or non-classification

The available results on SDBR do not indicate that classification is needed for repeated dose toxicity according to Regulation (EC) No 1272/2008.