Hydrogen chloride

Endpoint summary

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

Study period:

Not specified; published in 1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Experimental procedures for GPMT are not reported in details (minor reporting deficiencies). Purity and source of test material not reported. Individual animal data not reported. The study however included adequate positive controls, and (in the form of a ring study) appeared repeatable at multiple laboratories.

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

not applicable

Principles of method if other than guideline:

Method: Mouse Ear Swelling Test (MEST) AND Guinea Pig Maximization Test (GPMT)
In a study carried out to validate an alternative dermal sensitization  test, female mice were inducted by receiving intradermal injections of FCA (day 0 only) plus topical  applications of hydrochloric acid (1% in 70% ethanol) in the  stomach area previously clipped free of fur and tape-stripped up to a  glossy appearance of the skin (days 0, 1, 2 and 3). Challenge was done  applying hydrochloric acid (5% in 70% ethanol) to the left ear,  the right one receiving the vehicle alone. Swelling of the ears were  measured using a micrometer 24 and 48 hours after application and  comparing the results obtained in concurrent control animals. GPMT was  also carried out in 15 guinea pigs.

GLP compliance:

no

Remarks:

GLP was not compulsory at the time the study was conducted.

Type of study:

other: Mouse Ear Swelling Test AND Guinea Pig Maximization Test

Justification for non-LLNA method:

STudy happened to0 be available. With this data available there is no need to perform additionally an LLNA study.

Species:

other: female mouse and guinea pigs

Strain:

other: mouse: CF-1; strain of guinea pigs not specified

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Sex: mice: female; guinea pigs: sex not specified.
- Source: mice: Charles River or Harlan Sprague-Dawley or Buckshire Corporation. Source of guinea pigs not specified
- Age at study initiation: mice: 6-8 weeks. Age of guiea pigs not specified.
- Weight at study initiation: not specified
- Housing: not specified
- Diet (e.g. ad libitum): not specified
- Water (e.g. ad libitum): not specified
- Acclimation period: mice: 7 days. Guinea pigs: not specified.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): not specified
- Humidity (%): not specified
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): not specified


IN-LIFE DATES: not specified

Route:

intradermal and epicutaneous

Vehicle:

other: ethanol

Concentration / amount:

GPMT:
Intradermal injection, topical induction and challenge: 1% in ethanol

MEST:
Induction: 1% in 70% ethanol
Challenge: 5% in 70% ethanol

Route:

epicutaneous, occlusive

Vehicle:

other: ethanol

Concentration / amount:

GPMT:
Intradermal injection, topical induction and challenge: 1% in ethanol

MEST:
Induction: 1% in 70% ethanol
Challenge: 5% in 70% ethanol

No. of animals per dose:

10-15 mice, and 5-10 mice for concurrent control group. Guinea pigs not specified.

Details on study design:

Both a Mouse Ear Swelling Test (MEST) and traditional GPMT test was conducted. Each of these tests is described separately below.

GPMT:

RANGE FINDING TESTS:
Not specified.

MAIN STUDY
Experimental procedures for the GPMT are not reported in details.
Induction and challenge was conducted with 1% in ethanol.


MEST:

RANGE FINDING TESTS:
The concentrations used in MEST were chosen on the basis of irritation potential. Two mice were used in each of four groups induced and challenged at four different concentrations. Dosages used in the actual validation study were those minimally or non-irritating to the stomach area (for induction), non-irritating to the ear (challenge).
Ten different strains of mice were investigated to determine which were useful or not, and if there were a most sensitive strain. Male and female mice of different ages were tested to determine if there were a difference in sensitivity between the sexes, and what range of age was the most appropriate. Data reported refers to the final test design.

MAIN STUDY:
- Induction: 1% in 70% ethanol
- Challenge: 5% in 70% ethanol (no rechallenge)
- Control group: yes
- Evaluation (hr after challenge): 24 and 48 hours after application

Days -7 to 0 Quarantine/acclimation period
Days 0 to 4 Induction stage
Day 0
- fur of abdomen is clipped
- intradermal injection of FCA (two injections totalling 0.05 mL into the stomach area)
- abdomen skin is tape stripped (up to present a glossy appearance)
- topical application of 100 μL of test substance (or vehicle)
- abdominal skin site is dried rapidly (electric drier)
Days 1, 2 and 3
- abdomen skin is tape stripped (up to present a glossy appearance)
- topical application of 100 μL of test substance (or vehicle)
- abdominal skin site is dried rapidly (electric drier)
Day 10 Challenge stage (same procedure for both treated and control animals)
- topical application of 20 μL of test substance to the left ear
- topical application of 20 μL of vehicle to the right ear
- both ears are dried rapidly
Days 11 and 12 Ear thickness measurement using an “Oditest” D1000 micrometer. Animal maintained under light ether anaesthesia.

Challenge controls:

yes: vehicle.

Positive control substance(s):

yes

Remarks:

MEST: Positive controls during development/optimization: 1-chloro-2,4-dinitrochlorobenzene, 2-phenyl-4 ethoxymethylene oxazolone and toluene diisocyanate. 72 substances were tested in the validation test, including these positive controls

Concentration:

Not applicable

No. of animals per dose:

Not applicable

Details on study design:

Not applicable

Statistics:

Not applicable

Positive control results:

Not specified, but the study included adequate positive controls, and (in the form of a ring study) appeared repeatable at multiple laboratories.

Parameter:

SI

Remarks on result:

other: Not applicable.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Not applicable.

MEST: No difference in swelling compared to control was noted in treated mice (100% swelling). Hydrochloric acid resulted to be not a sensitizer.
GPMT: 0% sensitized animals.

Summary of results and discussion:

No difference in swelling compared to control was noted in treated mice (100% swelling).

No guinea pig showed a positive sensitisation reaction (0/15) in the GPMT.

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Hydrochloric acid does not posses any sensitizing potential both at MEST and GPMT.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Migrated from Short description of key information:
Hydrochloric acid does not possess any sensitizing potential both at MEST and GPMT.

Justification for selection of skin sensitisation endpoint:
Only report available.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Hydrochloric acid has not shown sensitizing potential in both MEST and GPMT. Lack of sensitising potential is also demonstrated in a HRIPT (Human Repeat Insult Patch Test - see 7.10.4 Sensitisation data (humans))

As chemical respiratory sensitisers also elicit positive results in predictive tests for contact sensitisation, a negative outcome for dermal sensitisation is also predictive for non respiratory sensitisation of the substance.

Migrated from Short description of key information:
HCl is not a respiratory sensitiser.

Justification for selection of respiratory sensitisation endpoint:
At present, recognised and validated animal models for the testing of respiratory hypersensitivity are not available.

Justification for classification or non-classification

Skin: not sensitising - conclusive but not sufficient for classification

Respiratory: not sensitising

Based on the test findings in an MEST and GPMT and in accordance to Regulation (EC) No 1272/2008, HCl does not have to be classified as a skin and respiratory sensitizer.