Alpha,alpha-trehalaseIUBMB 3.2.1.28

Endpoint summary

Description of key information

Trehalase was not tested for irritation, however, and enzyme from the same sub-subclass - alpha-amylase - was tested.

Alpha-amylase was not irritating to skin and shall be classified as non-irritant.

Alpha-amylase was not irritating to eyes and shall be classified as non-irritant.

Based on these results, trehalase should also be 'non-irritating' to eyes and skin.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sep. 26 - Oct. 01, 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Due to the similarity between the two enzymes, similar results are expected for trehalase.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

April 2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Bred by Charles River, Germany
- Weight at study initiation: between 1906 - 2174 g
- Age at study initiation: Adults
- Housing: Individually, in animal room with control of temperature (22-23°C) and humidity (50-70%RH)
- Diet (e.g. ad libitum): Standard diet ad libitum
- Air changes (per hr): 10 per hr
- Water (e.g. ad libitum): Tap water ad libitum
- Acclimation period: 5 days
- Photoperiod (hrs dark / hrs light): 12 hrs/12hrs

IN-LIFE DATES: From: 2007-10-01 To: 2007-10-04

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: Tested neat

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL
- Concentration (if solution): undiluted, i.e. 60 mg total protein/mL

Duration of treatment / exposure:

4 hours

Observation period:

72 hrs

Number of animals:

3

Details on study design:

The test compound alpha-amylase was assessed by semiocclusive application of 0.5 mL of the test material formulation to an area of 2.5 x 2.5 cm on the closely-clipped flank of three male New Zealand White rabbits for 4 hrs.
The study was conducted to comply with the following guidelines:
- Organisation for Economic Co-operation and Development (OECD) test guideline 404.

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritant / corrosive response data:

At 1 h and 24 h after removal of the test material, very slight erythema was observed in the three rabbits. No erythema was observed at the 48 and 72 h reading. No oedema was observed at the test sites at any of the three rabbits at any of the examinations 1 hour, 24, 48 or 72 hours after termination of exposure.

Other effects:

No other effects.

Interpretation of results:

GHS criteria not met

Conclusions:

Alpha-amylase was not irritating to skin and shall be classified as non-irritant.

Executive summary:

The acute dermal irritant effect of alpha-amylase was investigated according to the method recommended in the OECD Guideline No 404, “Acute Dermal Irritation/Corrosion”. The study was conducted in accordance with GLP.

The study was performed on three male New Zealand White rabbits. They were each exposed to 0.5 mL of the undiluted liquid test item applied under semiocclusive conditions to each of three closely-clipped test sites, 2.5 x 2.5 cm, on the flank. After a 4-hour exposure period, the test item was removed from the test site and the skin was examined. Only very slight erythema was noted at 1 h and 24 h after removal of the test material, whereas eschar formation or oedema was not observed at any of the test sites at any of the examinations. All reactions were fully reversible and no erythema was observed at the test or control sites of any of the animals at the examinations at 48 or 72 hours after termination of exposure.

The Test Item Mean Score for erythema after 4hrs of exposure to the test item was: 0.3

The Test Item Mean Score for oedema after 4hrs of exposure to the test item was: 0.0

In conclusion, alpha-amylase was not irritating to skin and shall be classified as non-irritant.

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

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 26 - October 04, 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Due to the similarity between the two enzymes, similar results are expected for trehalase.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

April 2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Bred by Charles River, Germany
- Age at study initiation: Adults
- Weight at study start: 1956 - 2064 g
- Housing: individually in stainless steel cages with perforated floor
- Diet (e.g. ad libitum): Standard diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 - 23°C
- Humidity (%): 50-70 %
- Air changes (per hr): 10 air changes per hr
- Photoperiod (hrs dark / hrs light): 12 hrs light/ 12 hrs dark cycle

IN-LIFE DATES: From: 2007-10-01 To: 2007-10-04

Vehicle:

other: Tested neat

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL
- Concentration (if solution): Undiluted test material, i.e. 60 mg total protein/mL

Observation period (in vivo):

The reactions were judged 1, 24, 48 and 72 hours after treatment

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): No washing


SCORING SYSTEM: According to OECD 405

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

ca. 0

Max. score:

0

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

ca. 0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

ca. 0

Max. score:

0

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

ca. 0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

0

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

ca. 0

Max. score:

0

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

ca. 0

Max. score:

0

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

ca. 0.3

Max. score:

1

Reversibility:

fully reversible within: 48 h

Irritant / corrosive response data:

At the 1 hour reading, discharge was present (score 1) in rabbit # 1. However, this symptom had disappeared at the following observations (24, 48 and 72 hours after treatment). At the examination at 1 hour and 24 hours after exposure, slight redness with or without slight swelling of the conjunctivae was present (score 1) in the three rabbits. However, these eye effects had cleared completely at the following observations, 48 and 72 hours after treatment.

