3-methoxybutyl acetate

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Remarks:

As a result of technological difficulties in formulation due to volatility of the test substance, the subchronic toxicity test in rats have to be done via inhalation.

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2020-2021

Reliability:

1 (reliable without restriction)

Justification for type of information:

In the Decision on a Compliance Check (dated December 11, 2018) ECHA requested a subchronic toxicity (90-days) oral route OECD 408 in rats. However, because of technological difficulties in formulation due to volatility of the test substance, the subchronic toxicity test in rats was done via inhalation.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 413 (90-Day (Subchronic) Inhalation Toxicity Study

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-methoxybutyl acetate

EC Number:

224-644-9

EC Name:

3-methoxybutyl acetate

Cas Number:

4435-53-4

Molecular formula:

C7H14O3

IUPAC Name:

3-methoxybutyl acetate

Constituent 2

Reference substance name:

butoxyl

IUPAC Name:

butoxyl

Specific details on test material used for the study:

Solvent: 3-methoxy butyl acetate (also known as Butoxyl®)
Lot Number: 120001260103
Storage Conditions: Room temperature
Purity: 99.9%
Correction Factor: 1.0
Expiry Date: 28 October 2020

Test animals

Species:

rat

Strain:

other: Crl:CD(SD)IGS Rats

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age: Approximately 6 to 7 weeks at receipt; approximately 8 to 9 weeks (and no more than 10 weeks) at initiation of dosing. Note: Females will be nulliparous and non-pregnant.
Weight: Males: approximately 250 to 290 grams at first exposure. Females: approximately 180 to 220 grams at first exposure.
Light/Dark Cycle: Twelve-hour light/dark cycle provided via automatic timer.
Temperature: it will be monitored in accordance with Testing Facility’s SOPs to ensure that the desired range of 20 to 26 C is maintained to the maximum extent possible.
Humidity: it will be monitored in accordance with Testing Facility’s SOPs to ensure that the desired range of 30 to 70% is maintained to the maximum extent possible.

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

Route: Inhalation - nose only vapor exposure.
Control: Air only.
Training for dosing: The animals on study were acclimated to the method of restraint, over a 3 day period immediately preceding the first test item exposure.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

• No 3-Methoxybutyl Acetate was detected in Group 1 samples (0 mg/L)
• Mean achieved concentration for Group 2 was on target (0.6 mg/L)
• Mean achieved concentration for Groups 3 and 4 were 5% (1.90 mg/L ) and 3% (5.83 mg/L) below target, respectively

Duration of treatment / exposure:

Duration of daily exposure 6 hours (360 minutes) per day, 5 days per week for 13 weeks.

Frequency of treatment:

5 days per week for 13 weeks.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0.6 mg/L air (nominal)

Doses / concentrations 2

Dose / conc.:

2 mg/L air (nominal)

Doses / concentrations 3

Dose / conc.:

6 mg/L air (nominal)

No. of animals per sex per dose:

10 males / 10 famales/ group

Control animals:

yes

Details on study design:

In the range finding inhalation toxicity study (Covance study 8442-349), rats were exposed to the test item for up to 6 hours per day, for 5 days per week, for 2 weeks at 0.2, 0.6, and 2.0 mg/L. Results to be added by amendment. On the basis of the range finding study, exposure levels will be selected to provide a range of effects.

Positive control:

no

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

There were no test item-related changes for clinical observations during or following the exposures. (Table 1. Signs - group total distribution of observations)

Mortality:

no mortality observed

Description (incidence):

All study animals survived to their scheduled necropsy.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

There were no adverse test item-related changes for male body weights during the study. However, there was a statistically significant (p≤0.05) lower body weight in the high exposure level males, but not in the mid exposure level males, at the end of the study. In addition, there were statistically significant decreases in body weight gains seen in the mid exposure level males (18% at end of exposures) and in the high exposure level males (22% at end of exposures). While these decreases in male body weight gains were likely treatment-related at the mid exposure level and clearly treatment-related at the high exposure level, they were not considered adverse since the mid exposure level animals had no statistically significant effects on body weight, compared to controls, and the high exposure level animals gained weight throughout the study. Also, the general health of the animals as well as their health as evaluated by terminal clinical pathology and anatomic pathology (see later discussions) was consistently not affected.
There were no statistically significant or biologically relevant changes in body weights or body weight gains in the females at any exposure level. At the end of treatment, females at the high exposure level had lower body weights (16%) than the females in the control group (not statistically significant), but the high exposure level females also had lower body weights (7%) at the start of the study. See tables in: "Any other information on results incl. tables"

