Registration Dossier

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Diss Factsheets

Administrative data

Key value for chemical safety assessment

Toxic effect type:
dose-dependent

Effects on fertility

Description of key information

Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.

There is no data available for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). However, data is available for structural analogue, Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%):

NOAEC for reproductive toxicity in rats ≥ 300 ppm (1720 mg/m3)

Additionally, OECD 443 tests are proposed for structural analogues, Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) (EC# 919-006-8) and Hydrocarbons, C11-C15, aromatics, <1% naphthalene (EC# 922-153-0). An OECD Guideline 422 screening reproductive/developmental toxicity study (oral route) in rodents is also planned with structural analogue Hydrocarbons, C14-C18, n-alkanes, isoalkanes, cyclics, aromatics (2-30 %) (EC# 920-360-0). This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

 

This endpoint will be updated subsequent to ECHA's approval of the testing proposals and availability of data upon completion of the studies.

Link to relevant study records

Referenceopen allclose all

Endpoint:
screening for reproductive / developmental toxicity
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1980
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.
Justification for type of information:
Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
GLP compliance:
no
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, MA
- Age at study initiation: males - 10 weeks, females - 9 weeks at initiation of pre-treatment mating period, 8 weeks at initiation of post-treatment mating period
- Weight at study initiation: 281-289 g
- Housing: stainless steel wire mesh cages, animals were housed individually during exposure and at a 2:1 female/male ratio during mating
- Diet (e.g. ad libitum): Purina Laboratory Chow, ad libitum
- Water (e.g. ad libitum): ad libitum

IN-LIFE DATES: From: August 21, 1978 To Oct. 13, 1978
Route of administration:
inhalation: vapour
Type of inhalation exposure (if applicable):
whole body
Details on exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: one cubic meter stainless steel and glass chamber
- Method of conditioning air: The MRD-78-25 (300 ppm) was transferred from a 500 ml Erlenmeyer flask using a metering pump, or a 50 cc Tomac glass syringe into a heated flask (100 ppm) and flash evaporated. Clean air was also passed through the flask to pick up vapor. The vapor air mixture was then fed into the chamber inlets and diluted to the desired concentration. The MRD-78-26 was put in fritted bottom gas-washing bottles (400 and 1200 ppm). Air was passed through the bottles, and the vapor air mixture was then fed into the chamber inlets and diluted to the desired concentration.
- Air flow rate: 132 l/min
- Air change rate: complete air change every 7.6 min, with a 99% equilibration time of 35 min.
Details on mating procedure:
Each male cohabitated for two weeks with two females. Females were sacrificed 18 days after beginning cohabitation. Males were then exposed to the test substance for 8 weeks. Two hours after the last exposure, two untreated virgin females were placed in the males cages. These females cohabitated for seven days and replaced with two new females.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
- Brief description of analytical method used: IR spectrum taken with a Miran IA Ambient Air Analyzer (Wilks Scientific Corp.), analyzed at 3.4 microns.
- Samples taken from breathing zone: yes, at 1, 3, and 5 hrs after exposure began each day
Duration of treatment / exposure:
6 hours/day
Frequency of treatment:
5 days/week for 8 weeks
Remarks:
Doses / Concentrations:
100 ppm
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
300 ppm
Basis:
nominal conc.
No. of animals per sex per dose:
10 males, 40 females
Control animals:
yes, concurrent no treatment
Positive control:
triethylenemelamine
- Justification for choice of positive control(s): Triethylenemelamine has been shown to induce dominant-lethal mutations
- Route of administration: intraperitoneally
- Doses / concentrations: 0.5 mg/kg
Parental animals: Observations and examinations:
Animals were examined for mortality, pharmacological observations, toxicological observations (twice daily), physical observations, body weight (weekly), gross necropsy, and histopathology (seminal vesicles, epididymis, testes, prostate).
Postmortem examinations (parental animals):
The following organs were examined in males: seminal vesicles, epididymis, testes, prostate.
Statistics:
Comparisons between controls and treatment groups were made using the Chi-square method. Data was compared using the F-test and student's t-test, with the student's t-test modified using Cochran's approximation.
Reproductive indices:
Males were considered fertile if at least one female became pregnant.
Offspring viability indices:
implantation sites, early resorption sites, late resorption sites, viable fetal swellings
Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Other effects:
not examined
Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
no effects observed
There was no mortality during the study. No treatment related physical observations were noted. Body weights were comparable between exposed animals and controls, except for the 100 ppm exposure group. However, this difference was not statistically significant. No statistically significant difference in pregnancy rates was noted. Statistically significant differences in the number of corpora lutea were noted, however, since females were not treated this was not considered treatment related. The implantation efficiency of the 100 ppm group at week 2 was significantly decreased as compared to the negative controls. This effect was deemed not to be treatment related as the effect was not seen in the 300 ppm dose group. The gross necropsy findings were unremarkable, as were the histopathological examinations.
Key result
Dose descriptor:
NOAEC
Effect level:
>= 300 ppm
Sex:
male/female
Basis for effect level:
other: 1720 mg/m3
Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Histopathological findings:
not examined
The implantation efficiency of the 100 ppm group at week 2 was decreased as compared to the negative controls. However, as the implantation efficiency was within the range of values noted for the pre-treatment mating, this was not considered to be treatment related. The mean number of early fetal deaths was comparable to negative control values. Late fetal deaths could not be evaluated, as there was an insufficient number. Total number of fetal deaths were comparable between treatment and negative controls. The gross necropsy findings were unremarkable, as were the histopathological examinations.
Key result
Dose descriptor:
NOAEC
Generation:
F1
Effect level:
>= 300 ppm
Sex:
male/female
Basis for effect level:
other: 1720 mg/m3
Reproductive effects observed:
not specified

