Caesium nitrate

Endpoint summary

Description of key information

Skin irritation/corrosion:
According to column 2 of the REACH Regulation (EC) No 1907/2006, Annex VIII, Section 8.1.1, testing for skin irritation/ corrosion (in vivo) is not required as an available acute toxicity study by the dermal route does not indicate any skin irritation potential up to the limit dose level (2000 mg/kg body weight). Furthermore, the results obtained in the in vitro skin irritation test (supporting study) indicate that the test item is not a skin irritant.
Eye irritation:
In the eye in vivo test the test substance applied to the rabbits' eye mucosa, caused slight to severe conjunctival irritant effects, fully reversible within 72 hours and is thus not classified as an eye irritant. 

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2011-07-27 to 2011-07-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: CLP and Guideline compliant study

Qualifier:

according to guideline

Guideline:

other: OECD 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method, adopted 22 July 2010

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU Method B.46 In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test, adopted 23 July 2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

other: reconstituted human epidermis

Strain:

other: reconstituted human epidermis

Details on test animals or test system and environmental conditions:

EpiSkinTM Small Model (EpiSkinTMSM), EPISKIN SNC Lyon, France, is a three-dimensional human epidermis model. Adult human-derived epidermal keratinocytes are seeded on a dermal substitute consisting of a collagen type I matrix coated with type IV collagen. A highly differentiated and stratified epidermis model is obtained after 13-day culture period comprising the main basal, supra basal, spinous and granular layers and a functional stratum corneum. Its use for skin irritation testing involves topical application of test materials to the surface of the epidermis, and the subsequent assessment of their effects on cell viability.

Source: Skinethic, Nice, France
Batch No.: 11-EKIN-030
Expiry date: 01 August 2011

Type of coverage:

other: not applicable (reconstituted human epidermis)

Preparation of test site:

other: not applicable (reconstituted human epidermis)

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

The test item was applied in its original form, no formulation was required. 10 mg of the test item was applied to each EpiSkin epidermis units.

Duration of treatment / exposure:

15 min

Observation period:

Not applicable (reconstituted human epidermis)

Number of animals:

Not applicable (reconstituted human epidermis). However, in this assay 3 replicates for the test item and 3 negative controls + 3 positive controls were used.

Details on study design:

The following steps were performed under axenic conditions.

Pre-incubation (day [-1]):
The “maintenance medium” was pre-warmed to 37°C. The appropriate number of assay plate wells were filled with the pre-warmed medium (2 mL per well). The epidermis units were placed, with the media below them in contact with the epidermis, into each prepared well and then incubated overnight at 37°C in an incubator with 5% CO2.

Application (day 0):
Test Item
Epidermal surface was first moistened with 10 µL deionised water and then 10 mg of the test item was applied evenly on the skin. Test substance was spread gently with a curved flat spatula in order to cover evenly all the epidermal surface.

Positive and negative control
A volume of 10 µL positive control (SDS 5 % aq.) or negative control (1x PBS) was applied on the skin surface by using a suitable pipette. Chemicals were spread gently with the pipette tip in order to cover evenly all the epidermal surface if necessary.

Exposure (day 0):
The plates with the treated epidermis units were incubated for the exposure time of 15 minutes at room temperature.

Rinsing (day 0):
After the incubation time the EPISKIN-SM units were removed and rinsed thoroughly with PBS 1x solution (0.9%) to remove all of the test material from the epidermal surface. The rest of the PBS was removed from the epidermal surface with a suitable pipette tip linked to a vacuum source (care was taken to avoid the damage of epidermis).

Post-incubation (day 0-2):
After rinsing the units were placed into the plate wells with fresh pre-warmed “maintenance medium” (2 mL/well) below them and then incubated for 42 hours at 37°C in an incubator with 5% CO2.

MTT test after 42 hours incubation (day 2):
After the 42 hours incubation the EPISKIN-SM units were transferred into the MTT solution filled wells (2 mL of 0.3 mg/mL MTT per well) and then incubated for 3 hours at 37°C in an incubator with 5 % CO2 protected from light.

Formazan extraction (day 2):
At the end of incubation with MTT a formazan extraction was undertaken:
A disk of epidermis from each replicate was cut from the unit using a biopsy punch. The epidermis was separated with the aid of forceps and both parts (epidermis and collagen matrix) were placed into a tube of 500 µL acidified isopropanol.

The capped tubes were thoroughly mixed by using a vortex mixer to achieve a good contact of all of the material with the acidified isopropanol then incubated for about two hours at room temperature protected from light with gentle agitation (~150 rpm) for formazan extraction.

Cell viability measurements (day 2):
Following the formazan extraction, 2×200 µL samples from each tube were placed into the wells of a 96-well plate (labelled appropriately). The OD (Absorbance / Optical Density) of the samples in a 96-well plate spectrophotometer was read at 570 nm using acidified isopropanol solution blank (6×200 µL).