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

There were no adverse test item-related changes for food consumption during the study.
However, significant decreases in food consumption were seen at 1.90 mg/L in the males (up to 10%) and at 5.83 mg/L in both sexes (up to 15% for males and 13% for females) and correlated with the effects on body weights discussed above. See tables in: "Overall remarks, attachments"

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

no effects observed

Description (incidence and severity):

There were no test item-related changes for ocular observations at end of 13 weeks of exposures. See Tables in: "Overall remarks, attachments"

Haematological findings:

no effects observed

Description (incidence and severity):

There were no 3-Methoxybutyl Acetate-related effects on hematology test results.
All differences in hematology test results, statistically significant or not, between control and 3-Methoxybutyl Acetate-treated animals were consistent with normal variation and considered incidental. Most or all of the following characterized these differences: small magnitude, lack of dose relationship, and/or the absence of correlative findings.

There were no 3-Methoxybutyl Acetate-related effects on coagulation test results.
All differences in coagulation test results, statistically significant or not, between control and 3-Methoxybutyl Acetate-treated animals were consistent with normal variation and considered incidental. Most or all of the following characterized these differences: small magnitude, lack of dose relationship, and/or the absence of correlative findings.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

3-Methoxybutyl Acetate-related effects on clinical chemistry test results included minimal decreases in glucose and minimal increases in phosphorus in males at exposures of 2.0 and 6.0 mg/L and females at exposures of 6.0 mg/L; and minimal to mild decreases in triglycerides in females at exposures of 2.0 and 6.0 mg/L and males at exposures of
6.0 mg/L. All of these changes were considered non-adverse due to their relatively small magnitude.
All other differences in clinical chemistry test results, statistically significant or not, between control and 3-Methoxybutyl Acetate-treated animals were consistent with normal variation and considered incidental. Most or all of the following characterized these differences: small magnitude, lack of dose relationship, and/or the absence of correlative findings.

All other differences in clinical chemistry test results, statistically significant or not, between control and 3-Methoxybutyl Acetate-treated animals were consistent with normal variation and considered incidental. Most or all of the following characterized these differences: small magnitude, lack of dose relationship, and/or the absence of correlative findings.

Endocrine findings:

not examined

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

There were no test item-related changes for Functional Observational Battery at end of 13 weeks of exposures.

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No test item-related effects were noted on organ weight parameters.
All differences in organ weight parameters, statistically significant or not, were consistent with normal variation and considered incidental. These differences were characterized by one or more of the following: inconsistency between sexes; presence only in absolute weight or in relative (to body or brain weight) ratios but not both; lack of a dose relationship or correlative findings; and/or the magnitude was considered small.

Gross pathological findings:

no effects observed

Description (incidence and severity):

Macroscopic observations: No test item-related macroscopic findings were observed in animals administered ≥0.6 mg/L of 3-methoxy butyl acetate. All macroscopic findings were considered spontaneous and/or incidental because they occurred at a low incidence, were randomly distributed across groups (including concurrent controls), and/or were as expected for this species/strain and age; therefore, they were considered not test article related.

Neuropathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were a few statistically significant differences between treated animals and control animals, listed below, however the differences were not consistent with any adverse test item-related changes at end of 13 weeks of exposures.
Horizontal Males There were no statistically significant differences between the 3-Methoxybutyl Acetate treated groups and the vehicle control group. Females The 3-Methoxybutyl Acetate at 6.0 mg/L group had significantly decreased motor activity compared to control during interval 11 (p=0.012, Williams’ test).
Vertical Males
The 3-Methoxybutyl Acetate at 6.0 mg/L group had significantly decreased motor activity compared to control during interval 1 (p=0.017, Williams’ test).
Females
The 3-Methoxybutyl Acetate at 6.0 mg/L group had significantly decreased motor activity compared to control during interval 3 (p=0.034, Williams’ test).

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

All differences in organ weight parameters, statistically significant or not, were consistent with normal variation and considered incidental. These differences were characterized by one or more of the following: inconsistency between sexes; presence only in absolute weight or in relative (to body or brain weight) ratios but not both; lack of a dose relationship or correlative findings; and/or the magnitude was considered small.

No test item-related macroscopic findings were observed in animals administered
≥0.6 mg/L of 3-methoxy butyl acetate.