Mean Body Weights (g)

Week

Negative Control

Positive Control

100 ppm

300 ppm

Initial

289

281

283

284

Pre-treatment mating 1

331

325

328

328

Pre-treatment mating 2

365

362

367

363

Treatment 1

413

418

416

407

Treatment 2

438

449

441

428

Treatment 3

452

470

458

443

Treatment 4

470

487

475

459

Treatment 5

480

504

490

470

Treatment 6

484

516

502

479

Treatment 7

496

531

518

487

Treatment 8

504

538

527

500

Post-treatment mating 1

514

508

535

507

Post-treatment mating 2

523

518

544

516

Reproduction Data

Pregnancy Rate (%)

Week

Negative Control

Positive Control

100 ppm

300 ppm

Pre-treatment mating 1

75.0

70.0

70.0

70.0

Pre-treatment mating 2

80.0

85.0

90.0

95.0

Post-treatment mating 1

85.0

75.0

80.0

65.0

Post-treatment mating 2

100.0

80.0

95.0

100.0

Mean Corpora Lutea

Pre-treatment mating 1

12.5

11.8

12.9

14.0

Pre-treatment mating 2

14.1

14.9

13.1

13.5

Post-treatment mating 1

13.1

11.1

13.9

13.4

Post-treatment mating 2

13.4

11.9

14.4

13.1

Mean Implantations

Pre-treatment mating 1

10.1

11.4

12.0

13.0

Pre-treatment mating 2

12.5

14.0

12.1

11.9

Post-treatment mating 1

11.9

8.8

12.6

12.6

Post-treatment mating 2

12.7

4.1

12.8

12.5

Implantation Efficiency

Pre-treatment mating 1

80.9

96.4

92.8

92.9

Pre-treatment mating 2

88.5

94.1

92.3

88.3

Post-treatment mating 1

91.0

79.0

91.0

94.3

Post-treatment mating 2

95.1

34.0

89.4

95.4

Mean Early Fetal Death

Pre-treatment mating 1

0.2

0.4

0.6

0.5

Pre-treatment mating 2

0.6

0.5

0.5

1.0

Post-treatment mating 1

0.8

5.9

0.5

0.8

Post-treatment mating 2

0.5

4.1

0.9

0.5

Mean Late Fetal Death

Pre-treatment mating 1

0.1

0.0

0.0

0.0

Pre-treatment mating 2

0.0

0.0

0.0

0.1

Post-treatment mating 1

0.0

0.1

0.0

0.0

Post-treatment mating 2

0.0

0.0

0.0

0.0

Viable Fetal Swellings

Pre-treatment mating 1

9.9

10.9

11.4

12.5

Pre-treatment mating 2

11.9

13.5

11.6

10.8

Post-treatment mating 1

11.1

2.8

12.1

11.8

Post-treatment mating 2

12.2

0.0

11.9

12.1

Conclusions:
The NOAEC for reproductive and developmental screening is 300 ppm in rats via inhalation.
Executive summary:

