Reaction mass of m-cresol and 2-chloro-m-cresol and 6-chloro-m-cresol

Endpoint summary

Description of key information

In a reliable GLP compliant OECD Guideline 431 in vitro study with reconstructed human epidermis EST-1000 the pure test substance decreased the viability of cells below 10 % after 3 and 60 minutes of application. 
According to the dangerous substance directive 67/548/EEC the test substance is classified as corrosive, R34 and according to CLP 1272/2008/EC as corrosive category 1B, H314.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant OECD guideline 431 study.

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 431 (In vitro skin corrosion / Human skin model test) (2004)

Deviations:

no

GLP compliance:

yes

Species:

human

Strain:

other: reconstructed human epidermis EST-1000 (CellSystems, St. Katharinen, Germany)

Details on test animals or test system and environmental conditions:

TEST SYSTEM
- Source: CellSystems, St. Katharinen, Germany


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 37 ± 2
- Humidity (%): maximum
- CO2 gas concentration: 5 %

Vehicle:

unchanged (no vehicle)

Controls:

other: 0.9% NaCl

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 µL
- Concentration (if solution): 100%

Duration of treatment / exposure:

3min. (RT) and 60 min. in the incubator

Number of animals:

3 inserts per period of incubation time and negative controls in triplicate

Irritation / corrosion parameter:

other: other: viability (in % of control)

Value:

9.13

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 3 min. Max. score: 100.0. Reversibility: other: not applicable. Remarks: A test substance is considered corrosive if the cell viability is below 50% after 3 min exposure period.. (migrated information)

Irritation / corrosion parameter:

other: other: viability (in % of control)

Value:

8.49

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 60 min. Max. score: 100.0. Reversibility: other: not applicable. Remarks: A test substance is considered corrosive if the cell viability is below 15% after 60 min exposure period.. (migrated information)

Irritant / corrosive response data:

The cell viability was 9.13% after the 3 min exposure period and 8.49% after 60 minutes.

Interpretation of results:

Category 1B (corrosive)

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Classification was done in accordance with the existing guideline and internationally accepted protocols, i.e. evaluation of LD50 values after 3 min. and/or less than 15% viability after a 60 min. incubation period.
CLP: Skin corrosion, H314
DSD: C, R34

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The relevant data on irritation/corrosion for Preventol KMX and the read across substance 4-chloro-3-methylphenol are summarized in the table below. The read across justification and additional data for m-cresol are attached to the Chemical Safety Report in Annex I. In comparison to the chlorocresol, m-cresol is only a minor component of Preventol KMX. Therefore these data are not considered for the assessment of the irritating potential of Preventol KMX.

Table 1: Comparison of relevant data on irritation/corrosion of Preventol KMX and 4-chloro-3-methylphenol

Endpoint	Preventol KMX	4-chloro-3-methylphenol
In vitro skin irritation	Corrosive	No data available
In vivo skin irritation	Data waiving due to in vitro corrosion	Rabbit: Moderately irritating (not classified)
In vivo eye irritation	Data waiving due to in vitro corrosion	Rabbit:Highly irritating

 

Skin irritation/corrosion:

A reliable GLP compliant OECD Guideline 431 in vitro study with reconstructed human epidermis (RHE) EST-1000 was performed. The model used for this study has a functional stratum corneum with an underlying layer of living cells as recommended by the OECD 431 guideline and the barrier function of the stratum corneum has been shown by the supplier.

Per insert 50 µL of test substance moistened with 50µL 0.9% NaCl to ensure good contact with the RHE was applied. The experiment was performed for 3 (at room temperature) and 60 minutes (in the incubator at 37°C and humidified atmosphere) in triplicate. After both exposure periods the reconstructed human epidermis was washed and the viability of cells was assessed using the MTT-assay. The viability of the RHE was found to be 9% for both time points.

In general an OECD guideline 431 study does not allow the discrimination of severe and less severe skin corrosives, meaning that a subcategorisation of corrosive substances as permitted in the CLP is not possible. As given in the guidance on information requirements and chemical safety assessment Chapter R.7a this leads to a classification as R35 (equals Category 1A). However for Preventol KMX further data are available which allow differentiating between severe and less severe skin corrosion, i.e. an acute dermal toxicity study according to OECD guideline 402. This acute dermal toxicity study was performed with doses of 1000 mg/kg bw on 5 young adult female Wistar rats and 2000 mg/kg bw on 5 young adult male Wistar rats (Gillissen, 2011). Animals of both dose groups were exposed to the pure test substance under semi occlusive conditions at the hair free back and the test substance was removed by washing with tepid water and soap after 24 hours. Clinical signs and mortality were determined several times at the day of application (defined as day 1) and at least once daily thereafter. Body weights were assessed once weekly. All animals were sacrificed after the observation period and were, as the animals found dead during the observation period, subjected to gross pathology. Males and females sacrificed at study termination showed a partial formation of scale on the site of application.

A summary of local signs of toxicity, their incidence as well as their onset and duration is given in Table 2.

 

Table 2: Summary of local effects seen in an OECD guideline 402 study with Preventol KMX

Parameter	Incidence	Duration of parameter
Females (1000 mg/kg bw)
partial induration	5/5	3 d – 10 d
dark discoloration	5/5	2 d – 10 d
thickening	5/5	2 d
scale skin	5/5	11 d – 22 d
encrustation	5/5	3 d – 20 d
Males (2000 mg/kg bw)
partial induration	4/5	2 d – 7 d
swelling	4/5	2 d
dark discoloration	3/5	2 d – 8 d
thickening	4/5	3 d – 7 d
scale skin	4/5	7 d – 22 d
encrustation	4/5	8 d – 21 d

 

No full thickness destruction of the skin was reported after the application of the pure test substance (analytical purity 100%). In addition, the only finding reported upon gross pathology at study termination was scale formation on the site of application. If a full destruction of the skin would have occurred scar formation can be expected which would have been noticed upon gross pathology as well. Therefore it is unlikely that Preventol KMX induced a full thickness destruction of the skin. As the local effects reported within the acute dermal study lasted partly until study termination Preventol KMX exerted corrosive potential after application to rat skin. Based on the discussion above it is very unlikely that Preventol KMX upon application to the skin will cause a full destruction of the skin within 3 minutes. Therefore the test substance is classified according to the dangerous substance directive 67/548/EEC as corrosive R34 and according to CLP 1272/2008/EC as corrosive category 1B, H314.

Eye irritation/corrosion:

According to Regulation EC No 1907/2006 (REACH) Annex VII, Section 8.2, Column 2 and Annex VIII, Section 8.2, Column 2 testing for eye irritation does not need to be conducted if “the available information indicates that a substance meets the criteria for classification as corrosive to the skin”. Therefore, in accordance with regulation No 1907/2006 no testing for eye irritation is required.

Justification for selection of skin irritation / corrosion endpoint:
Reliable GLP compliant OECD Guideline 431 in vitro key study.

Justification for selection of eye irritation endpoint:
According to Regulation EC No 1907/2006 (REACH) Annex VII, Section 8.2, Column 2 and Annex VIII, Section 8.2, Column 2 testing for eye irritation does not need to be conducted if “the available information indicates that a substance meets the criteria for classification as corrosive to the skin”.

Effects on skin irritation/corrosion: corrosive

Effects on eye irritation: corrosive

Justification for classification or non-classification

Preventol KMX has to be classified according to the dangerous substance directive 67/548/EEC as corrosive R34 and according to CLP 1272/2008/EC as corrosive category 1B, H314.