Prometryn

Endpoint summary

Description of key information

- Oral: LD50 >2000 mg/kg bw, female, rat, according to OECD 425, Moore 2004

- Inhalation: LC50 >2.17 mg/L, males/female, rat, according to OECD 403, Pinto 2004

- Dermal: LD50 >2000 mg/kg bw, male/female, rat, according to OECD 402, Moore 2004

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:

4 Aug 2004 to 25 Aug 2004

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:

December 2001

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Version / remarks:

December 2002

Qualifier:

according to guideline

Guideline:

other: JMAFF 59 NohSan No. 4200

Version / remarks:

January 28, 1985

GLP compliance:

yes

Test type:

up-and-down procedure

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Remarks:

derived, albino

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes
- Age at study initiation: Yound adult (11-12 weeks)
- Weight at study initiation: 197-222 grams
- Fasting period before study: overnight
- Housing: The animals were single housed in suspended stainless steel caging with mesh floors which conform to the size recommendations in the most recent Guide for the Care and Use of Laboratory Animals DHEW (NIH). Litter paper was placed beneath the cage and was changed at least three times per week.
- Diet: Rodent Chow
- Water: Filtered tap water was supplied ad-libitum by an automatic water dispensing system
- Acclimation period: 22-29 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 24
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 4 Aug 2004 To: 25 Aug 2004

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

1% w/w in distilled water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 25% w/w

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Body weights: Individual body of the animals were recorded prior to test substance administration (initial-Day 0) and again on Days 7 and 14 (termination) following dosing
- Cage-side observations: The animals were observed for mortality, sign of gross toxicity, and behavioural changes within the first several hours post-dosing and at least once daily thereafter for up to 14 days after dosing or until death occurred. Observations included gross evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behaviour pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea and coma.
- Necropsy of survivors performed: yes, all rats were euthanized via CO2 inhalation at the end of the 14-day observation period. Gross necropsies were performed on all animals. Tissues and organs of the thoracic and abdominal cavities were examined.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals survived study.

Clinical signs:

other: Following test substance administration, three of the five rats exhibited facial staining, piloerection and/or a reduced faecal volume but recovered by Day 3 and appeared active and healthy for the remainder of the 14-day observation period.

Gross pathology:

No gross abnormalties were noted.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study (OECD 425, GLP), the acute oral LD50 of the test material is greated than 2000 mg/kg bw in female rats.

Executive summary:

An acute oral toxicity test (Up and Down Procedure) was conducted with rats according to GLP and OECD guideline 425, to determine the acute toxicity resulting from a single dose via the oral route. An initial limit dose of 2000 mg of the test material per kg bw was administered to one healthy female rat by oral gavage. Due to the absence of mortality in this animal, four additional females were dosed in sequence at the same dose level. Since all of the animals survived, no additional animals were tested. Females were selected for the test because they are frequently more sensitive to the toxicity of test compounds than males. All animals were observed for mortality, signs of gross toxicity, and behavioural changes at least once daily for 14 days after dosing. Body weights were recorded prior to administration and again on Days 7 and 14 (termination) after dosing. Necropsies were performed on all animals at terminal sacrifice. 

All animals survived and gained body weight during the study. Following test material administration, three of the five rats exhibited facial staining, piloerection and/or a reduced faecal volume but recovered by Day 3 and appeared active and healthy for the remainder of the 14-day observation period. No gross abnormalities were noted for any of the animals when examined at the conclusion of the 14-day observation period.

Under the conditions of this study, the acute oral LD50 of the test material was greater than 2000 mg/kg bw in female rats. 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

GLP compliant OECD 425 study.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Sep 2004 to 13 Oct 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

1981

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Version / remarks:

May, 1993

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Version / remarks:

1998

GLP compliance:

yes

Test type:

fixed concentration procedure

Limit test:

no

Species:

rat

Strain:

Wistar

Remarks:

Alpk:APfSD (Wistar-derived)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 298-352 g (males), 233-241 g (females)
- Housing: the rats were housed 5 per cage, sexes separately, in multiple rat racks suitable for animals of this strain and the weight range expected during the course of the study. Additional animals were housed 1 per cage, sexes separately. Nylabones and cardboard tubes provided environmental enrichment during the study, except for during the exposure period. Paper in loose balls was supplied as nesting and bedding material.
- Diet: RM1, ad libitum, except during exposure
- Water: ad libitum, except during exposure
- Acclimation period: at least 5 days, prior to the start of exposure

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 - 70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 16 Sep 2004 To: 13 Oct 2004

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Mass median aerodynamic diameter (MMAD):

