Thionyl dichloride

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

other: read-across from the hydrolysis product of SOCl2 (HCl)

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.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1986

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

Hydrogen chloride

EC Number:

231-595-7

EC Name:

Hydrogen chloride

Cas Number:

7647-01-0

IUPAC Name:

chloride

Details on test material:

Hydrochloric acid; purity: at least 98% (purest available).
No further details specified

In vivo test system

Test animals

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

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

other: ethanol

Induction 2

Concentration / amount:

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

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

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

other: ethanol

Challenge 2

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

Study design: in vivo (LLNA)

Concentration:

Not applicable

No. of animals per dose:

Not applicable

Details on study design:

Not applicable

Statistics:

Not applicable

Results and discussion

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.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: Not applicable.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Not applicable.

Any other information on results incl. tables

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.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

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