1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-nortall-oil alkyl derivs.

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:

14-Jul-2011 to 06-Sep-2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Adequate existing data that allow a conclusion on the sensitizing potential of the substance were available

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

Animals: Albino Dunkin Hartley Guinea Pig, HsdPoc: DH, SPF
Rationale: Skin reactions in the guinea pig are classically used to determine the potential of test items to induce delayed contact hypersensitivity. No valid non-animal (in vitro) model is available at present for the testing of contact sensitisation.
Breeder: Harlan Laboratories B.V.; Kreuzelweg 53; 5961 NM Horst / The Netherlands

Number of Animals for Pretest / Main Test: 6 males / 15 males; Animals of either sex are acceptable for use according to guidelines Commission Regulation (EC) No 440/2008, B.6 and OECD 406.

Age at Pretest Start / Beginning of Acclimatization Period: 4 weeks

Body Weight at Pretest Start: Pretest groups: 337.6 – 386.1 g
Body Weight at Beginning of Acclimatization Period: Test and control groups: 325.9 – 358.5 g

Identification: By individual ear tattoo

Randomization: Selected by hand at time of delivery. No computer generated randomization program.

Acclimatization: Twenty-five days for the test and control groups of the main test under standard laboratory conditions after health examination. No acclimatization for the animals of the pretest. Only animals without any visible signs of illness were used for the study. A certificate of health was provided by the animal supplier at animal delivery and included in the raw data.

Conditions: Standard Laboratory Conditions. Air-conditioned with 10-15 air changes per hour, and continuously monitored environment with a room temperature of 22 ± 3 °C and a relative humidity between 30-70%, automatically controlled light cycle of 12 hours light and 12 hours dark and music played during the daytime light period.

Accommodation: In groups of up to 10 animals in stainless steel cages with standard softwood bedding (‘Lignocel’ J. Rettenmaier & Söhne GmbH & CoKG, 73494 Rosenberg / Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst / Switzerland).

Diet: Teklad Global Guinea pig diet 2040C (batch nos. 81/10 and 36/11, provided by Provimi Kliba AG, 4303 Kaiseraugst / Switzerland), ad libitum.
Results of analysis for contaminants are archived at Harlan Laboratories Ltd. A haystick 4642 (batch nos. 06/11 and 24/11, Provimi Kliba AG) was also provided for environmental enrichment. Results of analyses for contaminants are archived at Harlan Laboratories Ltd.

Water: Community tap water from Füllinsdorf, in bottles, ad libitum. Results of bacteriological, chemical and contaminant analyses are archived at Harlan Laboratories Ltd.

Route:

intradermal and epicutaneous

Vehicle:

polyethylene glycol

Concentration / amount:

Intradermal Induction: 0.05% (weight/weight) test item in PEG 300
Epidermal Induction: 3% (weight/weight) test item in PEG 300
Challenge: 1% (weight/weight) test item in PEG 300

Route:

epicutaneous, semiocclusive

Vehicle:

polyethylene glycol

Concentration / amount:

Intradermal Induction: 0.05% (weight/weight) test item in PEG 300
Epidermal Induction: 3% (weight/weight) test item in PEG 300
Challenge: 1% (weight/weight) test item in PEG 300

No. of animals per dose:

Intradermal pretest 1: 1 animal
Intradermal pretest 2: 1 animal
Epidermal pretest 1: 2 animals
Epidermal pretest 2: 2 animals
Control Group: 5 animals
Test Group: 10 animals

Details on study design:

Preparation of Dose Formulations
The test item and vehicle or auxiliary compounds were placed into a glass beaker on a tared Mettler balance and a weight/weight dilution was prepared. Homogeneity of the test item preparation was ensured and maintained during preparation and treatment using a magnetic stirrer. The preparations were made prior to each dosing. Dose concentrations were in terms of material as supplied by the Sponsor.

Selection of Test Item Concentration for Main Study

Intradermal Induction: The test item prepared at 0.05% (used for the intradermal induction) was selected by default as the last lower tested test item concentration of 1% in PEG 300 caused moderate skin irritation during the pretest.

Epidermal Induction: The test item at 3% in PEG 300 was the highest tested concentration causing mild skin irritation during the pretest. It was selected for the epidermal induction procedure.
E
pidermal Challenge: The test item at 1% was the highest tested concentration which did not cause any skin irritating reactions during the epidermal pretest. It was selected for the challenge procedure.

To determine the different concentrations, intradermal and epidermal pretests were performed as described below.

