Catalase

Endpoint summary

Description of key information

An acute oral toxicity study according to OECD Guideline No 425 has been performed and under the conditions of the study, the oral LD50 for Catalase was greater than 5000 mg TP/kg bw (equivalent to 6443 mg TOS/kg bw) for female rats.

No other acute toxicity studies were performed with Catalase.

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:

August 18, 2014 to December 9, 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

Version / remarks:

2008

GLP compliance:

yes (incl. QA statement)

Test type:

up-and-down procedure

Limit test:

no

Species:

rat

Strain:

other: Crl:CD(SD)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories International, Inc., Raleigh, North Carolina, U.S.A
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: approximately 10 weeks old
- Weight at study initiation: 240±5 grams
- Fasting period before study: The rats were fasted approximately 15-17 hours prior to dosing, with food being returned to the rats approximately 3 hours after the first dose
- Housing: Animals were housed individually in solid-bottom caging with bedding and appropriate species-specific enrichment.
- Diet (e.g. ad libitum): PMI® Nutrition International, LLC Certified Rodent LabDiet® 5002 ad libitum except during fasting
- Water (e.g. ad libitum): water ad libitum except during fasting
- Acclimation period: The rats were weighed and observed for general health during the 6-day quarantine period.

ENVIRONMENTAL CONDITIONS
- Temperature: 20-26ºC
- Humidity: 30-70%
- Air changes: 12-hour light/dark cycle

IN-LIFE DATES: From September 9, 2014 to September 26, 2014

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

The test substance was administered by oral gavage to fasted female rats at a dose of 5000 mg/kg, adjusted for the percentage of total protein in the neat test substance. The neat test substance was delivered in two fractions to each animal, approximately two hours apart, on a single day. The rats were dosed one or two at a time, at a minimum of 48-hour intervals.

The rats were approximately 10 weeks old on the day of dosing. The rats were fasted approximately 15-17 hours prior to dosing, with food being returned to the rats approximately 3 hours after the first dose. Individual dose volumes were calculated using the test substance composition of 167.41 mg total protein/mL and the fasted body weights obtained prior to dosing. The rats were dosed with the neat test substance at an approximate volume of 30 mL per kg of body weight, divided into two fractions of approximately 15 mL/kg each. Based on the exact volume located in the study database and the specific gravity in the COA, the total dose of the neat test substance was calculated as 31957 mg/kg. The weight of each animal was within the ±20% of the mean weight of any previously dosed animals. The neat test substance was inverted prior to the dosing procedure.

Doses:

The neat test substance was administered at a total dose level of 31957 mg/kg bw (equivalent to 5000 mg TP/kg bw or 6443 mg TOS/kg bw) at a volume of approximately 30 mL/kg, which was delivered in two fractions to each animal on a single day. The rats were dosed one or two at a time, at a minimum of 48-hour intervals.

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

Daily animal health observations were conducted throughout the study for mortality and signs of illness, injury, or abnormal behavior. Animals were weighed on test days -1, 1, 8, and 15, and were observed for clinical signs at the beginning of fasting, just before dosing (test day 1), once during the first 30 minutes after the first dose, and 2 more times on the day of dosing, and once each day thereafter. On test day 15, the rats were euthanized and necropsied to detect grossly observable evidence of organ or tissue damage. The rats were euthanized by exsanguination while under isoflurane anesthesia

Sex:

female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

other: TP (Total protein)

Remarks on result:

other: no effects observed

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 6 443 mg/kg bw

Based on:

other: TOS (Total Organic Solids)

Remarks on result:

other: no effects observed

Mortality:

No deaths occurred

Clinical signs:

other: There were no clinical abnormalities observed throughout the study.

Gross pathology:

No gross lesions were present in the rats at necropsy.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study, the oral LD50 for Catalase was greater than 5000 mg TP/kg bw (equivalent to 6443 mg TOS/kg bw) for female rats.

Executive summary:

The study was conducted to assess the acute oral toxicity of Catalase in accordance with the OECD Guideline 425 in compliance with GLP.

 

The test substance was administered by oral gavage to fasted female rats at a dose of 5000 mg/kg bw, adjusted for the percentage of total protein in the neat test substance. The neat test substance was a solution that was administered at a total dose level of 31957 mg/kg at a volume of approximately 30 mL/kg, which was delivered in two fractions to each animal on a single day. The rats were dosed one or two at a time, at a minimum of 48-hour intervals. All rats were observed for mortality, body weight effects, and clinical signs for 14 days after dosing. The rats were necropsied to detect grossly observable evidence of organ or tissue damage.

 

No incidents of mortality, overall bodyweight loss or clinical signs were observed. No gross lesions were present in the rats at necropsy.

Under the conditions of this study, the oral LD50 for Catalase was greater than 5000 mg TP/kg bw (equivalent to 6443 mg TOS/kg bw) for female rats.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

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

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:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

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.