α-(1→2) branching sucrase

Endpoint summary

Description of key information

The skin and eye irritation potential of the present target substance, Alpha-1,2 branching sucrase IUBMB 2.4.1.373, has not been tested but another enzyme (Cellulase, IUBMB 3.2.1.4) has been analyzed and used as a source substance for read-across.

The skin and eye irritation potential of cellulase has been tested and no dermal or eye irritation was observed.

The conclusion is that the target substance Alpha-1,2 branching sucrase IUBMB 2.4.1.373 is considered not to be irritant to skin and eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

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

Adequacy of study:

other information

Justification for type of information:

The skin irritation potential of the present target substance, Alpha-1,2 branching sucrase IUBMB 2.4.1.373, has not been determined but another enzyme ( Cellulase, IUBMB 3.2.1.4) has been analyzed and used as a source substance for read-across.
The conclusion is that the target substance Alpha-1,2 branching sucrase IUBMB 2.4.1.373 is considered not to be irritant to skin.
Justification for read-across: see attached justification.

Reason / purpose for cross-reference:

read-across source

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin irritation study does not need to be conducted because adequate data from an in vivo skin irritation study are available

Reference 3

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 April 2011 - 31 May 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Two New Zealand White strain rabbits were supplied by Harlan Laboratories U.K. Ltd., Loughborough, UK. At the start of the study the animals weighed 2.31 or 2.35 kg and were twelve to twenty weeks old.
The animals were individually housed in suspended cages with free access to drinking water and food.
The temperature and relative humidity were set to achieve limits of 17 to 23 C and 30 to 70% respectively.
The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light and twelve hours darkness.

Preparation of test site:

clipped

Vehicle:

not specified

Controls:

no

Amount / concentration applied:

0.5 ml of test item on three sites on the back of the rabbit

Duration of treatment / exposure:

One patch of removed at each of three time points: 3 minutes, 1 hour and 4 hours after application

Observation period:

Test sites were examined for evidence of primary irritation approximately 1, 24, 48 and 72 hours later.

Number of animals:

Two

Details on study design:

One rabbit was initially treated. Three suitable sites were selected on the back of the rabbit. A quantity of 0.5 ml of the test item was applied directly to the skin under a 2.5 cm x 2.5 cm cotton gauze patch. Each patch was secured in position with a strip of surgical adhesive tape. To prevent the animal interfering with the patches, the trunk of the rabbit was wrapped in an elasticated corset for the duration of the exposure period.

One patch was removed at each of three time points: 3 min, 1 hour and 4 hours after application. Any residual test item was removed by gentle swabbing with cotton wool soaked in distilled water.

After consideration of the skin reactions produced in the first animal, an additional animal was treated with 0.5 ml of test item. One patch was applied to the back of the rabbit and was allowed to remain in contact with the skin for a period of four hours.

Immediately following removal of the patches and approximately 1, 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored according to a scale.

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: Sum of 24 and 72-hr Readings

Score:

0.3

Max. score:

1

Reversibility:

fully reversible

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48 h

Score:

1

Max. score:

1

Reversibility:

fully reversible

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritant / corrosive response data:

No evidence of skin irritation was observed at any time following 3 minute or 1 hour exposures. Slight erythema was noted at one treated site at the 24 and 48 hour observation points following the 4 hour exposure period. This effect was fully reversed by 72 hours. The substance is not classified as a skin irritant under GHS and CLP criteria.

Other effects:

No corrosive effects were noted.

Interpretation of results:

GHS criteria not met

Conclusions:

Cellulase is classified as "Non Irritant".

