Pentane, 1,5-diisocyanato-

Endpoint summary

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:

2019

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

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: Orient Bio Co., Ltd. 8, Hwaaksan-ro 124beon-gil, Buk-myeon, Gapyeong-gun, Gyeonggi-do, Korea

- Age at study initiation: approx. 9 weeks
- Weight at study initiation: 200-211 g
- Housing: less than 3 animals per cage
- Diet (e.g. ad libitum): yes
- Water (e.g. ad libitum): yes
- Acclimation period: at least 6 days Quarantine and acclimatization periods

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C 20.6-23.6
- Humidity (%): 55 ± 10 °C 49.8-62.0
- Photoperiod (hrs dark / hrs light): 12h rhythm

IN-LIFE DATES: From: 22 January 2019 To: 28 February 2019

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

Test substance was formulated with vehicle at 30 mg/mL (1st step), 5 mg/mL (2nd, 3rd step) concentration. The administration volume was 10 mL/kg b.w. The formulated test substance was not analysed for concentration, stability and homogeneity.

Doses:

300 mg/kg and 50 mg/kg

No. of animals per sex per dose:

3 (300 mg/kg) and 6 (2x 3 at 50 mg/kg)

Control animals:

no

Details on study design:

Clinical signs were carefully observed for 0.5, 1, 2, 3 and 4 hours after administration and then once each day for 14 days.
Body weights were measured at animal receipt day, animal allocation day, just before treatment and on day 1, 3, 7 and 14 after the administration, found death animal.
At the end of observation period and death animal, external observations were conducted and sacrificed by blood letting under anesthesia for all survived animals.Then the organs were examine for gross lesions.

Statistics:

No statistical analysis could be performed (the method used is not intended to allow a calculation of a precise LD50 value).

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 50 - < 300 mg/kg bw

Based on:

test mat.

Mortality:

The test substance-related death of 2 animals was observed at the dose of 300 mg/kg bw on day 1 and day 2, respectively.

Clinical signs:

In clinical signs, diarrhea, staining around mouth, soiled perineal region were observed in the dose of 300 mg/kg body weight (1st step).
And, soft stool were observed in the dose of 50 mg/kg body weight (2nd, 3rd step).
Soiled perineal region were observed in the dose of 50 mg/kg body weight (3rd step).

Body weight:

In body weight for animal except dead animals, one animal showed body weight decrease in the dose of 300 mg/kg bw (1st step) on 1 day as compared with administration day. One animal showed body weight decrease in the dose of 50 mg/kg bw (2nd step) on 3 days as compared with 1 day. Three animals showed body weight decrease in the dose of 50 mg/kg bw (2nd, 3rd step) on 14 days as compared with 7 days after administration.

Gross pathology:

In the necropsy finding of dead animals, external findings of soiled perineal region were observed and internal findings of retention of test substance in the stomach and enlarged adrenal gland were observed in the dose of 300 mg/kg body weight (1st step). In the necropsy of survived animals, there were no abnormal findings caused by administration of the test substance.

Interpretation of results:

Category 3 based on GHS criteria

Executive summary:

The acute oral LD50 in rats is determined to >50 mg/kg bw and <300 mg/kg bw based on the results of a study performed according to OECD TG 423. The test dose of 300 mg/kg resulted in death (2 animals), clinical signs such as diarrhea, soft stool, soiled perineal region and staining around mouth, temporary body weight decrease in one animal and necropsy findings such as retention of test substance in the stomach and enlarged adrenal gland.

The test dose of 50 mg/kg resulted in clinical signs such as soft stool and soiled perineal region and temporary body weight decrease. 

In the necropsy of survived animals, there were no abnormal findings caused by administration of the test substance.