Irritation / corrosion parameter:

other: other: % Formazan production compared to the negative control

Value:

92

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 42 h total incubation time. (migrated information)

Irritant / corrosive response data:

The results obtained from the in vitro skin irritation test in the EPISKIN model with cesium nitrate indicated a mean viability of 92 % (SD 1.96) after a total 42 h incubation time and therfore the test item is considered to be a non-irritant (NI) [UN GHS: No Category].

Other effects:

none

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In this in vitro skin irritation test in the EPISKIN model (OECD 439) with test item cesium nitrate the results indicated that the test item is considered to be a non-irritant (NI) [UN GHS: No Category].

Executive summary:

In this in vitro skin irritation test using the EPISKIN model (OECD 439), the test item cesium nitrate did not show a significantly reduced cell viability in comparison to the negative control. All obtained test item viability results were above 50% when compared to the viability values obtained from the negative control. Positive and negative controls showed the expected cell viability values within acceptable limits, thus the experiment was considered to be valid. The results indicated that the test item revealed no skin irritantion potential under the utilised testing conditions. According to the current OECD Guideline No. 439, the test item is considered a non-irritant to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2011-12-07 to 2012-12-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: testing in compliance with guidelines and CLP

Qualifier:

according to guideline

Guideline:

other: OECD guideline for testing of chemicals No. 438, adopted 07 September 2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU Method B.48, adopted 08.12.2010

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

other: isolated chicken eyes. species: ROSS 308

Strain:

not specified

Details on test animals or tissues and environmental conditions:

The age and weight of the chickens used for this study were that of spring chickens traditionally processed by a poultry slaughterhouse (i.e., approximately 7 weeks old, 1.5 – 2.5 kg). Head collection was performed by a slaughter house technician. The heads were transported to TOXI-COOP ZRT. at the earliest convenience for use approximately within 2 hours from collection. All eyes used in the assay were from the same groups of eyes collected on one specific day.

Vehicle:

not specified

Controls:

not required

Amount / concentration applied:

The test item was applied in powder form at an amount of 0.03 g to the entire surface of the cornea attempting to cover the cornea surface uniformly. The positive control eyes were treated in a similar way with 0.03 g Imidazole. The negative control eye was treated with 30 μL of saline solution.

Duration of treatment / exposure:

10 s

Observation period (in vivo):

The control and test eyes were evaluated pre-treatment and at approximately 30, 75, 120, 180 and 240 minutes after the post-treatment rinse. Minor variations within ±5 minutes were considered acceptable.

Number of animals or in vitro replicates:

The treatment group and the concurrent positive control consisted of three eyes. The negative control group consisted of one eye.

Details on study design:

Eyes selection:
After removing the head from the plastic box, it was put on soft paper. The eyelids were carefully cut away with scissors, avoiding damaging the cornea. One small drop of fluorescein solution 2% (v/v) was applied onto the cornea surface for a few seconds and subsequently rinsed off with 20 mL saline solution. Then the fluorescein-treated cornea was examined with hand-held slit lamp or slit lamp microscope, with the eye in the head, to ensure that the cornea was not damaged. If the cornea was in good condition, the eyeball was carefully removed from the orbit.

Preparation of eyes:
The eye ball was carefully removed from the orbit by holding the nictitating membrane with a surgical forceps, while cutting the eye muscles with bent scissors. Care was taken to remove the eyeball from the orbit without cutting off the optical nerve too short. The procedure avoided pressure on the eye while removing the eyeball from the orbit, in order to prevent distortion of the cornea and subsequent corneal opacity. Once removed from the orbit, the eye was placed onto damp paper and the nictitating membrane was cut away with other connective tissue. The prepared eyes were kept on the wet papers in a closed box to maintain an appropriate humidity. The treatment group and the concurrent positive control consisted of three eyes. The negative control group consisted of one eye.

Eyes examination and acclimatisation time:
The enucleated eye was placed in a steel clamp with the cornea positioned vertically with the eye in the correct relative position (same position as in the chicken head). Again avoiding too much pressure on the eye by the clamp. Because of the relatively firm sclera of the chicken eyeball, only slight pressure was needed to fix the eye properly. The clamp with the eyeball was transferred to a chamber of the superfusion apparatus. The clamp holding the eye was positioned in such a way that the entire cornea was supplied with saline solution dripping from a stainless steel tube, at a rate of approximately 3 or 5 drops/minutes. The door of the chamber was closed except for manipulations and examinations, to maintain temperature and humidity.
The appropriate number of eyes was selected and after being placed in the superfusion apparatus, were examined again with the slit lamp microscope to ensure that they were in good condition. The focus was adjusted to see clearly the saline solution which was flowing on the cornea surface. Eyes with a high baseline fluorescein staining (i.e., > 0.5) or corneal opacity score (i.e., > 0.5) were rejected. The cornea thickness was measured using the depth measuring device on the slit lamp microscope (Haag-Streit BQ 900) with the slit-width set at 9½, equaling 0.095 mm. Any eye with cornea thickness deviating more than 10 % from the mean value for the eyes, or eyes that showed any other signs of damage, were rejected and replaced. If the selected eyes were appropriate for the test, acclimatisation started and was conducted for approximately 45 to 60 minutes. The temperature of the circulating water was verified to ensure that the temperature in all chambers was in the range of 32 ±1.5°C during the acclimatisation and treatment periods.