This study was conducted to assess the reproductive and developmental toxicity potential of MRD-78-25 when administered to male rats. Male rats were cohabitated for two weeks with two female rats. Males were exposed for 6 hrs/day, 5 days/week, for 8 weeks. At the end of the 8 week exposure period, the male rats the cohabitated for 7 days with two virgin female rats. After this cohabitation, the males were again cohabitated with two new virgin females for another 7 days. 18 days after the beginning of cohabitation, the females were sacrificed. There were also a negative control group, and a positive control group exposed to triethylenemelamine prior to mating. Animals were examined for mortality, pharmacological observations, toxicological observations, physical observations, body weight, gross necropsy, and histopathology. Males proven fertile were then exposed to 100 or 300 ppm of test substance vapors via inhalation (10 males per concentration). The number of implantation sites, early resorption sites, late resorption sites, and viable fetal swellings were also examined. Pregnancy rates, implantation rate, and implantation efficiency were comparable between exposure groups and negative controls. The NOAEC for reproductive screening is 300 ppm for rats via inhalation.

Endpoint:
extended one-generation reproductive toxicity - with developmental neurotoxicity (Cohorts 1A, 1B without extension, 2A and 2B)
Data waiving:
other justification
Justification for data waiving:
other:
Justification for type of information:
The 'Justification for the read across' is provided in the 'Attached justification' section below.
Species:
rat
Effect on fertility: via oral route
Endpoint conclusion:
no study available
Effect on fertility: via inhalation route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
1 720 mg/m³
Study duration:
subacute
Experimental exposure time per week (hours/week):
30
Species:
rat
Quality of whole database:
One Guideline OECD 421 reproductive toxicity screening study available from structural analogues.
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.

There is no data available for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). However, data is available for structural analogue, Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%)

A key read across OECD Guideline 421 screening reproductive toxicity study (ExxonMobil, 1980a), was conducted to assess the reproductive and developmental toxicity potential of the test material (Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%)) when administered to male rats. Male rats were cohabitated for two weeks with two female rats. Males were exposed for 6 hrs/day, 5 days/week, for 8 weeks. At the end of the 8 week exposure period, the male rats the cohabitated for 7 days with two virgin female rats. After this cohabitation, the males were again cohabitated with two new virgin females for another 7 days. 18 days after the beginning of cohabitation, the females were sacrificed. There were also a negative control group, and a positive control group exposed to triethylenemelamine prior to mating. Animals were examined for mortality, pharmacological observations, toxicological observations, physical observations, body weight, gross necropsy, and histopathology. Males proven fertile were then exposed to 100 or 300 ppm of test substance vapors via inhalation (10 males per concentration). The number of implantation sites, early resorption sites, late resorption sites, and viable fetal swellings were also examined. Pregnancy rates, implantation rate, and implantation efficiency were comparable between exposure groups and negative controls. The NOAEC for reproductive screening was determined to be 300 ppm for rats via inhalation.

Additionally, OECD 443 tests are proposed for structural analogues, Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) (EC# 919-006-8) and Hydrocarbons, C11-C15, aromatics, <1% naphthalene (EC# 922-153-0). An OECD Guideline 422 screening reproductive/developmental toxicity study (oral route) in rodents is also planned with structural analogue Hydrocarbons, C14-C18, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) (EC# 920-360-0). This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

 

This endpoint will be updated subsequent to ECHA's approval of the testing proposals and availability of data upon completion of the studies.

Effects on developmental toxicity

Description of key information

Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.

