Copper glycinate sulfate

Endpoint summary

Description of key information

Under consideration of reliable animal study data (LLNA and GPMT) with Cu2+, the target substance copper monoglycinate sulfate is not considered to be a skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across hypothesis is based on transformation of the target and source substances to common compounds (scenario 1 of the RAAF). The target substance copper monoglycinate sulfate and the source substances copper sulfate and copper bisglycinate consist of the Cu2+ cation and the respective anion. The amino acid glycine is constituent of both the target substance copper monoglycinate sulfate and the source substance copper bisglycinate.
It is generally accepted that the Cu2+ cation (as measure for dissolved copper species) is the determining factor for toxicity and ecotoxicity, but not sulfate or glycine.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The target substance copper monoglycinate sulfate is a chelate-complex which consists of the divalent copper ion as centre-ion and glycine as ligand. The remaining sulfate group stabilizes the center ion within the complex.
Copper monoglycinate sulfate and the source substance copper sulfate are ionic and consist of the Cu2+ cation and the respective anions. It is generally accepted that the copper cation is the determining factor for toxicity and ecotoxicity. Therefore, this read-across approach is based on the assumption that the metal cation of both the target and the source substance, copper, is the relevant component for assessment of toxicity and ecotoxicity.
The anion of the target substance is the essential amino acid glycine and the sulfate anion. In the source substance, it is the sulfate anion. These anions are not considered as (eco)toxicologically relevant at the given concentrations.
Please refer to the justification for read-across analogue approach in Chapter 13.2 for more detailed information.
3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the justification for read-across analogue approach in Chapter 13.2 for more detailed information.
4. DATA MATRIX
Please refer to the justification for read-across analogue approach in Chapter 13.2 for more detailed information.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

no

Type of study:

mouse local lymph node assay (LLNA)

Key result

Parameter:

SI

Value:

2.67

Test group / Remarks:

10 % copper sulfate pentahydrate in 20 % ethanol solution

Parameter:

SI

Value:

4.33

Test group / Remarks:

positive control CoCl2

Parameter:

SI

Value:

0

Test group / Remarks:

negative control, 20 % ethanol solution

Parameter:

SI

Value:

3.16

Test group / Remarks:

positive control K2Cr2O7

Interpretation of results:

GHS criteria not met

Conclusions:

Copper monoglycinate sulfate is not considered to be a sensitizer in the LLNA.

Executive summary:

In the study conducted by Ikarashi et al. (1992), copper sulfate pentahydrate was dissolved in 20% ethanol and applied to the dorsal surface of the ear on three consecutive days. After four days after initial application the mice were killed and the draining lymph nodes were dissected and incubated for 18 hours at 37°C in humidified air with [³H]TdR. After the incubation period the [³H]TdR incorporation was detected and the SI was determined. Incubation with 10% CuSO₄ in 20% ethanol resulted in a SI value of 2.67. Thus, under the conditions of the present test, the substance was not considered a sensitizer.

 

In a dermal sensitization study reported by Basketter and Scholes (1992) and Basketter et al. (1999) similar to OECD guideline 429, copper was administered as copper chloride in DMSO and tested with young adult CBA/CA mice (4/group) in an LLNA at concentrations of 1, 2.5 and 5 %. Additionally, besides copper, other metals were investigated in the LLNA which are known dermal sensitizers and these metal salts are therefore considered to be the positive controls. At the concentrations used, the copper salt in dimethyl sulfoxide (DMSO) was extremely irritant, and this was thought to have contributed to relatively high stimulation indices observed (8.1 to 13.6). Copper was identified a true false positive in this study as reviewed by Basketter et al. (1999). Proliferation of the treated lymph nodes was in no concentration increased to over 3-fold of that of the vehicle control lymph nodes. Thus, copper was identified in Basketter et al. (1999) as a false positive, but not a dermal sensitizer.

 

No data are available regarding the skin sensitizing potential of glycine. Beside the QSAR prediction of skin sensitization using the VEGA-Module data was also gathered from the OECD QSAR Toolbox. The QSAR Toolbox revealed two identical entries exhibiting the same result from a test conducted accoding to OECD guideline 429 (LLNA). In both cases glycine was not classified as skin sensitizer because there was no SI value above 3 in the mentioned study reports, thus, glycine is not considered to be a skin sensitizer.

 

Under consideration of reliable data from adequate source substances, the target substance copper monoglycinate sulfate is not considered to be a sensitiser in the LLNA.

 

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across hypothesis is based on transformation of the target and source substances to common compounds (scenario 1 of the RAAF). The target substance copper monoglycinate sulfate and the source substances copper sulfate and copper bisglycinate consist of the Cu2+ cation and the respective anion. The amino acid glycine is constituent of both the target substance copper monoglycinate sulfate and the source substance copper bisglycinate.
It is generally accepted that the Cu2+ cation (as measure for dissolved copper species) is the determining factor for toxicity and ecotoxicity, but not sulfate or glycine.
2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The target substance copper monoglycinate sulfate is a chelate-complex which consists of the divalent copper ion as centre-ion and glycine as ligand. The remaining sulfate group stabilizes the center ion within the complex.
Copper monoglycinate sulfate and the source substance copper sulfate are ionic and consist of the Cu2+ cation and the respective anions. It is generally accepted that the copper cation is the determining factor for toxicity and ecotoxicity. Therefore, this read-across approach is based on the assumption that the metal cation of both the target and the source substance, copper, is the relevant component for assessment of toxicity and ecotoxicity.
The anion of the target substance is the essential amino acid glycine and the sulfate anion. In the source substance, it is the sulfate anion. These anions are not considered as (eco)toxicologically relevant at the given concentrations.
Please refer to the justification for read-across analogue approach in Chapter 13.2 for more detailed information.
3. ANALOGUE APPROACH JUSTIFICATION
Please refer to the justification for read-across analogue approach in Chapter 13.2 for more detailed information.
4. DATA MATRIX
Please refer to the justification for read-across analogue approach in Chapter 13.2 for more detailed information.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Type of study:

guinea pig maximisation test

Species:

guinea pig

Route:

intradermal

Vehicle:

petrolatum

Concentration / amount:

