Lithium nickel potassium oxide

Endpoint summary

Description of key information

Skin Sensitisation:

In a Contact Dermal Sensitization Test - Buehler Method Test, the challenge sites of the test group with 100% topical induction dose had a score of one in 7 out of 20 animals (35%) at 24 hours and 3 out of 20 animals (15%) at 48 hours following patch removal, which is above 15%, the GHS criteria for skin sensitization. Based on the topical induction dose of 100% (> 20%), lithium nickel potassium oxide (KDLNO) is considered to be a Category 1B dermal sensitizer according to GHS Classification and Labeling of Chemicals.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Remarks:

This study is designed to comply with the standards set forth in U.S. Environmental Protection Agency (EPA) Health Effects Test Guideline OCSPP 870.2600: Skin Sensitization, and The OECD Guideline for the Testing of Chemicals No. 406: Skin Sensitization.

Type of information:

experimental study

Remarks:

This study was initially designed to meet regulatory needs in North America. This study is designed to comply with the standards set forth in U.S. Environmental Protection Agency (EPA) Health Effects Test Guideline OCSPP 870.2600: Skin Sensitization

Adequacy of study:

key study

Study period:

Study Completed On
22 Oct 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

OECD Guideline 406 is referenced in OCSPP 870.2600 as an acceptable method to assess the potential of a substance to promote skin sensitization reaction.
Contact Dermal Sensitization is an immunological process where the host animal, through repeated skin exposure, acquires a specific allergic sensitivity (reactivity) to a substance. In the Buehler guinea pig model, contact dermal sensitivity is manifested as increased erythema

Species:

guinea pig

Strain:

Hartley

Sex:

male/female

Route:

epicutaneous, occlusive

Vehicle:

water

Concentration / amount:

Induction: Group 1, 100%: Ten males and 10 females were dosed with 0.4 g of the test article
(moistened with 0.1 ml of distilled water). The dose was applied to the left shoulder area using a 25-mm Hilltop Chamber® which is designed to keep the test article on a 25 mm area of the site. The chamber was covered with a strip of rubber dental dam sufficient to cover the treated sites. The torso was wrapped with non-irritating tape to provide occlusion. Six hours post-dosing, the dams and test article were removed. Any residual test article was cleansed from the sites with distilled water and the sites were dried with gauze or soft toweling. This procedure was performed once per week on the same day each week for a three week period, a total of three six-hour exposures.
Group 2: Five males and five females were untreated for the three-week induction period and
served as the naive control.

Day(s)/duration:

This procedure was performed once per week on the same day each week for a three week period, a total of three six-hour exposures.

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

acetone/olive oil (4:l v/v)

Concentration / amount:

Challenge: Fourteen days after the last induction exposure, animals in Groups 1 and 2 were challenged using the same dosing procedure as in the induction phase. As specified in the protocol, 50% HCA in acetone was chosen as the highest non-irritating concentration for the challenge. The doses were applied to a naive site on the lower left dorsal area.

Day(s)/duration:

Fourteen days after the last induction exposure

No. of animals per dose:

Group 1: Ten males and 10 females were dosed with 0.4 g of the test article
(moistened with 0.1 ml of distilled water).

Group 2: Five males and five females were untreated for the three-week induction period and
served as the naive control.

Details on study design:

EXPERIMENTAL DESIGN

Test Animals
Animals were received from Elm Hill Breeding Labs., Inc., Chelmsford, MA on 29 May 2019. Following an acclimation period of at least five days, fifteen healthy male and fifteen healthy female non-pregnant and nulliparous Hartley Albino guinea pigs were assigned to the study without conscious bias. The animals were born on 05 May 2019. The pre-test body weight range was 313 to 381 g for males and 311 to 370 g for females. All study animals gained body weight by study termination, which was considered to be similar to that expected for normal untreated animals of the same age and strain.The animals were identified by cage notation and a uniquely numbered metal ear tag and individually housed in suspended wire-bottom cages. Absorbent paper bedding was placed beneath the cages and changed at least three times per week. Fresh, Certified Guinea Pig LabDiet® No. 5026 and water were available ad libitum. The animal room, reserved exclusively for guinea pigs on acute tests, was temperature controlled, had a 12-hour light/dark cycle, and was kept clean and vermin free.

Site Preparation
The day prior to the first induction application, Site 1 of Group 1 animals was clipped free of hair on the upper left dorsal area with an electric clipper. The clipped area was approximately 5 x 5 cm. Any animal with skin irregularities or irritation was eliminated from the study. The treated sites were re-clipped the day prior to each induction application. Thirteen days after the last induction application, a naive site (Site 3) on the lower left dorsal area of each animal was clipped free of hair. Sites 2 and 4 (right upper and lower dorsal areas, respectively) were reserved for alternate sites in the event that severe irritation was noted during the induction phase and/or a re-challenge was required.

Dosing
Induction: Group 1, 100%: Ten males and 10 females were dosed with 0.4 g of the test article
(moistened with 0.1 ml of distilled water). The dose was applied to the left shoulder area (Site 1) using a 25-mm Hilltop Chamber® which is designed to keep the test article on a 25 mm area of the site. The chamber was covered with a strip of rubber dental dam sufficient to cover the treated sites. The torso was wrapped with non-irritating tape to provide occlusion. Six hours post-dosing, the dams and test article were removed. Any residual test article was cleansed from the sites with distilled water and the sites were dried with gauze or soft toweling. This procedure was performed once per week on the same day each week for a three week period, a total of three six-hour exposures.

Group 2: Five males and five females were untreated for the three-week induction period and
served as the naive control.