Treatment Method
The animal's fur was shaved with a fine clipper blade just prior to exposure. Intradermal injections or closed patches were applied to the animals as follows: 0.1 mL/site for the intradermal administrations or 0.2 to 0.3 mL on a patch of filter paper for the epidermal administrations.
The patch was covered by a strip of aluminium foil and firmly secured by an elastic plaster wrapped around the trunk of the animal and secured with impervious adhesive tape. The occlusive dressing was left in place for 24 (epidermal pretest and epidermal challenge) or 48 hours (epidermal induction). Identical patching method was used for the epidermal pretest, epidermal induction and epidermal challenge.

Pretest
The pretest was performed during the acclimatization period of the animals for the main test. The test item concentrations described below were selected during a preliminary solubility testing which was performed before the study initiation date.

Intradermal Injections
Four intradermal injections (0.1 mL/site) of a 1:1 (v/v) mixture of Freund's Complete Adjuvant/physiological saline were made into the shaved neck of one guinea pig. Five days later, three intradermal injections (0.1 mL/site) were made into the clipped flank of the same guinea pig at concentrations of 75%, 50% and 25% of the test item in PEG 300. Dermal reactions were assessed 24 hours later.

At this stage of procedure, no test item concentration causing mild-to-moderate skin irritation could be chosen. Therefore, a second intradermal pretest animal was treated in the same manner as described with first the animal, just the concentrations were changed. The animal was first treated, 6 days prior to the test item injections, with four intradermal injections (0.1 mL/site) of a 1:1 (v/v) mixture of Freund's Complete Adjuvant/physiological saline made into the shaved neck. Thereafter, it was treated intradermally with the test item at 10, 3 and 1% in PEG 300. Based on the results, a test item concentration of 0.05% was selected by default for intradermal induction in the main test.

Epidermal Applications
Four intradermal injections (0.1 mL/site) of a 1:1 (v/v) mixture of Freund's Complete Adjuvant/physiological saline were made into the shaved neck of two guinea pigs. Five days later, four patches of filter paper (3 x 3 cm) were saturated with the test item at 100% (neat test item), 75%, 50%, 25% in PEG 300 and applied to the shaved flanks of the same guinea pigs. The volume of test item preparation applied was approximately 0.2 mL. The occlusive dressings were left in place for 24 hours. The reaction sites were assessed 22 hours after removal of the bandage for erythema and oedema according to the method of Magnusson and Kligman. The animals were sacrificed immediately therafter for ethical reasons, due to burnt skin (maculated necrosis) observed at the 4 treated test sites.

Therefore, a second epidermal pretest was performed with 2 naive animals. The two guinea pigs were treated in the same manner, using the test item concentrations of 10%, 3%, 1%, 0.3% in PEG 300. The reaction sites were assessed 24 and 48 hours after removal of the bandage for erythema and oedema according to the method of Magnusson and Kligman. Based on the results the test item concentration selected for epidermal induction and challenge in the main test was 3% and 1% in PEG 300, respectively.

Induction
Intradermal Injection / Performed on Test Day 1
An area of dorsal skin from the scapular region (approximately 6 x 8 cm) was clipped free of hair. Three pairs of intradermal injections (0.1 mL/site) were made just within the boundaries of a 4 x 6 cm area in the clipped region as follows:

Test Group:
1) 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.
2) The test item at 0.05% in PEG 300.
3) The test item at 0.05% in a 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.

Control Group:
1) 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.
2) PEG 300.
3) 1:1 (w/w) mixture of PEG 300 in a 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.

Epidermal Induction / Performed on Test Day 8
One week after the intradermal induction, the scapular area (approximately 6 x 8 cm) was again shaved prior to epidermal induction. A 2 x 4 cm patch of filter paper was saturated with the test item at 3% in PEG 300 and placed over the injection sites of the test animals. The volume of the test item applied was approximately 0.3 mL. The patch was covered with aluminum foil and firmly secured by an elastic plaster wrapped around the trunk of the animal and secured with impervious adhesive tape. The occlusive dressings were left in place for 48 hours. The epidermal application procedure described ensured intensive contact of the test item.

The guinea pigs of the control group were treated as described above with PEG 300 only, applied at a volume of approximately 0.3 mL. The reaction sites were assessed 24 and 48 hours after removal of the bandage for erythema and oedema according to the method of Magnusson and Kligman.

