Reaction mass of 2-methylbutyl acetate and pentyl acetate

Endpoint summary

Description of key information

Oral: LD50, rats > 5000mg/kg

Dermal: LD50, rats and rabbits >> 2000mg/kg

Inhalation: rats: no mortality up to 19.3mg/L (saturated vapour concentration) after 4h exposure. Mortality occurs after longer exposure times

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:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Principles of method if other than guideline:

The acute toxicity was examined following oral administration of various amounts of primary amyl acetate to male and female rats. Rats were observed for up to 14 days post-dosing. A gross pathological examination was performed on each rat.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

other: Hilltop-Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

The animals are maintained on appropriate commercial diet and municipal water. Both are available ad libitum except during periods of fasting (rat peroral test), manipulation or restraint.

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

Hilltop-Wistar albino rats, weighing between 200 and 300 g, receive the test material by stomach intubation with a ball-end stainless steel needle. The
sample is injected through the needle by means of a syringe and doses are varied by adjusting the volume of the test material or its dilution. The rats are fasted overnight before dosing. Five males and 5 females are included on each level.

Doses:

4.0, 8.0 and 16.0 ml/kg for males and 4.0, 8.0, 11.3 and 16.0 ml/kg for females (corresponding to 3502.4, 7004.8 and 14009.6 mg/kg for males and 3502.4, 7004.8, 9894.3 and 14009.6 mg/kg for females, calculated assuming a test substance density of 0.8756 g/ml)

No. of animals per sex per dose:

5 male and 5 female

Control animals:

not specified

Details on study design:

Groups of 5 male or female rats were weighed and dosed with undiluted primary amyl acetate. Survivors were weighed 7 and 14 days post-dosing. Animals were observed for 14 days post-dosing. Animals that died or survived were subjected to a gross necropsy examination.

Statistics:

LD50's are calculated by the moving average method (Thompson, 1947) and are based on a 14-day observation period.

Reference
Thompson, W.R. (1947). Use of moving averages and interpolation to estimate median-effective dose. Bact. Reviews 11:115.

Preliminary study:

Not applicable.

Sex:

male

Dose descriptor:

LD50

Effect level:

> 7 004.8 - < 14 009.6 mg/kg bw

Based on:

test mat.

Remarks on result:

other: calculated from 8 and 16 ml/kg

Sex:

female

Dose descriptor:

LD50

Effect level:

12 258.4 mg/kg bw

Based on:

test mat.

95% CL:

10 594.8 - 14 272.3

Remarks on result:

other: calculated from 14 ml/kg (12.1 - 16.3 ml/kg)

Mortality:

Male rats
2/5 died one day after dosing with 16.0 ml/kg
0/5 died following dosing with 4.0 or 8.0 ml/kg

Female rats
4/5 died one day after dosing with 16.0 ml/kg
0/5 died after dosing with 4.0, 8.0 or 11.3 ml/kg

Clinical signs:

other: Male rats dosed with 16.0 ml/kg: Sluggishness, unsteady gait at 45 min; lacrimation, slow respiration prostration at 4 hr. Survivors recovered at 2 days. No clinical signs noted in male rats dosed with 4.0 or 8.0 ml/kg. Female rats dosed with 16.0 ml/kg

Gross pathology:

Male rats
16.0 ml/kg: In victims, 1 with liver blanched, intestines green; 1 with hydronephrosis. In survivors, nothing remarkable.
8.0 ml/kg: Nothing remarkable.
4.0 ml/kg: Nothing remarkable.

Female rats
16.0 ml/kg: In victims, livers blanched red discoloration on peri-nasal fur of 1. In survivor nothing remarkable.
11.3 ml/kg: Lungs mottled dark red and red.
8.0 ml/kg: Nothing remarkable.
4.0 ml/kg: Nothing remarkable.

Other findings:

No additional information available.

No additional information available.

Interpretation of results:

GHS criteria not met

Conclusions:

The oral LD50 for male and female rats is >16.0 and 14.0 ml/kg, respectively.

