2,2,2-trichloroethane-1,1-diol

Endpoint summary

Description of key information

Skin sensitisation:

Chloral hydrate was expected to have weak sensitization potential as per the study. However, since the number of animals with positive reaction were 0, chloral hydrate has been considered to be not sensitising.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Data is from Peer reviewed journal

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

A modified guinea pig maximization test (GPMT) was adopted.

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Modified guinea pig maximization test (GPMT) was sufficient to classify the substance.

Specific details on test material used for the study:

- Name of test material: 2,2,2-Trichloroethane-1,1-diol (Chloral hydrate)
- Molecular formula: C2-H3-Cl3-O2
- Molecular weight: 165.4026g/mol
- Smiles notation: C(C(O)O)(Cl)(Cl)Cl
- InChl: RNFNDJAIBTYOQL-UHFFFAOYSA-N
- Substance type: Organic
- Physical state: Solid

Species:

guinea pig

Strain:

other: FMMU

Sex:

not specified

Details on test animals and environmental conditions:

Source: Medical laboratory animal center (China).
Weight at study initiation: 300-350g
- Housing: Housed in an animal rooms.
- Diet (e.g. ad libitum): Standard guinea pig diet and Fresh vegetable
- Water (e.g. ad libitum): Tap water
- Acclimation period: One week
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23°C±1.5 °C
- Humidity (%): 55% ±10%
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): 12 h day/night cycle

Route:

intradermal and epicutaneous

Vehicle:

water

Concentration / amount:

Induction: Intradermal concentration: 1%
Topical concentration: 5%
Challenge topical concentration : 2%

Route:

epicutaneous, open

Vehicle:

water

Concentration / amount:

Induction: Intradermal concentration: 1%
Topical concentration: 5%
Challenge topical concentration : 2%

No. of animals per dose:

14 animals

Details on study design:

Details on study design
RANGE FINDING TESTS: Yes, primary irritation studies were performed before the start of induction and challenge phase.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period:
- Test groups: 7 groups
- Control group: 6
- Site: Dorsal skin of scapular region
- Frequency of applications: 3
- Duration: 21 days
- Concentrations:
Intradermal : 1%
Topical concentration: 5%

CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge:
- Exposure period: 24 hrs
- Test groups: 7 groups
- Control group: 6
- Site: Dorsal skin of scapular region
- Concentrations: 2%
- Evaluation (hr after challenge): 24 hrs and 48 hrs

Challenge controls:

No data available

Positive control substance(s):

not specified

Positive control results:

No data available

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2%

No. with + reactions:

0

Total no. in group:

14

Clinical observations:

None of the animals exhibited positive sensitization

Remarks on result:

no indication of skin sensitisation

Allergenic reaction observed in animal groups were graded as follows:

                 0: No reaction

                 1: Scattered mild redness

                 2: Moderate and diffuse redness

                 3: intensive erythema and swelling

Chloral hydrate was expected to have weak sensitization potential as per the study. However, since the number of animals with positive reaction were 0, chloral hydrate has been considered to be not sensitizing.

Interpretation of results:

other: not sensitising

Conclusions:

Chloral hydrate was expected to have weak sensitization potential as per the study. However, since the number of animals with positive reaction were 0, chloral hydrate has been considered to be not sensitising.

Executive summary:

Skin sensitizing reaction was performed in guinea pigs usingGuinea pig maximisation test. 3-4 guinea pigs were used for primary irritation studies. Later on induction and challenge exposure were performed on 7 groups with 10-14 animals.

For Induction, dorsal skin in the scapular region was shaved and after 24 hrs 3 intradermal injections were injected. Control animals were supplied with vehicle only.

After intradermal induction, animals were challenged by topical application of test agent by closed patch test and observed for 24 hrs and 48 hrs. Based on percentage of animals sensitized the grading of allergenicity was calculated.

Therefore, from the above experiment chloralhydrate (302-17-0) was found to be not sensitising to guinea pig.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitisation:

Available data for the target substance Chloral hydrate (CAS 302 -17 -0) and data for its read across substances Chloral (CAS 75 -87 -6) were reviewed to classify the target substance for skin irritation. The same is presented below as key and supporting study:

In key study from Biomedical and Environmental Sciences 15, 113-118 (2002) skin sensitizing reaction was performed in guinea pigs using Guinea pig maximisation test. 3-4 guinea pigs were used for primary irritation studies. Later on induction and challenge exposure were performed on 7 groups with 10-14 animals. For Induction, dorsal skin in the scapular region was shaved and after 24 hrs 3 intradermal injections were injected. Control animals were supplied with vehicle only. After intradermal induction, animals were challenged by topical application of test agent by closed patch test and observed for 24 hrs and 48 hrs. Based on percentage of animals sensitized the grading of allergenicity was calculated.

Therefore, from the available data chloral hydrate (302-17-0) was found to be not sensitizing to guinea pig.

Further supporting data obtained from TSCATS low detailed report; 1992, suggests that test for sensitization of read across substance chloral (CAS 75 -87 -6) revealed that allergic contact dermatitis did not develop. A 2% solution was not sensitising to the skin of guinea pig. It can be concluded that the Trichloroacetaldehyde is not sensitizing.

Thus considering the key and supporting studies the substance chloral hydrate is considered to be classified as Non sensitising as per CLP classification criteria.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

As per the available data the substance chloral hydrate is considered to be classified as Non sensitising as per CLP classification criteria.