2,6,8-trimethylnonan-4-ol

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 August - 30 September 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to test guidelines and in accordance with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: USEPA OPPTS 870.3650 (2000)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,6,8-trimethylnonan-4-ol

EC Number:

204-606-8

EC Name:

2,6,8-trimethylnonan-4-ol

Cas Number:

123-17-1

Molecular formula:

C12H26O

IUPAC Name:

2,6,8-trimethylnonan-4-ol

Details on test material:

- Name of test material (as cited in study report): 2,6,8-Trimethylnonan-4-nonanol
- Molecular weight (if other than submission substance): 186.3
- Physical state: Liquid, transparent pale yellow
- Analytical purity: The purity of the major component Trimethyl nonanol was 96.05 ± 0.055%, water was 0.32 ± 0.002%, and five minor components were present at 0.1% or greater as measured by area percent gas chromatography and coulometric Karl Fisher water determination. The structure was confirmed via infrared (IR) spectroscopy and gas chromatographic mass spectrometry (GC/MS).
- Lot/batch No.: RC1355T3D4

Test animals

Species:

rat

Strain:

other: CRL:CD(SD)Rats

Sex:

male/female

Details on test animals or test system and environmental conditions:

Supplier and Location
Charles River Laboratories Inc. (Raleigh, North Carolina)

Age at Study Start
Approximately eight weeks of age at initiation of treatment

Physical and Acclimation
Each animal was evaluated by a laboratory veterinarian, or a trained animal/toxicology technician under the direct supervision of a laboratory veterinarian, to determine the general health status and acceptability for study purposes upon arrival at the laboratory (fully accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International - AAALAC International). The animals were housed two-three per cage in stainless steel cages, in rooms designed to maintain adequate conditions (temperature, humidity, and photocycle), and acclimated to the laboratory for at least one week prior to the start of the study.

Housing
Animals were housed one per cage in stainless steel cages. The relative humidity was maintained within a range of 40-70%. The average room temperature was maintained at 22 ± 1°C (with a maximum permissible excursion of ± 3°C). A 12-hour light/dark photocycle was maintained for all animal room(s) with lights on at 6:00 a.m. and off at 6:00 p.m. Room air was exchanged approximately 12-15 times/hour. Cages had wire mesh floors and were suspended above absorbent paper. Cages contained a feed crock and a pressure activated lixit valve-type watering system.

Feed and Water
Animals were provided LabDiet Certified Rodent Diet #5002 (PMI Nutrition International, St. Louis, Missouri) in meal form. Feed and municipal water was provided ad libitum. Analyses of the feed were performed by PMI Nutrition International to confirm the diet provides adequate nutrition and to quantify the levels of selected contaminants. Drinking water obtained from the municipal water source was periodically analyzed for chemical parameters and biological contaminants by the municipal water department. In addition, specific analyses for chemical contaminants were conducted at periodic intervals by an independent testing facility. The results indicated no contaminants that would interfere with the conduct of the study or interpretation of the results.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

Groups of 12 male and 12 female Crl:CD(SD) rats were administered the test material daily, by gavage, at dose levels of 0 (control), 20, 100, or 500 mg/kg/day. Female rats were dosed once daily for approximately two weeks prior to breeding, during breeding (two weeks), gestation (three weeks), and lactation through postpartum day 4. Male rats were dosed beginning approximately two weeks prior to breeding and continuing through breeding (two weeks) for a minimum exposure period of 33 days.

