Potassium benzoate

Endpoint summary

Description of key information

The Human Cornea Model Test with potassium benzoate had almost exactly the same score as lithium benzoate and it was decided to read-across and classify potassium benzoate as Eye Dam 1

For the same reason, it was considered valid to read-across to the skin endpoint and classify potassium benzoate as Skin Irrit 2 based on the lithium benzoate conclusions.

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:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

60 minute exposure

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Study performed to guidelines under GLP conditions
The Potassium salt appears to be a less severe irritant to eyes than the concurrently tested Lithium salt; therefore, it is safe to consider this to be a suitable read-across model to allow classification as skin Irrit 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name Lithium benzoate
Batch no. 16B/02
Appearance white powder
Composition Lithium benzoate > 98%
Purity min. 98.0 %
Homogeneity homogeneous
Expiry date 09. Jun. 2019

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Details on test system:

The tissues were wetted with 25 µL Dulbecco’s Phosphate Buffered Saline (DPBS) buffer before applying the test item

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

ca 25 mg applied and spread over surface of wetted tissue

Duration of treatment / exposure:

60 minutes

Duration of post-treatment incubation (if applicable):

23 hours at 37C

Number of replicates:

three

Irritation / corrosion parameter:

% tissue viability

Value:

ca. 14

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

Range of viablity 13.8 - 14.4 % (mean 14.1%).
Positive control 3.5 - 3.9% (mean 3.7%)

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

The relative absorbance values were reduced to 14.1% after the treatment. This value is below the threshold for skin irritation (50%). Therefore, the test item is considered as irritant to skin. A corrosive test was performed on lithium benzoate and it is concluded that it is not Corrosive.

Executive summary:

Data for lithium and potassium benzoate indicates that there is the same level of potential irritation and read-across is valid.

Public data for potassium benzoate concludes it is non-corrosive.

It is concluded that potassium benzoate is Skin Irrit 2, Eye Dam 1

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

GLP compliance:

yes (incl. QA statement)

Controls:

yes

yes, concurrent positive control

yes, concurrent negative control

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean

Value:

ca. 2.5

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Under the conditions of the test system, Potassium benzoate is considered as eye irritant in the EpiOcularTM Eye Irritation Test.
After treatment with the test item, the relative absorbance values were reduced to 2.5 %.
This value is below the threshold for eye irritation potential (≤ 60%).
All validity criteria were met. The criterion for optical density of the negative control was fulfilled
The positive control induced a decrease in the relative absorbance as compared to the negative control to 39%.

Executive summary:

Note the viability score of 2.5 is almost identical to that of lithium benzoate (2.6) and this was concluded to be Eye Dam 1 as a result of an subsequent BCOP study

For this reason, it is proposed to classify potassium benzoate as Eye Dam 1.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)