0.1, 0.05, 0.01%

Adequacy of induction:

not specified

Route:

other: epicutaneous

Vehicle:

petrolatum

Concentration / amount:

25%

Day(s)/duration:

20

Adequacy of induction:

not specified

No.:

#1

Route:

other: not specified

Vehicle:

petrolatum

Concentration / amount:

0.1% copper sulphate

Adequacy of challenge:

not specified

No.:

#2

Route:

other: not specified

Vehicle:

petrolatum

Concentration / amount:

0.5, 0.25, 0.05% nickel sulphate

Adequacy of challenge:

not specified

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.1% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no exact values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.1% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.1% i.c., 25% e.c.; Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

The maximum number of reactions was one animal per challenge concentration. For further information please refer to the 'any other information on results incl. tables' section.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.1% i.c., 25% e.c.; Challenge 1, 0.5, 0.1 %

Remarks on result:

other: No values were reported

Remarks:

No positive control results were reported

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.05% i.c. 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.05% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.05% i.c., 25% e.c.; Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

The maximum number of reactions was one animal per challenge concentration. For further information please refer to the 'any other information on results incl. tables' section.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.05% i.c., 25% e.c., Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

No positive control results were reported

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.01& i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control (challenge with nickel sulphate)

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.01% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control (challenge with nickel sulphate)

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.01% i.c., 25% e.c.; Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

The maximum number of reactions was one animal per challenge concentration. For further information please refer to the 'any other information on results incl. tables' section.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.01% i.c., 25% e.c., Challenge 1, 0.5, 0.1%

Remarks on result:

other: No valures were reported

Remarks:

No positive control results were reported

Interpretation of results:

GHS criteria not met

Conclusions:

Copper monoglycinate sulfate is not considered to be a sensitizer in the GPMT.

Executive summary:

In the publication by Karlberg et al., 1983, a guinea pig-maximization test (GPMT) was conducted. Studies with varying concentrations of copper sulphate at intradermal induction (0.1%, 0.05% and 0.01%), were carried out. 20 animals per dose were used. At epicutaneous induction 25 % of copper sulphate salt in petrolatum was used in all series. Challenge testing was performed on day 21 with 1.0, 0.5 and 0.1% of the salt in petrolatum. The animals exposed to 0.1% copper sulphate at intradermal induction were also challenged with nickel sulphate at  0.5, 0.25 and 0.05% in petrolatum. Parameters as described for the GPMT test were analysed. No significant differences were detected between the control animals and the treated animals with regard to the parameters analysed in the guinea pig maximization test. Based on the presented results, copper sulphate is not considered to be a sensitizer.

 

In the publication by Basketter and Scholes, 1992, a test was conducted according to Magnussen & Kligman (1970). Guinea pigs were treated intradermally and epicutaneously with copper chloride at concentrations of 0.0001% (i.c.), 0.1% (e.c.) and challenged with 0.25% copper chloride. The guinea-pigs were treated with a series of six intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48-hr occluded patch placed over the injection site. 12-14 days later, the animals were challenged on one flank by a 24-hr occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema (scale 0-3) and oedema 24 and 48 hr after removal of the patches. The classification scheme for the assessment of skin sensitization potential was based on that outlined by Magnusson and Kligman (1970). None of the treated animals showed a response to copper chloride, thus copper was not considered to be a sensitizer in guinea pigs.

 

The EU Risk Assessment on COPPER, COPPER II SULPHATE PENTAHYDRATE, COPPER(I)OXIDE, COPPER(II)OXIDE and DICOPPER CHLORIDE TRIHYDROXIDE (2008) reports a GPMT guideline study (Mercier, 1994). Induction involved intradermal injection of test substance (0.1% in water) on day 0, a concentration which produced weak to moderate irritation in the sighting study.  This was followed by topical application of test substance (10% in water) on day 7 for 48 hours.  Sodium lauryl sulphate (10%) was also applied at topical induction, prior to the test substance, as the test substance alone at a concentration of 10% failed to provoke signs of irritation in the sighting study. The skin response at topical induction in the main study was not reported. After an 11-day treatment-free period, animals were challenged by topical application of the test substance (10% in water) under an occlusive dressing for 24 hours.  Skin response was assessed in animals (20 treated and 9 controls) at 24 and 48 hours after challenge.  Slight erythema was observed in one treated animals at 24 hours, but not at 48 hours.  No skin reactions occurred other treated animals or in controls at either time-point. In conclusion, copper sulphate pentahydrate produced a 0% sensitisation rate under the conditions of this test and is therefore considered to have no skin sensitising potential in guinea pigs. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification. In terms of the other copper compounds tested (copper(I)oxide, copper(II)oxide, copper oxychloride and copper powder), available animal data indicate that these do not meet the criteria to be classified for skin sensitisation.

 

The test described in the abstract of Boman et al., 1979, was conducted according to Magnusson & Kligman (1970). Groups of 10 guinea pigs were treated intradermally and epicutaneously with 0.01% and 25%, respectively. 21 days after the intradermal application the animals were challenged with 1.0, 0.5, and 0.1% copper sulphate solution in petrolatum. After 24 h (first reading) 2 animals were scored positive for sensitisation and after 48h 7 animals were scored positive for skin sensitisation, thus, copper sulphate was regarded positive with respect to skin sensitisation. Only an abstract is provided. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification.

