Amylase, gluco-

Endpoint summary

Description of key information

The acute oral toxicity of glucoamylase has been tested, while the acute inhalation and dermal toxicity was regarded as scientifically unjustified.

The acute oral toxicity was a short-term toxicity test conducted according to OECD guideline, and in compliance with GLP. The conclusion is that glucoamylase is non-toxic by oral exposure (GHS Toxicity category V).

Acute toxicity via the inhalation and dermal route is waived based on exposure considerations and the known properties of the substance. Based on weight of evidence, glucoamylase does not exert any acute dermal or inhalation toxicity under foreseeable realistic exposure levels for both workers and consumers.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 30 to October 21, 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Version / remarks:

Dec. 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

- Source: Taconic Europe, DK-4623 Lille Skensved, Denmark.
- Fasting period before dosing: Overnight
- Housing: Two animals per cage, transparent polycarbonate cages floor area 1500 cm2 – height 21 cm
- Weight at time of dosing: between 147-152 g
- Housing: In animal room with control of temperature and humidity
- Diet: Standard diet ad libitum
- Water: Tap water ad libitum
- Acclimation period: 5 days
- Temperature (°C): 18-24°C
- Humidity : 40-70 %

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Remarks:

The liquid test material was dosed undiluted

Details on oral exposure:

Maximum Dose Volumen applied: 10 mL/kg

Doses:

Undiluted test material 10 mL/kg bw, corresponding to 1996.3 mg total protein/kg body weight (limit test).

No. of animals per sex per dose:

5 (only females)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations for clinical signs of effect: 15 minutes and 1, 3 and 6 hours and daily after dosing. Weighing:at arrival, on Days 1, 2, 3, 8 and 15
- Necropsy of survivors performed: yes

Preliminary study:

Sighting study: The starting dose level was based on information from the Sponsor. One female animal was treated with 1996.3 mg total protein/kg body weight. As no evident signs of toxicity were observed in this animal, the main study was carried out at this dose level.

Key result

Sex:

female

Dose descriptor:

other: Limit test - no effects were seen

Effect level:

> 1 996.3 mg/kg bw

Based on:

other: total protein

Mortality:

No mortality.

Clinical signs:

other: No clinical signs.

Gross pathology:

No abnormalities.

Interpretation of results:

Category 5 based on GHS criteria

Conclusions:

No signs of toxicity were observed among the rats treated with a single oral dose of 1996.3 mg/kg based on total protein, which was the highest possible dose at dose volume 10 mL/kg, using the undiluted test item.

Executive summary:

The objective of this study was to assess the acute toxicity of glucoamylase when administered as a single oral dose to rats followed by an observation period of 14 days. A preliminary sighting study using one female animal was included to estimate the dose effect for toxicity and to provide information on dose selection for the main study.

The study was conducted in accordance with the OECD Guideline No 420, “Acute Oral Toxicity – Fixed Dose Procedure”. The limit test was used. The test item was supplied as a brown liquid ready to use. The dose volume administered was 10 mL/kg.

The study was initiated with a sighting study at dose level 1996.3 mg/kg based on total protein, using one female animal. This was the highest possible dose level at dose volume 10 mL/kg, using the undiluted test item. On the basis of the results of the sighting study, the main study was performed in four additional female rats given a dose of 1996.3 mg/kg body weight. No clinical signs were observed and the overall body weight gain during the study was considered to be normal. The post-mortem inspection revealed no abnormalities.

In conclusion, no signs of toxicity were observed among the rats treated with a single oral dose of 1996.3 mg/kg based on total protein, which was the highest possible dose at dose volume 10 mL/kg, using the undiluted test item.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

1 996.3 mg/kg bw

Quality of whole database:

Toxicological data has been generated within the enzyme producing industry during the last 40 years. Substantial documentation on the safety of the production strains have been generated, and the enzyme test materials are thoroughly characterized. High quality studies for all relevant endpoints, in vivo studies as well as in vitro studies, show that industrial enzymes from well-known and well-characterized production strains have very similar safety profiles across the catalytic activities. Read-across can therefore be applied for the majority of toxicological endpoints. The database can thus be considered of high quality.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Toxicological data has been generated within the enzyme producing industry during the last 40 years. Substantial documentation on the safety of the production strains have been generated, and the enzyme test materials are thoroughly characterized. High quality studies for all relevant endpoints, in vivo studies as well as in vitro studies, show that industrial enzymes from well-known and well-characterized production strains have very similar safety profiles across the catalytic activities. Read-across can therefore be applied for the majority of toxicological endpoints. The database can thus be considered of high quality.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the physicochemical and toxicological properties suggest no potential for a significant rate of absorption through the skin

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Toxicological data has been generated within the enzyme producing industry during the last 40 years. Substantial documentation on the safety of the production strains have been generated, and the enzyme test materials are thoroughly characterized. High quality studies for all relevant endpoints, in vivo studies as well as in vitro studies, show that industrial enzymes from well-known and well-characterized production strains have very similar safety profiles across the catalytic activities. Read-across can therefore be applied for the majority of toxicological endpoints. The database can thus be considered of high quality.

Additional information

In general, enzymes are of very low toxicity due to ready biodegradability and very low bioavailability. In traditional acute toxicity testing, mortality has been the endpoint. However, because enzymes show very low toxicity, extremely high doses that are far above human exposure levels typically have been applied. Therefore, acute toxicity studies are not considered to provide appropriate knowledge and are as such not a relevant test system for enzymes. Systemic exposure by the dermal route is unlikely based on the existing toxicokinetic knowledge of enzymes, which due to their relatively large molecular weight, are not expected to be absorbed through the skin (Basketter et al. 2008, Smith Pease et al. 2002). Therefore, it can be safely assumed that technical enzymes do not exert any acute dermal toxicity (Basketter et al 2012). This conclusion is confirmed by the toxicological data available. Sub-acute dermal toxicity studies with protease in rabbits (Novozymes, unpublished data) did not provide evidence for systemic effect to enzymes. This finding is confirmed by data from acute dermal toxicity studies (Novozymes, unpublished data) of other enzyme products in both rats and rabbits. None of these studies revealed any acute toxic effect through the dermal administration route. No clinical signs or adverse effects due to systemic exposure could be observed. Data waivers will further be established through exposure scenarios, i.e. no significant dermal exposure to consumers and professionals due to the toxicologically insignificant enzyme concentrations in end products and in the case of workers due to occupational hygiene measures associated with the prevention of respiratory allergy which includes protective clothing. In conclusion, toxicokinetic data together with evidence from animal studies and historical human experience derived from the use of detergent enzymes for decades confirm that exposure to technical enzymes will not result in any toxicologically relevant uptake by dermal route. Acute systemic exposure to a toxicologically significant amount of enzymes by this route can, therefore, be excluded and will further be prohibited by the obligatory setting of a DMEL value for enzymes, resulting in negligible exposure to enzymes (Basketter et al 2010). In vivo acute dermal toxicity studies will not add any value and cannot be expected to provide valuable knowledge and are considered scientifically and ethically unjustified. Therefore, in accordance with column 2 of REACH Annex VIII acute toxicity testing by the dermal route is inappropriate.  

References:

- Basketter DA, English JS, Wakelin SH, White IR (2008). Enzymes, detergents and skin: facts and fantasies.Br. J. Dermatol., 158 (6):1177-1181.

- Smith Pease CK, White IR, Basketter DA (2002). Skin as a route of exposure to protein allergens.Clin. Exp. Dermatol., 27(4):296-300.  

- Basketter D, Berg N, Broekhuizen C, Fieldsend M, Kirkwood S, Kluin C, Mathieu S, Rodriguez C (2012a). Enzymes in Cleaning Products: An Overview of Toxicological Properties and Risk Assessment/Management.Regul. Toxicol. Pharmacol., 64(1):117-123.

- Basketter DA, Broekhuizen C, Fieldsend M, Kirkwood S, Mascarenhas R, Maurer K, Pedersen C, Rodriguez C, Schiff HE (2010). Defining occupational and consumer exposure limits for enzyme protein respiratory allergens under REACH.Toxicology, 268(3):165-170.

Justification for classification or non-classification

GHS criteria not met.