>= 2.76 - <= 2.94 µm

Geometric standard deviation (GSD):

>= 1.48 - <= 1.52

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE
The test atmosphere was generated using a Rotating Brush Generator (RBG). A 28 mm can was used, hand-packed. The brush speed was 650 rpm, the vertical speed van 18-20 mm/hour. Clean, dry air (dried and filtered) was passed through the RGB at a nominal flow rate of 25 L/minute (at normal temperature and 20 psi) and carried the atmosphere to the exposure chamber, having an internal volume of 27.6 litres, in order to achieve a minimum of 12 air changes per hour. Since diluting air was not employed, the flow rate through the exposure chamber was the same as that employed in the generation the test atmosphere. Air flows were monitored continuously and recorded at least 3 times using variable area flowmeters and were altered as necessary to maintain the target concentration.

TEST ATMOSPHERE
The particulate concentration of test atmosphere, close to the animals’ breathing zone, was measured gravimetrically at least twice during exposure. This was done by drawing the test atmosphere, at a known flow rate, for a known time, through a 25 mm diameter, polyvinyl chloride (PVC) GLA 5000 filter housed in a Delrin open-face filter holder. The filter was weighed before and after the sample was taken. The concentration calculated as follows:

Concentration (mg/L) = (weight of filter after sampling (mg) – weight of filter prior to sampling (mg)) / time (minutes) x airflow (L/minute)

The aerodynamic particle size distribution was measured three times during the exposure period, using a Marple Cascade Impactor which aerodynamically separated airborne particles into pre-determined size ranges. The amount of aerosol, by weight, in each size range, was then used to calculate the aerodynamic particle size distribution of the aerosol.
Using a spreadsheet, the data were transformed using a log/probit transform and a linear regression derived from the cumulative data. Using this regressing line, the mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) were calculated.

EXPOSURE SYSTEM
Animals were exposed nose-only to the test atmosphere. Animals were restrained in polycarbonate tubes. These were inserted into a PERSPEX exposure chamber. The chamber was covered with an aluminium cone and stood on an aluminium base.
Before exposure of the test animals, the atmosphere was shown to have been acceptably stable for approximately 30 minutes. During this period the holes of the exposure chamber were plugged. The animals were exposed for 4 hours.
The temperature and relative humidity in each chamber were recorded at least 3 times during exposure using a portable, digital temperature and relative humidity monitor; they were withing the range of 21.8-22ºC and 10-12% respectively.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

- Target concentration: 2 mg/L
- Particulate concentration: 2.17 mg/L
- Analysed concentration: 2.08 mg/L

No. of animals per sex per dose:

- One main group: 5 animals per sex per dose
- Second group: 1 male and 1 female

Control animals:

no

Details on study design:

- Second group was used for trial exposures to the target concentration.
- Duration of observation period following administration: 14 days
- Clinical observations: Prior to the start of the study, all rats were examined to ensure that they were physically normal and exhibited normal activity. During exposure, they were observed frequently and, at the end of the 4-hour exposure period, each rat was given a detailed clinical examination. The animals were also subjected to detailed clinical observations, included the finding of ‘no abnormalities detected’, daily during the 14 day observation period.
- Body weights: The body weight of each rat was recorded on day -1 (to ensure animals of one sex were withing a similar weight range), 1, 8 and prior to termination on day 15.
- Necropsy of survivors performed: yes, all rats were killed by an over-dose of anaesthetic (halothane Ph Eur vapour) followed by exsanguination. All animals were examined post mortem. This involved an external observation and a careful internal examination of all thoracic and abdominal viscera

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.17 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

There were no deaths during the exposure or observation periods.

Clinical signs:

other: associated with restraint

Remarks:

wet fur and chromoacryorrhoea

Body weight:

All male animals had gained weight by day 8 of the study and continued to gain weight to the end of the study. All females gained weight by the end of the study.

Gross pathology:

There were no treatment-related findings seen at necropsy.

Other findings:

- All test animals had test substance around the snout.
- Changes indicated of mild irritation of the upper respiratory tract (breathing rate reduced, breathing depth increased, reduced response to sound) were seen in all animals during exposure and in some or all of the animals post-exposure.
- Changes indicative of mild toxicity (decreased activity, salivation, reduced foot withdrawal reflex) were observed in some or all animals post-exposure).
- All animals had fully recovered by day 2 of the study.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the study (OECD 403, GLP), it is concluded that the median lethal concentration of the test material exceeds 2.17 mg/L.