 

No data are available regarding the skin sensitizing potential of glycine. Beside the QSAR prediction of skin sensitization using the VEGA-Module data was also gathered from the OECD QSAR Toolbox. The QSAR Toolbox revealed two identical entries exhibiting the same result from a test conducted accoding to OECD guideline 429 (LLNA). In both cases glycine was not classified as skin sensitizer because there was no SI value above 3 in the mentioned study reports, thus, glycine is not considered to be a skin sensitizer.

 

Under consideration of reliable data from adequate source substances, the target substance copper monoglycinate sulfate is not considered to be a sensitiser in the GPMT.

Reference 3

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

no

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

Source: Wako Pure Chemical Industries, Ltd., Osaka, Japan.

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Females (if applicable) nulliparous and non-pregnant: not specified
- Age at study initiation: 6-8 weeks

Vehicle:

other: ethanol (20 %)

Concentration:

10%

No. of animals per dose:

3

Details on study design:

TREATMENT PREPARATION AND ADMINISTRATION:
The mice (n = 3) received 25 µL of test chemical solution, or vehicle alone, on the dorsum of each ear. The application was repeated for three consecutive days. In some experiments, the dorsal surface of each ear was gently abraded by lightly dragging a 19-g needle across the dorsal surface of each ear five times (without causing bleeding) just prior to the application of test chemicals. Four days following the initial application, mice were killed and the draining lymph nodes (auricular and axillary) were excised and pooled per animal. A single cell suspension of LNC was prepared by mechanical disaggregation through sterile 200-mesh steel gauge. Lymphocyte suspensions were washed twice in phosphate-buffered saline (PBS) and resuspended in RPMI-1640 culture medium supplemented with 10% fetal calf serum (FCS), 25 mM N-2-hydroxyethylpiperazine-N’-2-ethanesulfonic acid (Hepes), 100 µg/ml penicillin and 100 U/ml streptomycin. The cell concentration was adjusted to give 5 E+06 cells/mL.. Lymphocyte suspensions were seeded into 96-well microtiter plates at a concentration of 1 E+06 cells/well (5 wells per animal), and cultured with 0.5 µCi [3H]methyl thymidine ([3H]TdR) for 18 h at 37°C in a humidified atmosphere of 5% CO2 in air.
Culture was terminated by automatic cell harvesting. The incorporation of [3H]TdR was measured using a liquid scintillation counter and expressed as mean counts per min (cpm) ± standard deviation per node of three animals for each test group. Increases in [3H]TdR incorporation relative to vehicle-treated controls were calculated for each test group, and expressed as stimulation indices (SI).

Positive control substance(s):

other:

Positive control results:

The SI values observed with CoCl2 and K2Cr2O7 were 4.3 and 3.1, respectively.

Key result

Parameter:

SI

Value:

2.67

Test group / Remarks:

10 % copper sulfate pentahydrate in 20 % ethanol solution

Parameter:

SI

Value:

4.33

Test group / Remarks:

positive control CoCl2

Parameter:

SI

Value:

0

Test group / Remarks:

negative control, 20 % ethanol solution

Parameter:

SI

Value:

3.16

Test group / Remarks:

positive control K2Cr2O7

Cellular proliferation data / Observations:

In the present study only the results from one treatment group were reported.

THE LOCAL LYMPH NODE ASSAY PERFORMED WITH FIVE METAL SALTS

Chemical	[3H]TdR incorporation (mean cpm±SD (x 10^-3)	SI
20% EtOH	1.52± 0.67	-
10% FeSO4	2.03±0.63	1.32
10% MnCl2	1.26±0.08	0.82
10% ZnSO4	2.14±0.77	1.41
10% CuSO4	4.08±1.20	2.67
10% NiSO4	3.56±0.25	2.32

Interpretation of results:

GHS criteria not met

Conclusions:

In the present study conducted by Ikarashi et al. (1992), copper sulfate pentahydrate is not considered to be a sensitizer in the LLNA.

Executive summary:

In the present study conducted by Ikarashi et al. (1992), copper sulfate pentahydrate was dissolved in 20% ethanol and applied to the dorsal surface of the ear on three consecutive days. After four days after initial application the mice were killed and the draining lymph nodes were dissected and incubated for 18 hours at 37°C in humidified air with [³H]TdR. After the incubation period the [³H]TdR incorporation was detected and the SI was determined.

Incubation with 10% CuSO₄ in 20% ethanol resulted in a SI value of 2.67. Thus, under the conditions of the present test, the substance was not considered a sensitizer.

Reference 4

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

adopted 22 July, 2010

Principles of method if other than guideline:

- Principle of test:
Test conducted similar to OECD guideline 429
- Short description of test conditions:
Groups of 4 CBAKa mice were treated with 25 µL of test material, or with an equal volume of the vehicle alone, on the dorsum of both ears. Treatment was performed once daily for 3 consecutive days. Five days after the initiation of exposure, all mice were injected by the tail vein with 250 µL of phosphate buffered saline (PBS) containing 20 µCi of tritiated thymidine. Mice were killed 5 hours later and the draining lymph nodes excised and pooled for each experimental group. A single-cell suspension of lymph node cells was prepared by mechanical disaggregation. The lymph node cell suspension was washed twice in an excess of PBS and then precipitated with 5% trichloroacetic acid (TCA) at 4°C for 18 hours. Pellets were resuspended in TCA and the incorporation of tritiated thymidine measured by β-scintillation counting.
- Parameters analysed / observed: cell proliferation measured by incorporation of tritiated thymidine