Executive summary:

The acute oral toxicity of primary amyl acetate was examined in rats. The oral LD50 for male and female rats is >16.0 and 14.0 ml/kg, respectively.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

6 500 mg/kg bw

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:

1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPP 81-3 (Acute inhalation toxicity)

Principles of method if other than guideline:

Rats were exposed to primary amyl acetate for 6 hrs using static conditions or 4 hrs using dynamic conditions. Survivors were observed for 14 days following exposure. All rats were subjected to a gross necropsy examination.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

No additional information available.

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

Groups of male and female rats were exposed to primary amyl acetate for 6 hours under static conditions. The test material is enclosed in a sealed 120 liter chamber for approximately 18 hours before the introduction of the rats.

Groups of male and female rats were exposed to primary amyl acetate for 4 hours under dynamic airflow conditions. The test material is metered with an FMI Lab Pump (G-6) into a heated glass evaporator. Air containing vapors of test material were swept at a flow rate of 300 l/m into the chamber which had a volume of Approximately 1330 liters with pyramidal top and bottom.

Monitoring Chamber Concentrations
Dynamic Exposure
The chamber atmosphere was analyzed for amyl acetate isomers approximately once every 8 minutes during the exposure. The mean concentration +/- standard deviation) was 976 (+/- 13.0) ppm. The mean analytical/nominal concentration ratio was 0.98; the nominal concentration being an estimate calculated from the quantity of test material consumed during the exposure and the chamber airflow rate. The concentration ratio of the n-amyl acetate isomer to total amyl acetate isomers in the chamber atmosphere was 58%
.
Static Exposure
The concentration of amyl acetate isomers was determined hourly in each of the two exposure chambers. The females were exposed to a mean concentration of 3628 (+/- 330) ppm and the males to 3693 (+/- 257) ppm. The concentration ratio of the n-amyl acetate isomer to total amyl acetate isomers in the chamber atmosphere was 68%.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 - 6 h

Concentrations:

976.1 (+/- 13.0) ppm (dynamic airflow conditions)
3628 (+/-330) ppm (static airflow condtions) females
3693 (+/- 257) ppm (static airflow conditions) males

No. of animals per sex per dose:

5 male and 5 female rats (dynamic airflow conditions)
5 male and 5 female rats (static airflow conditions)

Control animals:

not specified

Details on study design:

Rats were exposed for 4 hrs under dynamic conditions to the test material. Animals were observed during exposure and for 14 days following exposure for clinical symptoms. All animals were submitted to a gross pathological examination upon death or the end of the observation period.

Statistics:

Means and standard deviations were calculated.

Preliminary study:

Not applicable.

Sex:

male/female

Dose descriptor:

LC0

Effect level:

>= 19.28 mg/L air

Based on:

test mat.

Exp. duration:

6 h

Remarks on result:

other: static conditions (original value: 3628 ppm)

Mortality:

There was no mortality in rats exposed under dynamic (4 hr) or static (6 hr) conditions.

Clinical signs:

other: Rats exposed under dynamic condtions (4 hrs at 976 ppm) Group Observations: There were no clinical signs of toxicity. Rats exposed under static conditions (6 hrs at ~3650 ppm) Group Observations:. Forced respiration and hypoactivity during exposure, abno

Body weight:

Rats exposed under dynamic condtions (4 hrs at 976 ppm)
Males gained on average 90 g during the 14 day observation period while females gained 20 g during the same time period.

Rats exposed under static conditions (6 hrs at ~3650 ppm)
Males gained on average 88 g during the 14 day observation period while females gained 10 g during the same time period.

Gross pathology:

There were no grossly visible lesions noted in rats subjected to the test material under dynamic or static conditions.

Other findings:

No additional information available.

No additional information available.

Interpretation of results:

GHS criteria not met

Conclusions:

The results of these studies indicate that the 4- or 6-hour LC50 values for primary amyl acetate are greater than 19.3 mg/L

Executive summary:

The acute inhalation toxicity of primary amyl acetate was examined. In rats exposed (static conditions) to primary amy1 acetate vapor as high as 3600 ppm (~19.3 mg/L) for six hours, no deaths occurred. Signs of toxicity were observed during the exposure, but these signs disappeared shortly after termination of the exposure. Rats exposed under dynamic conditions to 976 ppm for 4 hours also survived the exposure with less visible signs of toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating conc.