There is no data available for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). However, data is available for structural analogue, Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%):

NOAEC for developmental toxicity ≥ 300 ppm (1720 mg/m3)

Additional OECD Guideline 414 rodent and non-rodent species tests are proposed for structural analogues Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) (EC# 919-006-8) and Hydrocarbons, C11-C15, aromatics, <1% naphthalene (EC# 922-153-0).

This endpoint will be updated subsequent to ECHA's approval of the testing proposals and availability of data upon completion of the studies.

Link to relevant study records

Referenceopen allclose all

Endpoint:
developmental toxicity
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
11 Sept. 1978 - 6 Oct. 1978
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study.
Justification for type of information:
Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
according to guideline
Guideline:
other: Guidelines for Reproduction Studies for Safety and Evaluation of Drugs for Human Use, Segment II (Teratology Study)
GLP compliance:
no
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc.
- Age at study initiation: 7 weeks
- Fasting period before study: Animals were not given food during exposure.
- Housing: Individually, except during mating, in stainless steel cages, animals identified by ear tags
- Diet (e.g. ad libitum): Purina Lab Chow, ad libitum
- Water (e.g. ad libitum): Elizabethtown Water Company, ad libitum
- Acclimation period: Aug. 17, 1978-Sept. 4, 1978


ENVIRONMENTAL CONDITIONS
- Temperature (°C): monitored twice daily, room temperature
- Humidity (%): dry air
- Photoperiod (hrs dark / hrs light): 12 hrs light/12 hrs dark


IN-LIFE DATES: days 6-15 of gestation From: 11-27 Sept. 1978 To: 20 Sept. - 6 Oct. 1978
Route of administration:
inhalation: vapour
Type of inhalation exposure (if applicable):
whole body
Vehicle:
unchanged (no vehicle)
Details on exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: one cubic meter exposure chamber
- Temperature, humidity, pressure in air chamber: room temperature, dry air
Analytical verification of doses or concentrations:
no
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/1
- Length of cohabitation: Overnight and removed in morning to check for pregnancy, this was repeated until females were pregnant
- Proof of pregnancy: vaginal plug and sperm in vaginal smear referred to as day 0 of pregnancy
Duration of treatment / exposure:
6 hrs/day
Frequency of treatment:
days 6-15 of gestation
Duration of test:
days 6-15 of gestation
No. of animals per sex per dose:
20
Control animals:
yes, concurrent no treatment
Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily
- Cage side observations: mortality, toxicological signs, pharmacological effects

BODY WEIGHT: Yes
- Time schedule for examinations: days 0, 6-15, 21 of gestation

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #: 21
- Organs examined: uterus, ovaries

Ovaries and uterine content:
The ovaries and uterine content were examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: number of live fetuses, number of dead fetuses
Fetal examinations:
- External examinations: Yes: all per litter examined for sex, crown-rump distance, weighed, and malformations
- Soft tissue examinations: Yes: 2/3 per litter examined for gross dissection and examination of viscera, internal sex determination, ureter, kidneys, and heart
- Skeletal examinations: Yes: 2/3 per litter examined for skeletal malformations, and ossification
- Head examinations: Yes: 1/3 per litter examined for neural defects
Statistics:
Analysis was done using the chi-square method, or the F-test and Student's t-test. When the variance differed significantly, the Student's t-test was modified suing Chochran's approximation. The mean number of live fetuses, resorptions, implantations, and corpora lutea were analyzed using the one-tailed t-test.
Indices:
implantation efficiency,
Details on maternal toxic effects:
Maternal toxic effects:no effects