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

Source: Aldrich, Gillingham, United Kingdom.
Purity: >99 %

Species:

mouse

Strain:

CBA/Ca

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Olac, Bicester, United Kingdom)
- Age at study initiation: 7- 12 weeks
- Housing: in groups of four animals

Vehicle:

dimethyl sulphoxide

Concentration:

1, 2.5, 5 %

No. of animals per dose:

4

Details on study design:

MAIN STUDY

Groups of 4 CBA/Ca mice were treated with 25 µL of test material, or with an equal volume of the vehicle alone, on the dorsum of both ears. Treatment was performed once daily for 3 consecutive days. Five days after the initiation of exposure, all mice were injected by the tail vein with 250 µL of phosphate buffered saline (PBS) containing 20 µCi of tritiated thymidine (2 Ci mmol/L; Amersham International, Amersham, UK). Mice were killed 5 hours later and the draining lymph nodes excised and pooled for each experimental group. A single-cell suspension of lymph node cells was prepared by mechanical disaggregation. The lymph node cell suspension was washed twice in an excess of PBS and then precipitated with 5% trichloroacetic acid (TCA) at 4°C for 18 hours. Pellets were resuspended in TCA and the incorporation of tritiated thymidine measured by B-scintillation counting.

- Criteria used to consider a positive response:
A substance was regarded as a skin sensitizer if, at any test concentration, the proliferation in treated lymph nodes was threefold or greater than that in the concurrent vehicle treated controls.

Positive control substance(s):

other: see 'Remarks'

Statistics:

Not reported

Positive control results:

Treatment with mercury and cobalt resulted in a SI value of over 3 at least in two of three concentrations and were thus considered as dermal sensitisers.

Key result

Parameter:

SI

Test group / Remarks:

at 1 % copper chloride

Remarks on result:

other: copper was identified as a false positive in the LLNA.

Key result

Parameter:

SI

Test group / Remarks:

at 2.5 % copper chloride

Remarks on result:

other: copper was identified as a false positive in the LLNA.

Key result

Parameter:

SI

Test group / Remarks:

at 5 % copper chloride

Remarks on result:

other: copper was identified as a false positive in the LLNA.

Cellular proliferation data / Observations:

CLINICAL OBSERVATIONS: the copper salt tested caused substantial local adverse effects, with necrosis at the higher test concentrations.

At the concentrations used, the copper salt in dimethyl sulfoxide (DMSO) was extremely irritant, and this may have contributed to relatively high stimulation indices observed. Cu is a true false positive as the stimulation indices obtained are higher than seen with the significant skin irritant, sodium dodecyl sulfate, which at most are typically in the range of 4 to 5.

Interpretation of results:

GHS criteria not met

Conclusions:

In this study similar to OECD guideline 429 (LLNA), copper was identified as a false positive in the LLNA and is not considered to be a dermal sensitiser.

Executive summary:

In a dermal sensitization study reported by Basketter and Scholes (1992) and Basketter et al. (1999) similar to OECD guideline 429, copper was administered as copper chloride in DMSO and tested with young adult CBA/CA mice (4/group) in an LLNA at concentrations of 1, 2.5 and 5 %. Additionally, besides copper, other metals were investigated in the LLNA which are known dermal sensitizers and these metal salts are therefore considered to be the positive controls.

At the concentrations used, the copper salt in dimethyl sulfoxide (DMSO) was extremely irritant, and this was thought to have contributed to relatively high stimulation indices observed (8.1 to 13.6). Copper was identified a true false positive in this study as reviewed by Basketter et al. (1999).

Proliferation of the treated lymph nodes was in no concentration increased to over 3-fold of that of the vehicle control lymph nodes. Thus, copper was identified in Basketter et al. (1999) as a false positive, but not a dermal sensitizer and does not need to be classified as dermal sensitizer according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemicals (GHS).

Reference 5

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: A guinea pig-maximization test (GMPT) was conducted.
- Short description of test conditions: 3 studies with varying concentrations of copper sulphate at intradermal induction (0.1%, 0.05% and 0.01%), were carried out. At epicutaneous induction 25 % of copper sulphate salt in petrolatum was used in all series. Challenge testing was performed on day 21 with 1.0, 0.5 and 0.1% of the salt in pet. The animals exposed to 0.1% copper sulphate at intradermal induction were also challenged with nickel sulphate at 0.5, 0.25 and 0.05% in pet.
- Parameters analysed / observed: Parameters as described for the GMPT test were analsysed.

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A GPMT is available, which is considered reliable with restrictions as an adequate supporting information for classification and labelling purposes. Futhermore several other studies are available which are considered in a Weight of Evidence approach. For this reason and for reasons of animal welfare no additional LLNA was conducted.