Value:

19 300 mg/m³ air

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:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline available

Principles of method if other than guideline:

The acute dermal toxicity of primary amyl acetate was examined with male and female rabbits. The test material was in contact with skin for 24 hours. The application site was examined 1 hour and 7 and 14 days after the contact period.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

The animals are maintained on appropriate commercial diet and municipal water. Both are available ad libitum except during periods of restraint.

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

New Zealand White rabbits, weighing between 2.0 and 3.0 kg, are immobilized during a 24-hr contact period. The test material is retained under impervious sheeting on the clipped, intact skin of the trunk. Doses are varied by adjusting the volume or weight of the test material. After the contact period, excess fluid is removed to diminish ingestion.

Duration of exposure:

24 hours

Doses:

4.0, 8.0 and 16.0 ml/kg for males or 16.0 ml/kg for females (corresponding to 3502.4, 7004.8 and 14009.6 mg/kg for males and or 14009.6 mg/kg for females, calculated assuming a test substance density of 0.8756 g/ml)

No. of animals per sex per dose:

5 males or 5 females/dose

Control animals:

not specified

Details on study design:

Test material is applied to the trunk of the rabbits for 24 hours under occlusive conditions. The application site is examined 1 hour and 7 and 14 days after removal of the test material.

Statistics:

LD50's are calculated by the moving average method (Thompson, 1947) and are based on a 14-day observation period.

Reference
Thompson, W.R. (1947). Use of moving averages and interpolation to estimate median-effective dose. Bact. Reviews 11:115.

Preliminary study:

Not applicable

Sex:

male

Dose descriptor:

LD50

Effect level:

8 326.96 mg/kg bw

Based on:

test mat.

95% CL:

5 693.22 - 14 797.64

Remarks on result:

other: calculated from 9.51 ml/kg (5.36-16.9 ml/kg)

Sex:

female

Dose descriptor:

LD50

Effect level:

> 14 009.6 mg/kg bw

Based on:

test mat.

Mortality:

Male rabbits
16.0 ml/kg: 4 of 5 died. Deaths occurred 1, 1, 2 and 5 days after dosing
8.0 ml/kg: 2 of 5 died. Deaths occurred 2 and 7 days after dosing.
4.0 ml/kg: 0 of 5 died.

Female rabbits
16.0 ml/kg: 1 of 5 died. Death occurred two days after dosing.

Clinical signs:

other: Male rabbits 16.0 ml/kg: Immediate signs of discomfort (intense squirming and struggling); sluggishness, unsteady gait at 1 day. Prostration before death. Survivor recovered at 5 days. 8.0 ml/kg: Sluggishness, unsteady gait at 1 day. Survivors recovere

Gross pathology:

Male rabbits
16.0 ml/kg: In victims, liver with multiple yellow or white foci; intestines red. In survivor, liver with multiple cream-colored foci.
8.0 ml/kg: In victims, lungs of 1 mottled; liver of 1 with cream-colored foci; testes of 1 small; bladder of 1 filled with light red fluid. In survivors lungs of 1 dull dark red, with creamcolored patches, red-tan fluid in thoracic cavity.
4.0 ml/kg: Nothing remarkable

Female rabbits
16.0 ml/kg: In victim, trachea with red patches; liver with multiple white foci and dark dimpling. In survivors, nothing remarkable.

Other findings:

Clinical signs at application site
Male rabbits
16.0 ml/kg: Erythema immediately; ecchymosis at 1 day; survivor with necrosis, edema, fissuring at 14 days.
8.0 ml/kg: Erythema immediately desquamation at 7 days.
4.0 ml/kg: Erythema immediately desquamation at 7 days.

Female rabbits
16.0 ml/kg: Erythema immediately ecchymosis, desquamation, scab formation at 14 days.

No additional information available.

Interpretation of results:

GHS criteria not met

Conclusions:

The acute dermal toxicity of primary amyl acetate in male and female rabbits was 9.51 and >16.0 ml/kg, respectively.

Executive summary:

The acute dermal LD50 of primary amyl acetate was examined. The acute dermal toxicity of primary amyl acetate in male and female rabbits was 9.51 and >16.0 ml/kg, respectively.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

14 009.6 mg/kg bw

Additional information

Several acute toxicity studies are available with the reaction mass of 2 -methylbutyl acetate and pentyl acetate available. Data were also included for the reactants pentyl acetate (CAS: 628-63-7 = amyl acetate) and 2-methylbutyl acetate (= isoamyl acetate; CAS: 123-92-2).

