Magnesium octadecylbenzenesulphonate

Skin sensitisation

Administrative data

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:

other: Read-across

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

THE GUINEA-PIG MAXIMISATION TEST METHOD

GLP compliance:

no

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The study pre-dates the devleoment of the LLNA method.

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

EC Number:

615-420-5

Cas Number:

71786-47-5

Test material form:

liquid

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Hazleton Dutchiand, Inc., Denver, PA
- Females (if applicable) nulliparous and non-pregnant: Yes
- Age at study initiation: 5 to 6 weeks
- Weight at study initiation: 295 to 369 grams
- Housing: Individual - suspended stainless steel cages
- Diet: ad libitum - Purina Guinea Pig Chow (pellets)
- Water: Automatic watering system (ad libitum)
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature: 65 to 71 F
- Humidity (%): 40 to 70%
- Air changes (per hr): Not specified
- Photoperiod (hrs dark / hrs light): 12 hours light, 12 hours dark by automatic timer
- IN-LIFE DATES: From: To: 5th July 1983 to 17th August 1983

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal and epicutaneous

Vehicle:

other: Primol 185 (white oil)

Concentration / amount:

Intradermal Injection - 5% test item in vehicle/FCA
Epicutaneous - 100% Test item

Day(s)/duration:

Intradermal Injection - Day 0. Epicutaneous - Day 7 (48 hour exposure)

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Challenge

No.:

#1

Route:

epicutaneous, semiocclusive

Vehicle:

other: Primol 185 (White oil)

Concentration / amount:

0.5 mL of 5% test item in vehicle

Day(s)/duration:

Day 21 - 24 hours exposure

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Treatment Group - 15 animals
Control Group - 15 animals

Details on study design:

A preliminary range finding screen was conducted from June 20, 1983 to July 13, 1983 to determine the appropriate concentrations of test item to be used in the 3 phases of dosing: intradermal induction, topical induction, and topical challenge.

For the first phase of dosing, the attempted induction of sensitization by intradermal injection, solutions of 5.0% (w/v) test item in vehicle and 5.0% (w/v) test tiem in diluted FCA were prepared. The preliminary screen indicated that this was the highest concentration of test material that could be initradermally injected without producinq local necrosis or ulceration of the injection site and was sufficiently free of systemic toxicity, so as not to impair the health of the animal.

Neat (100%) test tetm was prepared for the second phase of dosing, attempted induction by occlusive topical application. The preliminary screen indicated that this was the highest concentration of test material which would produce no more than mild to moderate irritation (erythema score less than or equal to 2) when applied topically.

A solution of 5.0% (w/v) test item in vehicle was prepared for the third phase of dosing, challenge by occlusive topical .app1ication The preliminary screen indicated that this was the highest concentration of test material that could be topically applied without producing any macroscopic signs of irritation.

Administration of test material

The sensitization assay was conducted in 3 phases:

1) Day 0 — induction of sensitization by intraderm.al injection of a maximally tolerated dose of test material, alone and in combination with adjuvant;
2) Day 7 — subsequent induction by occlusive epidermal application of a mild to moderately irritating dose; and
3) Day 21 — challenge for sensitization by occlusive epidermal application of a non—irritating dose of the test material.

Administration of induction injections - Day 0:
A pair of 0.1 ml injections of the following solutions was intradermally administered to each of 3 sites in the clipped mid-dorsal reqion of all animals, near the
scapula:

Site 1 — diluted ECA to both treated and control groups
Site 2 — 5.0% test item in vehicle to the treated group and undiluted vehicle to the control group
Site 3 — 5.0% test item in diluted FCA to the treated group and diluted ECA to the control group

The solutions were intradermally injected via a 1.0 cc syringe and 25 gauge needle. A row of 3 injections, 0.1 ml of each solution, were given along both sides of the spinal cord for a total of 6 injections. Solutions for Site 1 and Site 2 were injected close toqether and near the first thoracic vertebra; the solution for Site 3 was injected more caudally. All injections were made 1 to 2 cm from the midline, within a 3 x 4 cm area, and within, the boundaries of the clipped region.