Executive summary:

The objective of this study was to assess the local irritant effect of Cellulase when applied topically as a single dose. The study was conducted according to the method recommended in the OECD Guideline No 404, “Acute Dermal Irritation/Corrosion” and Method B4 Acute Toxicity (Skin Irritation) of Commission Regulation (EC) No. 440/2008. The study complied with all GLP standards. A sequential approach was used. In the initial test, the back of one New Zealand rabbit was divided into four test sites. Cellulase (0.5 ml which is equivalent to 82.91 mg enzyme concentrate dry matter/kg bw or 43.21 mg active enzyme protein/kg bw) was applied (semi-occlusive) to three sites whereas the fourth site served as control. One patch was removed at each of the three time points, 3 minutes, 1 hour and 4 hours after application. After consideration of the skin reaction in the initial test, a confirmatory test was conducted with one rabbit. One patch is applied and removed after 4 hours of exposure.  Immediately after removal of the patches and at 1, 24, 48 and 72 hours later, all animals were examined for signs of erythema and edema and the responses scored. No deaths or overt signs of toxicity were observed. No effects on feed consumption and body weight were recorded. At the 3-minute and 1-hour exposure periods, no evidence of skin irritation was noted. At the 4-hour exposure period, very slight erythema was noted in one animal at the 24 and 48-hour observation periods with a maximum score of 1. All findings were fully reversible at the 72-hour observation period. No edema was observed in any of the observation period. Cellulase shall be classified as “Non Irritant”.

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

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

Adequacy of study:

other information

Justification for type of information:

The eye irritation potential of the present target substance, Alpha-1,2 branching sucrase IUBMB 2.4.1.373, has not been determined but another enzyme (Cellulase, IUBMB3.2.1.4) has been analyzed and used as a source substance for read-across.
The conclusion is that the target substance Alpha-1,2 branching sucrase IUBMB 2.4.1.373 is considered not to be irritant to the eye.
Justification for read-across: see attached justification.

Reason / purpose for cross-reference:

read-across source

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro eye irritation study does not need to be conducted because adequate data from an in vivo eye irritation study are available

Reference 3

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 April 2011 - 07 June 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

Two New Zealand White strain rabbits were supplied by Harlan Laboratories U.K. Ltd., Loughborough, UK. At the start of the study the animals weighed 2.67 or 2.84 kg and were twelve to twenty weeks old.
The animals were individually housed in suspended cages with free access to main drinking water and food. The temperature and relative humidity were set to achieve limits of 17 to 23 C and 30 to 70% respectively. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light and twelve hours darkness.

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.1 ml

Duration of treatment / exposure:

Eyelids were held together for about one second and then released

Observation period (in vivo):

Assessment of ocular damage/irriation was made approx 1 hour and 24, 48 and 72 hours following treatment.

Number of animals or in vitro replicates:

2

Details on study design:

Immediately after administration of the test item, an assessment of the initial pain reaction was made according to the six point scale.

Irritation parameter:

overall irritation score

Basis:

mean

Score:

0

Max. score:

0

Remarks on result:

other: No ocular effects were noted during the study

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No ocular effects were observed in either subject at any time during the study. The substance is not classified as an eye irritant under CLP or GHS criteria based on the results of this study.

Interpretation of results:

GHS criteria not met

Conclusions:

Cellulase should be classified as "Non Irritant".

Executive summary:

The objective of this study was to assess the ocular irritation potential of Cellulase when applied as a single dose (0.1 ml which is equivalent to 16.58 mg enzyme concentrate dry matter/kg bw or 8.64 mg active enzyme protein/kg bw) to the eye of New Zealand rabbits. The study was conducted according to OECD Guideline No. 405 and complied with all GLP standards. A sequential approach was used. In the initial test, the test material was applied at 0.1 ml to the left eye and the grade of ocular reaction was recorded at 1, 24, 48 and 72 hours later. The right eye served as control. At the 24-hour reading, fluorescein was instilled and then rinsed with 0.9% NaCl. The eye was then examined with an UV-light to detect corneal damage. A confirmatory test was conducted with 1 rabbit.

No ocular effects were noted during the study. The primary irritation score was 0.0 and Cellulase should be classified as “Non Irritant”.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)