No test item-related microscopic findings were observed in animals administered
6.0 mg/L of 3-methoxy butyl acetate.

Bronchoalveolar Lavage (BAL) Fluid Results: 3-Methoxybutyl Acetate-related effects on BAL test results included minimal increases in macrophage percentages and decreases in neutrophil percentages in males at all exposure levels. These changes were considered non-adverse due to their relatively small magnitude.
All other differences in BAL test results, statistically significant or not, between control and 3-Methoxybutyl Acetate-treated animals were consistent with normal variation and considered incidental. Most or all of the following characterized these differences: small magnitude, lack of dose relationship, and/or the absence of correlative findings.
Macroscopic observations: No test item-related macroscopic findings were observed in animals administered ≥0.6 mg/L of 3-methoxy butyl acetate. All macroscopic findings were considered spontaneous and/or incidental because they occurred at a low incidence, were randomly distributed across groups (including concurrent controls), and/or were as expected for this species/strain and age; therefore, they were considered not test article related.

Microscopic examination: No test item-related microscopic findings were observed in animals administered 6.0 mg/L of 3-methoxy butyl acetate. All microscopic findings were considered spontaneous and/or incidental because they occurred at a low incidence, were randomly distributed across groups (including concurrent controls), and/or similarity to background pathology of this strain of rats (McInnes, 2012); therefore, they were considered not test article-related.

Histopathological findings: neoplastic:

no effects observed

Description (incidence and severity):

Macroscopic observations: No test item-related macroscopic findings were observed in animals administered ≥0.6 mg/L of 3-methoxy butyl acetate. All macroscopic findings were considered spontaneous and/or incidental because they occurred at a low incidence, were randomly distributed across groups (including concurrent controls), and/or were as expected for this species/strain and age; therefore, they were considered not test article related.

Microscopic examination: No test item-related microscopic findings were observed in animals administered 6.0 mg/L of 3-methoxy butyl acetate. All microscopic findings were considered spontaneous and/or incidental because they occurred at a low incidence, were randomly distributed across groups (including concurrent controls), and/or similarity to background pathology of this strain of rats (McInnes, 2012); therefore, they were considered not test article-related.

Other effects:

no effects observed

Description (incidence and severity):

No test item-related macroscopic findings were observed in animals administered
≥0.6 mg/L of 3-methoxy butyl acetate.

No test item-related microscopic findings were observed in animals administered 6.0 mg/L of 3-methoxy butyl acetate.

Details on results:

No test item-related macroscopic findings were observed in animals administered
≥0.6 mg/L of 3-methoxy butyl acetate.

No test item-related microscopic findings were observed in animals administered 6.0 mg/L of 3-methoxy butyl acetate.

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

>= 6 mg/L air

Based on:

test mat.

Basis for effect level:

body weight and weight gain

Remarks on result:

other: No-Observed-Adverse-Effect-Level (NOAEL) for male rats exposed to 3-methoxybutyl acetate is 2 mg/L and the Lowest-Observed-Adverse-Effect-Level (LOAEL) is 6 mg/L. The highest dose tested of 6 mg/L is the NOAEL for female rats.

Target system / organ toxicity

Key result

Critical effects observed:

no

Organ:

other: no adverse effects

Any other information on results incl. tables

Body weight - group mean values (g) MALES Continue
Group/Sex		Day		Day	Day	Day	Day	Day	Day	Day	Day	Day	Day
(mg/L)		Ra8	Ra14	1	4	8	11	15	18	22	25	29	32
Statistics	test	Av	Av	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi
Group 1/M	Mean	206	256	264	278	298	310	334	345	367	372	393	403
Air Control	SD	14.5	18.3	18.7	21.6	23.6	24.8	28.6	32.1	36.4	40.5	45.1	47.6
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 2/M	Mean	201	253	259	272	295	305	325	337	355	361	377	385
(0.6)	SD	12.4	18.7	19.9	21.6	26.2	27.4	32.4	36.0	38.5	38.3	39.8	41.7
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 3/M	Mean	202	252	259	271	294	302	323	332	350	353	370	375
(2.0)	SD	6.2	10.4	9.6	10.4	13.6	14.9	17.5	22.4	23.3	24.8	25.1	25.9
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 4/M	Mean	204	256	260	271	293	303	323	331	350	353	371	376
(6.0)	SD	10.7	14.8	14.5	15.7	18.1	19.0	22.2	24.6	29.0	30.1	32.6	34.1
	N	10	10	10	10	10	10	10	10	10	10	10	10
*Statistically significant (p<0.05); ** Statistically significant (p<0.01)

