Sodium iodide

Endpoint summary

Description of key information

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the skin sensitization potential of the test chemical. Based on the summarized studies,it can be concluded that the testchemical is unable to cause skin sensitization and considered as not sensitizing. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Weight of evidence based on similar chemicals

Justification for type of information:

Weight of evidence based on similar chemicals

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: Weight of evidence based on similar substances

Principles of method if other than guideline:

The weight of evidence report has been prepared based on the WoE-2, WoE-3 and WoE-4 to assess the dermal sensitization potential of test chemical.

GLP compliance:

not specified

Type of study:

other: 1. Patch test 2.Buehler test 3.Guinea pig maximization test

Justification for non-LLNA method:

Currently no LLNA study is available for assessment. The Non-LLNA studies have been carried out as an animal test to predict human sensitization for over a decade and is recommended by international test guidelines such as OECD.

Species:

other: humans and guinea pigs

Strain:

other: 1, 3.not specified 2.Pirbright albino

Sex:

not specified

Details on test animals and environmental conditions:

No data available

Route:

other: 1.epicutaneous, open

Vehicle:

petrolatum

Adequacy of induction:

not specified

Route:

other: 2.epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

4%

Day(s)/duration:

6 hours

Adequacy of induction:

not specified

Route:

other: 3.intradermal and epicutaneous

Vehicle:

other: 0.5% NaCl solution

Concentration / amount:

1st: Induction 5 %, intracutaneous
2nd: Induction 25 % , occlusive epicutaneous

Adequacy of induction:

not specified

No.:

#1

Route:

other: 1.epicutaneous, open

Vehicle:

petrolatum

Adequacy of challenge:

not specified

No.:

#1

Route:

other: 2.epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

1%

Day(s)/duration:

6 hours

Adequacy of challenge:

not specified

No.:

#1

Route:

other: 3.epicutaneous, occlusive

Vehicle:

other: 0.5% NaCl

Concentration / amount:

Challenge 10 %, occlusive epicutaneous

Adequacy of challenge:

not specified

No. of animals per dose:

1.8 patients,
2.Total :46
Preliminary study: 6 animals
Main study
Treated group:30
Control group:10
3.20 guinea pigs

Details on study design:

1.No data available

2.Details on study design
RANGE FINDING TESTS:

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures:3
- Exposure period: 6hr
- Test groups:30
- Control group:10
- Site: 2 x 2 cm cellulose patch to the clipped skin of the left flank.
- Frequency of applications: on day 1,8 and 15
- Duration: 15 days
- Concentrations: 4%

B. CHALLENGE EXPOSURE
- No. of exposures:1
- Day(s) of challenge: on day 29
- Exposure period:6hr
- Test groups:30
- Control group:10
- Site: 2 x 2 cm patch to the clipped skin of the right flank and covered with an occlusive dressing
- Concentrations:1%
- Evaluation (hr after challenge): 24 and 48hr

OTHER: All animals were observed daily for signs of systemic toxicity. Body weights were recorded on days 1 and 31.

3.RANGE FINDING TESTS: no data available

MAIN STUDY
A. INDUCTION EXPOSURE
Intracutenous exposure
- No. of exposures: single
- Exposure period: 24 hours
- Test groups: 20
- Control group:
- Site: no data
- Frequency of applications: single
- Duration:
- Concentrations: 5 %

Epicutaneous, Occlusive

- No. of exposures: single
- Exposure period: 48 hours
- Test groups: 20
- Control group: no data available
- Site: no data availalbe
- Frequency of applications: single
- Duration: 48 hours
- Concentrations: 0.5 ml of 25 %

B. CHALLENGE EXPOSURE
- No. of exposures: single
- Day(s) of challenge: day 22
- Exposure period: 24 hours
- Test groups: 20
- Control group: no data available
- Site: clipped skin of the flank
- Concentrations: 0.5 ml of 10 %
- Evaluation (hr after challenge): 24 and 48 hours after removal of the occlusive dressing