Details on maternal toxic effects:
There was no mortality in either of the dosage groups. Pregnancy rates were comparable between the exposure groups and negative controls. Weight gain was significantly higher in the exposure groups post-dosing. There were no significant clinical observations in either exposure group. The mean number of corpora lutea was significantly decreased in the 300 ppm group. Since ovulation occurred prior to exposure, this was not considered to be treatment related. The mean number of implantations was comparable between exposure groups and negative controls. The implantation efficiency values were actually significantly higher in exposure groups as compared to negative controls. The mean number of live fetuses, resorption sites, and number of dams with more than one resorption site were comparable between exposures and negative controls. The gross postmortem examination of dams showed no treatment related effects.
Key result
Dose descriptor:
NOAEC
Effect level:
>= 300 ppm
Basis for effect level:
other: Systemic toxicity
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
The body weights of fetal males in the 100 ppm group were significantly higher than negative controls. There were some statistically significant differences in mean crown-rump distance between both dosage levels and negative controls, these differences were slight and the effect inconsistant between dosages and sex. These differences were therefore not considered to be indicative of a treatment related effect. Mean numbers of male and female fetuses, and sex ratios were similar between exposure groups and negative controls. Ossification variations were similar in exposure groups and negative controls, as was the incidence of litters with fetuses containing ossification variations. No malformations externally or in the soft tissues were noted in the fetuses except in the positive controls. Though skeletal defects were noted in the exposure group, the types of malformations are common in rat fetus and not considered to be treatment related.
Key result
Dose descriptor:
NOAEC
Effect level:
>= 300 ppm
Based on:
test mat.
Basis for effect level:
other: Developmental Toxicity
Abnormalities:
not specified
Developmental effects observed:
not specified

Results - Dams

Endpoint

Negative Control

400 mg/kg ASA

100 ppm

300 ppm

Pregnancy Rate (%)

100.0

95.0

100.0

90.0

Mortality Rate (%)

0.0

10.0

0.0

0.0

Mean Body Weight Gain  (g)

Dams - Days 15-21

84

32

108

103

Mean Corpora Lutea

15.2

14.5

15.5

13.8

Mean No. Implantations

13.0

13.2

13.8

13.2

Implantation Efficiency (%)

85.8

91.1

88.7

95.6

Mean No. Live Fetuses

12.5

7.4

12.9

12.6

Mean No. Dead Fetuses

0.0

0.0

0.0

0.0

Mean No. Resorptions

0.6

5.8

0.9

0.7

Dams with more than one Resorption (%)

10.0

58.8

25.0

11.1

Results – Fetuses

Endpoint

Negative Control

400 mg/kg ASA

100 ppm

300 ppm

Male Mean Fetal Weight (g)

5.57

3.88

5.82

5.62

Female Mean Fetal Weight (g)

5.29

3.62

5.44

5.33

Male Mean Crown-Rump Distance (cm)

4.3

3.7

4.4

4.2

Female Mean Crown-Rump Distance (cm)

4.2

3.6

4.2

4.1

Sex Ratio (%)

91.5

98.4

88.3

105.5

Ossification Variations (%)

70.7

100.0

79.4

79.3

Litters with Ossification Variations (%)

100.0

100.0

95.0

100.0

Soft Tissue Malformations (%)

2.4

26.8

1.1

3.9

Litters with Soft Tissue Malformations (%)

10.0

54.5

5.0

16.7

Gross Evisceration Malformations (%)

5.4

3.6

1.8

4.0

Litters with Gross Evisceration Malformations

25.0

8.3

10.0

16.7

Skeletal Malformations (%)

0.0

21.4

2.9

1.3

Litters with Skeletal Malformations

0.0

66.7

15.0

11.1

Conclusions:
The NOAEC for developmental toxicity in rats is >=300 ppm (1575 mg/m3) via inhalation. The test substance is also non-teratogenic.
Executive summary:

This study determined the developmental toxicity of MRD-78 -25 in rats exposed via inhalation. Groups of 20 pregnant female rats were exposed 6 hrs/day during days 6 -15 of gestation. Test concentrations of 100 or 300 ppm test substance. In addition to a negative control group, there was also a positive control group that was exposed to acetylsalicylic acid on days 6 -15 of gestation. Dams were observed for toxicological signs and pharmacological effects. On day 21 of gestation, the animals were sacrificed, and examined for corpora lutea and uterine implantation parameters. Fetuses were examined for fetal size, sex ratio, and external, soft-tissue, and skeletal malformations. No adverse effects due to exposure to the test substance were seen in either dams or fetuses. No treatment related malformation effects were noted in the fetuses. The developmental NOAEC for rats by inhalation is >=300 ppm. The test substance is also not teratogenic.