Species:

guinea pig

Strain:

not specified

Sex:

not specified

Details on test animals and environmental conditions:

Further details on test animals and environmental conditions were not reported

Route:

intradermal

Vehicle:

petrolatum

Concentration / amount:

0.1, 0.05, 0.01%

Adequacy of induction:

not specified

Route:

other: epicutaneous

Vehicle:

petrolatum

Concentration / amount:

25%

Day(s)/duration:

20

Adequacy of induction:

not specified

No.:

#1

Route:

other: not specified

Vehicle:

petrolatum

Concentration / amount:

0.1% copper sulphate

Adequacy of challenge:

not specified

No.:

#2

Route:

other: not specified

Vehicle:

petrolatum

Concentration / amount:

0.5, 0.25, 0.05% nickel sulphate

Adequacy of challenge:

not specified

No. of animals per dose:

20

Details on study design:

Details on study design were not reported

Positive control substance(s):

not specified

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.1% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no exact values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.1% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.1% i.c., 25% e.c.; Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

The maximum number of reactions was one animal per challenge concentration. For further information please refer to the 'any other information on results incl. tables' section.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.1% i.c., 25% e.c.; Challenge 1, 0.5, 0.1 %

Remarks on result:

other: No values were reported

Remarks:

No positive control results were reported

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.05% i.c. 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.05% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.05% i.c., 25% e.c.; Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

The maximum number of reactions was one animal per challenge concentration. For further information please refer to the 'any other information on results incl. tables' section.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.05% i.c., 25% e.c., Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

No positive control results were reported

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.01& i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control (challenge with nickel sulphate)

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.01% i.c., 25% e.c.

Remarks on result:

other: treatment not significant different from control (challenge with nickel sulphate)

Remarks:

no values have been reported, instead any significant difference was reported

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.01% i.c., 25% e.c.; Challenge 1, 0.5, 0.1%

Remarks on result:

other: No values were reported

Remarks:

The maximum number of reactions was one animal per challenge concentration. For further information please refer to the 'any other information on results incl. tables' section.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

0.01% i.c., 25% e.c., Challenge 1, 0.5, 0.1%

Remarks on result:

other: No valures were reported

Remarks:

No positive control results were reported

Sensitization and testing of guinea pigs according to GPMT:

Induction	CuSO4 x 5 H2O	time (h)
i.c.	0.1%
e.c.	25%
Challenge concentration (%w/w)			1	0.5	0.1	Control (pet.)
Controls		24	0	1	1	1
n=18		48	1	1	0	1
Exposed n=19		24 & 48	0	0	0	0
		24	-	N.S.	N.S.	N.S.
		48	N.S.	N.S.	-	N.S.

- not analyzed; N.S. not significant.

Induction	CuSO4 x 5 H2O	time (h)
i.c.	0.05%
e.c.	25%
Challenge concentration (%w/w)			1	0.5	0.1	Control (pet.)
Controls		24	0	0	0	0
n=20		48	1	1	2	1
Exposed n=19		24	0	0	0	0
		48	1	0	0	0
		24	-	-	-	-
		48	-	N.S.	N.S.	N.S.

- not analyzed; N.S. not significant.

Induction	CuSO4 x 5 H2O	time (h)
i.c.	0.01%
e.c.	25%
Challenge concentration (%w/w)			1	0.5	0.1	Control (pet.)
Controls		24 & 48	0	0	0	0
n=20
Exposed n=19		24 & 48	0	0	0	0

Interpretation of results:

GHS criteria not met

Conclusions:

In a guinea pig maximization test animals were intradermally treated with 0.1%, 0.05% and 0.01% copper sulphate and epicutaneously with 25% copper sulphate. The animals were challenged at day 21 after treatment with either nickel sulphate (0.5, 0.25, 0.05%) or copper sulphate (1.0, 0.5, 0.1%). All treatments were conducted in petrolatum. No significant differences were detected between the control animals and the treated animals with regard to the parameters analysed in the guinea pig maximization test. Based on the presented results copper sulphate is not considered to be a sensitizer.

Executive summary:

In the publication by Karlberg et al., 1983, a guinea pig-maximization test (GMPT) was conducted. Studies with varying concentrations of copper sulphate at intradermal induction (0.1%, 0.05% and 0.01%), were carried out. 20 animals per dose were used. At epicutaneous induction 25 % of copper sulphate salt in petrolatum was used in all series. Challenge testing was performed on day 21 with 1.0, 0.5 and 0.1% of the salt in petrolatum. The animals exposed to 0.1% copper sulphate at intradermal induction were also challenged with nickel sulphate at  0.5, 0.25 and 0.05% in petrolatum. Parameters as described for the GMPT test were analysed.

No significant differences were detected between the control animals and the treated animals with regard to the parameters analysed in the guinea pig maximization test. Based on the presented results, copper sulphate is not considered to be a sensitizer.

Reference 6

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test:
The test method carried out is based on and similar to that described by Magnusson and Kligman (1970).
- Short description of test conditions: Guinea-pigs were then treated by a series of six intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48-hr occluded patch placed over the injection site. 12-14 days later, the animals were challenged on one flank by a 24-hr occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema (scale 0-3) and oedema 24 and 48 hr after removal of the patches.
- Parameters analysed / observed: The classification scheme for the assessment of skin sensitization potential was based on that outlined by Magnusson and Kligman (1970).

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The results published were obtained from a GMPT test according to Magnussen & Klingman (1970). Although GLP compliance was not reported the method is considered to be reliable and the results are expected to provide useful information about the sensitizing potential of copper.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

not specified

Details on test animals and environmental conditions:

animals weighed approximately 350 g, other details on test animals and environmental conditions were not reported

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

0.0001%

Day(s)/duration:

6-8

Adequacy of induction:

other: six intradermal injections in the shoulder region to induce sensitisation

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

1.0%

Day(s)/duration:

2

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

0.25%

Day(s)/duration:

after 12-14 days

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

not reported

Details on study design:

not reported

Challenge controls:

not reported

Positive control results:

not reported

Key result

Reading:

other: reading time points not reported

Group:

test chemical

Dose level:

0.0001%

No. with + reactions:

0

Remarks on result:

other: only the final result was reported

Remarks:

No time points for reading nor exact values were reported

Key result

Reading:

other: No time points for reading were reported

Group:

negative control

Remarks on result:

other: results of negative control were not reported

Key result

Reading:

other: No time points for reading were reported

Group:

positive control

Remarks on result:

other: No results of a positive control were reported

Interpretation of results:

GHS criteria not met

Conclusions:

In the present test conducted according to Magnussen & Kligman (1970), guinea pigs were treated intradermally and epicutaneously with copper chloride at concentrations of 0.0001% (i.c.), 0.1% (e.c.) and challenged with 0.25% copper chloride. None of the treated animals showed a response, thus copper was not considered to be a sensitizer.

