Reaction products of sodium glucoheptonate with zinc sulfate and sodium hydroxide

Endpoint summary

Description of key information

Skin sensitisation

To address the endpoint skin sensitization, read-across on gluconates and derivatives and zinc compounds was performed within the frame of a weight-of-evidence approach.The underlying hypothesis for the read-across is that glucoheptonates and gluconates, structurally similar sugar-like carbohydrate metal-complexes, share the same metabolism pathways in mammals (they are oxidized by pentose phosphate pathway) and that their possible toxicity is a function of the metal cation rather than of the gluconate or glucoheptonate anion.

Overall, according to the CLP criteria, the registered substance does not meet criteria for classification and labelling as skin sensitizer according to the Regulation (EC) No 1272/2008.

local lymph node assay (LLNA) in mice (zinc sulfate)

In a dermal sensitization study with zinc sulphate heptahydrate in 20% ethanol solution, 6-8 week old female Balb/c mice (three animals / dose) were tested in the murine local lymph node assay (Ikarashi et al., 1992). The test substance was applied on three consecutive days on the dorsum of each ear, local lymph nodes were isolated on fourth day after application. Isolated cells were cultivated with [3H]methyl thymidine ([3H]TdR) and [3H]TdR incorporation was measured with a scintillation counter. The stimulation index (SI) for ZnSO4 was determined to be 1.41 (SI < 2), showing no significant increase in lymphocyte proliferation compared to vehicle alone. In this study, ZnSO4 is not a dermal sensitizer. This study is considered to be reliable and to fulfill general scientific requirements.

In another study zinc sulphate was also negative in LLNA (Basketter et al. 1999)

Due to the fact that the Zn ion is the toxicological relevant moiety of zinc glucoheptonate, the target substance zinc glucoheptonate is expected to be also negative in LLNA.

opinion on disaccharides (CIR, 2014)

Structurally similar to glucoheptonate moiety, gluconic acid and its derivatives are not skin sensitisers and are used in a variety of food, cosmetic and consumer products (SIDS, 2004, CIR, 2014; Regulation (EC) No 1925/2006). "The Panel acknowledged that sucrose and glucose are used in cosmetics at relatively high concentrations, and that data from irritation and sensitization studies at maximum use concentrations of these ingredients (i.e. calcium gluconate or gluconic acid) are lacking; however, based on the clinical experience of the Panel, there is little concern that these ingredients are irritants or sensitizers".

Based on these pieces of evidence, zinc glucoheptonate is considered to be not skin sensitizing.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable well-documented peer-reviewed reports.

Qualifier:

no guideline available

Principles of method if other than guideline:

Summary of sensitization study results (non-human and human) conducted with monosaccharides, disaccharides, and related Ingredients as used in cosmetics.

GLP compliance:

not specified

Type of study:

patch test

Justification for non-LLNA method:

The REACH Regulation, Annex VII, paragraph 8.3 states "The Murine Local Lymph Node Assay (LLNA) is the first-choice method for in vivo testing. Only in exceptional circumstances should another test be used. Justification for the use of another test shall be provided." These non-human and human sensitisation study results are already available and their use is considered in the view of its relevance for the toxicological evaluation of iron glucoheptonate.

Reading:

other: Mono- and disaccharides did not produce hypersensitivity skin reactions when tested in animals and In human repeated insult patch tests (HRIPTs).

Remarks on result:

other: Reading: other: Mono- and disaccharides did not produce hypersensitivity skin reactions when tested in animals and In human repeated insult patch tests (HRIPTs)..

A face and neck formulation containing 2.48% lactose did not produce irritation or hypersensitivity in a 4-wk safety-in use ophthalmological evaluation. Thirty-one subjects participated in the study.

In non-human studies, a 50% aq. solution of gluconic acid was not a dermal irritant and lactitol was not an irritant or sensitizer in rabbits. In human repeated insult patch tests (HRIPTs), formulations containing 10% rhamnose, up to 8% glucose, 5% mannose, 2.48% lactose, and less than 1% isomalt, kefiran, lactitol, sucralose, and xylobiose were not irritants or sensitizers. A formulation containing 10% rhamnose did induce a significant irritation reaction in one subject, and irritation was observed in 16% of the subjects during induction in an HRIPT of a rinse-off hair product containing 29% sucrose (tested as a 50% dilution); no sensitization reactions were reported for this product.

Interpretation of results:

not sensitising

Conclusions:

Calcium gluconate and gluconic acid, structurally similar anlogues to glucoheptonates, have been assessed by the Panel as non-sensitizers in cosmetic formulations.

Executive summary:

"The Panel acknowledged that sucrose and glucose are used in cosmetics at relatively high concentrations, and that data from irritation and sensitization studies at maximum use concentrations of these ingredients (i.e. calcium gluconate and gluconic acid) are lacking; however, based on the clinical experience of the Panel, there is little concern that these ingredients are irritants or sensitizers".