Endpoint:
developmental toxicity
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
1978
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented study report equivalent or similar to OECD guideline 414
Justification for type of information:
Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.
Reason / purpose for cross-reference:
read-across: supporting information
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Principles of method if other than guideline:
Exposure on GD 6-15 with sacrifice on GD 21
GLP compliance:
not specified
Limit test:
no
Species:
rat
Strain:
Sprague-Dawley
Details on test animals or test system and environmental conditions:
Source - Charles River Breeding Labs, Inc. Wilmington, Mass 01887
Age at receipt - 7 weeks
Age at mating - 9 weeks (females)
Food - Purina lab chow ad libitum expect during 6-hour exposure period
Water - Ad libitum except during 6-hour exposure period

Temperature - monitored twice daily
Light cycle - 12/12 light/dark cycle
Route of administration:
inhalation: vapour
Type of inhalation exposure (if applicable):
whole body
Vehicle:
air
Details on exposure:
Dry air at room temperature was drawn directly through the one cubic meter exposure chamber. Animals were exposed for 6 hours each day.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Charcoal traps were removed from effluent line and transfered to scintillation-type containers. Samples were collected from two dose levels at various intervals during the exposure period (day 0 - 5 hr, day 1 - 1 hr, day 2 - 3 hr, day 3 - 5 hr, day 4 - 1 hr, week 3 - 5 hr and week 6 - 1 hr). Samples were desorbed using tetrahydrofuran, injected into a gas chromatograph for evaluation against a previously injected standard of MRD-78-26. Results of the evaluation period demonstrated that no appreciable change occurred in the distribution of the components of the test article in the vapor phase.
Details on mating procedure:
Females selected for mating were placed with males nightly in a 1:1 ratio. Vaginal smears were taken early in the morning and females were considered to have mated if sperm and/or vaginal plug were observed. Day on which evidence of mating was observed was defined as Day 0 of gestation.
Duration of treatment / exposure:
Gestation days 6-15
Frequency of treatment:
6 hours/day
Duration of test:
Gestation days 0-21
Remarks:
Doses / Concentrations:
0, 100 or 300 ppm
Basis:
nominal conc.
No. of animals per sex per dose:
20 females/group
Control animals:
yes, sham-exposed
other: Positive control - 400 mg/kg Acetylsalicylic acid
Details on study design:
20 pregnant female rats were included as a positive control. Rats were dosed orally with 400 mg/kg/day acetylsalicylic acid (ASA) on gestation days 6-15. Appropriate amounts of acetyl salicylic acid (ASA) were suspended in 0.5% Methocel® and administered (daily as a single dose) at a constant volume of 10 ml/kg/day. Individual doses were adjusted by daily body weights taken on Days 6-15 of gestation.
Maternal examinations:
For mortality and gross evaluations - Twice daily
Detailed physical examinations for sings of local or systemic toxicity - Days 0, 6-15 and 21 of gestation
Body weight - Measured on days 0, 6-15 and 21 of gestation
Body weight change - calculated for days 0-6, 6-15 and 15-21 of gestation
Ovaries and uterine content:
Number and location in each uterine horn of live/dead fetuses, late/early resorptions and implantation sites were evaluated. Number of corpora lutea per ovary were assessed.
Fetal examinations:
Gross dissection and examination of viscera (including internal sex determination). Skeletons were examined for malformations and ossification variations after Alizarin red staining using a modified Crary method. Approximately 1/3 of fetuses were fixed with Bouin's stain and examined for neural and visceral defects after being serially sectioned by the slicing technique of Wilson.
Statistics:
Comparisons between control Group I and control Group II, and between control Group I and each test substance-treated groups were made where applicable (incidence data) by the chi-square method or by the F-test and Student's t-test (absolute data). When variances differed significantly. Student's t-test was appropriately modified using Cochran's approximation (t1). Mean number of live fetuses, resorptions, implantations and corpora lutea were compared to control by the one-tailed t-test.
Details on maternal toxic effects:
Maternal toxic effects:no effects

Details on maternal toxic effects:
No effects on mortality, mean body weight gain and pregnancy rate compared to chamber controls. Physical evaluation revealed no indication of a treatment-related effect. Mean numbers of implantation sites, implantation efficiency, mean number of live fetuses, resorption sites and incidence of dams with one or more resorption sites were comparable between treatment and chamber-exposed control groups. Mean number of corpora lutea was statistically significantly lower in the 300 ppm dose group however this was not considered treatment-related as ovulation occurred prior to initiation of treatment.