Details on mating procedure:

Breeding of the adults commenced after approximately two weeks of treatment. Each female was placed with a single male from the same dose level (1:1 mating) until pregnancy occurred or two weeks had elapsed. During the breeding period, daily vaginal lavage samples were evaluated for the presence of sperm as an indication of mating. The day on which sperm were detected or a vaginal copulatory plug was observed in situ was considered GD 0. The sperm- or plug-positive (presumed pregnant) females were then separated from the males and returned to their home cages. If mating had not occurred after two weeks, the animals were separated without further opportunity for mating.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analysis
Homogeneity
The low- and high-dose formulations from the first mix of the main study were analyzed to confirm homogeneous distribution of the test material concurrent with the start of the study.
Stability
Stability of the test material in the vehicle was initiated prior to the start of the study at concentrations of 0.25, 2.5 and 250 mg/ml. Dose formulations for the current study were prepared and used within these stability limits.
Concentration Verification
Analysis of all dosing solutions from the first mix of the main study were initiated prior to the start of dosing using gas chromatography with flame ionization and external standards to determine target concentrations.

Duration of treatment / exposure:

Male rats were dosed daily for 14 days prior to mating and continuing throughout the mating for 33 days. Female rats were dosed once daily for 14 days prior to breeding, and during breeding (two weeks), gestation (three weeks), and lactation through post partum day 4.

Frequency of treatment:

Daily

Details on study schedule:

Groups of 12 male and 12 female Crl:CD(SD) rats were administered the test material daily, by gavage, at dose levels of 0 (control), 20, 100, or 500 mg/kg/day. Female rats were dosed once daily for approximately two weeks prior to breeding, during breeding (two weeks), gestation (three weeks), and lactation through postpartum day 4. Male rats were dosed beginning approximately two weeks prior to breeding and continuing through breeding (two weeks) for a minimum exposure period of 33 days. Effects on general toxicity, neurobehavioral activity, clinical chemistry, urine parameters, hematology, gonadal function, mating behavior, conception, development of the conceptus, parturition and early postnatal growth and survival were evaluated. In addition, a gross necropsy of the adults was conducted with histopathologic examination of tissues. Gavage dosing for both males
and females began on August 10, 2005. The adult males were necropsied on September 12, 2005. The adult females were necropsied from September 19, 2005 to September 30, 2005. In the offspring, litter size, pup survival, sex, body weight, and the presence of gross external abnormalities were assessed. Pups were euthanized on PND 4.

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 20, 100 and 500 mg/kg
Basis:
nominal conc.
analytically verified and rats were orally gavaged

No. of animals per sex per dose:

12/sex/dose level

Control animals:

yes, concurrent vehicle

Details on study design:

See Repeated Dose Toxicity: Oral of IUCLID for the observations and examination of the parental animals

Positive control:

No data.

Examinations

Parental animals: Observations and examinations:

See Repeated Dose Toxicity: Oral of IUCLID for the observations and examination of the parental animals

Oestrous cyclicity (parental animals):

No data

Sperm parameters (parental animals):

No data

Litter observations:

Females were observed for signs of parturition beginning on or about GD 20. In so far as possible, parturition was observed for signs of difficulty or unusual duration. The day of parturition was recorded as the first day the presence of the litter was noted and was designated as LD 0. All litters were examined as soon as possible after delivery. The following information was recorded on each litter: date of parturition, litter size on the day of parturition (LD 0), the number of live and dead pups on days 0, 1, and 4 postpartum, and the sex and the weight of each pup on LD 1 and 4. Any visible physical abnormalities or demeanor changes in the neonates were recorded as they were observed during the lactation period (see Daily In-Life Observations in the Repeated Dose Toxicity: Oral of IUCLID). In addition, pup clinical observations were recorded on each litter on days 0 through 4 postpartum. Any pups found dead were sexed and examined grossly, if possible, for external and visceral defects and then discarded.

Postmortem examinations (parental animals):

See Repeated Dose Toxicity: Oral of IUCLID for the postmortem examination of the parental animals

Postmortem examinations (offspring):

All pups surviving to PND 4 were euthanized by intraperitoneal administration of sodium pentobarbital solution, examined for gross external alterations, and then discarded. Any pups found dead or which were euthanized in moribund condition were examined to the extent possible and discarded.

Statistics:

See Repeated Dose Toxicity: Oral of IUCLID for the statistics used in this study.

