Lyase, pectate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 5, 1999 to April 20, 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

Adopted 12 May 1981.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Lyase, pectate

EC Number:

232-766-9

EC Name:

Lyase, pectate

Cas Number:

9015-75-2

Molecular formula:

Not available

IUPAC Name:

Pectate lyase IUBMB 4.2.2.2

Constituent 2

Reference substance name:

Protein as a constituent of enzyme deriving from the fermentation or extraction process

Molecular formula:

Not available

IUPAC Name:

Protein as a constituent of enzyme deriving from the fermentation or extraction process

Constituent 3

Reference substance name:

Inorganic salts as a constituent of enzyme deriving from the fermentation or extraction process

Molecular formula:

Not available.

IUPAC Name:

Inorganic salts as a constituent of enzyme deriving from the fermentation or extraction process

Constituent 4

Reference substance name:

Carbohydrates constituent of enzyme deriving from the fermentation or extraction process

Molecular formula:

Not available.

IUPAC Name:

Carbohydrates constituent of enzyme deriving from the fermentation or extraction process

Constituent 5

Reference substance name:

Lipids as a constituent of enzyme deriving from the fermentation or extraction process

Molecular formula:

Not available.

IUPAC Name:

Lipids as a constituent of enzyme deriving from the fermentation or extraction process

Test material form:

liquid

Details on test material:

- Lot/batch No.: PPE 6345
- Expiration date of the lot/batch: 2008-11-30
- Stability under test conditions: Stability at ambient temperature >4 hours
- Storage condition of test material: Stored below minus 18 degrees of C in the dark.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: 6-7 weeks
- Mean body weight just before exposure: 203 g (males), 149 g (females)
- Fasting period before study: Not specified
- Housing: In animal room in suspended stainless steel cages with wire-mesh floor and front.
- Diet (e.g. ad libitum): Standard diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20.5 - 23.0 °C
- Humidity: 38 - 60 %
- Air changes: 10 per hour
- Photoperiod (hrs dark / hrs light): 12 hours light and 12 hours dark

IN-LIFE DATES: From: 1999-03-17 To: 1999-03-31

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Remarks:

The test atmosphere was generated by nebulizing the test material into small droplets by using a compressed air driven nebulizer.

Mass median aerodynamic diameter (MMAD):

2.8 µm

Geometric standard deviation (GSD):

2

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Nose-only inhalation chamber from ADG Developments Ltd., Codicote, Hitchin, Herts, United Kingdom
- Exposure chamber volume: 50 L
- Method of holding animals in test chamber: Nose only
- Source and rate of air: Air was supplied in a volume of 53.1 L/min
- Method of conditioning air and generate aerosols: The test atmosphere was generated by nebulizing the test material into droplets by using as compressed air driven nebulizer (Schlick, Coburg, Germany, type 970/S).
- Method of particle size determination: Once during preliminary tests and once during exposure using a 10-stage cascade impactor (Anderssen, Atlanta, USA) with the largest cut-off size of 32 µm.
- Temperature and humidity in air chamber: Mean temperature during exposure 21.1 ± 0.2 °C (range 20.9 - 21.5 °C), mean relative humidity 53 ± 1 (range 51-54 %).

TEST ATMOSPHERE
- Brief description of analytical method used: Concentration of the test material in the test atmosphere was determined approx. once per hour by gravimetric analysis. 10 L test atmosphere samples were passed through fibre glass filters (Sartorius) at 5 L/min. The collected material was weighed to determine the concentration of test material in the exposure chamber.
- Samples taken from breathing zone: yes

TEST ATMOSPHERE
- Particle size distribution: 80% contained in particles with an aerodynamic diameter equal to or smaller than 5 µm
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): MMAD= 2.8 µm, GSD=2.0 µm

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

>= 4 h

Concentrations:

5.07 mg/L

No. of animals per sex per dose:

5

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: Just before exposure, during exposure, shortly after and at least daily during the observation period. Weighing: Prior to exposure (day 0), and on days 7 and 14.
- Necropsy of survivors performed: yes

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC0

Effect level:

>= 5.07 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality.

Clinical signs:

other: A decreased breathing rate could be seen in all animals. Its severity increased from slight to moderate over the 4 hour exposure period. Abnormalities could not be seen shortly after exposure or during the 14-days observation period.

Body weight:

No effects on body weight gain were observed.

Gross pathology:

No abnormalities.

Applicant's summary and conclusion

Interpretation of results:

not classified

Conclusions:

There were no unscheduled deaths or evidence of a toxic response following exposure of rats for 4 hours to a droplet aerosol generated from pectate lyase, PPE 6345 at a chamber concentration of 5.07 mg/L in air. Thus, it was concluded that the LC50 for pectate lyase is greater than 5.07 mg/m3.

Executive summary:

The acute inhalation toxicity of pectate lyase (Batch number PPE 6345) was studied by nose-only exposure of one group of five male and five female rats each for a 4-hour period to a test atmosphere containing an aerosol of pectate lyase at a concentration of 5.07 ± 0.11 g/m3. The mass median aerodynamic diameter of the particles in the aerosol was 2.8 μm and the geometric standard deviation was 2.0. After exposure, the animals were kept for a 14-day observation period. During exposure, breathing abnormalities were restricted to a decreased breathing rate. No abnormalities were seen shortly after exposure or during the 14-day observation period. No mortality occurred. Weight gain in the animals was considered normal for animals of this strain and age. No abnormalities were seen at necropsy.

It was concluded that the 4-hour LC50 value of an aerosol of pectate lyase (Batch number PPE 6345) was greater than 5.07 g/m3 for both sexes.