 

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

> 50 - < 300 mg/kg bw

Quality of whole database:

The study is GLP-compliant and has a high quality (Klimisch score=1)

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

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:

(2009)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Strain: Hsd Cpb:WU (SPF)
- Source: Harlan, AD Horst, Netherlands
- Age at study initiation: approximately 2 months
- Weight at study initiation: At the study start the variation of individual weights did not exceed ± 10 per cent of the mean for each sex
- Housing: singly in conventional Makrolon® Type IIIH cages (based on A. Spiegel and R. Gönnert, Zschr. Versuchstierkunde, 1, 38, 1961 and G. Meister, Zschr. Versuchstierkunde, 7, 144-153, 1965).
- Diet and water: ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 40 - 60 %
- Air changes (per hr): approximately 10
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: mixture of vapour and aerosol / mist

Type of inhalation exposure:

nose only

Vehicle:

air

Mass median aerodynamic diameter (MMAD):

>= 1.25 - <= 2.5 µm

Geometric standard deviation (GSD):

>= 1.79 - <= 2.51

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Mode of exposure: Animals were exposed to the aerosolized test substance in restrainers made of Plexiglas. Restrainers were chosen that accommodated the animals' size. The type of exposure principle is comparable with a directed-flow exposure design (Moss and Asgharian, Respiratory Drug Delivery IV, 1994, 197) and minimizes re-breathing of exhaled test-atmosphere.
- Exposure apparatus: The chambers used are commercially available (TSE, Bad Homburg, Germany) and the performance as well as their validation has been published (Pauluhn, Journal of Applied Toxicology 14, 55-62, 1994, and Pauluhn & Thiel, Journal of Applied Toxicology 27, 160-167, 2007). The aluminum inhalation chamber has the following dimensions: inner diameter= 14 cm, outer diameter= 35 cm (two-chamber system), height = 25 cm (internal volume = about 3.8 L). Each inhalation chamber segment was suitable to accommodate 20 rats at the perimeter location. The ratio between supply and exhaust air was selected so that 90 % of the supplied air was extracted via the exhaust air location and, if applicable, via sampling ports. The slight positive balance between the air volume supplied and extracted ensured that no passive influx of air into the exposure chamber occurred.
- Source and rate of air: Dry conditioned air, 15 L/min
- Method of conditioning air: Compressed air was supplied by Boge compressors and was conditioned (freed from water, dust and oil) automatically by a VIA compressed air dryer.
- System of generating particulates/aerosols: A modified BGI 3-nozzle Collison nebulizer (Type CN-25 MRE, BGI Inc., Waltham MA, USA) was used in order to attain a high and temporally stable concentration of exposure atmospheres. The temperature was maintained at 5 °C using a digitally controlled cryostat. Nebulization used conditioned, pressurized air (15 L/min; dispersion pressure approximately 200 kPa). The test atmosphere was directly entrained into the inhalation chamber with additional dilution of air (pull/push dilatation cascade which maintains the specified total flow rate into the inhalation chamber).
- Optimization of respirability: In order to increase the efficiency of the generation of respirable particles and prevent larger particles from entering the chamber a pre-separator (baffle) system was used (Tillery, Environmental Health Perspectives, 16, 25-40, 1976).
- Inhalation chamber equilibrium concentration: The test atmosphere generation conditions provide an adequate number of air exchanges per hour (15 L/min x 60 min/(3.8 L) > 200, continuous generation of test atmosphere). Under such test conditions chamber equilibrium is attained in less than one minute of exposure. At each exposure port a minimal air flow rate of 0.75 L/min was provided. The test atmosphere can by no means be diluted by bias-air-flows.
- Method of particle size determination: Cascade impactor (Berner critical orifice cascade impactor)
- Treatment of exhaust air: The exhaust air was purified via filter systems.
- Temperature, humidity: Temperature and humidity measurements were performed by the computerized Data Acquisition and Control System using HC-S3 sensors (Rotronic Messgeräte GmbH, Ettlingen, Germany). The position of the probe was at the exposure location of rats.

