Hydrocarbons, C18-C24, iso-alkanes <2% aromatics

Endpoint summary

Description of key information

In a guideline skin sensitisation study conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics, the substance was not sensitising to skin.

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:

01 July - 15 August 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

(1992)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

(2008)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

(2003)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nohsan, Notification No. 8147, April 2011; including the most recent partial revisions.

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A Guinea Pig Maximisation test was carried out as the available test data on structural analogues used this method.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River France, L’arbresle Cedex, France.
- Age at study initiation: Young adult animals (approx. 4 weeks old)
- Weight at study initiation: 298 g
- Housing: Group housing of maximally 5 animals per labeled cage.
- Diet (e.g. ad libitum): Complete breeding diet for guinea pigs (SSNIFF® MS-Z, V2273; SSNIFF® Spezialdiäten GmbH, Soest, Germany). Hay (TecniLab-BMI BV, Someren, The Netherlands) was provided at least twice a week.
- Water: Free access to tap water.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, approximately 15 room air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study.

IN-LIFE DATES: 01 July - 15 August 2014

Route:

intradermal

Vehicle:

corn oil

Concentration / amount:

50%

Route:

intradermal

Vehicle:

other:

Remarks:

100% test substance with 1:1 Freund's adjuvant

Concentration / amount:

50%

Route:

epicutaneous, semiocclusive

Vehicle:

corn oil

Concentration / amount:

100%

Route:

epicutaneous, occlusive

Vehicle:

corn oil

Concentration / amount:

50%

No. of animals per dose:

Test animals: 10
Control animals: 5

Details on study design:

RANGE FINDING TESTS: (4 animals, age: between 4 and 9 weeks old)

Intradermal injections:
A series of four test substance concentrations was used, the highest concentration being the maximum concentration that could technically be injected. Each of two animals received two different concentrations in duplicate (0.1 mL/site) in the clipped scapular region. The injection sites were assessed for irritation 24 and 48 hours after treatment.
For results see appendix.

Epidermal application:
A series of four test substance concentrations was used, the highest concentration being the maximum concentration that could technically be applied. Two different concentrations were applied (0.5 mL each) per animal to the clipped flank, using Metalline patches# (2x3 cm) mounted on Medical tape# which were held in place with Micropore tape# and subsequently Coban elastic bandage#. The animals receiving intradermal injections were treated with the lowest concentrations and two further animals with the highest concentrations. After 24 hours, the dressing was removed and the skin cleaned of residual test substance using water. The treated skin areas were assessed for irritation 24 and 48 hours after exposure.
#. Suppliers: Lohmann & Rauscher B.V., Almere, The Netherlands (Metalline) and 3M, St. Paul, Minnesota, U.S.A. (Medical tape, Micropore and Coban).
For results see appendix.

MAIN STUDY
INDUCTION - Experimental animals
Day 1 The scapular region was clipped and three pairs of intradermal injections (0.1 mL/site) were made in this area as follows:
A) A 1:1 w/w mixture of Freunds' Complete Adjuvant (Difco, Detroit, U.S.A.) with water for injection (B.Braun Melsungen AG, Melsungen. Germany).
B) The test substance at a 50% concentration.
C) A 1:1 w/w mixture of the test substance, at twice the concentration used in (B) and Freunds' Complete Adjuvant.
Note: One of each pair was on each side of the midline and from cranial A) to caudal C).
Day 3 The dermal reactions caused by the intradermal injections were assessed for irritation.
Day 8 The scapular area between the injection sites was clipped and subsequently treated with 0.5 mL of a 100% test substance concentration using a Metalline patch (2x3 cm) mounted on Medical tape, which was held in place with Micropore tape and subsequently Coban elastic bandage. The dressing was removed after 48 hours exposure, the skin cleaned of residual test substance using water and the dermal reactions caused by the epidermal exposure
were assessed for irritation.
INDUCTION - Control animals
The control animals were treated as described for the experimental animals except that, instead of the test substance, vehicle alone was administered.

CHALLENGE - All animals
Day 21 One flank of all animals was clipped and treated by epidermal application of a 50% test substance concentration and the vehicle (0.1 mL each), using Patch Test Plasters (Curatest®, Lohmann, Almere, The Netherlands). The patches were held in place with Micropore tape and subsequently Coban elastic bandage. The dressing was removed after 24 hours exposure and the skin cleaned of residual test substance and vehicle using water. The treated sites were assessed for challenge reactions 24 and 48 hours after removal of the dressing.
After termination, animals were sacrificed using isoflurane (Abbott B.V., Hoofddorp, The Netherlands) and an intra-peritoneal injection of Euthasol® 20% (AST Farma BV, Oudewater, The Netherlands).

Challenge controls:

Not applicable

Positive control substance(s):

yes

Remarks:

(the results of the latest reliability check, performed in July/August 2014 with Alpha- Hexylcinnamaldehyde, are reported)

Positive control results:

The study reports that the latest reliability check (performed less than 6 months ago) shows a sensitisation rate of 90%.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50%

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

100% corn oil (induction) 50% test substance in corn oil (challenge)

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

100% corn oil (induction) 50% test substance in corn oil (challenge)

No. with + reactions:

0

Total no. in group:

5

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

20% alpha-hexylcinnamaldehyde

No. with + reactions:

8

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Remarks:

Positive control reliability check carried out July/August 2014

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

20% alpha-hexylcinnamaldehyde

No. with + reactions:

8

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Remarks:

Positive control reliability check carried out July/August 2014

Signs of irritation during induction:
For skin effects caused by the intradermal injections and epidermal exposure during the induction phase see appendix.

