Tris(1,3-dihydroxyprop-2-yl) borate

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:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

No data

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study. Study conducted on the hydrolysis product of reference substance, boric acid.

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

Buehler test

Species:

guinea pig

Strain:

Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Davidson’s Mill Farms, South Brunswick, NJ
- Age at study initiation: Young adult
- Weight at study initiation: Males: 314 -411 g; females: 282-376 g

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

Induction: 0.4 g 95 % w/w boric acid
Challenge: 95 % w/w boric acid

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

Induction: 0.4 g 95 % w/w boric acid
Challenge: 95 % w/w boric acid

No. of animals per dose:

Test Group: 20 animals
Naive Control: 10 animals
Positive Control: 20 animals
Positive Naive Control: 10 animals

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Concentrations: 0.4 g 95 % w/w boric acid moistened with distilled water to enhance skin contact.


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: Day 28
- Exposure period: Test substance was wiped off with water after 6 h.

Challenge controls:

No data

Positive control substance(s):

yes

Remarks:

Dinitrochlorobenzene

Positive control results:

No data

Reading:

1st reading

Hours after challenge:

34

Group:

test chemical

Dose level:

0.4 g 95% w/w/boric acid

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

Very faint erythema seen in one animal at induction stage and 2 animals at challenge stage and also in one naïve control. No other adverse effect observed

Remarks on result:

other: see Remark

Remarks:

Reading: 1st reading. . Hours after challenge: 34.0. Group: test group. Dose level: 0.4 g 95% w/w/boric acid . No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: Very faint erythema seen in one animal at induction stage and 2 animals at challenge stage and also in one naïve control. No other adverse effect observed.

Observations:

Treatments	Buehler test	Observations/Remarks
	Day of treatment
Induction 1	day 0	Very faint erythema (0.5) observed at one test site at 24 hours after first induction dose. No other irritation observed
Induction 2	7	No irritation observed
Induction 3	14	No irritation observed
Challenge	28	No irritation observed
Scoring 1	29	Very faint erythema (0.5) observed at two test sites at 24 hours after  challenge dose. Irritation persisted at one site for 48 hours.  Very faint erythema (0.5) observed at one test site at 24 hours in one naive control.
Scoring 2	30

Results of skin sensitisation test:

	Number of animals with signs of allergic reactions / number of animals in group
	Negative control	Test group	Positive control
scored after 24h	0 / 10	0 / 20	10/20
scored after 48h	0 / 10	0 / 20	7/20

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

OECD Guide-line 406 "Skin Sensitisation" method (Buehler test ) was performed using 95 % w/w boric acid moistened with distilled water to enhance skin contact. Very faint erythema was observed in one animal at induction stage and 2 animals at challenge stage and also in one naïve control. No other adverse effects were observed therefore the test substance was considered a non-sensitiser.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The reference substance (BAGE) hydrolyses within less than an hour to its hydrolysis products: Boric acid and glycerol. Therefore, conducting irritation studies on the reference substance will give a result representative of the hydrolysis products mentioned above.

Boric acid is considered to be the hydrolysis product of main concern, due to its known toxic effects. An assessment of the skin sensitisation of boric acid has therefore been made based on available study data on boric acid.

Boric acid

Wnorowski G (1994):

OECD Guide-line 406 "Skin Sensitisation" method (Buehler test ) was performed using 95 % w/w boric acid moistened with distilled water to enhance skin contact. Very faint erythema was observed in one animal at induction stage and 2 animals at challenge stage and also in one naïve control. No other adverse effects were observed. No animals in the test or negative control groups showed positive response for skin sensitisation. Therefore the test substance (boric acid) was considered a non-sensitiser.

Glycerol

Glycerol is the other hydrolysis product of BAGE. It is not classified for human health according to CLP or DSD and is essentially non-toxic. Further evaluation of the skin sensitisation potential of glycerol has not been assessed.

Refer to section 13, Toxicological expert report, for further details of the evalaution of the hydrolysis of BAGE and its consequences for toxicity testing.

Supporting data:

As skin sensitisation studies are not feasible to conduct on the reference substance itself, DEREK predictions were made to assess the skin sensitisation of the reference substance itself.

No alerts were triggered by the structure of the substance, but predictions were able to be made regarding photoallergenicity and skin sensitisation.

Photoallergencity and skin sensitisation were deemed to be improbable, meaning there is at least one strong argument that the proposition is false and there are no arguments that it is true.

Migrated from Short description of key information:
A skin sensitisation test on boric acid was performed according to OECD Guideline 406 (Buehler method). Boric acid is not a skin sensitiser based on the results of this study.

Justification for selection of skin sensitisation endpoint:
Study conducted on boric acid, the hydrolysis product of the reference substance, which is of most concern to human health and is most applicable to evaluate.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Migrated from Short description of key information:
There is no data to suggest that boric acid is a respiratory sensitiser.

Justification for classification or non-classification

Boric acid is not a skin sensitiser.