Executive summary:

In a GLP compliant study performed according to OECD guideline 403, groups of five male and five female Alpk:APfSD (Wistar-derived) rats were exposed nose-only for a single four-hour period to the test material at a target particulate concentration of 2 mg/L. Test atmospheres were analysed for particulate concentration and test material. The particle size distribution of the test atmosphere was analysed three times during the exposure period. Following exposure, the animals were retained without treatment for 14 days. Clinical observations and body weights were recorded throughout the study. At the end of the scheduled period, the animals were killed and examined post-mortem. The achieved test atmosphere had the following characteristics: a) Target concentration: 2 mg/L; b) Particulate concentration: 2.17 mg/L; c) MMAD: 2.76, 2.94, and 2.92 µm; d) GSD: 1.48, 1.52, and 1.51. There were no deaths. Clinical symptoms indicative of irritation of the upper respiratory tract and of mild systemic toxicity were seen during and after exposure. All animals had fully recovered by day 2 of the study.

Nose-only exposure for 4 hours to a particulate concentration of 2.17 mg/L resulted in no deaths and no adverse effects. It is concluded that the median lethal concentration, LC50, of the test material exceeds 2.17 mg/L.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating conc.

Value:

2 170 mg/m³ air

Quality of whole database:

GLP compliant OECD 403 study.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 Aug 2004 to 18 Aug 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

1997

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Version / remarks:

1998

Qualifier:

according to guideline

Guideline:

other: JMAFF 59 NohSan No. 4200

Version / remarks:

January 28, 1985

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Remarks:

albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 9-10 weeks
- Weight at study initiation: 282-336 grams (males), 201-225 grams (females)
- Housing: The animals were singly housed in suspended stainless steel caging with mesh floors which conform to the size recommendations in the most recent Guide for the Care and Use of Laboratory Animals DHEW (NIH). Litter paper was placed beneath the cage and was changed at least three times per week.
- Diet: Rodent Chow
- Water: Filtered tap water was supplied ad libitum by an automatic water dispensing system
- Acclimation period: 15 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-22
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 4 Aug 2004 To: 18 Aug 2004

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Remarks:

moistened with distilled water to achieve a dry paste

Details on dermal exposure:

PREPARATION AND SELECTION OF ANIMALS
On the day prior to application, a group of animals was prepared by clipping the dorsal area and the trunk. After clipping and prior to application, the animals were examined for health, weighed (initial) and the skin checked for any abnormalities. Ten healthy rats (five males and five females) were selected for test.

APPLICATION OF TEST SUBSTANCE
Prior to application, the test substance was moistened with distilled water to achieve a dry paste by preparing a 45% w/w mixture. The test substance was then applied to a 2 inch x 3 inch, 4-ply gauze pad and placed on a dose area of approximately 2 inches x 3 inches (approximately 10% of the body surface). The gauze pad and entire trunk of each animal were then wrapped with 3-inch Durapore tape to avoid dislocation of the pad and to minimize loss of the test substance. The rats were then returned to their designated cages. The day of application was considered Day 0 of the study. After 24 hours of exposure to the test substance, the pads were removed and the test sites were gently cleansed of any residual test substance.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Body weights: Individual body weights of the animals were recorded prior to test substance application (initial) and again on Days 7 and 14 (termination).
- Cage-side observations: The animals were observed for mortality, signs of gross toxicity, and behavioural changes during the first several hours after application and at least once daily thereafter for 14 days. Observations included gross evaluation of skin and fur, eyes and mucous membranes, respiratory, circulatory, autonomic and central nervous systems, somatomotor activity and behaviour pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea and coma.
- Necropsy of survivors performed: yes, all rats were euthanized via CO2 inhalation on Day 14. Gross necropsies were performed on all animals. Tissues and organs of the thoracic and abdominal cavities were examined.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals survived the study.

Clinical signs:

other: All animals appeared active an healthy during the study. There were no signs of gross toxicity, adverse pharmacologic effects or abnormal behaviour.

Gross pathology:

No gross abnormalities were noted for any of the animals when necrosied at the conclusion of the 14-day observation period.

Other findings:

There were no signs of dermal irritation.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this study (OECD 402, GLP), the single dose acute dermal LD50 of the test substance is greater than 2000 mg/kg of body weight in male and female rats.

