Lithium bis(oxalato)borate

Endpoint summary

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

Study period:

2004-10-06 to 2004-10-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline compliant study.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Paris Cedex, April 2002

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

April 2004

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

March 2003

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Mice: inbred, SPF-Quality, nulliparous, non-pregnant

Vehicle:

dimethylformamide

Concentration:

2.5 %, 10 % and 25 % and control

No. of animals per dose:

5 female each group

Details on study design:

Test substance concentrations selected for the main study were based on the results of a preliminary study:
Irritation: At 50 % erythema (grade 3 with wounds on both ears) were observed on Day 3. There was no irritation with 25 %.

In the main study, three groups of five experimental animals were epidermally exposed to the test material at concentrations of 2.5 %, 10 % and 25 %, respectively on three consecutive days. The dorsum surface of both ears was epidermally treated (25 µl/ear) with the test substance
concentration, at approximately the same time each day.
Five vehicle control animals were similarly treated, but with vehicle alone (N,N-dimethylformamide).
Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised.
After precipitating the DNA of the lymph node cells, radioactivity measurements were done.

Interpretation:
DPM values are presented for each animal and for each dose group. A Stimulation Index (SI) is calculated for each group. The SI is the ratio of the DPM/group compared to DPM/vehicle control group.
lf the results indicate a SI >= 3, the test substance may be regarded as a skin sensitiser, based on the test guideline and recommendations done by ICCVAM (NIH publication; No 99-4494, February 1999).

Observations:
Mortality/Viability: Twice daily.
Toxicity: At least once daily.
Body weights: On days 1 (pre-treatment) and 6.
Irritation: On day 3 (3-4 hours after treatment), the skin reactions were assessed. lf possible, skin reactions were graded according to the following numerical scoring system. Furthermore descriptions of all other (local) effects were recorded.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Positive control results:

The SI (stimulation indices) values calculated for HCA (Hexyl cinnamic aldehyde) concentrations of 5 %, 10 % and 25 % were 1.0, 3.2 and 7.1, respectively. An EC3 value of 9.5 % was calculated using linear interpolation.
The calculated EC3 value was found to be in the acceptable range of 2 % to 20 %. The results of the 6 monthly reliability checks of the recent years were 8.8, 5.5, 7.3 and 10.3.

Parameter:

SI

Value:

3.9

Test group / Remarks:

2.5%

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: The DPM/animal values for the experimental groups treated with the test substance at concentrations of 2.5 %, 10 % and 25 % were 1054, 2423 and 7022, respectively. The mean DPM/animal value for the vehicle control group was 268.

Parameter:

SI

Value:

9

Test group / Remarks:

10%

Parameter:

SI

Value:

26.2

Test group / Remarks:

25%

This data showed a dose response and the EC3 value was considered to be below 2.5 %.

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

The sizes of the nodes increased with increasing dose levels. No other macroscopic abnormalities of the nodes were noted.

Table: Skin reactions after 3rd induction, body weight and relative size nodes (+ = enlarged; n = considered to be normal):

group	Day 1	Day 3				Day 6
	bw	skin grading dorsal surface ear				bw	size nodes
	(g)	left		right		(g)	left	right
		erythema	oedema	erythema	oedema
Vehicle control	25	0	0	0k	0	24	n	n
	23	0	0	0	0	24	n	n
	24	0k	0	0	0	25	n	n
	23	0	0	0	0	24	n	n
	22	0	0	0	0	24	n	n
2.5 % test substance	24	0	0	0	0	26	n	n
	23	0	0	0	0	24	n	n
	25	0	0	0	0	24	n	n
	21	0	0	0k	0	22	n	n
	21	0	0	0	0	23	n	n
10 % test substance	24	0	0	0	0	25	n	n
	19	0	0	0	0	20	+	+
	22	0	0	0	0	20	+	+
	24	0s	0	0	0	22	n	n
	25	0	0	0	0	26	++	++
25 % test substance	22	0	0	0	0	22	++	++
	24	0k	0	0k	0	23	++	++
	22	0	0	0	0	21	++	++
	24	0	0	0	0	23	++	++
	24	0	0	0	0	23	++	++

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

Based on these results and according to the recommendations made in the test guidelines (OECD No.429, EC B.42 and EPA OPPTS 870.2600), lithium bis(oxalato)borate should be regarded as a skin sensitiser.

Executive summary:

A local lymph node assay was conducted with lithium bis(oxalato)borate according to OECD guideline 429 and EU method B.42. In the main study, three groups of five mice were epidermally exposed to the test substance at concentrations of 2.5 %, 10 % and 25 %, respectively on three consecutive days. Five vehicle control mice were similarly treated, but with vehicle alone (N,N-dimethylformamide). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised. After precipitating the DNA of the lymph node cells, radioactivity measurements were done. The sizes of the nodes increased with increasing dose levels. No other macroscopic abnormalities of the nodes were noted. Mean DPM/animal values for the experimental groups treated with test substance concentrations of 2.5 %, 10 % and 25 % were 1054, 2423 and 7022, respectively. The mean DPM/animal value for the vehicle control group was 268. The SI values calculated for the substance concentrations of 2.5 %, 10 % and 25 % were 3.9, 9.0 and 26.2, respectively. This data showed a dose-response and the EC3 value was considered to be below 2.5 %. Based on these results lithium bis(oxalato)borate should be regarded as a skin sensitiser. (NOTOX, 2004)

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

A local lymph node assay was conducted with lithium bis(oxalato)borate according to OECD guideline 429 and EU method B.42. In the main study, three groups of five mice were epidermally exposed to a 2.5 %, 10 % and 25 % concentration respectively on three consecutive days. Five vehicle control mice were similarly treated, but with vehicle alone (N,N-dimethylformamide). Three days after the last exposure, all animals were injected with 3H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised. After precipitating the DNA of the lymph node cells, radioactivity measurements were done. The sizes on the nodes increased with increasing dose levels. No other macroscopic abnormalities of the nodes were noted. Mean DPM/animal values for the experimental groups treated with test substance concentrations 2.5, 10 and 25 % were 1054, 2423 and 7022 respectively. The mean DPM/animal value for the vehicle control group was 268. The SI (stimulation index) values calculated for the substance concentrations 2.5 %, 10 % and 25 % were 3.9, 9.0 and 26.2, respectively. This data showed a dose-response and the EC3 value was considered to be below 2.5 %. Based on these results lithium bis(oxalato)borate should be regarded as a skin sensitiser. (NOTOX, 2004)

Short description of key information:
Based on these results and according to the recommendations made in the test guidelines (OECD No.429, EC B.42 and EPA OPPTS 870.2600), lithium bis(oxalato)borate should be regarded as a skin sensitiser.

Justification for selection of skin sensitisation endpoint:
GLP and guideline compliant study.

Justification for classification or non-classification

Based on the available data on sensitisation LiBOB should be classified and labelled as sensitising to the skin (R43) according to Directive 67/548/EEC (DSD) and as may cause an allergic skin reaction (H317), category 1 according to Regulation (EC) No 1272/2008 (CLP).