OTHER:
Day 1 : Intradermal induction exposure (Injection)
The injection sites were not covered.
Day 1-7: The application area was investigated.
Day 9 : Dermal induction exposure-
0.5ml of the test substance preparation was applied to a cellulose patch of 2x4 cm. This patch covered the area of the intradermal injection sites. An occlusive dressing with impermeable foil and an elastic bandage sealed the application site for 48 hours.
Day 11 : Removal of the occlusive dressing. Recording of the irritation
Day 22 : Dermal challenge exposure-
0.5ml of test substance preparation were applied to a cellulose patch and placed onto the clipped skin of the flank. An occlusive dressing with impermeable foil and an elastic bandage sealed the application site for 24 hours.
Day 23 : Removal of the occlusive dressing
Day 24-25: Assessment of the skin

Challenge controls:

1 and 3.no data available
2.yes, concurrent vehicle used

Positive control substance(s):

not specified

Positive control results:

no data available

Reading:

other: 1.1st reading

Group:

test chemical

Dose level:

Concentrations ranging from 5 to 20 per cent in petrolatum

No. with + reactions:

3

Total no. in group:

8

Clinical observations:

In five of eight patients, the reactions were negative

Remarks on result:

no indication of skin sensitisation

Reading:

other: 2.1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1%

No. with + reactions:

0

Total no. in group:

30

Clinical observations:

No skin sensitization reaction was observed

Remarks on result:

no indication of skin sensitisation

Reading:

other: 3.1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10%

No. with + reactions:

2

Total no. in group:

20

Clinical observations:

The treated animals did not show any signs of toxicity throughout the study period.

Remarks on result:

no indication of skin sensitisation

Interpretation of results:

other: not sensitizing

Conclusions:

The test chemical was considered to be not sensitizing to the skin of human and guinea pigs.

Executive summary:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the skin sensitization potential of the test chemical. The studies are as mentioned below:

 A Patch test was conducted to determine the dermal sensitization potential of similar read across chemical test chemical in humans. 8 patients were tested with the test chemical in concentrations ranging from 5 to 20 per cent in petrolatum, and observed for signs of irritation. (duration not specified). In five of eight patients tested with the test chemical, the reactions were negative for skin sensitization. Hence the test chemical was considered to be not sensitizing to skin.

 

The above result was supported by the Buehler test conducted on read across chemical using 30 female Pirbright albino guinea pigs in treated group and 10 in control group. Doses were selected on the bases of preliminary study using 6 animals. In induction phase, induction given on day 1, using 4 % concentration in water by topical application as2 x 2 cm cellulose patch to the clipped skin of the left flank. The patch was covered with an occlusive dressing for 6 hours and removed afterwards. The second induction given on day 8 and third on day 15 using same procedure on day first. During the induction phase, the skin sites were examined for local effects 24 hours after each treatment. In challenge phase, on day 29 test substance 1% concentration in same vehicle applied on a 2 x 2 cm patch to the clipped skin of the right flank and covered with an occlusive dressing for 6 hour and evaluated 24 and 48hr after removal of occlusive dressing .All animals were observed daily for signs of systemic toxicity. Body weights were recorded on days 1 and 31.No skin sensitizing reaction observed after challenge application also no clinical effects were observed. Body weight development of the treated group was not different from that of the control group. During the induction phase, treated animals showed slight to well-defined erythema and very slight oedema at the treated skin area. After challenge, skin reactions were observed neither in the treated group nor in the control group. Hence the test chemical was considered to be not skin sensitizing in guinea pig. 

 

The above results were further supported by a Guinea pig Maximization assay performed on read across chemical. The study was performed as per EPA 540/9-82-025 Guidelines. 20 female Pirbright White guinea pigs were used for the study. 0.9% NaCl Solution was used as a vehicle. The following concentrations were used for the induction and challenge exposure.During the first phase of induction, intracutaneous injections were given to the test animals and injection sites were investigated till day 7. On day 9, 0.5ml of the test substance preparation was applied to a cellulose patch of 2x4 cm. This patch covered the area of the intradermal injection sites. An occlusive dressing with impermeable foil and an elastic bandage sealed the application site for 48 hours. At the end of 48 hours of exposure, the occlusive bandages were removed and the test sites were observed for signs of erythema and edema. The animals were rested for 10-11 days then subjected to challenge exposure. 0.5ml of test substance preparation were applied to a cellulose patch and placed onto the clipped skin of the flank. An occlusive dressing with impermeable foil and an elastic bandage sealed the application site for 24 hours. 24 hours later the occlusive patches were removed and the test sites were assessed for dermal irritation. Ten percent of the animals of treatment group demonstrated a positive reaction after the challenge exposure (classification criteria – 30%). Hence, the test chemical was considered to be not sensitizing to skin.

