Oligomerisation and alkylation reaction products of 2-phenylpropene and phenol

Endpoint summary

Description of key information

In a skin sensitisation Local Lymph Node Assay (LLNA) according to OECD TG 429 using the substance oligomerisation and alkylation reaction products of 2-phenylpropene and phenol (OAPP), a SI of 2.68 was observed for the 3 % preparation. SI for the 30 % preparation was 16.35. An EC3 of 3.63 % was determined by linear interpolation between the 3 % and 30 % data points. Based on this data, OAPP is considered to be a moderate skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Novares LA 300 (phenol, methylstyrenated)
- Lot/batch No.: 28166
- Composition of test material: composition is specified in IUCLID Sect. 13 - Assessment reports under Certificate of Analysis_Novares LA 300_phenol, methylstyrenated
- Stability under test conditions: no measured data; based on chemical structure assumed to be stable
- Storage condition of test material: room temperature, exclusion of light

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Breeding farm VELAZ s.r.o., Koleč u Kladna, Czech Republic
- Age at study initiation: 8 - 10 wks
- Weight at study initiation: 17 - 19 g
- Housing: macrolon cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +- 3
- Humidity (%): 30 – 70
- Photoperiod (hrs dark / hrs light): 12 / 12

Vehicle:

other: DAE 433

Concentration:

mixture of 40% dimethylacetamide, 30% acetone and 30% ethanol

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: dispersion
- Irritation: no
- Lymph node proliferation response: not examined


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response:
Stimulation index (SI) is ≥ 3
Response increases in dose-related manner
Criteria for irritation potential: individual and mean ear weight


TREATMENT PREPARATION AND ADMINISTRATION:
Days 1-3: 25 µL test suspension in DAE 433 , 1x on day 1, 2, and 3
Days 4 and 5: no treatment
Day 6: Injection of 250 μL of phosphate-buffered saline (PBS) containing 7.5 x105 Bq (c. 21 µCi) of 3H-methyl thymidine
into all test and control mice via the tail vein. Five hours later, the animals were killed.

Positive control substance(s):

other: DNCB (dinitrochlorbenzene, 0.5% (w/v) solution)

Statistics:

Non-parametric Kruskal-Wallis test, and then the non-parametric two-group Mann-Whitney rank test (probability level 0.05) was applied to all two-group comparisons [using software Statgraphic ® Centurion (version XV, USA)].

Key result

Parameter:

EC3

Value:

3.63

Parameter:

SI

Value:

2.36

Test group / Remarks:

0.3% test substance in vehicle; 5 animals

Parameter:

SI

Value:

2.68

Test group / Remarks:

3% test substance in vehicle; 5 animals

Parameter:

SI

Value:

16.35

Test group / Remarks:

30% test substance in vehicle; 5 animals

Table 1: Individual and mean radioactivity in cell suspensions (Report Table 4)

	Activity (DPM)
Animal No.	NC (1-5)	PC (6-10)	30% (11-15)	3% (16-20)	0.3% (21-25)
1	550.98	11374.69	9354.53	1425.77	1232.24
2	485.39	10401.94	9984.31	1475.60	1484.48
3	568.93	10347.82	11634.71	1367.08	1128.80
4	526.30	8837.38	9107.79	1301.28	1222.94
5	596.74	9493.34	4517.77	1748.67	1091.42
Group mean	545.67	10091.03	8919.82	1463.68	1231.98
SI	1.00	18.49	16.35	2.68	2.26

NC = vehicle control; PC = positive control

Table 2: Individual and average ear weights (Report Table 5)

	Weight of ear biopsies (milligrams)
Animal No.	NC (1-6)	PC (7-12)	30% (13-18)	3% (19-24)	0.3% (25-30)
1	24.5	27.4	32.7	25.0	21.8
2	25.2	27.5	28.4	23.0	23.1
3	23.8	26.5	34.2	21.4	21.4
4	23.4	26.7	29.4	21.5	21.0
5	24.7	27.2	41.2	21.7	25.0
Group mean	24.32	27.06*	33.18*	22.52	22.46
SD	0.72	0.44	5.07	1.53	1.62

NC = vehicle control; PC = positive control

* statistically significant with p =< 0.05, Mann-Whitney test

Table 3:  Summary table (Report Table 6)

Group	Radioisotope incorporation in lymph nodes		Ear weight
	Mean DPM	SI	Mean (mg)
NC	545.67	1.0	24.32
PC	10091.03	18.49+	27.06
30%	8919.82	16.35+	33.18
3%	1463.68	2.68	22.52
0.3%	1231.98	2.26	22.46

Bold figures with + = values >= 3

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

In this LLNA according to OECD TG 429, an EC3 of 3.63 was determined for the substance oligomerisation and alkylation reaction products of 1-phenylpropene and phenol. Resulting EU/GHS classification is skin sensitising Cat. 1B (EC3 > 2).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

In a mouse local lymph node assay according to OECD TG 429 performed under GLP conditions using 0.3, 3, and 30 % preparations of the test substance in vehicle (mixture of 40 % dimethylacetamide, 30 % acetone, and 30 % ethanol), an increase of the Stimulation Index (SI) for the test groups over controls was observed (SI = 2.26, 2.68, and 16.35). For a concentration of 30 % the SI was > 3 demonstrating a sensitising response of the test animals following the treatment with test substance. The mean ear weight was below (0.3 and 3 % test group, 22.46 and 22.52 mg, respectively) and above (30 % test group = 33.18 mg) the ear weight of the controls (24.32 mg). The SI > 3 for the 30 % test group indicates a sensitising potential for OAPP (Brabnikova/VUOS 2010). An EC3 of 3.63 can be calculated by linear interpolation between the data points 3 % and 30 % indicating a moderate skin sensitising potential.

Based on the positive results of the mouse LLNA (Brabnikova/VUOS 2010), OAPP is rated as a potential contact allergen.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

There is no data for respiratory sensitisation.

Justification for classification or non-classification

The substance oligomerisation and reaction products of 2-phenylpropene and phenol showed a skin sensitising effect in a mouse LLNA test. EC3 was determined to be > 2% (3.63%). According to Regulation (EC) No 1272/2008, the substance is classified as skin sensitising Cat 1B, H317.

There is no data to support respiratory sensitisation as such. No classification is required under Regulation (EC) No 1272/2008.