Disodium hexatitanate

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 October 2012 - 07 May 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

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)

Version / remarks:

Revised 03 October 2008

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OPPTS 870.3050, Repeated Dose 28-Day Oral Toxicity Study in Rodents

Version / remarks:

July 2000

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Disodium hexatitanate

EC Number:

815-182-4

Cas Number:

12058-75-2

Molecular formula:

Na2Ti6O13

IUPAC Name:

Disodium hexatitanate

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

- Storage condition of test material: Room temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crl:CD (SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: not specified
- Age at study initiation: 43 to 49 days old
- Weight at study initiation: males: 227 - 271g; females: 186 - 228g
- Fasting period before study: Not applicable
- Housing: Polycarbonate cages with a stainless steel mesh lid.
- Diet: Ad libitum (removed overnight before blood sampling)
- Water: Ad libitum
- Acclimation period: Two weeks before start of treatment

ENVIRONMENTAL CONDITIONS
- Temperature: 19 - 23°C
- Humidity: 40-70%RH
- Air changes: Filtered fresh air which was passed to atmosphere and not recirculated.
- Photoperiod: 12 hours light: 12 hours dark

IN-LIFE DATES: From: 19 December 2012 (animal arrival) To: 30 January 2013 (Date of necropsy)

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

methylcellulose

Remarks:

1% aqueous

Details on oral exposure:

- PREPARATION OF DOSING SOLUTIONS: Fresh formulations were prepared weekly

- VEHICLE
- Concentration in vehicle: 3, 30, 100 mg/mL
- Amount of vehicle: 10 mL/kg

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The analytical procedure was successfully validated with respect to specificity, method accuracy and precision.

The specificity of the analysis was confirmed to be acceptable.

The homogeneity was confirmed for Terracess DSR in 1% w/v aqueous methylcellulose formulations at nominal concentrations of 3 mg/mL and 100 mg/mL during distribution between the bottles, during magnetic stirring for 2 hours, ambient temperature storage for 1 day and refrigerated storage for up to 15 days.

The mean concentrations of Terracess DSR in test formulations analysed for the study were within +10%/-15% of nominal concentrations, confirming accurate formulation.

Samples were analysed gravimetrically

Duration of treatment / exposure:

28 days

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Remarks:

Vehicle control

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

Dose / conc.:

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

Doses / concentrations 4

Dose / conc.:

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

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
- Rationale for animal assignment: Random

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: At least twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Weekly

BODY WEIGHT: Yes
- Time schedule for examinations: The weight of each animal was recorded one week before treatment commenced (Week -1), on the day that treatment commenced (Week 0), weekly throughout the study and before necropsy. The last scheduled bodyweight was recorded on Day 28 prior to overnight deprivation of food for clinical pathology investigations on Day 29.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Not specified

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Fluid intake was assessed by daily visual observation. No effect was observed and consequently quantitative measurements were not performed.

OPHTHALMOSCOPIC EXAMINATION: Not specified

HAEMATOLOGY: Yes
- Time schedule for collection of blood: All animals were assessed on day 29
- Anaesthetic used for blood collection: Yes isoflurane
- Animals fasted: Yes
- How many animals: All animals
- Parameters checked in table 1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day 29
- Animals fasted: Yes
- How many animals: All animals
- Parameters checked in table 2 were examined.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (table 3)

HISTOPATHOLOGY: Yes (table 3)

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

There were no deaths and the general appearance and behaviour of the animals was unaffected by treatment.
Pale faeces were noted throughout the study in the cages housing animals receiving 1000 mg/kg/day.

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

Slightly low bodyweight gain was apparent during weeks 2 to 4 in males receiving 1000 mg/kg/day resulting in an overall reduction of 10%, when compared to the controls.
The majority of individual bodyweight gains for the high dose males were, however, within the concurrent control range of bodyweight gains seen during that period. Consequently, this finding was considered incidental and not related to treatment.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

no effects observed

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

Lower than control lymphocyte, monocyte and large unstained cell counts and consequentially low total white blood cell counts were observed in all treated groups of females on Day 28 but there was no dose relationship. The majority of individual values for the affected parameters were, however, still within the 90th percentile range of background data for these laboratories (see below). The lack of dose-relationship and slight reduction in differential white blood cell counts renders these findings of doubtful relationship to treatment. The white blood cell parameters for males were unaffected by treatment.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

Aspartate amino-transferase activities were slightly low (maximum reduction of 0.78 X Control) for all treated groups of females. A review of the individual data revealed that 11/15 values were within the expected background control range for this parameter at these laboratories (90 percentile range: 56 to 98 U/L (n=301)). Those values that were just outside this range were distributed throughout the treated groups without any dose-relationship.
Consequently, this finding was considered to have a doubtful relationship to treatment.

Urinalysis findings:

not specified

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

Epididymis, testis and spleen weights were slightly high, when compared with the Controls, for males which received 1000 mg/kg/day but only the adjusted values attained statistical significance.

Gross pathological findings:

no effects observed

Description (incidence and severity):

The nature and incidence of all findings were consistent with the commonly seen background of macroscopic changes in Sprague-Dawley rats at these laboratories.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Description (incidence and severity):

The nature and incidence of all findings were consistent with the commonly seen background of macroscopic changes in Sprague-Dawley rats at these laboratories.

Effect levels

Key result

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:

behaviour (functional findings)

body weight and weight gain

clinical biochemistry

clinical signs

food consumption and compound intake

gross pathology

haematology

histopathology: non-neoplastic

mortality

organ weights and organ / body weight ratios

water consumption and compound intake

Target system / organ toxicity

Key result

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

The oral administration of Terracess DSR to Sprague-Dawley (Crl:CD(SD)) rats for 4 weeks at dosages up to 1000 mg/kg/day was well tolerated with no adverse effect of treatment. Consequently, the No-Observed-Adverse-Effect-Level (NOAEL) was considered to be 1000 mg/kg/day.