Identification:
The eyes were identified by chamber number, marked on the door of the chamber.

The base line assessments:
At the end of the acclimatisation period, a zero reference measurement was recorded for cornea thickness and opacity to serve as a base line (t=0) for each individual eye. The cornea thickness of the eyes should not increase by more than 5-7% between the -45 to 60 minutes and the zero time. Slight thinning and changes in thickness (-5% to 3%) were observed in the eyes, this is considered normal when maintaining enucleated eyes. Following the equilibration period, the fluorescein retention was measured. Base line values were required to evaluate any potential test item related effects after treatment. The locations of any minor findings were marked on the record sheet as a drawing. All eyes were considered to be suitable for the assay.

Treatment:
After the zero reference measurements, the first eye was taken out of its chamber and placed on a layer of tissue with the cornea facing upwards. The eye was held in horizontal position over a container to catch waste, while the test item was applied onto the centre of the cornea. The test item was applied at an amount of 0.03 g by powdering the entire surface of the cornea attempting to cover the cornea surface uniformly with the test substance while taking care not to damage or touch the cornea with the application equipment.
The positive control eyes were treated in a similar way with 0.03 g Imidazole.
The negative control eye was treated with 30 μL of saline solution.

Test item removal:
The time of application was monitored, then after an exposure period of 10 seconds from the end of the application the cornea surface was rinsed thoroughly with 20 mL saline solution at ambient temperature, while taking care not to damage the cornea but attempting to remove all the residual test item if possible. The eye in the holder was then returned to its chamber. The time while the eye was out of the chamber was limited to the minimum.
Residues of Imidazole were still adhering to the corneas surface 30 minutes after the post-treatment rinse. The gentle rinsing with 20 mL saline was performed after the 30 minutes of observation.
The cornea surfaces were not cleared 240 min after the post-treatment rinse.

Observation and assessment of corneal effects:
The control and test eyes were evaluated pre-treatment and at approximately 30, 75, 120, 180 and 240 minutes after the post-treatment rinse. Minor variations within ±5 minutes were considered acceptable.
The cornea thickness and cornea opacity were measured at all time points. Fluorescein retention was measured on two occasions, at base line (t=0) and 30 minutes after the post-treatment rinse.

Evaluation:
The endpoints evaluated were corneal opacity, swelling, fluorescein retention, and morphological effects (e.g., pitting or loosening of the epithelium).
Results from corneal opacity, swelling, and fluorescein retention were evaluated separately to generate an Isolated Chicken Eye (ICE) class for each endpoint. The ICE classes for each endpoint were then combined to generate an Irritancy Classification for each test substance.

Irritation parameter:

corneal swelling 

Run / experiment:

1st experiment (mean 75 min)

Value:

3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation parameter:

corneal swelling 

Run / experiment:

2nd experiment (mean 240 min)

Value:

4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

No corrosion/severe irritation effects were observed. A slight irritation potential of the test item was observed.

Interpretation of results:

study cannot be used for classification

Conclusions:

In this in vitro eye corrosives and severe irritants study, using the Isolated Chicken Eye model with cesium nitrate, no ocular corrosion or severe irritation potential was observed. Thus, according to the guideline OECD 438, the test item cannot be classified as an ocular corrosive or severe eye irritant. Furthermore, the results suggest that the test item was not irritating.

Executive summary:

The in vitro Isolated Chicken Eye Test (ICET) was perfomed according to OECD guideline 438 and EU method B.48 to evaluate the potential ocular corrosivity or severe irritancy of the test item cesium nitrate. The test compound was applied in its powdered form via a single dose of 0.03 g onto the cornea of isolated chicken eyes.

During the testing no ocular corrosion or severe irritation potential of the test item was observable. Thus, according to the guideline OECD 438, cesium nitrate cannot be classified as an ocular corrosive or severe eye irritant. Furthermore, the results suggest that the test item was not irritating. However, to obtain a definitive classification in relation to the irritation potential, a further in vivo rabbit study is required.