TEST ATMOSPHERE
- The integrity end stability of the aerosol generation and exposure system was measured by using a Microdust Pro real-time aerosol photometer (Casella, USA), if technically feasible.
- Brief description of analytical method used: gravimetric analysis of filter samples (filter: Glass-Fibre-Filter, Sartorius, Göttingen, Germany; digital balance). Additionally, a derivatization nitro-reagent method was used (Adsorption tubes containing glass powder coated N-4-Nitrobenzyi-N-npropylamine (nitro reagent). The eluated urea-derivatives were quantified by HPLC.
- Samples taken from breathing zone: yes
- Particle size distribution: The particle size distribution was analysed using a BERNER critical orifice cascade impactor. Aerosol mass < 3 µm: 83.4 % at 35 mg/m³, 83.1 at 69 mg/m³, 64.9 at 114 mg/m³, and 62.4 at 211 mg/m³.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The respirability of the aerosol was adequate and in compliance with test guidelines, i.e. the average mass median aerodynamic diameter (MMAD) was 1.25 µm at 35 mg/m³, 1.36 µm at 69 mg/m³, 2.33 µm at 114 mg/m³, and 2.5 µm at 211 mg/m³; GSD was in the range of 2.51-1.79.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Target concentrations: 10, 20, 40, 75, and 150 mg/m³
Analytical concentrations (HPLC): 19, 35, 69, 114, and 211 mg/m³

No. of animals per sex per dose:

5

Control animals:

yes

Remarks:

air control

Details on study design:

- Duration of observation period following administration: 2 weeks
- Frequency of observations and weighing: Bodyweights were recorded prior to exposure and on days 1, 3, and 7, and weekly thereafter. The appearance and behavior of each rat were examined carefully several times on the day of exposure and at least once daily thereafter.
- Necropsy of survivors performed: yes
- Other examinations performed: Reflexes were tested, based on recommendations made by Irwin (Psychopharmacologica 13, 1968, 222-257). Rectal temperatures were measured shortly after cessation of exposure (approximately within ½hour after the end of exposure) using a digital thermometer with a rectal probe for rats.

Statistics:

Pair-wise Fisher test after the R x C chi-squared test used for necropsy findings (Procedure in accordance with Gad and Weil, Statistics for Toxicologists. Principles and Methods of Toxicology, ed. A.W. Hayes, Raven Press, New York, 280, 1982).
Analysis of variance (ANOVA) used for statistical evaluation (e.g. body weights, rectal temperatures).
If calculation of a LC50 is possible, it is performed by computer (PC) according to the method of Rosiello et al. (J. Toxicol. Environ. Health 3, 797-809, 1977) as modified by Pauluhn (1983). This method is based on the maximumlikelihood method of Bliss (Q.J. Pharm. Pharmacol. 11, 192-216, 1938). If only 2 pairs of values with greater than 0 % lethality and less than 100 % are available then the first linear approximation is based on these values and a X²-homogeneity test is not performed. In this case the interpolated concentration at 50 % lethality is designated the approximate LC50. Additionally, the moving average interpolation according to Schaper et al. (Arch. Toxicol. 68, 332-337, 1994) is used for calculation, if applicable.

Sex:

male

Dose descriptor:

LC50

Effect level:

84 mg/m³ air

95% CL:

52 - 135

Exp. duration:

4 h

Key result

Sex:

female

Dose descriptor:

LC50

Effect level:

53 mg/m³ air

95% CL:

35 - 81

Exp. duration:

4 h

Mortality:

Mortality occurred at and above exposure concentrations of 114 and 35 mg/m³ in male and female rats, respectively, from the day of exposure up to the postexposure day 4 (one rat succumbed on day 18). Thus, female rats displayed a higher susceptibility.
mortalities - males (time of onset): 4/5 at 114 mg/m³ (<24 h, 2 d, 18 d), 5/5 at 211 mg/m³ (< 24 h).
mortalities - females (time of onset): 2/5 at 35 mg/m³ (1 d, 2 d), 3/5 at 69 mg/m³ (< 24 h, 1 d, 4 d), 4/5 at 114 mg/m³ (< 24 h, 1 d, 4 d), 5/5 at 211 mg/m³ (< 24 h, 1 d, 2 d).

Clinical signs:

other: See "Other findings"

Body weight:

Significantly decreased body weights after exposure with evidence of recovery during the postexposure period.

Gross pathology:

Gross necropsy findings considered to be causal for death by an acute lung edema. The macroscopic findings of extrapulmonary organs were essentially indistinguishable amongst exposure and control groups.
Findings for animals sacrificed at the end of the observation period: Lung discoloration and enlarged lymph nodes draining the lung.
Findings for animals succumbed during observation period: The findings show evidence of lung injury and airway irritation.