 

Based on the above summarized studies for target chemical and its structurally and functionally similar read across substances,it can be concluded that the test chemical is unable to cause skin sensitization and considered as non-skin sensitizer. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the skin sensitization potential of the test chemical. The studies are as mentioned below:

 A Patch test was conducted to determine the dermal sensitization potential of similar read across chemical test chemical in humans. 8 patients were tested with the test chemical in concentrations ranging from 5 to 20 per cent in petrolatum, and observed for signs of irritation. (duration not specified). In five of eight patients tested with the test chemical, the reactions were negative for skin sensitization. Hence the test chemical was considered to be not sensitizing to skin.

 

The above result was supported by the Buehler test conducted on read across chemical using 30 female Pirbright albino guinea pigs in treated group and 10 in control group. Doses were selected on the bases of preliminary study using 6 animals. In induction phase, induction given on day 1, using 4 % concentration in water by topical application as2 x 2 cm cellulose patch to the clipped skin of the left flank. The patch was covered with an occlusive dressing for 6 hours and removed afterwards. The second induction given on day 8 and third on day 15 using same procedure on day first. During the induction phase, the skin sites were examined for local effects 24 hours after each treatment. In challenge phase, on day 29 test substance 1% concentration in same vehicle applied on a 2 x 2 cm patch to the clipped skin of the right flank and covered with an occlusive dressing for 6 hour and evaluated 24 and 48hr after removal of occlusive dressing .All animals were observed daily for signs of systemic toxicity. Body weights were recorded on days 1 and 31.No skin sensitizing reaction observed after challenge application also no clinical effects were observed. Body weight development of the treated group was not different from that of the control group. During the induction phase, treated animals showed slight to well-defined erythema and very slight oedema at the treated skin area. After challenge, skin reactions were observed neither in the treated group nor in the control group. Hence the test chemical was considered to be not skin sensitizing in guinea pig. 

 

The above results were further supported by a Guinea pig Maximization assay performed on read across chemical. The study was performed as per EPA 540/9-82-025 Guidelines. 20 female Pirbright White guinea pigs were used for the study. 0.9% NaCl Solution was used as a vehicle. The following concentrations were used for the induction and challenge exposure.During the first phase of induction, intracutaneous injections were given to the test animals and injection sites were investigated till day 7. On day 9, 0.5ml of the test substance preparation was applied to a cellulose patch of 2x4 cm. This patch covered the area of the intradermal injection sites. An occlusive dressing with impermeable foil and an elastic bandage sealed the application site for 48 hours. At the end of 48 hours of exposure, the occlusive bandages were removed and the test sites were observed for signs of erythema and edema. The animals were rested for 10-11 days then subjected to challenge exposure. 0.5ml of test substance preparation were applied to a cellulose patch and placed onto the clipped skin of the flank. An occlusive dressing with impermeable foil and an elastic bandage sealed the application site for 24 hours. 24 hours later the occlusive patches were removed and the test sites were assessed for dermal irritation. Ten percent of the animals of treatment group demonstrated a positive reaction after the challenge exposure (classification criteria – 30%). Hence, the test chemical was considered to be not sensitizing to skin.

 

Based on the above summarized studies for target chemical and its structurally and functionally similar read across substances,it can be concluded that the testchemical is unable to cause skin sensitization and considered as non-skin sensitizer. Comparing the above annotations with the criteria of CLP regulation, it can be classified under the category “Not Classified”.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The skin sensitization potential of test substance andits structurally and functionally similar read across substanceswere observed in various studies. From the results obtained from these studies it is concluded that the chemical is not likely to cause skin sensitization and hence can be classified as non-skin sensitizer.