Reference 2

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2012-10-09 to 2012-10-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline compliant study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

(2002)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Version / remarks:

(2008)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Version / remarks:

(1998)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: S & K LAP Kft. 2173 Kartal, Császár út 135, HUNGARY
- Age at study initiation: Young adult rabbits
- Weight at study initiation: 2870-2925 g
- Housing: Animals were housed individually in metal cages.
- Diet: Fattening mixed diet, ad libitum
- Water: Tap water, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): 9-12 changes/hour
- Photoperiod: Artificial light, from 6 a.m. to 6 p.m.

Vehicle:

unchanged (no vehicle)

Controls:

other: contralateral eye

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0. 1 g

Duration of treatment / exposure:

The eyelids were held closed gently for several seconds to prevent the loss of the test item. The contralateral eye served as control. Immediately after the administration of the test item, an assessment of the initial pain reaction was made according to the six point scale

Observation period (in vivo):

The eyes were examined at 1, 24, 48 and 72 hours after the application.

Number of animals or in vitro replicates:

3 animals

Details on study design:

REMOVAL OF TEST SUBSTANCE
None

SCORING SYSTEM: The eye irritation scores were evaluated according to the scoring system by Draize (1977) and OECD 405 (24th April 2002).

TOOL USED TO ASSESS SCORE: Hand-slit lamp

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #2

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

animal #2

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0.66

Max. score:

3

Reversibility:

fully reversible within: 72 h

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Remarks:

discharge

Basis:

animal #1

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Remarks:

discharge

Basis:

animal #2

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 48 h

Irritation parameter:

conjunctivae score

Remarks:

discharge

Basis:

animal #3

Time point:

other: 24, 48, 72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 48 h

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, the test substance applied to the rabbits' eye mucosa, caused slight to severe conjunctival irritant effects, fully reversible within 72 hours and is thus not considered to be irritating to the eye.

Executive summary:

In an eye irritation test (in vivo) according to OECD No. 405 rabbits' eyes were examined at 1, 24, 48 and 72 hours after the application of the test item. One hour after the treatment, slight conjunctival redness, slight to moderate chemosis and slight to severe discharge were observed. 48 hours after the treatment, slight redness was recorded in one animal. Two animals became free of symptoms. 72 hours after treatment the study was terminated, as all animals were free of symptoms of irritation. In conclusion, the test substance applied to the rabbits' eye mucosa, caused slight to severe conjunctival irritant effects, fully reversible within 72 hours. Thus cesium nitrate is not considered to be irritating to the eye.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation/corrosion

According to column 2 of the REACH Regulation (EC) No 1907/2006, Annex VIII, Section 8.1.1, testing for skin irritation/corrosion (in vivo) is not required as an available acute toxicity study by the dermal route does not indicate any skin irritation potential up to the limit dose level (2000 mg/kg body weight). Furthermore, the results obtained in the in vitro skin irritation test indicate that the test item is not a skin irritant.

 

Supporting: Skin irritation

In the in vitro skin irritation test using the EPISKIN model, the test item cesium nitrate did not show a significantly reduced cell viability in comparison to the negative control. All obtained test item viability results were above 50% when compared to the viability values obtained from the negative control. Positive and negative controls showed the expected cell viability values within acceptable limits, thus the experiment was considered to be valid. The results indicated that the test item revealed no skin irritation potential under the utilised testing conditions. According to the current OECD Guideline No. 439, the test item is considered a non-irritant to skin and is therefore not classified.

 

WoE: Eye irritation in vivo

The eye irritation in vivo study with white rabbits was conducted according to the OECD guideline 405 (2002). The eyes were examined at 1, 24, 48 and 72 hours after the application. The applied volume was 0.1 g. During the study the control eyes of the animals were symptom-free. General state and the behaviour of the animals were normal throughout the study period. There were no effects on body weight attributable to the treatment with the test item during the contact and observation period. In conclusion, the test substance applied to the rabbits' eye mucosa, caused slight to severe conjunctival irritant effects, fully reversible within 72 hours and is thus considered not irritating to the eye.

 

WoE: Eye irritation in vitro

The in vitro Isolated Chicken Eye Test (ICET) was performed according to OECD guideline 438 and EU method B.48 to evaluate the potential ocular corrosivity or severe irritancy of the test item cesium nitrate. The test compound was applied in its powdered form via a single dose of 0.03 g onto the cornea of isolated chicken eyes. During the testing no ocular corrosion or severe irritation potential of the test item was observable. Thus, according to the guideline OECD 438, cesium nitrate cannot be classified as an ocular corrosive or severe eye irritant. Furthermore, the results suggest that the test item was not irritating.

 

Justification for classification or non-classification

Based on skin irritation data available for the test substance no classification and labelling is required according to Regulation No (EC) 1272/2008 (CLP) criteria.

Based on the eye irritation study (in vitro/ in vivo) to the test substance, classification and labelling is not warranted according to Regulation No (EC) 1272/2008 (CLP) criteria.