Reproductive indices:

Reproductive indices were calculated for all dose level groups as follows:
• Female mating index = (No. females with evidence of mating/No. paired) x 100
• Male mating index = (No. males with evidence of mating/No. paired) x 100
• Female conception index = (No. females with evidence of pregnancy/No. mated) x 100
• Male conception index = (No. males siring a litter/No. mated) x 100
• Female fertility index = (No. females with evidence of pregnancy/No. paired) x 100
• Male fertility index = (No. males siring a litter/No. paired) x 100
• Gestation index = (No. females delivering a viable litter/No. females with
evidence of pregnancy) x 100
• Gestation survival index = percentage of delivered pups alive at birth
• Post-implantation loss = (No. implants – No. viable offspring)/(No. implants) x 100

Offspring viability indices:

• Day 1 or 4 pup survival index = (No. viable pups on day 1 or 4/No. born live) x 100

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

See repeated dose section of IUCLID

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:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

See repeated dose section of IUCLID

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not specified

Reproductive function: sperm measures:

not specified

Reproductive performance:

no effects observed

Details on results (P0)

See Repeated Dose Toxicity: Oral section of IUCLID for additional information on results of repeated dose toxicity

Effect levels (P0)

Dose descriptor:

NOEL

Effect level:

20 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Increase in absolute and relative liver weights and corresponding hepatocellular hypertrophy in males given 100 or 500 mg/kg/day and in females given 500 mg/kg/day.

Results: F1 generation

General toxicity (F1)

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:

not examined

Histopathological findings:

not examined

Details on results (F1)

Reproductive Indices, Pup Survival, and Sex Ratio
There were no treatment-related effects at any dose level on any of the reproductive parameters or pup survival indices evaluated. Although there was a statistically identified difference in the sex ratio of pups given 20 mg/kg/day, this was not considered to be toxicologically significant because sex ratio was not altered at 100 and 500 mg/kg/day.

Litter Observations
Observations recorded in the offspring occurred at low frequency and bore no relationship to treatment. One high-dose pup was observed with an umbilical hernia (an external variation, not a malformation). This was an isolated occurrence bearing no relationship to treatment.

Litter Size and Pup Body Weights
There were no treatment-related effects on litter or pup body weights at any dose level tested.

Effect levels (F1)

Dose descriptor:

NOEL

Generation:

F1

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No observed effects on reproductive parameters at the highest dose examined in this study.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Text Table. Sex Ratio

	Sex Ratio
mg/kg/day	0	20	100	500
Sex Ratio (%)	49:51	60:40*	51:49	53:47

*Statistically Different from Expected Value of 50% by the Binomial Distribution Test.

Applicant's summary and conclusion

Conclusions:

Based on the results of conducted study, the no-observed effect level(NOEL) for general toxicity was 20mg/kg/day. The NOEL for neurological and reproductive effects was 500mg/kg/day, the highest dose level tested.

Executive summary:

Groups of 12 male and 12 female Crl:CD(SD) rats were administered trimethyl nonanol daily, by oral gavage at dose levels of 0 (control), 20, 100, or 500 mg/kg/day. Females were dosed once daily for two weeks prior to breeding, during breeding (two weeks), gestation (three weeks), and lactation through postpartum day 4. Females were necropsied on post-partum day 5. Males were dosed two weeks prior to breeding and continuing through breeding (two weeks) until necropsy (test day 34). Effects on reproductive and neurological function as well as general toxicity were evaluated. In addition, post mortem examinations included a gross necropsy of the adults with collection of organ weights and histopathologic examination of tissues. Litter size, pup survival, sex, body weight, and the presence of gross external abnormalities were also assessed.

Administration of 100 or 500 mg/kg/day trimethyl nonanol resulted in parental systemic toxicity (see repeated dose toxicity section of IUCLID).

There were no adverse effects of trimethyl nonanol on reproductive function.

The no-observed-effect level (NOEL) for general toxicity was 20 mg/kg/day. The NOEL for reproductive effects was 500 mg/kg/day, the highest dose level tested.