Challenge / Performed on Test Day 22
The test and control guinea pigs were challenged two weeks after epidermal induction and treated in the same way. Two patches (3 x 3 cm) of filter paper were saturated with the test item at the highest tested non-irritating concentration of 1% in PEG 300 (applied to the left flank) and the vehicle only (PEG 300 applied to the right flank) using the same method as for the epidermal application. The volume of test item preparation and vehicle applied was approximately 0.2 mL. The dressings were left in place for 24 hours. The scoring method used for the pretest, induction and epidermal challenge was identical. It was performed 24 ± 2 hours after removal of the dressings for the intradermal and epidermal pretest, induction and challenge and repeated 24 ± 2 hours later (48-hour grades) for the epidermal pretest, epidermal induction and challenge.

Observations
Viability / Mortality: Daily from delivery of the animals to the termination of the test.
Clinical Signs: Daily from delivery of the animals to the termination of test.
Local signs: Skin responses were graded during the pretest, induction and challenge period
Body Weights: At delivery/acclimatization start, at test item treatment day in the pretest, at the end of the pretest, at test day 1 (day of treatment) and at the termination of the study.

Necropsy
No necropsy was performed on all surviving animals. The control and test animals were euthanized at the end of the test period by intraperitoneal injection of pentobarbitone at a dose of 2.0 mL/kg of 162 mg/mL sodium pentobarbitone and discarded. The intradermal pretest II animal was euthanized as described above at the treatment start of the main study. The intradermal and epidermal pretest I animals were euthanized on the day of the 24-hour reading in the epidermal pretest I.

Determination of Skin Reactions
The test item treated skin area of the animals used for the epidermal pretest and challenge was depilated approximately 21 hours after the dressings had been removed, using an approved depilatory cream (VEET Cream, Reckitt & Colman AG, 4123 Allschwil / Switzerland). The depilation was performed to clean the stratum corneum from the possible staining produced by the test item and to facilitate the reading of a possible skin reaction. The depilatory cream was placed on the patch sites and surrounding areas, and left on for up to 3 - 5 minutes. It was then thoroughly washed off with a stream of warm water. The animals were then dried with a disposable towel, and returned to their cages.

The scoring method used for the pretest, induction and epidermal challenge was identical. It was performed 24 ± 2 hours after removal of the dressings for the intradermal and epidermal pretest and induction and for challenge and repeated 24 ± 2 hours later (48-hour grades) for the epidermal pretest, epidermal induction and challenge.

The scoring was performed by visual assessment of erythema and oedema. They were graded according to Magnusson and Kligman as follows:
0 = no visible change
1 = discrete or patchy erythema
2 = moderate and confluent erythema
3 = intense erythema and swelling
Any other gross lesions not covered by this scoring system were described.

Each animal was scored by positioning under true-light (Philips Master TLS HE 28W/840).

Challenge controls:

5 control animals treated with vehicle only during induction. See 2Details on study design"

Positive control substance(s):

yes

Remarks:

alpha-hexylcinnamaldehyde

Positive control results:

The sensitivity and reliability of the experimental technique employed was assessed by use of alpha-hexylcinnamaldehyde which is recommended by the OECD 406 Guidelines and is known to have moderate skin sensitisation properties in the guinea pig strain. The results from the most recent positive control test (Harlan Laboratories Study D24531, performed from 29-Mar-2011 to 20-May-2011) confirm alpha-hexylcinnamaldehyde as skin sensitizer, as it produced allergic contact dermatitis in >30% of the test animals.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

1% in PEG 300

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

none

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 1% in PEG 300. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: none.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1% in PEG 300

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 1% in PEG 300. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

1% in PEG 300

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

none

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 1% in PEG 300. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: none.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1% in PEG 300

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 1% in PEG 300. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

PEG 300 only

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

none

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: PEG 300 only. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: none.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

PEG 300 only

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: PEG 300 only. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

PEG 300 only

No. with + reactions:

0

Total no. in group:

5

Clinical observations:

none

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: PEG 300 only. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: none.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

PEG 300 only

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: PEG 300 only. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.

 Viability / Mortality / Macroscopic Findings

No intercurrent deaths occurred during the course of the study, hence no necropsies were performed.

 Clinical Signs

No clinical signs were recorded throughout the entire observation period.

  

 Body Weights

The body weight of the animals was within the range commonly recorded for animals of this strain and age.

 

 Skin Reactions in the Intradermal Induction / Performed on Test Day 1

Expected common findings were observed in the test and control groups after the different injections using FCA intradermally. These findings consisted of erythema, oedema, necrotizing dermatitis, encrustation and exfoliation of encrustation. No detailed description of the skin reactions is given in the report as these FCA effects are well-known.

  

 Skin Reactions in the Epidermal Induction / Performed on Test Day 8

Control Group: No local skin reactions were observed in the control animals when treated with PEG 300 alone.