Executive summary:

An acute dermal toxicity test was conducted with rats according to GLP and OECD guideline 402, to determine the potential acute toxicity resulting from a single topical application. Two thousand milligrams per kilogram of body weight of the test substance was moistened with distilled water and applied under semi-occlusive conditions to the skin of ten healthy rats for 24 hours. The animals were observed for mortality, signs of gross toxicity, and behavioural changes at least once daily for 14 days. Body weights were recorded prior to application and again on Days 7 and 14 (termination). Necropsies were performed on all animals at terminal sacrifice. All animals survived, gained body weight and appeared active and healthy during the study. There were no signs of gross toxicity, dermal irritation, adverse pharmacologic effects or abnormal behaviour. No gross abnormalities were noted for any of the animals when examined at the conclusion of the 14-day observation period.

Under the conditions of this study, the single dose acute dermal LD50 of the test substance was greater than 2000 mg/kg of body weight in male and female rats.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

GLP compliant OECD 402 study.

Additional information

Acute toxicity: oral 

An acute oral toxicity test (Up and Down Procedure) was conducted with rats according to GLP and OECD guideline 425, to determine the acute toxicity resulting from a single dose via the oral route.

An initial limit dose of 2000 mg of the test material per kg bw was administered to one healthy female rat by oral gavage. Due to the absence of mortality in this animal, four additional females were dosed in sequence at the same dose level. Since all of the animals survived, no additional animals were tested. Females were selected for the test because they are frequently more sensitive to the toxicity of test compounds than males. All animals were observed for mortality, signs of gross toxicity, and behavioural changes at least once daily for 14 days after dosing. Body weights were recorded prior to administration and again on Days 7 and 14 (termination) after dosing. Necropsies were performed on all animals at terminal sacrifice.

All animals survived and gained body weight during the study. Following test material administration, three of the five rats exhibited facial staining, piloerection and/or a reduced faecal volume but recovered by Day 3 and appeared active and healthy for the remainder of the 14-day observation period. No gross abnormalities were noted for any of the animals when examined at the conclusion of the 14-day observation period. Under the conditions of this study, the acute oral LD50 of the test material was greater than 2000 mg/kg bw in female rats.

 

A further acute oral toxicity study was conducted on male and female albino rats using the test material. The test material was administered at 25.0% w/v concentration in 0.5% w/v aqueous carboxymethyl cellulose. The acute oral LD50 values (with 95% confidence limits) were calculated to be 4790 (4230-5420) mg/kg bw for males and 4460 (4240-4680) mg/kg bw for females. The combined LD50 value for males and females was 4550 (4260-4870) mg/kg bw.

 

Acute toxicity: inhalation 

In a GLP compliant study performed according to OECD guideline 403, groups of five male and five female Alpk:APfSD (Wistar-derived) rats were exposed nose-only for a single four-hour period to the test material at a target particulate concentration of 2 mg/L. Test atmospheres were analysed for particulate concentration and test material. The particle size distribution of the test atmosphere was analysed three times during the exposure period. Following exposure, the animals were retained without treatment for 14 days. Clinical observations and body weights were recorded throughout the study. At the end of the scheduled period, the animals were killed and examined post-mortem. The achieved test atmosphere had the following characteristics: a) Target concentration: 2 mg/L; b) Particulate concentration: 2.17 mg/L; c) MMAD: 2.76, 2.94, and 2.92 µm; d) GSD: 1.48, 1.52, and 1.51. There were no deaths. Clinical symptoms indicative of irritation of the upper respiratory tract and of mild systemic toxicity were seen during and after exposure. All animals had fully recovered by day 2 of the study.

Nose-only exposure for 4 hours to a particulate concentration of 2.17 mg/L resulted in no deaths and no adverse effects. It is concluded that the median lethal concentration, LC50, of the test material exceeds 2.17 mg/L.

 

Acute toxicity: dermal 

An acute dermal toxicity test was conducted with rats according to GLP and OECD guideline 402, to determine the potential acute toxicity resulting from a single topical application. Two thousand milligrams per kilogram of body weight of the test substance was moistened with distilled water and applied under semi-occlusive conditions to the skin of ten healthy rats for 24 hours. The animals were observed for mortality, signs of gross toxicity, and behavioural changes at least once daily for 14 days. Body weights were recorded prior to application and again on Days 7 and 14 (termination). Necropsies were performed on all animals at terminal sacrifice. All animals survived, gained body weight and appeared active and healthy during the study. There were no signs of gross toxicity, dermal irritation, adverse pharmacologic effects or abnormal behaviour. No gross abnormalities were noted for any of the animals when examined at the conclusion of the 14-day observation period.

Under the conditions of this study, the single dose acute dermal LD50 of the test substance was greater than 2000 mg/kg of body weight in male and female rats.

Justification for classification or non-classification

Based on the results of the acute oral, inhalation and dermal toxicity studies classification for acute toxicity is not warranted in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation No. (EC) 1272/2008.