Induction by occlusive topical application — Day 7:

Seven days after intradermal induction, 0.5 ml of 100% test item was topically applied over the injection sites on the shoulder reqion of the treated group animals. The test material was applied beneath a Webril cotton pad, covered by overlapping Derrnicel plastic tape and firmly secured to the torso of the animals with elastic adhesive bardaging. Control group animals received 0.5 ml of vehicle alone, applied identically. The oil based solution was applied directly to the skin. The pads and sleeving were removed from both the treated and control group animals after approximately 48 hours.

Challenge by occlusive topical application — Day 21:

Twenty-one days after intradermal induction 0.5 ml of 5.0% test item in vehicle was topically applied to the clipped area on the right flank of both treated and control group animals. The test material was applied beneath a Webril cotton pad, covered by overlapping Blenderm plastic tape, arid firmly secured to the torso of the animals with elastic adhesive bandaging in a manner such that no adhesive came in contact with the skin at the challenge site. The oil based solution was applied directly to the skin. The pads and sleeving were removed from both treated and control animals after approximately 24 hours.

Experimental evaluation

The animals were checked for viability once in the morning (before approximately 10:30 AM) and once in the afternoon (after approximately 3:00 PM).

In-life observations were made as to the nature, onset and severity and duration of toxicological signs immediately after dosing on Day 0 and on Days 7, 10, 14, 21 and each time dermal observations were made.

Body weights were recorded on Days 0, 7, 14, 21 and at sacrifice.

On Day 10, approximately 24 hours after removal of the induction patch, dermal responses were evaluated. On Day 23, approximately 21 hours after removal of the challenge patch, the challenqe area was genitly cleaned with physiological saline and clipped. Dermal responses were evaluated at approximately 24 and 48 hours after removal of the challenqe patch according to the Draize Method of Scoring. Sensitization was evaluated by comparing the reactions of treated animals with the reactions of control animals that had received a single epidermal exposure to the test material. Control responses were used to distinguish true sensitization from local irritation produced by the same concentration of test material.

After the final dermal observations, all animals were weighed, sacrificed by carbon dioxide asphyxiation, and discarded without fither examination.

Challenge controls:

Treated and control group animals were handled identically in all 3 phases of dosing with the only exception being that control group animals received vehicle in place of test material during the intradermal and topical induction phases.

Positive control substance(s):

no

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5%

No. with + reactions:

0

Total no. in group:

15

Remarks on result:

no indication of skin sensitisation

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5%

No. with + reactions:

0

Total no. in group:

15

Remarks on result:

no indication of skin sensitisation

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

5%

No. with + reactions:

0

Total no. in group:

15

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

5%

No. with + reactions:

0

Total no. in group:

15

Results 5

Group:

positive control

Remarks on result:

not measured/tested

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In the opinion of the Study Director, the test item should notbeclassified as a skin sensitizer.

Executive summary:

The allergic contact sensitization potential of test itemwasevaluated in15 female Hartley Albino guinea pigs following intradermal injection and 2 topical occlusive exposures. A control group of 15 female guinea pigs received only a single topical exposure to the test material The technique employed was similar to that described by B. Magnusson arid A. Kligman in: ‘The identification of contact allergens by animal assay. Theguineapig maximization test’, Journal of Investigative Dermatology, Vol. 52: 268-276, 1969. Evaluation of sensitization potential was based on a comparison of treated and control group dermal scores.

 

Dermal responses were evaluated approximately 24 hours after removal of the induction patch, and 24and 48hours after removal of the challenge patch, according to the Draize Method of scoring. Observations were made as to the nature, onset, severity and duration of toxicological signs immediately after dosing on Day 0 and on Days 7, 10, 14, 21, 23 and 24. body weights were recorded at initiation of dosing and on Days 7, 14, 21 and at sacrifice. After the final dermal observations and weighing, all animals were sacrificed by carbon dioxide asphyxiation and discarded without further examination.

 

All animals survived to study termination displaying normal weight gain patterns.

 

Animals of the treated group received 5.0% and 100% test item during the intradermal and topical induction phases, respectively. Following topical challenge with 5.0% test item, animals of the treated group exhibited a lower incidence of dermal irritation than the control group animals. In the opinion of the Study Director, the test item should notbeclassified as a skinsensitizer.