Body weight - group mean values (g) MALES
Group/Sex		Day	Day	Day	Day	Day	Day	Day	Day	Day	Day		Change
(mg/L)		36	39	43	46	50	57	64	71	78	85		1-4
Statistics	test	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi		Wi
Group 1/M	Mean	418	413	435	433	452	468	482	492	503	513		14
Air Control	SD	49.7	51.9	55.7	56.5	57.9	61.7	64.4	65.5	67.7	68.3		5.9
	N	10	10	10	10	10	10	10	10	10	10		10
Group 2/M	Mean	398	394	413	410	429	443	453	461	466	480		13
(0.6)	SD	43.1	42.6	46.6	45.4	48.0	50.9	52.5	51.4	52.4	53.1		3.9
	N	10	10	10	10	10	10	10	10	10	10		10
Group 3/M	Mean	383	380	399	396	412	426	438	451	456	464		12
(2.0)	SD	32.1	29.3	30.9	32.3	35.4	41.4	41.7	41.0	42.6	43.2		3.0
	N	10	10	10	10	10	10	10	10	10	10		10
Group 4/M	Mean	387	382	399	395	412	422	430*	436*	442*	455*		11
(6.0)	SD	34.9	34.0	35.7	35.0	35.6	38.9	39.1	37.1	39.5	42.6		5.1
	N	10	10	10	10	10	10	10	10	10	10		10
*Statistically significant (p<0.05); ** Statistically significant (p<0.01)

Body weight - group mean values (g) MALES Continue
Group/Sex		Change	Change	Change	Change	Change	Change	Change	Change	Change	Change	Change	Change
(mg/L)		1-8	1-11	1-15	1-18	1-22	1-25	1-29	1-32	1-36	1-39	1-43	1-46
Statistics	test	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi
Group 1/M	Mean	34	46	70	81	103	108	129	139	154	149	171	169
Air Control	SD	6.2	14.7	15.1	20.0	24.0	28.7	34.6	37.7	40.2	42.9	46.8	47.7
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 2/M	Mean	37	47	66	78	96	102	119	126	140	135	155	151
(0.6)	SD	8.3	11.0	15.6	19.5	23.1	22.5	23.9	25.6	27.9	27.0	31.3	29.9
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 3/M	Mean	35	43	64	73	91	94	111	116	124	121	140	137
(2.0)	SD	6.0	9.1	11.6	15.7	16.8	18.7	18.9	20.5	28.1	25.6	26.3	27.3
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 4/M	Mean	34	43	63	71	90	93	111	116	127	122	139	135*
(6.0)	SD	8.8	9.2	11.6	14.6	18.5	19.7	21.9	23.4	24.4	24.5	25.1	24.3
	N	10	10	10	10	10	10	10	10	10	10	10	10
*Statistically significant (p<0.05); ** Statistically significant (p<0.01)

Body weight - group mean values (g) MALES
Group/Sex		Change	Change	Change	Change	Change	Change
(mg/L)		1-50	1-57	1-64	1-71	1-78	1-85
Statistics	test	Wi	Wi	Wi	Wi	Wi	Wi
Group 1/M	Mean	188	204	217	227	238	249
Air Control	SD	48.8	51.5	54.7	55.1	57.5	58.1
	N	10	10	10	10	10	10
Group 2/M	Mean	170	184	195	202	208	222
(0.6)	SD	32.7	35.5	37.3	35.8	37.0	37.8
	N	10	10	10	10	10	10
Group 3/M	Mean	153*	167*	179*	192	197*	205*
(2.0)	SD	30.2	36.1	37.0	36.0	37.3	37.3
	N	10	10	10	10	10	10
Group 4/M	Mean	152*	162*	170*	176**	182**	195**
(6.0)	SD	25.2	28.7	29.0	25.7	28.6	32.7
	N	10	10	10	10	10	10
*Statistically significant (p<0.05); ** Statistically significant (p<0.01)

