Zinc sulphate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Zinc oxide

EC Number:

215-222-5

EC Name:

Zinc oxide

Cas Number:

1314-13-2

Molecular formula:

ZnO

IUPAC Name:

oxozinc

Test material form:

solid: nanoform

Details on test material:

- Name of test material (as cited in study report): Z-Cote HP1
- Substance type: ZnO nanoscaled coated on its surface with Triethoxycaprylylsilane (CAS # 2943-75-1)
- Physical state:solid, homogenous
- Lot/batch No.: CNHK1402
- Expiration date of the lot/batch: 30 Sep 2013
- Stability under test conditions: The stability of the test substance under storage conditions over the test period was guaranteed by the sponsor, and the sponsor holds this responsibility.
- Storage condition of test material: Room temperature

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH
- Age at study initiation: 11 -14 weeks
- Weight at study initiation: 146.0 - 192.1 g
- Fasting period before study: no
- Housing: individually, dust-free wooden bedding, enrichment: wooden gnawing blocks
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%): 30-70%.
- Air changes (per hr): 15/h
- Photoperiod (hrs dark / hrs light): 12h/12h

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure (if applicable):

nose/head only

Vehicle:

air

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: flow-past nose-only exposure system, individually exposure of each rat, exhaled air is immediately exhausted
- Method of holding animals in test chamber: individual acrylic tubes
- Source and rate of air: conditioned and compressed air, 6 m3/h
- System of generating particulates/aerosols: feeding system and high-pressure, high-velocity pressurized air dispersion with computerized control
- Temperature, humidity, pressure in air chamber: 22 +/- 2°C, 50 +/- 20%,
- Air flow rate: 6 m3/h
- Method of particle size determination: cascade impactor/ Marple impactor
- Treatment of exhaust air: disposal in compliance with local, federal and state regulations

TEST ATMOSPHERE
- Brief description of analytical method used: gravimetrically by filter samples
- Samples taken from breathing zone: yes

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentrations of the inhalation atmospheres of test group 1 – 3 were analyzed by gravimetrical analysis. Daily means were calculated based on two measured samples per concentration and exposure. From the daily mean values of each concentration, mean concentrations and standard deviations for the entire study were derived. In these groups, the constancy of concentration in each inhalation system was continuously monitored using scattered light photometers.
In the control group (test group 0) no sample was analyzed over the study period. The analyses were carried out at the Inhalation Laboratory of the Experimental Toxicology and Ecology of BASF SE.

Details on mating procedure:

The animals were paired by the breeder (“time-mated”) and supplied on GD 0 (= detection of vaginal plug/sperm). The animals arrived on the same day (GD 0) at the experimental laboratory.

Duration of treatment / exposure:

6 hours on 14 consecutive days

Frequency of treatment:

daily

Duration of test:

from implantation to one day prior to the expected day of parturition

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0.3 mg/m³ air

Doses / concentrations 2

Dose / conc.:

1.5 mg/m³ air

Doses / concentrations 3

Dose / conc.:

7.5 mg/m³ air

No. of animals per sex per dose:

25 pregnant females per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: request of the sponsor
- Rationale for animal assignment: random
The inhalation route was selected since it is relevant in terms of potential human exposure.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice a day

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once a day

BODY WEIGHT: Yes
- Time schedule for examinations: All animals were weighed on gestation day (GD) 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20.
The corrected body weight gain was calculated after terminal sacrifice (terminal body weight on GD 29 minus weight of the unopened uterus minus body weight on GD 6).

FOOD CONSUMPTION
The consumption of food was recorded for GD 1-3, 3-6, 6-8, 8-10, 10-13, 13-15, 15-17, 17-19 and 19-20.

POST-MORTEM EXAMINATIONS: Yes / No / No data
- Sacrifice on gestation day #20
- Organs examined: Organ weights of the lungs, the unopened uterus and the placentas were determined. For each dam, corpora lutea were counted and number and distribution of implantation sites (differentiated by resorptions, live and dead fetuses) were determined. The fetuses were removed from the uterus, sexed, weighed and further investigated for external, soft tissue and skeletal (incl. cartilage) findings. Larynx, lungs, mediastinal and tracheobronchial lymph nodes, trachea and nasal cavities were examined histopathologically in the control and high-dose groups.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: all per litter

Statistics:

clinical and fetal examination:
Simultaneous com-parison of all dose groups with the control group using the DUNNETT-test (two-sided) for the hypothesis of equal means
Pairwise comparison of each dose group with the control group using FISHER'S EXACT test (one-sided) for the hypothesis of equal proportions
Pairwise comparison of each dose group with the control group using the WILCOXON-test (one-sided) for the hypothesis of equal medians

Pathology:
Non-parametric one-way analysis using KRUSKAL-WALLIS test (two-sided). If the resulting p-value was equal or less than 0.05, a pairwise comparison of each dose group with the control group was performed using the WILCOXON test for the hypothesis of equal medians

Historical control data:

used to interprete results of present study

Results and discussion

Results: maternal animals

Effect levels (maternal animals)

1

Dose descriptor:

NOAEC

Effect level:

1.5 mg/m³ air

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEC

Effect level:

7.5 mg/m³ air

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
no effects observed

Effect levels (fetuses)

Dose descriptor:

NOAEC

Effect level:

7.5 mg/m³ air

Based on:

test mat.

Sex:

male/female

Basis for effect level:

changes in sex ratio

fetal/pup body weight changes

changes in litter size and weights

external malformations

skeletal malformations

visceral malformations

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

The following test substance-related adverse effects/findings were noted:

 

 

Test group 3 (7.5 mg/m³):

 

·        Increase in absolute and relative lung weights (up to 47%)

·        Moderate alveolar lipoproteinosis in all animals examined

·        Slight, diffuse inflammation in all animals examined

·        Minimal to slight focal hemorrhage in three of ten animals

·        No test substance-related adverse effects on gestational parameters or fetuses

 

 

Test group 2 (1.5 mg/m³):

 

·        No test substance-related adverse effects on dams, gestational parameters or fetuses

 

 

Test group 1 (0.3 mg/m³):

 

·        No test substance-related adverse effects on dams, gestational parameters or fetuses

 

Applicant's summary and conclusion

Executive summary:

Under the conditions of this prenatal developmental toxicity study, the inhalative administration of Z-Cote HP1 to pregnant Wistar rats from implantation to one day prior to the expected day of parturition (GD 6-19) at a dose of 7.5 mg/m³ caused moderate alveolar lipoproteinosis and slight inflammation. These histopathologic findings are regarded to be adverse in nature. The relevance for humans however is not clear.

 

In conclusion, the no observed adverse effect concentration (NOAEC) for maternal toxicity is1.5 mg/m³.

 

The no observed adverse effect concentration (NOAEC) for prenatal developmental toxicity is7.5 mg/m³.There were no adverse fetal findings evident at any dose.