lysophospholipaseIUBMB 3.1.1.5

Endpoint summary

Description of key information

Lysophospholipase was tested orally in rats. No signs of toxicity were observed among the rats treated with a single oral dose of 2085 mg total organic solids/kg body weight for a period of 14 days.

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 23, 2013 - November 21, 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

Adopted 17 December 2001.

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

other: CD (Crl:CD ‘SD’) albino rats

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd
- Females nulliparous and non-pregnant: Yes
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 221 to 238 g
- Fasting period before study: overnight fasting prior to dosing
- Housing: Barriered rodent facility with control of temperature, humidity and lighting. The cages were solid bottomed polycarbonate cages with a stainless steel mesh lid. Softwood bark-free fibre were provided as bedding. Aspen chew block and plastic shelter for environmental enrichment.
- Diet: standard rodent diet (Rat and Mouse No. 1 Maintenance Diet) ad libitum
- Water: ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 23°C
- Humidity (%): 40-70%
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 2013-10-01 To: 2013-10-15

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

Undiluted test material for the top dose.

Doses:

Dose volume was 16 mL/kg bodyweight (equivalent to 2085 g TOS/kg bodyweight).

No. of animals per sex per dose:

6 (female only)

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: soon after dosing, and at frequent intervals for the remainder of Day 1. On subsequent days, animals were observed once in the morning and again at the end of the experimental day (with the exception of Day 15 - morning only). The weight of each rat was recorded on Days 1 (prior to dosing), 8 and 15.
- Necropsy of survivors performed: All animals were subject to a macroscopic examination which consisted of opening the cranial, thoracic and abdominal cavities. The macroscopic appearance of all examined organs was recorded.

Statistics:

No

Key result

Sex:

female

Dose descriptor:

LD0

Effect level:

>= 2 085 mg/kg bw

Based on:

other: Total Organic Solids (TOS)

Mortality:

No animals died during the study.

Clinical signs:

No animals died and no sign of toxicity or ill health was seen at the routine physical examination.

Body weight:

No effect was observed on the body weights.

Gross pathology:

Effects on organs:
Macroscopic examination of animals killed on Day 15 of the observation period did not reveal any treatment-related findings.

Interpretation of results:

GHS criteria not met

Conclusions:

No signs of toxicity were observed in any of the rats treated with a single oral dose of 2085 mg total organic solids/kg body weight for a period of 14 days.

Executive summary:

The objective of the study was to assess the acute toxicity of lysophospholipase when administered by gavage as a single oral dose to one group six female rats followed by an observation period of 14 days.

The study was conducted in accordance with the OECD Guideline No 423, “Acute Oral Toxicity – Acute Toxic Class method”. The design of the limit test was used. The test item was supplied as a liquid ready to use. The dose volume administered was 2085 mg/kg body weight, based on the Total Organic Solids (TOS) content of the test substance.

A group of three fasted female rats received a single oral gavage dose of the test substance. As results at this dose level indicated the acute lethal oral dose of the test substance to be greater than 2085 mg TOS/kg body weight, in compliance with the study guidelines, a further group of three fasted females was similarly dosed at 2085 mg TOS/kg body weight to complete the study.

There were no deaths during the study. There were no clinical signs of reaction to treatment throughout the study. All animals were considered to have achieved satisfactory body weight gains throughout the study. No abnormalities were noted in any animal at the macroscopic examination at study termination on Day 15.

In conclusion, the acute median lethal oral dose (LD50) to rats of lysophospholipase, batch PPW35424 was demonstrated to be greater than 2085 mg TOS/kg body weight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Value:

2 085 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

Lysophospholipase cannot be classified as toxic upon acute administration.