Other findings:

Reduced reflexes and hypothermia were observed.
Clinical observations revealed the following signs: bradypnea, irregular breathing pattern, labored breathing pattern, dyspnea, breathing sounds, stridor, motility reduced, atony, tremor, high-legged gait, squatting posture, piloerection, haircoat ungroomed, cyanosis, nose reddened, nasal discharge (serous), nostrils with red encrustations, nose/muzzle area red encrusted, emaciation, prone position.
Signs persisted up to the end of the postexposure period.

The respirability of the aerosol was adequate to achieve the objective of study. However, in the range of the LC50 the predominating exposure phase was vapour rather than aerosol.

Executive summary:

A rat study on the acute inhalation toxicity of the substance has been conducted in accordance with OECD TG 403 (2009). Test procedures were adapted so as to comply also with the EU Directive 92/69/EEC, and especially OECD GD 39 (2009). In this study groups of rats were nose-only exposed to the liquid aerosol of the test article at actual concentrations of 19, 35, 69, 114, and 211 mg/m³. The respirability of the aerosol was adequate to achieve the objective of study. However, in the range of the LC50 the predominating exposure phase was vapour rather than aerosol.

The LC50 in this study was 84 mg/m³ for male, and 53 mg/m³ for female rats. Mortality occurred at and above exposure concentrations of 114 and 35 mg/m³ in male and female rats, respectively. Thus, female rats displayed a higher susceptibility. Clinical observations revealed signs reflective of respiratory tract irritation. Mortality occurred from the exposure day up to the postexposure day 4 (one rat succumbed on day 18). Signs persisted up to the end of the postexposure period. Gross necropsy findings (lung injury and airway irritation) considered to be causal for death by an acute lung edema.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

53 mg/m³

Quality of whole database:

The study is GLP-compliant and has a high quality (Klimisch score=1)

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Additional information

Acute toxicity: oral

An acute oral toxicity study was recently conducted according to OECD TG 423.

The acute oral LD50 in rats was determined to be >50 mg/kg bw and <300 mg/kg bw. The test dose of 300 mg/kg resulted in death (2 animals), clinical signs such as diarrhea, soft stool, soiled perineal region and staining around mouth, temporary body weight decrease in one animal and necropsy findings such as retention of test substance in the stomach and enlarged adrenal gland.  Mortalities occurred on day 1 and day 2 after dosing.

The test dose of 50 mg/kg resulted in clinical signs such as soft stool and soiled perineal region and transient body weight decrease. 

No abnormal findings were noted at necropsy in the surviving animals that could be attributed to the administration of the test substance.

 

Acute toxicity: dermal

There is no study on acute dermal toxicity available. Read across to the structurally similar substance HDI reveals no indications for adverse effects after dermal exposure, consequently "no adverse effect observed" is chosen as endpoint conclusion for acute dermal toxicity.

 

Acute toxicity: inhalation

A study on acute inhalation toxicity was recently conducted according to OECD TG 403 and OECD GD 39. In this study groups of rats were nose-only exposed to the liquid aerosol of the test article at actual concentrations of 19, 35, 69, 114, and 211 mg/m³. The respirability of the aerosol was adequate to achieve the objective of study. However, in the range of the LC50 the predominating exposure phase was vapour rather than aerosol.

The LC50 in this study was 84 mg/m³ for male, and 53 mg/m³ for female rats. Mortality occurred at and above exposure concentrations of 114 and 35 mg/m³ in male and female rats, respectively. Thus, female rats displayed a higher susceptibility. Mortality occurred from the exposure day up to the postexposure day 4 (one rat succumbed on day 18). Clinical observations revealed signs reflective of respiratory tract irritation. Signs persisted up to the end of the postexposure period. Gross necropsy findings (lung injury and airway irritation) considered to be causal for death by an acute lung edema.

Justification for classification or non-classification

According to Regulation (EC) No 1272/2008, Annex I, classification is warranted for acute oral toxicity as Cat. 3 (H301: Toxic if swallowed).

According to Regulation (EC) No 1272/2008, Annex I, no classification is warranted for acute dermal toxicity.

According to Regulation (EC) No 1272/2008, Annex I, classification is warranted for acute inhalation toxicity (vapour) as Cat. 1 (H330: Fatal if inhaled).