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable well documented publication which meets basic scientific principles.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

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

Vehicle:

dimethyl sulphoxide

Concentration:

5.0, 10.0 and 25 %

No. of animals per dose:

4

Positive control substance(s):

other: In these investigations, the LLNA was used to determine the skin sensitization potential of 13 metal salts, 8 of which were considered to possess a significant ability to sensitize man, whereas the remaining 5 were judged to lack such potential.

Statistics:

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 results:

Of the 13 metals considered here, 8 (Au, Be, Co, Cr, Hg, Ni, Pt, and Sn) were judged to possess significant ability to cause ACD. Nickel showed evidence of a positive dose-response trend, but could not be tested at higher application concentrations to determine whether it might reach a threshold positive level. In the LLNA, 7 of these 8 sensitizing metals were identified correctly, with nickel being the only allergen that was missed. At first sight, this might seem to be an important predictive error, because, as mentioned above, nickel is a very frequent cause of ACD in humans.

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

Zinc did not stimulate lymph node cell proliferation at least threefold greater than that observed in concurrent vehicle-treated control and therefore was judged to be negative. Stimulation index (SI) was as follows: 5.0 % : 1.3; 10.0 %: 2.0; 25.0 %: 2.3. With Zn, there was a slight suggestion of a dose-response trend, but even at 25% {ihc highest concentration at which it was possible to test), the stimulation index reached only 2.3, and so it was recorded as negative.

Interpretation of results:

not sensitising

Conclusions:

Zn was not considered to possess, to any significant degree, the ability to cause skin sensitization in humans, and, thus, would not be classified and labeled as sensitizer.

Executive summary:

The LLNA was used to determinethe skin sensitization potential of 13 metal salts. With Zn, there was a slight suggestion of a dose-response trend, but even at 25% (the highest concentration at which it was possible to test), the stimulation index reached only 2.3, and so it was recorded as negative.

In conclusion, among the metals tested, 5 metals evaluated (Al, Cu, Mn, Pb, and Zn) were not considered to possess, to any significant degree, the ability to cause skin sensitization in humans, and, thus, would not be classified and labeled as sensitizers. In the present LLNA, 4 of the 5 were correctly identified, the false positive being Cu.

Reference 3

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Performed similar to guideline EU B.42. only three animals used per dose, only one dose (10% solution) tested, no raw data given. However, given data indicate that test was well performed.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

Only one concentration tested, three instead of four animals used, animals were sacrificed on day 4

Principles of method if other than guideline:

Application of the test substance on three consecutive days on the dorsum of each ear, local lymph node isolation on fourth day after application, cultivation of isolated cells with [3H]methyl thymidine ([3H]TdR), measurement of [3H]TdR incorporation with scintillation counter.

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Japan SLC Inc., Shizuoka, Japan
- Age at study initiation: 6-8 weeks
No further data on test animals is given.

Vehicle:

other: 20% ethanol solution

Concentration:

10%

No. of animals per dose:

3

Details on study design:

RANGE FINDING TESTS:
No details on range finding test are given.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response: Stimulation index > 2 (SI, ratio of incorporated [3H]TdR after treatment with test material to treatment with vehicle only)

TREATMENT PREPARATION AND ADMINISTRATION:
No details on treatment preparation are given.
25 µL of test solution (10 % MnCl2 in 20% ethanol solution) were applied on the dorsum of each ear of three mice. The dorsal surface 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 chemical.

Positive control substance(s):

other: nickel sulphate

Statistics:

Incorporation of [3H]TdR is given as mean cpm +/- standard deviation (SD) per node of three mice per group.

Positive control results:

SI of 2.32

Parameter:

SI

Value:

1.41

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean counts per minute ± SD (x 10E-3): 2.14 ± 0.77

Mean counts per minute (vehicle 20% Ethanol solution): 1.52 x 10E-3 +/- 0.67 x 10E-3

Interpretation of results:

not sensitising

Conclusions:

Although there are some deficiencies in the test conduction, the stimulation index was determined to be 1.41 (mean cpm is even below the mean cpm of the vehicle). Hence, it can be concluded that the provided data is sufficient for classification as "not sensitizing" according to 1272/2008/EC and further testing would not reveal any other contradicting data.

Executive summary:

In a dermal sensitization study with Zinc sulphate heptahydrate in 20% ethanol solution, 6-8 week old female Balb/c mice (three animals / dose) were tested in the murine local lymph node assay. The test substance was applied on three consecutive days on the dorsum of each ear, local lymph nodes were isolated on fourth day after application. Isolated cells were cultivated with [3H]methyl thymidine ([3H]TdR) and [3H]TdR incorporation was measured with a scintillation counter.

The stimulation index (SI) for ZnSO4 was determined to be 1.41 (SI < 2), showing no significant increase in lymphocyte proliferation compared to vehicle alone. In this study, ZnSO4 is not a dermal sensitizer. This study is considered to be reliable and to fulfill general scientific requirements.

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

According to the CLP criteria, the registered substance does not meet criteria for classification and labelling as skin sensitizer according to the Regulation (EC) No 1272/2008.