Necropsy evaluations revealed no treatment-related effects.
Key result
Dose descriptor:
NOAEC
Effect level:
>= 300 ppm (nominal)
Basis for effect level:
other: maternal toxicity
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Mean fetal weights and mean crown-rump distances in both sexes were comparable to chamber controls. Incidence of fetuses with at least one ossification variation was comparable to chamber controls. Incidence of litters containing fetuses with ossification variations, types and incidences of ossification variations noted where generally similar between control and test substance-treated groups.
Fetal examinations revealed no malformations in any of the treated groups.
Key result
Dose descriptor:
NOAEC
Effect level:
>= 300 ppm (nominal)
Basis for effect level:
other: teratogenicity
Abnormalities:
not specified
Developmental effects observed:
not specified
Conclusions:
The NOAEC for developmental toxicity was 300 ppm, the highest concentration tested.
Executive summary:

A segment II inhalation teratology study was conducted in Sprague-Dawley rats with a C8-C13 mixed aliphatic/aromatic solvent containing 19% aromatics. In this study, pregnant female rats (20/dose group) were exposed to 0, 100, and 300 ppm of test material for 6 hours per day on days 6 through 15 of gestation. This study included a chamber-exposed negative control and an acetylsalicyclic acid positive control (400 mg/kg/day by gastric intubation from days 6 to 15). Parameters evaluated included the following: maternal mortality, pregnancy rate, body weight gain, physical observations and necropsy observations; corpora lutea and uterine implantation data; fetal size, sex ratios and ossification variation data; and fetal external, soft tissue and skeletal malformation data.

No mortality occurred during the study. No treatment-related physical observations were observed. Treated females gained more weight than chamber-exposed controls during the post-dosing interval. Pregnancy rates were comparable to chamber-exposed controls. The mean number of corpora lutea was significantly decreased in the 300 ppm dose group but was not considered to be a treatment-related effect since ovulation occurred prior to initiation of treatment. An increase in implantation efficiency was observed in treated groups but is not considered indicative of an adverse effect. The number of live fetuses, resorption sites and the incidence of dams with one or more resorption sites were comparable with controls. A few gross lesions were observed at necropsy but no treatment-related effects were indicated.

Mean crown-rump distances (both sexes) were considered comparable between the chamber-exposed and treated groups. Although some statistically significant differences were observed in crown-rump distances between these same groups, the differences were slight with no apparent dose-response pattern and were not considered to be treatment-related. Sex ratio was unremarkable. The incidence of fetuses with ossification variations was comparable to chamber-exposed controls. No treatment-related effects were observed for external, soft tissue and skeletal evaluations of fetuses recovered from treated females.

In summary, under the conditions of this test, the C8-C13 mixed aliphatic/aromatic solvent containing 19% aromatics was neither embryotoxic nor teratogenic in the rats. The NOAEC for maternal and developmental toxicity was 300 ppm.

Endpoint:
developmental toxicity
Data waiving:
other justification
Justification for data waiving:
other:
Justification for type of information:
The 'Justification for the read across' is provided in the 'Attached justification' section below
Species:
rat
Endpoint:
developmental toxicity
Data waiving:
other justification
Justification for data waiving:
other:
Justification for type of information:
The 'Justification for the read across' is provided in the 'Attached justification' section below.
Species:
rabbit
Effect on developmental toxicity: via oral route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
1 575 mg/m³
Study duration:
subacute
Species:
rat
Quality of whole database:
Two inhalation developmental toxicity studies from structural analogues available for assessment.
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) straddles Hydrocarbons, C9-C14, Aliphatics, (2-25% Aromatics) and Hydrocarbons, C14-C20, Aliphatics (2-30% Aromatics). Read across justification documents have been provided for the same in Section 13 of the dossier. For this substance, a worst case scenario approach has been used for each endpoint.

