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

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

There is data available for Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%).

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

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

Additionally, an OECD 443 test is proposed for structural analogue, Hydrocarbons, C9-C10, aromatics, >1% naphthalene. This data is read across to Hydrocarbons, C9 -C12, n-alkanes, isoalkanes, cyclics, aromatics (2 -25%) 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 proposal and availability of data upon completion of the study.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1980

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study.

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.

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 for assessment.

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

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.

Effects on developmental toxicity

Description of key information

There is data available for Hydrocarbons, C9-C12, n-alkanes, isoalkanes, cyclics, aromatics (2-25%).

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 analogue Hydrocarbons, C9-C10, aromatics, >1% naphthalene. 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

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

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.

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.

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:

One inhalation developmental toxicity study available for assessment.

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

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

A key study (ExxonMOnil, 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.

Justification for classification or non-classification

Based on available substance specific data, Hydrocarbons, C9-C12, 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 443 and OECD 414 (rodent and 2nd species)) are proposed on a structural analogue 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.