Test Group: Discrete/patchy erythema was observed in 5 and 1 out of 10 test animals at the 24- and 48-hour reading, respectively after treatment with the test item concentration of 3% in PEG 300.

  

Skin Reactions in the Challenge/ Performed on Test Day 2

Control Group: No local skin reactions were observed in the control animals when treated with PEG 300 alone or when treated with the test item applied at 1% in PEG 300.

Test Group: No local skin reactions were observed in the test animals when treated with PEG 300 alone or when treated with the test item applied at 1% in PEG 300.

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the above mentioned findings in an adjuvant sensitisation test (M&K-test) in guinea pigs and in accordance to Regulation (EC) No 1272/2008, 1-(2-Hydroxyethyl)-2-Tall Oil-2-Imidazoline does not have to be classified and labeled as a skin sensitizer.

Executive summary:

In order to assess the cutaneous allergenic potential of 1-(2-Hydroxyethyl)-2-Tall Oil-2-Imidazoline, the Maximization-Test was performed in 15 (10 test and 5 control) male albino Dunkin Hartley guinea pigs, in accordance with OECD Guideline No. 406 and the Commission Regulation (EC) No 440/2008, B.6.

 

The intradermal induction of sensitisation in the test group was performed in the nuchal region with a 0.05% dilution of the test item in PEG 300 and in an emulsion of Freund's Complete Adjuvant (FCA)/physiological saline. The epidermal induction of sensitisation was conducted for 48 hours under occlusion with the test item at 3% in PEG 300 one week after the intradermal induction. The animals of the control group were intradermally induced with PEG 300 and FCA/physiological saline.

 

Two weeks after epidermal induction the test and control animals were challenged by epidermal application of the test item at 1% in PEG 300 and PEG 300 alone under occlusive dressing.

 

Cutaneous reactions were evaluated at 24 and 48 hours after removal of the dressing.

No deaths occurred during the cause of the study and no clinical signs were observed. The body weight of the animals was within the range normally recorded for this strain and age.

No local skin reactions were observed in the control animals when treated with PEG 300 alone or when treated with the test item applied at 1% in PEG 300. No local skin reactions were observed in the test animals when treated with PEG 300 alone or when treated with the test item applied at 1% in PEG 300.

Based on the above mentioned findings in an adjuvant sensitisation test (M&K-test) in guinea pigs and in accordance to Regulation (EC) No 1272/2008, 1-(2-Hydroxyethyl)-2-Tall Oil-2-Imidazoline does not have to be classified and labeled as a skin sensitizer. 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In order to assess the cutaneous allergenic potential of 1-(2-Hydroxyethyl)-2-Tall Oil-2-Imidazoline, the Maximization-Test was performed in 15 (10 test and 5 control) male albino Dunkin Hartley guinea pigs, in accordance with OECD Guideline No. 406 and the Commission Regulation (EC) No 440/2008, B.6.

 

The intradermal induction of sensitisation in the test group was performed in the nuchal region with a 0.05% dilution of the test item in PEG 300 and in an emulsion of Freund's Complete Adjuvant (FCA)/physiological saline. The epidermal induction of sensitisation was conducted for 48 hours under occlusion with the test item at 3% in PEG 300 one week after the intradermal induction. The animals of the control group were intradermally induced with PEG 300 and FCA/physiological saline.

 

Two weeks after epidermal induction the test and control animals were challenged by epidermal application of the test item at 1% in PEG 300 and PEG 300 alone under occlusive dressing.

 

Cutaneous reactions were evaluated at 24 and 48 hours after removal of the dressing.

No deaths occurred during the cause of the study and no clinical signs were observed. The body weight of the animals was within the range normally recorded for this strain and age.

No local skin reactions were observed in the control animals when treated with PEG 300 alone or when treated with the test item applied at 1% in PEG 300. No local skin reactions were observed in the test animals when treated with PEG 300 alone or when treated with the test item applied at 1% in PEG 300.

Based on the above mentioned findings in an adjuvant sensitisation test (M&K-test) in guinea pigs and in accordance to Regulation (EC) No 1272/2008, 1-(2-Hydroxyethyl)-2-Tall Oil-2-Imidazoline does not have to be classified and labeled as a skin sensitizer. 

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

A Maximization-Test performed in 15 (10 test and 5 control) male albino Dunkin Hartley guinea pigs, in accordance with OECD Guideline No. 406 and the Commission Regulation (EC) No 440/2008, B.6. produced no significant effects.

Based on the study results the test material is not considered to be a skin sensitizer.