Executive summary:

In the publication by Basketter and Scholes, 1992, a test was conducted according to Magnussen & Kligman (1970). Guinea pigs were treated intradermally and epicutaneously with copper chloride at concentrations of 0.0001% (i.c.), 0.1% (e.c.) and challenged with 0.25% copper chloride. The guinea-pigs were treated with a series of six intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48-hr occluded patch placed over the injection site. 12-14 days later, the animals were challenged on one flank by a 24-hr occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema (scale 0-3) and oedema 24 and 48 hr after removal of the patches. The classification scheme for the assessment of skin sensitization potential was based on that outlined by Magnusson and Kligman (1970).

None of the treated animals showed a response to copper chloride, thus copper was not considered to be a sensitizer.

Reference 7

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

other: reported in the European Union Risk Assessment Report (2008) on copper and copper compounds.

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

not provided

Route:

intradermal

Vehicle:

water

Concentration / amount:

0.1%

Day(s)/duration:

7

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

10 %

Day(s)/duration:

1

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

20 treated, 9 controls

Details on study design:

A. INDUCTION EXPOSURE
- No. of exposures: 1
- Site: not reported
- Frequency of applications: 1
- Duration: 7
- Concentrations: 0, 10 %

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 1
- Site: not reported
- Concentrations: 10 %
- Evaluation (hr after challenge): 24, 48

Positive control substance(s):

not specified

Positive control results:

not specified

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

9

Clinical observations:

none

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 %

No. with + reactions:

1

Total no. in group:

20

Clinical observations:

slight erythema

Copper sulphate pentahydrate failed to induce skin sensitisation in a GPMT (Mercier 1994 a– unpublished).  Concentrations of test substance selected for induction and challenge were based on results of a sighting study.  Induction involved intradermal injection of test substance (0.1% in water) on day 0, a concentration which produced weak to moderate irritation in the sighting study.  This was followed by topical application of test substance (10% in water) on day 7 for 48 hours.  Sodium lauryl sulphate (10%) was also applied at topical induction, prior to the test substance, as the test substance alone at a concentration of 10% failed to provoke signs of irritation in the sighting study. The skin response at topical induction in the main study was not reported. After an 11-day treatment-free period, animals were challenged by topical application of the test substance (10% in water) under an occlusive dressing for 24 hours.  Skin response was assessed in animals (20 treated and 9 controls) at 24 and 48 hours after challenge.  Slight erythema was observed in one treated animals at 24 hours, but not at 48 hours.  No skin reactions occurred other treated animals or in controls at either time-point.  In conclusion, copper sulphate pentahydrate produced a 0% sensitisation rate under the conditions of this test and is therefore considered to have no skin sensitising potential in guinea pigs. 

Interpretation of results:

study cannot be used for classification

Conclusions:

Copper sulphate pentahydrate produced a 0% sensitisation rate under the conditions of this test and is therefore considered to have no skin sensitising potential in guinea pigs. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification.

Executive summary:

The EU Risk Assessment on COPPER, COPPER II SULPHATE PENTAHYDRATE, COPPER(I)OXIDE, COPPER(II)OXIDE and DICOPPER CHLORIDE TRIHYDROXIDE (2008) reports a GMPT guideline study (Mercier, 1994). Only an abstract is provided. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification.

Induction involved intradermal injection of test substance (0.1% in water) on day 0, a concentration which produced weak to moderate irritation in the sighting study.  This was followed by topical application of test substance (10% in water) on day 7 for 48 hours.  Sodium lauryl sulphate (10%) was also applied at topical induction, prior to the test substance, as the test substance alone at a concentration of 10% failed to provoke signs of irritation in the sighting study. The skin response at topical induction in the main study was not reported. After an 11-day treatment-free period, animals were challenged by topical application of the test substance (10% in water) under an occlusive dressing for 24 hours.  Skin response was assessed in animals (20 treated and 9 controls) at 24 and 48 hours after challenge.  Slight erythema was observed in one treated animals at 24 hours, but not at 48 hours.  No skin reactions occurred other treated animals or in controls at either time-point.

In conclusion, copper sulphate pentahydrate produced a 0% sensitisation rate under the conditions of this test and is therefore considered to have no skin sensitising potential in guinea pigs. 

In terms of the other copper compounds tested (copper(I)oxide, copper(II)oxide, copper oxychloride and copper powder), available animal data indicate that these do not meet the criteria to be classified for skin sensitisation.

The EU VRAR also states that human data on skin sensitisation properties of copper or its compounds are insufficient to require classification for skin sensitisation.

Reference 8

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1979

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

abstract

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Test according to the principle of Magnusson & Kligman 1970.
- Short description of test conditions: Two groups of 20 animals were used for each metal compound. One group was actively sensitiactl and the other group (control was treated in the same way as the experimental group (Freund's complete adjuvant, petrolatum occlusion. etc.) except for the test compound. The groups were kept separately in plastic cages. challenged simultaneously and the readings performed blind.
- Parameters analysed / observed: Number of positive animals (as scored according to Magnusson & Kligman (1970)) for each concentration is given.