 

Oral exposure

No guideline conform study is available, but a couple of studies were conducted similar to the OECD guideline 401. The LD50 after acute oral treatment ranges from 6500 to 17249.3 mg/kg bw in rats.

In a study by Union Carbide (1983), 5 male and female rats per group were treated with approx. 3500, 7000, 9900, and 14000 mg/kg of the registered substance. Rats were observed for up to 14 days post-dosing. A gross pathological examination was performed on each rat. 2 males and 4 females died in the high dose group, none in the low and mid-dose groups. Sluggishness, unsteady gait, lacrimation, slow respiration and prostration, as well as blanched liver, green intestines (some with hydronephrosis), and/or discoloration on peri-nasal fur at necropsy, were observed in the animals that died. Based on the above results, the LD50 is >7004.8 – 14009.6 mg/kg bw in males and ca. 12258.4 mg/kg bw in females. In two additional Union Carbide Corporation studies the LD50 was 6500 mg/kg bw in males (1955), and 17249.3 mg/kg bw in female rats (1976).

In a publication by Smyth (1962), single oral dose toxicity is estimated by the gastric intubation of Carworth-Wistar rats (5 animals per dose group). Based upon mortalities during the 14 -day observation period, the LD50 was estimated to be 6500 mg/kg bw.

Amyl acetate

Groups of 10 young adult Osborne-Mendel rats evenly divided by sex were treated by intubation with pentyl acetate (Jenner, 1964). All animals were maintained under close observation for signs of toxicity until the animals appeared normal and showed weight gain. The usual observation period was 2 weeks. The resulting LD50 was 16550 mg/kg bw in male and female rats.

CAS 123-92-2

In an oral study with rats an LD50 value greater than 5000 mg/kg was identified for isoamyl acetate, CAS 123 -92 -2 (Moreno, 1973).

When isoamyl acetate was given to male and female rabbits, the LD50 value was 7410 mg/kg bw (Munch, 1972). In this study, the Narcotic Dose (ND50; i.e. which is the quantity producing stupor, loss of voluntary movements in half of the rabbits) was also determined as 4160 mg/kg.

 

Dermal exposure

A couple of studies are available with the registered substance, conducted similar to the OECD guideline 402, with LD50 after acute dermal treatment >14009.6 mg/kg bw in female rats and ranging from 8326.96 to >17600 mg/kg bw in rabbits

In a Union Carbide Corporation study (1983), the acute dermal toxicity of test substance was examined in male and female rabbits. The test substance was brought in contact with skin for 24 hours (app. 3500, 7000 and 14000 mg/kg, 5 animals per sex and dose). The animals were examined up to 14 days after the contact period. 4/1 males/female died in the high dose group, 2 males in the mid-dose and none in the low group. Immediate signs of discomfort (intense squirming and struggling); sluggishness, unsteady gait and/or prostration were observed in the high dose and partially in the mid-dose. At necropsy, liver with multiple yellow or white foci, reddened intestines, mottled lungs and/or filled bladder were observed, principally in the animals that died. The obtained LD50 was ca. 8326.96 mg/kg in males and >14009.6 mg/kg bw in females.

Smyth et al. (1962) determined the dermal toxicity of primary amyl acetate in male rabbits. Additionally, penetration of the skin was estimated by a technique closely akin to the one-day cuff method of Draize and associates (Draize, J.H., Wodhard, G. and Calvery, H.O.: Methods for Study of Irritation and Toxicity of Substances Applied Topically to the Skin and Mucous Membranes, J. Pharmacol. Exp. Therap., 82, 377, Nov. 1944). A group of 4 male New Zealand White rabbits received app. 17580mg/kg dermally of the test substance for 24 h under occluded conditions on the clipped, intact skin of the trunk. The LD50 was reported to be >17580 mg/kg bw.

A second Union Carbide Corporation (1955) study conducted in male rabbits with 4378, 8756 or 17512 mg/kg bw test substance yielded an LD50 value above 17512 mg/kg bw. One animal of four died at this dose

In a rat study (Union Carbide Corporation, 1976) conducted similar to the OECD guideline 402, the test substance was applied to the shaved skin sites of female animals for 4 hours. Survivors were observed for 14 days. The obtained LD50 was >14009.6 mg/kg bw.

