A mixture of RR and RS isomers of: (2-(2-methoxy-1-methyl)ethoxy)-1-methylethyl acetate; (2-(2-methoxy-2-methyl)ethoxy)-1-methylethyl acetate; (2-(2-methoxy-2-methyl)ethoxy)-2-methylethyl acetate; (2-(2-methoxy-1-methyl)ethoxy)-2-methylethyl acetate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1982

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The data quality from this study is considered acceptable. The report included documentation for methods and results. This study reaches Klimisch Level 2.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

not specified

Test type:

standard acute method

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): Dowester A50B or Dipropylene glycol methyl ether acetate ("Herb Jackson, 1710")
- Physical state: Clear liquid.
- Analytical purity: not specified in the report
- Impurities (identity and concentrations): not specified in the report
- Composition of test material, percentage of components: not specified in the report
- Isomers composition: not specified in the report
- Purity test date: not specified in the report
- Lot/batch No.: not specified in the report
- Expiration date of the lot/batch: not specified in the report
- Stability under test conditions: not specified in the report
- Storage condition of test material: not specified in the report

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: 12 weeks
- Weight at study initiation: not specified in the report
- Fasting period before study: not specified in the report
- Housing: standard conditions
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 1-week prior to testing


ENVIRONMENTAL CONDITIONS
- Temperature (°C): standard conditions
- Humidity (%): standard conditions
- Air changes (per hr): standard conditions
- Photoperiod (hrs dark / hrs light): 12 hours light : 12 hours dark

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
The vapor atmosphere was generated by metering DPMA into a J tube into which heated air (100°C) was directed. The resulting vapor was diluted to the desired concentration with room temperature air

TEST ATMOSPHERE
- Brief description of analytical method used: not analysed
- Samples taken from breathing zone: not applicable

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: not applicable
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): not applicable

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

4 h

Concentrations:

5.7 mg/liter or 5,700 mg/cubic meter (734 ppm).

No. of animals per sex per dose:

6 males

Control animals:

yes

Details on study design:

- Six male rats were exposed to 0 and 5.7 mg/liter DPMA for 4 hours in 112-liter, stainless steel and glass whole-body inhalation chambers. The test atmosphere was not analyzed. Rather, the exposure concentration was calculated (as nominal) from the amount of DMPA used divided, by the air flow. Rats were observed for mortality and signs of toxicity over the course of exposure and the 2-week observation period. After 24 hours, one control and one DPMA-exposed rat were sacrificed and subjected to gross necropsy. After 14 days of observation, the remaining animals were sacrificed and a necropsy was performed
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All animals were observed and weighed prior to exposure and at intervals post-exposure for 2 weeks.
- Necropsy of survivors performed: yes

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

LC50

Effect level:

> 5.7 mg/L air

Exp. duration:

4 h

Remarks on result:

other: equivalent to approximately 734 ppm)

Mortality:

No mortality observed during the study period.

Clinical signs:

other: None of the exposed rats exhibited any adverse signs during or after the exposure period

Body weight:

All rats showed body weight gain comparable to control rats

Gross pathology:

No treatment related lesions were observed in any of the animals at necropsy.

Any other information on results incl. tables

Table 1: Concentrations and results of mortality

Nominal conc.	Analytical conc.	No. dead/total males	No. dead/total females	Total no. dead/total
0 mg/l	-	0/6	-	0/6
5.7 mg/l	-	0/6	-	0/6

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The DPMA 4-hour inhalation LC50 for males is greater than 5.7 mg/l (or > 5,700 mg/m3). No deaths occurred in 6 males at this exposure level so the actual LC50 may be considerably higher than this value. Actual concentrations were not measured and the calculated vapor concentration is greater than the theoretical maximum. However, no condensation was reported on the chamber walls so a supersaturated condition may have existed.

Executive summary:

Dipropylene Glycol Monomethyl Ether Acetate (Dowester A50B/DPC-Herb Jackson 1710) was evaluated for acute inhalation toxicity on male Fischer 344 rats to a calculated vapour concentration of 5.7 mg/l (equivalent to 734 ppm) and the exposure did not result in any adverse effects during or after the exposure period. All exposed rats showed body weight gain comparable to control rats and no treatment related lesions were observed in any of the animals at necropsy.

Under the conditions of the study, the DPMA 4-hour inhalation LC50 for males is greater than 5.7 mg/l (or > 5,700 mg/m3).