Body weight - group mean values (g) FEMALES Continue
Group/Sex		Day		Day
(mg/L)		Ra8	Ra14	1	4	8	11	15	18	22	25	29	32
Statistics	test	Av	Av	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi
Group 1/F	Mean	194	217	216	221	230	230	236	235	242	241	251	253
Air Control	SD	20.3	21.1	19.8	20.5	21.2	21.0	20.9	20.8	20.1	18.6	19.5	20.4
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 2/F	Mean	197	218	217	225	228	232	238	240	245	247	256	260
(0.6)	SD	19.5	21.2	23.5	25.7	25.3	26.1	24.9	27.1	29.8	29.3	28.7	31.3
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 3/F	Mean	196	217	219	223	234	234	241	246	252	251	260	259
(2.0)	SD	19.2	25.6	22.3	22.0	24.7	29.8	33.3	31.5	32.6	30.5	32.3	35.8
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 4/F	Mean	184	202	203	208	213	215	220	221	231	226	235	234
(6.0)	SD	13.2	16.5	13.5	13.8	13.9	14.4	15.3	17.5	19.6	16.8	16.9	19.3
	N	10	10	10	10	10	10	10	10	10	10	10	10

Body weight - group mean values (g) FEMALES
Group/Sex		Day											Change
(mg/L)		36	39	43	46	50	57	64	71	78	85		1-4
Statistics	test	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi		Wi
Group 1/F	Mean	258	248	262	254	266	270	276	277	277	280		5
Air Control	SD	20.3	21.0	21.5	19.3	20.7	22.4	23.3	22.5	24.7	24.3		4.4
	N	10	10	10	10	10	10	10	10	10	10		10
Group 2/F	Mean	263	259	268	264	275	278	282	288	289	288		7
(0.6)	SD	31.8	31.0	29.6	32.3	35.4	31.1	32.0	32.6	33.6	30.0		6.1
	N	10	10	10	10	10	10	10	10	10	10		10
Group 3/F	Mean	264	260	273	270	278	281	286	290	291	293		4
(2.0)	SD	34.3	35.9	41.3	38.5	38.2	43.3	43.3	44.9	46.8	45.8		3.3
	N	10	10	10	10	10	10	10	10	10	10		10
Group 4/F	Mean	240	234	243	236	246	250	252	258	256	258		5
(6.0)	SD	18.0	20.4	18.9	20.5	20.2	19.3	18.1	20.2	21.6	20.9		5.2
	N	10	10	10	10	10	10	10	10	10	10		10

Body weight - group mean values (g) FEMALES
Group/Sex		Change	Change	Change	Change	Change	Change	Change	Change	Change	Change	Change	Change
(mg/L)		1-8	1-11	1-15	1-18	1-22	1-25	1-29	1-32	1-36	1-39	1-43	1-46
Statistics	test	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	lWi	Wi
Group 1/F	Mean	14	14	20	19	26	25	35	37	42	32	46	38
Air Control	SD	6.2	5.6	8.1	7.0	6.4	8.7	8.6	10.0	9.6	10.5	10.8	9.4
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 2/F	Mean	11	14	20	23	28	30	39	42	46	42	50	47
(0.6)	SD	6.2	7.0	8.9	6.9	9.2	8.9	8.9	11.2	12.3	12.0	9.2	14.0
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 3/F	Mean	15	15	22	27	33	32	41	40	45	41	54	51
(2.0)	SD	4.3	9.8	14.7	13.3	15.0	12.8	15.5	18.9	18.2	18.3	24.1	20.8
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 4/F	Mean	10	12	17	18	28	23	31	31	37	31	40	33
(6.0)	SD	5.3	4.0	5.2	8.4	13.8	7.4	7.0	8.3	8.6	10.2	9.3	10.6
	N	10	10	10	10	10	10	10	10	10	10	10	10

Body weight - group mean values (g) FEMALES Continue
Group/Sex		Change	Change	Change	Change	Change	Change
(mg/L)		1-50	1-57	1-64	1-71	1-78	1-85
Statistics	test	Wi	lWi	Wi	Wi	Wi	lWi
Group 1/F	Mean	50	55	60	61	61	64
Air Control)	SD	8.6	11.6	12.9	12.3	14.6	13.7
	N	10	10	10	10	10	10
Group 2/F	Mean	58	61	65	71	72	71
(0.6)	SD	17.3	12.3	12.5	13.8	16.1	9.2
	N	10	10	10	10	10	10
Group 3/F	Mean	59	62	67	71	72	74
(2.0)	SD	21.5	27.5	27.3	29.1	30.2	29.9
	N	10	10	10	10	10	10
Group 4/F	Mean	43	47	49	55	53	54
(6.0)	SD	10.9	10.5	10.8	15.0	12.8	12.2
	N	10	10	10	10	10	10