Evidence of sensitisation of the challenge concentration:

No skin reactions were evident after the challenge exposure in the experimental and control animals

Toxicity / Mortality:

No mortality occurred and no symptoms of systemic toxicity were observed in the animals of the main study.

Body weights:

Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

Interpretation of results:

GHS criteria not met

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

In a guinea pig maximisation test, conducted in accordance with OECD 406 and GLP, Hydrocarbons, C18-C24, isoalkanes, <2% aromatics was tested at a challenge concentration of 50% v/v in corn oil. Intradermal induction was performed at a concentration of 50% v/v, and topical induction used undiluted test substance. No skin reactions were observed in any test or control group animals at challenge indicating that the substance is not sensitising to skin.

Executive summary:

Assessment of Contact Hypersensitivity to Hydrocarbons, C18-C24, isoalkanes, <2% aromatics in the Albino Guinea Pig (Maximization Test).

The study was carried out based on the guidelines described in:

OECD No. 406 (1992) "Skin Sensitization"

EC No 440/2008; B6: "Skin Sensitization: Guinea-Pig Maximization Test (GPMT)"

EPA OPPTS 870.2600 (2003) “Skin Sensitization”

JMAFF Guidelines (2000), including the most recent revisions.

The study was based on the method described by Magnusson and Kligman, "Allergic Contact Dermatitis in the Guinea Pig - Identification of Contact Allergens" (1970).

Test substance concentrations selected for the main study were based on the results of a preliminary study.

In the main study, ten experimental animals were intradermally injected with a 50% concentration and epidermally exposed to a 100% concentration. Five control animals were similarly treated, but with vehicle alone (corn oil). Two weeks after the epidermal application all animals were challenged with a 50% test substance concentration and the vehicle. No skin reactions were evident after the challenge exposure in the experimental and control animals. There was no evidence that Hydrocarbons, C18-C24, isoalkanes, <2% aromatics had caused skin hypersensitivity in the guinea pig, since no responses were observed in the experimental animals in response to a 50% test substance concentration in the challenge phase. This result indicates a sensitization rate of 0 per cent.

Based on these results Hydrocarbons, C18-C24, isoalkanes, <2% aromatics does not have to be classified and has no obligatory labelling requirement for sensitization by skin contact according to the:

- Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2007) (including all amendments),

- Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a guinea pig maximisation test, conducted in accordance with OECD 406 and GLP (WIL Research, 2014), Hydrocarbons, C18-C24, isoalkanes, <2% aromatics was tested at a challenge concentration of 50% v/v in corn oil. Intradermal induction was performed at a concentration of 50% v/v, and topical induction used undiluted test substance. No skin reactions were observed in any test or control group animals at challenge indicating that the substance is not sensitising to skin.

In a guinea pig maximisation test, conducted in accordance with OECD 406 and GLP, limited range GTL Kerosine (C8-C12) was tested at challenge concentrations of 50% v/v and 10% v/v in paraffin oil (Huntingdon Life Sciences, 1997e). Intradermal induction was performed at a concentration of 50% v/v, and topical induction used undiluted test substance.

Challenge application of 50% v/v gave rise to eschar formation or oedema in six test and five control animals, moderate erythema in one test animal and slight erythema in test and six control animals. Exfoliation was evident in seventeen test and nineteen control animals.

Challenge application of 10% v/v caused eschar formation in two test and no control animals; a further seven test and two control animals showed slight erythema. Exfoliation was evident in twelve test and sixteen control animals.

Challenge application of paraffin oil alone gave rise to slight erythema in two control animals. Exfoliation was evident in 13 test and 14 control animals.

Abrasions were evident in the majority of test animals after the second (topical) induction; the control animals remained in overt good health. One test group animal was found dead on Day 2; necropsy revealed incomplete collapse of the lungs. There were no clinical observations and no effects on overall bodyweight gains.

A significant dermal response (a reaction more marked than the most severe evident amongst the control animals) was observed in no test animal following challenge with 50% v/v GTL Kerosine in paraffin oil, and in 2/20 test animals following challenge application of 10% v/v GTL Kerosine in paraffin oil.

Under the conditions of the test, limited range GTL Kerosine was therefore not sensitising.

In a guinea pig maximisation test conducted according to OECD 406 and GLP, Paraffin Waxes (Fischer-Tropsch), light, C15-27, branched and linear (GTL Paraffin Waxes, C15-27) was tested at challenge concentrations of 100% and 50% in liquid paraffin (Phycher, 2007). At the 100% challenge concentration, slight erythema was observed in 3/11 test group animals and 1/5 control group animals at the 24-hour observation. All skin reaction had fully resolved at the 48-hour observation. No skin reactions were observed in any test or control group animals at the 50% challenge concentration.

Under the conditions of the test, GTL Paraffin Waxes (C15-27) was therefore not sensitising.

In a guinea pig maximisation test, conducted in accordance with OECD 406 and GLP, GTL Base Oil Distillates (C18-C50 – branched, cyclic and linear) was tested at challenge concentrations of 100% and 50% in liquid paraffin (SafePharm, 2008e).

Intradermal induction was performed at a concentration of 100%, and topical induction used undiluted test substance also. Under the conditions of the test, the test material produced a 0% sensitisation rate and was found not sensitising to guinea pig skin.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available in vivo skin sensitisation data, Hydrocarbons, C18-C24, isoalkanes, <2% aromatics does not require classification as a skin sensitiser according to the criteria of Regulation (EC) No. 1272/2008.