Challenge: Fourteen days after the last induction exposure, animals in Groups 1 and 2 were challenged using the same dosing procedure as in the induction phase. Based on the results of the induction application, 100% was chosen as the highest non-irritating concentration for the challenge. The doses were applied to a naive site on the lower left dorsal area (Site 3).

Type and Frequency of Observations
Skin reactions:
Induction - The treated sites of animals in Group 1 were examined and scored at 24 and 48 hours
following each patch removal for each induction period.
Challenge - The challenge sites of animals in Groups 1 and 2 were scored at 24 and 48 hours
following patch removal.
All reactions were evaluated according to the scoring code described below. Additional signs were described.

Skin Scoring Code
No reaction 0
Very faint erythema, usually non-confluent 0.5
Obvious faint erythema, usually confluent 1
Moderate erythema 2
Strong erythema, with or without edema 3

Animals were observed at least once daily for toxicity, pharmacologic effects and mortality. Observations included, but not be limited to, evaluation of skin and fur, eyes and mucous membranes, respiratory and circulatory effects, autonomic effects such as salivation, central nervous system effects including tremors and convulsions, changes in the level of activity, gait and posture, reactivity to handling or sensory stimuli, altered strength, and stereotypies or bizarre behavior (e.g., self-mutilation, walking backwards).

Body weights were recorded pre-test and at test termination.

All animals were humanely sacrificed using CO2 following test termination.


Analysis of Data
A score of 1 or greater at challenge in 15% or more of the animals is indicative of a sensitizing response.
To aid in the analysis of the data, two indices were calculated from the erythema scores: one to evaluate incidence and the other to evaluate severity. The indices were calculated for both the test article group and the naive control group using the 24 and 48-hour scores following challenge patch removal.

Incidence Index
The incidence index was calculated by counting the number of animals showing an erythema response (1 or greater) for a specified time period and dividing the number of test sites (animals) examined at that time period:
Incidence Index = No. of responses/No. per group

Severity Index
The severity index was calculated by adding the erythema scores for a specified time period and dividing the number of scores added:
Severity Index = Sum of erythema scores/No. of scores added

GHS Classification:
The test article was assigned to a category according to the current Globally Harmonized System (GHS) of Classification and Labeling of Chemicals.

Challenge controls:

Group 2: Five males and five females were untreated for the three-week induction period and
served as the naive control.

Positive control substance(s):

no

Remarks:

Group 2: Five males and five females were untreated for the three-week induction period and served as the naive control.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100% topical induction dose. Lithium nickel potassium oxide (KDLNO) at a concentration of 100%. The test article (0.4 g) moistened with 0.1 ml distilled water was applied dermally to a site.

No. with + reactions:

7

Total no. in group:

20

Clinical observations:

Clinical findings including, soiling, wetness and yellow staining of the anogenital area, brown staining on the abdomen and left hip area were observed.

Remarks on result:

positive indication of skin sensitisation

Remarks:

Based on the topical induction dose of 100% (> 20%), lithium nickel potassium oxide (KDLNO) is considered to be a Category 1B dermal sensitizer according to GHS Classification and Labeling of Chemicals.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100% topical induction dose. Lithium nickel potassium oxide (KDLNO) at a concentration of 100%. The test article (0.4 g) moistened with 0.1 ml distilled water was applied dermally to a site.

No. with + reactions:

3

Total no. in group:

20

Clinical observations:

Clinical findings including, soiling, wetness and yellow staining of the anogenital area, brown staining on the abdomen and left hip area were observed.

Remarks on result:

positive indication of skin sensitisation

Remarks:

Based on the topical induction dose of 100% (> 20%), lithium nickel potassium oxide (KDLNO) is considered to be a Category 1B dermal sensitizer according to GHS Classification and Labeling of Chemicals.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

other: Naive Control

Dose level:

Group 2 (five males and five females) was not induced and served as a naive control

No. with + reactions:

0

Total no. in group:

10

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

other: Naive Control

Dose level:

Group 2 (five males and five females) was not induced and served as a naive control

No. with + reactions:

0

Total no. in group:

10

Reading:

1st reading

Hours after challenge:

0

Group:

positive control

Dose level:

No positive control group in the study

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

No positive control group in the study

Reading:

1st reading

Hours after challenge:

0

Group:

negative control

Dose level:

There was a naive control group in stead

No. with + reactions:

0

Total no. in group:

0

Clinical observations:

There was a naive control group in stead

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The challenge sites of the test group with 100% topical induction dose had a score of one in 7 out of 20 animals (35%) at 24 hours and 3 out of 20 animals (15%) at 48 hours following patch removal, which is above 15%, the GHS criteria for skin sensitization. Based on the topical induction dose of 100% (> 20%), lithium nickel potassium oxide (KDLNO) is considered to be a Category 1B dermal sensitizer according to GHS Classification and Labeling of Chemicals.

Executive summary:

The purpose of this study was to determine the potential of the test article, lithium nickel potassium oxide (KDLNO), to promote skin sensitization reactions after repeated applications. This study was designed to comply with the standards set forth in EPA Health Effects Test Guidelines, OCSPP 870.2600. OECD Guideline 406 is referenced in OCSPP 870.2600 as an acceptable method to assess the potential of a substance to promote skin sensitization reaction.

The challenge sites of the test group with 100% topical induction dose had a score of one in 7 out of 20 animals (35%) at 24 hours and 3 out of 20 animals (15%) at 48 hours following patch removal, which is above 15%, the GHS criteria for skin sensitization. Based on the topical induction dose of 100% (> 20%), lithium nickel potassium oxide (KDLNO) is considered to be a Category 1B dermal sensitizer according to GHS Classification and Labeling of Chemicals.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)