Interpretation of results:

GHS criteria not met

Conclusions:

The test material alpha-amylase is not irritating to eyes.

Executive summary:

The study was carried out according to OECD guideline no. 405. Three rabbits were treated as follows: One rabbit was treated first and two more aprox. one hour later. An amount of 0.1 mL of the undiluted test substance was instilled in the conjunctival cul-de-sac of one of the eyes of the rabbit. After administration, the upper and the lower eye lid were carefully closed and subsequently held together for at least one second before releasing to prevent loss of material. The other eye remained untreated and served as a control. The reactions of the eyes were judged at 1 h, 24 h, 48 h and 72 h after treatment.

The only effects seen were ocular discharge (score 1) in one rabbit at the 1 hour reading, and slight redness with or without slight swelling of the conjunctivae (score 1) in all rabbits at the examination at 1 hour and 24 hours after exposure. However, these slight effects were cleared completely at the following observations 48 and 72 hours after treatment. According to the Globally Harmonised System of Classification and labelling of Chemicals (GHS, UN/ECE 2003) alpha-amylase should not be classified as eye irritating.

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

November 15 2002 to January 16 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Justification for type of information:

Due to the similarity between the two enzymes, similar results are expected for trehalase.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye Test Method for Identifying Ocular Corrosives and Severe Irritants)

GLP compliance:

yes

Vehicle:

physiological saline

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): The chicken eye cornea was treated with 0.03 mL
- Concentration (if solution): undiluted test sample

Duration of treatment / exposure:

The exposure period was 10 seconds

Observation period (in vivo):

The eyes were examined at ca 0, 30, 75, 120, 180 and 240 minutes after treatment.

Details on study design:

Alpha-amylase was examined for potential irritation/corrosive properties in an ex vivo bioassay, the Chicken Enucleated Eye Test (CEET). Three main parameters were measured to disclose possible adverse effects, the corneal thickness/swelling, corneal opacity and fluorescein retention of damaged epithelial cells.
The study was carried out at the contract laboratory TNO Nutrition and Food Research, The Netherlands. Three enucleated chicken eyes per sample and one control per test run were selected for testing. At time t = 0, immediately after a zero reference measurement, the following procedure was applied for each test eye: The eye cornea was treated with 0.03 mL of the undiluted test item. After an exposure period of 10 seconds, the corneal surface was rinsed thoroughly with 20 mL isotonic saline of ambient temperature. The control eye was treated with saline only. The eyes were examined at ca 0, 30, 75, 120, 180 and 240 minutes after treatment. Fluorescein retention was only evaluated at ca 30 minutes after treatment. All examinations were carried out with a slit-lamp microscope.
In addition, the eyes were collected for histopathological examination of the cornea.

Irritation parameter:

percent corneal swelling

Value:

2

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

not specified

Irritation parameter:

cornea opacity score

Value:

0

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

not specified

Remarks on result:

no indication of irritation

Irritation parameter:

fluorescein retention score

Value:

0

Vehicle controls validity:

valid

Negative controls validity:

not specified

Positive controls validity:

not specified

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

After treatment, the corneal thickness of the test eyes remained unchanged. None of the three eyes showed any corneal opacity or fluorescein retention. Microscopic examinations of the treated corneas did not reveal any indications of possible adverse effects.

Interpretation of results:

GHS criteria not met

Conclusions:

On the basis of the results obtained by slit-lamp examination and according to the EC classification system of the Chicken Enucleated Eye Test, it was concluded that the tested alpha-amylase batch was not irritating to eyes.

Executive summary:

Alpha-amylase was examined for potential irritation/corrosive properties in an ex vivo bioassay, the Chicken Enucleated Eye Test.

Three main parameters were measured to disclose possible adverse effects, the corneal swelling, corneal opacity and fluorescein retention of damaged epithelial cells.

Three enucleated chicken eyes per sample and one control were selected for testing. The individual eye cornea was treated with 0.03 mL of the undiluted test material. After an exposure period of 10 seconds, the corneal surface was rinsed with 20 mL isotonic saline. The control eye was treated with saline only. The eyes were examined at 0, 30, 75, 120, 180 and 240 minutes after treatment. All examinations were carried out with a slit-lamp microscope.

In addition, the eyes were collected for histopathological examination of the cornea.

The results showed that the corneal thickness of the test eyes remained unchanged. None of the three eyes showed any corneal opacity or fluorescein retention. Microscopic examinations of the treated corneas did not reveal any indications of possible adverse effects.

According to the EC classification system of the Chicken Enucleated Eye Test, it was concluded that the tested alpha-amylase was not irritating to eyes.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Justification for classification or non-classification

Not classified.