Body weight change - group mean values (g) MALES Continue
Group/Sex		Day		Day
(mg/L)		Ra8-Ra14	Ra14-1	1-4	4-8	8-11	11-15	15-18	18-22	22-25	25-29	29-32	32-36
Statistics	test	Av	Wi	Wi	Wi	Sh	Wi	Wi	Wi	Wi	Wi	Wi	Sh
Group 1/M	Mean	50	8	14	20	12	24	11	22	5	21	10	15
Air Control	SD	5.7	3.8	5.9	8.3	16.0	7.2	5.7	6.2	5.4	8.5	3.5	4.1
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 2/M	Mean	51	6	13	24	10	20	12	19	6	16	7	14
(0.6)	SD	7.8	3.1	3.9	5.3	3.9	5.9	4.8	4.8	2.6	3.3	4.3	4.1
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 3/M	Mean	49	8	12	23	9	21	9	18	3	17	4	8
(2.0)	SD	4.5	2.8	3.0	4.1	4.1	3.9	6.8	3.8	3.8	3.9	8.5	12.2
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 4/M	Mean	51	4**	11	22	10	20	8	18	4	18	5	11*
(6.0)	SD	6.2	2.5	5.1	4.9	2.8	3.9	4.0	4.9	3.7	4.3	3.3	3.8
	N	10	10	10	10	10	10	10	10	10	10	10	10
*Statistically significant (p<0.05); ** Statistically significant (p<0.01)

Body weight change - group mean values (g) MALES
Group/Sex		Day
(mg/L)		36-39	39-43	43-46	46-50	50-57	57-64	64-71	71-78	78-85
Statistics	test	Wi	Wi	Wi	Sh	Wi	Wi	Wi	Wi	Wi
Group 1/M	Mean	-5	22	-2	20	16	14	10	11	10
Air Control	SD	3.7	4.8	3.6	4.1	7.0	6.0	7.3	6.5	6.4
	N	10	10	10	10	10	10	10	10	10
Group 2/M	Mean	-5	20	-3	19	14	11	8	5*	14
(0.6)	SD	4.1	6.7	3.5	5.0	4.6	3.6	4.2	2.1	4.0
	N	10	10	10	10	10	10	10	10	10
Group 3/M	Mean	-3	19	-3	16	14	12	12	5*	8
(0.6)	SD	6.4	7.5	6.3	7.6	10.6	4.6	4.5	5.9	4.5
	N	10	10	10	10	10	10	10	10	10
Group 4/M	Mean	-4	17	-4	17	10	8**	6	7*	13
(6.0)	SD	4.2	3.9	3.6	2.0	5.9	4.5	7.3	5.8	9.6
	N	10	10	10	10	10	10	10	10	10
*Statistically significant (p<0.05); ** Statistically significant (p<0.01)

Body weight change - group mean values (g) FEMALES Continue
Group/Sex		Day		Day
(mg/L)		Ra8-Ra14	Ra14-1	1-4	4-8	8-11	11-15	15-18	18-22	22-25	25-29	29-32	32-36
Statistics	test	Av	Wi	Wi	Du	Wi	Wi	Wi	Sh	Wi	Wi	Wi	Wi
Group 1/F	Mean	23	-1	5	9	0	6	-1	7	-1	10	2	5
Air Control	SD	7.8	4.7	4.4	4.0	4.3	3.7	5.0	4.1	3.8	3.2	6.0	3.6
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 2/F	Mean	21	-1	7	4**	3	6	2	5	2	9	4	4
(0.2)	SD	5.7	4.9	6.1	3.2	3.9	5.1	4.7	3.8	5.9	3.7	4.5	2.9
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 3/F	Mean	20	2	4	10	0	7	5	6	-1	9	-2	6
(0.6)	SD	9.3	5.3	3.3	4.7	7.4	7.2	7.1	3.5	4.7	3.7	5.9	2.9
	N	10	10	10	10	10	10	10	10	10	10	10	10
Group 4/F	Mean	18	1	5	6	2	5	1	10	-5	8	0	6
(6.0)	SD	8.6	6.4	5.2	1.7	3.3	2.3	4.5	10.1	9.0	3.3	4.3	3.6
	N	10	10	10	10	10	10	10	10	10	10	10	10