There is no data available for Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). However, data is available for structural analogue, Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%). This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%)

A key study (ExxonMobil, 1979b) determined the developmental toxicity of the test material (Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%)) in rats exposed via inhalation. Groups of 20 pregnant female rats were exposed 6 hrs/day during days 6 -15 of gestation. Test concentrations of 100 or 300 ppm test substance. In addition to a negative control group, there was also a positive control group that was exposed to acetylsalicylic acid on days 6 -15 of gestation. Dams were observed for toxicological signs and pharmacological effects. On day 21 of gestation, the animals were sacrificed, and examined for corpora lutea and uterine implantation parameters. Fetuses were examined for fetal size, sex ratio, and external, soft-tissue, and skeletal malformations. No adverse effects due to exposure to the test substance were seen in either dams or fetuses. No treatment related malformation effects were noted in the fetuses. The developmental NOAEC for rats by inhalation was determined to be >=300 ppm. The test substance is also not teratogenic.

A segment II inhalation teratology study (ExxonMobil, 1979d) was conducted in Sprague-Dawley rats with a C8-C13 mixed aliphatic/aromatic solvent containing 19% aromatics. In this study, pregnant female rats (20/dose group) were exposed to 0, 100, and 300 ppm of test material for 6 hours per day on days 6 through 15 of gestation. This study included a chamber-exposed negative control and an acetylsalicyclic acid positive control (400 mg/kg/day by gastric intubation from days 6 to 15). Parameters evaluated included the following: maternal mortality, pregnancy rate, body weight gain, physical observations and necropsy observations; corpora lutea and uterine implantation data; fetal size, sex ratios and ossification variation data; and fetal external, soft tissue and skeletal malformation data.

No mortality occurred during the study. No treatment-related physical observations were observed. Treated females gained more weight than chamber-exposed controls during the post-dosing interval. Pregnancy rates were comparable to chamber-exposed controls. The mean number of corpora lutea was significantly decreased in the 300 ppm dose group but was not considered to be a treatment-related effect since ovulation occurred prior to initiation of treatment. An increase in implantation efficiency was observed in treated groups but is not considered indicative of an adverse effect. The number of live fetuses, resorption sites and the incidence of dams with one or more resorption sites were comparable with controls. A few gross lesions were observed at necropsy but no treatment-related effects were indicated.

Mean crown-rump distances (both sexes) were considered comparable between the chamber-exposed and treated groups. Although some statistically significant differences were observed in crown-rump distances between these same groups, the differences were slight with no apparent dose-response pattern and were not considered to be treatment-related. Sex ratio was unremarkable. The incidence of fetuses with ossification variations was comparable to chamber-exposed controls. No treatment-related effects were observed for external, soft tissue and skeletal evaluations of fetuses recovered from treated females.

In summary, under the conditions of this test, the C8-C13 mixed aliphatic/aromatic solvent containing 19% aromatics was neither embryotoxic nor teratogenic in the rats. The NOAEC for maternal and developmental toxicity was 300 ppm.

Additional OECD Guideline 414 rodent and non-rodent species tests are proposed for structural analogues Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) (EC# 919-006-8) and Hydrocarbons, C11-C15, aromatics, <1% naphthalene (EC# 922-153-0). This endpoint will be updated subsequent to ECHA's approval of the testing proposals and availability of data upon completion of the studies.

Justification for classification or non-classification

Based on available read across data from structural analogues, Hydrocarbons, C12-C16, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) does not warrant the classification as a reproductive or developmental toxicant under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP). However, further tests (OECD 422, 443, and OECD 414 (rodent and 2nd species)) are proposed on structual analogues and will be conducted subsequent to ECHA's approval of the same. This endpoint will be updated upon completion of the above studies subject to ECHA's approval.

Additional information