 

CAS: 123-92-2

In Fragrance raw materials monographs, a dermal LD 50 value in rabbits of above 5000mg/kg is cited (Moreno, 1973), without further data.  

 

Inhalation exposure

Several acute inhalation studies are available in rats, all of which were conducted according to the inhalation hazard test protocols. In general, no death occurred when the test animals were exposed to an atmosphere saturated with vapors the reaction mass of 2-methylbutyl acetate and pentyl acetate up to an exposure duration of 4 hours. Mortality was however observed when the exposure protocols duration was augmented to 6-8 hours. The weight of evidences from the 4-hours exposure-period results suggest that the LC50 is greater than 19.3 mg/l after acute inhalation exposure to test atmosphere saturated with vapours of the test substance.

In a study conducted according to EPA OPP 81-3 (Union Carbide 1984), rats were exposed to the reaction mass of 2 -methylbutyl acetate for 6 hours using static conditions (19.7mg/L) or 4 hours using dynamic conditions (5.2 mg/l). Survivors were observed for 14 days and all rats were subjected to a gross necropsy examination at the end of the observation period. While no mortality occurred, the clinical signs observed only in the 6-hour exposure group during exposure were: forced respiration and hypoactivity, abnormal righting, abnormal toe and tail pinch reflex, periocular wetness and a slight dermal irritation immediately following the exposure. All rats appeared normal throughout the post-exposure period. No adverse effects were found at necropsy.

In another Union Carbide Corporation (1955) study also conducted according to EPA OPP 81-3, rats were exposed to vapours of primary amyl acetate for 4 or 8 hours. Survivors were observed for a 14 day period. While all rats exposed for 8 hours to 6100 ppm (corresponding to approx. 32.4 mg/l) died, all rats exposed to 5200 ppm (corresponding to approx. 27.6 mg/l) for 4 hours survived. The only notable clinical sign was narcosis (within 2 hours of exposure).

In a third the Union Carbide Corporation (1984) study conducted similar to the OECD Guideline 403, groups of 5 rats per sex were exposed to nearly saturated vapours of test substance under static conditions for 6 hours. Survivors were observed for 14 days following exposure. Only one male rat died while all other rats survived the 6 hr exposure as well as the 14 day observation period. The following clinical signs were observed: hypoactivity (within 1 hr), laboured breathing (2 hr) in males, as well as periocular wetness, ataxia, negative righting reflex, negative toe and tail pinch reflex. Survivors recovered at 1 day. At necropsy, dark red lungs were observed in the animal that died, while no adverse effects were observed in survivors.

Groups of 6 rats were also exposed to substantially saturated vapour (5200 ppm, corresponding to approx. 27.6 mg/l)) of the reaction mass of 2 -methylbutyl acetate and pentyl acetate for 0.25 - 8 hours to observe the inhalation toxicity of the test substance (Smyth, 1962). Mortality of 100% was reported for the 8 h exposure group, and 0% for the 4 h exposure group.

 

CAS 628-63-7

No mortality occurred in a neurotoxicity test where mice were also exposed to test substance vapours (whole-body inhalation exposure for 20 min to 0, 500, 1000, 2000, 4000 ppm test substance, corresponding to approx. 0, 2.7, 5.3, 10.6 and 21.3 mg/l)). Neurotoxicity was evaluated by locomotor activity and a functional observational battery. No seizures, biphasic activity or change in motor activity were observed at any concentration. Animals of the high dose exhibited decreased arousal and rearing during exposure, but recovery was rapid and rearing frequency was normal within 4 minutes after termination of exposure. Increased palpebral closure, increased reactivity (to an auditory stimulus and to pain - tail pinch) and defecation were also displayed in the high dose group, as well as decrease arousal, increased handling reactivity, and clonic movements in the 2000 and 4000 ppm dose groups.

Justification for classification or non-classification

Based on the results discussed above: oral LD50 ≥ 6500 mg/kg bw, dermal LD50 ≥ 14009.6 mg/kg bw and inhalation LC50 ≥ 19300 mg/m3;

• GHS classification (REGULATION (EC) No 1272/2008 (CLP)):no classification required