GLP compliance:

no

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

not specified

Sex:

not specified

Details on test animals and environmental conditions:

Animals were kept in plastic cages, size was not reported. No further details on test animals and environmental conditions were given.

Route:

intradermal

Vehicle:

petrolatum

Concentration / amount:

0.01%

Adequacy of induction:

other: no information on concentration finding test, duration was also not reported

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Concentration / amount:

25%

Adequacy of induction:

other: no information on concentration finding tests, duration was not reported

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

petrolatum

Concentration / amount:

1.0, 0.5, 0.1%

Adequacy of challenge:

other: no information on concentration finding tests, duration was not reported

No. of animals per dose:

10

Details on study design:

No further details on study design reported

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1% challenge concentration

No. with + reactions:

2

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1% challenge concentration

No. with + reactions:

7

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Interpretation of results:

study cannot be used for classification

Conclusions:

The test described in the abstract of Boman et al., 1979, copper sulphate was regarded positive with respect to skin sensitisation. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification.

Executive summary:

The test described in the abstract of Boman et al., 1979, was conducted according to Magnusson & Kligman (1970). Groups of 10 guinea pigs were treated intradermally and epicutaneously with 0.01% and 25%, respectively. 21 days after the intradermal application the animals were challenged with 1.0, 0.5, and 0.1% copper sulphate solution in petrolatum. After 24 h (first reading) 2 animals were scored positive for sensitisation and after 48h 7 animals were scored positive for skin sensitisation, thus, copper sulphate was regarded positive with respect to skin sensitisation.

Only an abstract is provided. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification.

Reference 9

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
VEGA-QSAR:AI inside a platform for predictive toxicology
2. MODEL (incl. version number)
1.1.5
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
O=C(O)CN
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
For more detailed information please refer to the 'attached justification' section

5. APPLICABILITY DOMAIN
For more detailed information please refer to the 'attached justification' section

6. ADEQUACY OF THE RESULT
For more detailed information please refer to the 'attached justification' section

Qualifier:

no guideline followed

Principles of method if other than guideline:

Result of a QSAR prediction using VEGA-QSAR platform Skin Sensitization model (CAESAR) 2.1.6.

GLP compliance:

no

Justification for non-LLNA method:

No data are available for the source substance glycine, thus, based on a weight of evidence approach i.a. the results of a QSAR prediction were used to determine the skin sensitizing potential of glycine.

Species:

other: not applicable for an in silico system

Strain:

other: not applicable for an in silico system

Details on test animals and environmental conditions:

not applicable for an in silico system

Vehicle:

other: not applicable for an in silico system

Concentration:

not applicable for an in silico system

No. of animals per dose:

not applicable for an in silico system

Details on study design:

not applicable for an in silico system

Key result

Parameter:

other: not applicable for an in silico system

Remarks on result:

no indication of skin sensitisation based on QSAR/QSPR prediction

Interpretation of results:

study cannot be used for classification

Conclusions:

In the present QSAR calculation using VEGA-QSAR platform and its Skin Sensitization model (CAESAR) 2.1.6. the skin sensitizing potential of Glycine was estimated. There are no indications for skin sensitisation by appliying this QSAR prediction method. The results are considered to be reliable because the substance falls in the applicability domain of the used model. Glycine is not a sensitizier according to this prediction.

Executive summary:

No data are available for the soure substance glycine with regard to its skin sensitizing potential. Thus, a QSAR prediction with the VEGA module was performed. It predicts the skin sensitizing potential based on atom-centered fragments of a set of structural similar molecules. Based on the evaluation summary contained in the prediction results the QSAR estimation can be regarded as reliable. The accuracy of the prediction for similar structures is considered to be good, the concordance for similar structures is good, the Atom Centered Fragments similarity is good. Thus, there are no inconclusive predictions to be discussed and Glycine is predicted as NOT SENSITIZING TO THE SKIN.

Reference 10

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

other: Information from the QSAR Toolbox database

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

not specified

Sex:

not specified

Details on test animals and environmental conditions:

not specified

Vehicle:

not specified

Key result

Parameter:

EC3

Remarks on result:

other: Value not reported in QSAR Toolbox

Key result

Parameter:

SI

Value:

< 3

Test group / Remarks:

mean of all tested groups

Remarks on result:

other:

Remarks:

Result as reported by the OECD QSAR Toolbox

Interpretation of results:

GHS criteria not met

Conclusions:

The OECD QSAR Toolbox was used in order to gather all available information about the skin sensitizing potential of glycine. The QSAR Toolbox revealed two identical entries exhibiting the same result from a test conducted accoding to OECD guideline 429 (LLNA). Glycine does not meet the classification criteria of Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemcials (GHS) and is therefore no classified as dermal sensitizer.

Executive summary:

No data are available regarding the skin sensitizing potential of glycine. Beside the QSAR prediction of skin sensitization using the VEGA-Module data was also gathered from the OECD QSAR Toolbox. The QSAR Toolbox revealed two identical entries exhibiting the same result from a test conducted accoding to OECD guideline 429 (LLNA). In both cases glycine was niot classified as skin sensitizer because there was no SI value above 3 in the mentioned study reports, thus, glycine is not considered to be a skin sensitizer according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemcials (GHS).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

LLNA

In the study conducted by Ikarashi et al. (1992), copper sulfate pentahydrate was dissolved in 20% ethanol and applied to the dorsal surface of the ear on three consecutive days. After four days after initial application the mice were killed and the draining lymph nodes were dissected and incubated for 18 hours at 37°C in humidified air with [3H]TdR. After the incubation period the [3H]TdR incorporation was detected and the SI was determined. Incubation with 10% CuSO4 in 20% ethanol resulted in a SI value of 2.67. Thus, under the conditions of the present test, the substance was not considered a sensitizer.