Body weight change - group mean values (g) FEMALES
Group/Sex		Day
(mg/L)		36-39	39-43	43-46	46-50	50-57	57-64	64-71	71-78	78-85
Statistics	test	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi	Wi
Group 1/F	Mean	-10	14	-8	12	4	5	1	0	2
Air Control	SD	3.7	5.4	5.2	4.1	6.4	5.6	4.5	5.6	5.3
	N	10	10	10	10	10	10	10	10	10
Group 2/F	Mean	-4**	8	-3	11	3	4	6	1	-1
(0.2)	SD	3.6	3.5	5.8	4.5	7.2	3.7	6.8	5.5	9.1
	N	10	10	10	10	10	10	10	10	10
Group 3/F	Mean	-4**	13	-3	8	3	5	4	1	2
(0.6)	SD	6.0	6.8	5.8	2.9	9.3	4.7	4.3	4.5	4.7
	N	10	10	10	10	10	10	10	10	10
Group 4/F	Mean	-6**	9	-8	10	4	2	6	-2	2
(6.0)	SD	3.9	3.8	6.1	5.0	3.3	4.0	6.7	9.0	3.6
	N	10	10	10	10	10	10	10	10	10

 

Applicant's summary and conclusion

Conclusions:

No test item-related adverse effects on mortality, clinical observations (including FOD/MA), food consumption, ophthalmology, hematology, clinical chemistry, bronchiolar lavage, macroscopic pathology, or microscopic pathology were detected. No statistically significant and biologically relevant effects on body weights, body weight gain, or food consumption were noted in the male low- and mid-dose groups or any female group. However, statistically significant decreased body weights (p ≤0.05) were noted in the high-dose males during the last four weeks of treatment and were accompanied by statistically significant decreases in body weight gain and food consumption. Although the males in the high-dose group gained weight throughout the study, and there were no other signs of toxicity, the statistically significant decreases in body weight and body weight gain were considered adverse.
In summary, the No-Observed-Adverse-Effect-Level (NOAEL) for male rats exposed to 3-methoxybutyl acetate is 2 mg/L and the Lowest-Observed-Adverse-Effect-Level (LOAEL) is 6 mg/L. The highest dose tested of 6 mg/L is the NOAEL for female rats.

Executive summary:

Sprague-Dawley CD^® rats (10/sex/group) were exposed via nose-only vapor inhalation to 0 (Air control), 0.6, 2.0 or 6.0 mg/L of 3-Methoxybutyl Acetate for 6 hours/day, 5 days/week, for 13 consecutive weeks. At the end of the treatment period, 10 animals/sex/group were euthanized and necropsied.  Parameters evaluated during the study were: viability, clinical observations, ophthalmology, body weights, food consumption, locomotor activity and functional observational battery (Week 12), clinical pathology (prior to terminal necropsy), bronchoalveolar lavage (at terminal necropsy) organ weights, macroscopic observations, and microscopic pathology.

Mean 3-Methoxybutyl Acetate atmosphere vapor concentrations are summarized below:

Group	Atmosphere Concentration (mg/L)
	Target	Mean Achieved
1	0	0
2	0.6	0.60
3	2.0	1.90
4	6.0	5.83

No 3-Methoxybutyl Acetate was detected in Group 1 samples.  Mean achieved concentration for Group 2 was on target.  Mean achieved concentration for Groups 3 and 4 were 5% and 3% below target, respectively.

No test item-related adverse effects on mortality, clinical observations (including FOD/MA), food consumption, ophthalmology, hematology, clinical chemistry, bronchiolar lavage, macroscopic pathology, or microscopic pathology were detected. No statistically significant and biologically relevant effects on body weights, body weight gain, or food consumption were noted in the male low- and mid-dose groups or any female group. However, statistically significant decreased body weights (p ≤0.05) were noted in the high-dose males during the last four weeks of treatment and were accompanied by statistically significant decreases in body weight gain and food consumption. Although the males in the high-dose group gained weight throughout the study, and there were no other signs of toxicity, the statistically significant decreases in body weight and body weight gain were considered adverse.

In summary, the No-Observed-Adverse-Effect-Level (NOAEL) for male rats exposed to 3-methoxybutyl acetate is 2 mg/L and the Lowest-Observed-Adverse-Effect-Level (LOAEL) is 6 mg/L. The highest dose tested of 6 mg/L is the NOAEL for female rats.