 

In a dermal sensitization study reported by Basketter and Scholes (1992) and Basketter et al. (1999) similar to OECD guideline 429, copper was administered as copper chloride in DMSO and tested with young adult CBA/CA mice (4/group) in an LLNA at concentrations of 1, 2.5 and 5 %. Additionally, besides copper, other metals were investigated in the LLNA which are known dermal sensitizers and these metal salts are therefore considered to be the positive controls. At the concentrations used, the copper salt in dimethyl sulfoxide (DMSO) was extremely irritant, and this was thought to have contributed to relatively high stimulation indices observed (8.1 to 13.6). Copper was identified a true false positive in this study as reviewed by Basketter et al. (1999). Proliferation of the treated lymph nodes was in no concentration increased to over 3-fold of that of the vehicle control lymph nodes. Thus, copper was identified in Basketter et al. (1999) as a false positive, but not a dermal sensitizer.

 

Under consideration of reliable data from adequate source substances, copper is not considered to be a sensitiser in the LLNA.

 

GPMT

 

In the publication by Karlberg et al., 1983, a guinea pig-maximization test (GPMT) was conducted. Studies with varying concentrations of copper sulphate at intradermal induction (0.1%, 0.05% and 0.01%), were carried out. 20 animals per dose were used. At epicutaneous induction 25 % of copper sulphate salt in petrolatum was used in all series. Challenge testing was performed on day 21 with 1.0, 0.5 and 0.1% of the salt in petrolatum. The animals exposed to 0.1% copper sulphate at intradermal induction were also challenged with nickel sulphate at  0.5, 0.25 and 0.05% in petrolatum. Parameters as described for the GPMT test were analysed. No significant differences were detected between the control animals and the treated animals with regard to the parameters analysed in the guinea pig maximization test. Based on the presented results, copper sulphate is not considered to be a sensitizer.

 

In the publication by Basketter and Scholes, 1992, a test was conducted according to Magnussen & Kligman (1970). Guinea pigs were treated intradermally and epicutaneously with copper chloride at concentrations of 0.0001% (i.c.), 0.1% (e.c.) and challenged with 0.25% copper chloride. The guinea-pigs were treated with a series of six intradermal injections in the shoulder region to induce sensitization. After 6-8 days, sensitization was boosted by a 48-hr occluded patch placed over the injection site. 12-14 days later, the animals were challenged on one flank by a 24-hr occluded patch at the maximum non-irritant concentration. Challenge sites were scored for erythema (scale 0-3) and oedema 24 and 48 hr after removal of the patches. The classification scheme for the assessment of skin sensitization potential was based on that outlined by Magnusson and Kligman (1970). None of the treated animals showed a response to copper chloride, thus copper was not considered to be a sensitizer in guinea pigs.

 

The EU Risk Assessment on COPPER, COPPER II SULPHATE PENTAHYDRATE, COPPER(I)OXIDE, COPPER(II)OXIDE and DICOPPER CHLORIDE TRIHYDROXIDE (2008) reports a GPMT guideline study (Mercier, 1994). Induction involved intradermal injection of test substance (0.1% in water) on day 0, a concentration which produced weak to moderate irritation in the sighting study.  This was followed by topical application of test substance (10% in water) on day 7 for 48 hours.  Sodium lauryl sulphate (10%) was also applied at topical induction, prior to the test substance, as the test substance alone at a concentration of 10% failed to provoke signs of irritation in the sighting study. The skin response at topical induction in the main study was not reported. After an 11-day treatment-free period, animals were challenged by topical application of the test substance (10% in water) under an occlusive dressing for 24 hours.  Skin response was assessed in animals (20 treated and 9 controls) at 24 and 48 hours after challenge.  Slight erythema was observed in one treated animals at 24 hours, but not at 48 hours.  No skin reactions occurred other treated animals or in controls at either time-point. In conclusion, copper sulphate pentahydrate produced a 0% sensitisation rate under the conditions of this test and is therefore considered to have no skin sensitising potential in guinea pigs. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification. In terms of the other copper compounds tested (copper(I)oxide, copper(II)oxide, copper oxychloride and copper powder), available animal data indicate that these do not meet the criteria to be classified for skin sensitisation.

 

The test described in the abstract of Boman et al., 1979, was conducted according to Magnusson & Kligman (1970). Groups of 10 guinea pigs were treated intradermally and epicutaneously with 0.01% and 25%, respectively. 21 days after the intradermal application the animals were challenged with 1.0, 0.5, and 0.1% copper sulphate solution in petrolatum. After 24 h (first reading) 2 animals were scored positive for sensitisation and after 48h 7 animals were scored positive for skin sensitisation, thus, copper sulphate was regarded positive with respect to skin sensitisation. Only an abstract is provided. Due to insufficient documentation, the reliability is not assignable and the study cannot be used for classification.

 

Under consideration of reliable data from adequate source substances, copper is not considered to be a sensitiser in the GPMT.

 

No data are available regarding the skin sensitizing potential of glycine. Beside the QSAR prediction of skin sensitization using the VEGA-Module data was also gathered from the OECD QSAR Toolbox. The QSAR Toolbox revealed two identical entries exhibiting the same result from a test conducted accoding to OECD guideline 429 (LLNA). In both cases glycine was not classified as skin sensitizer because there was no SI value above 3 in the mentioned study reports, thus, glycine is not considered to be a skin sensitizer. 

 

In conclusion, available reliable animal data on copper indicate that copper monoglycinate sulfate is not a skin sensitiser and does therefore not meet the classification criteria of Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemcials (GHS).