Guerbet alcohols, C24-26, branched and cyclic

Endpoint summary

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 2019 to April 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

This study was performed for the notification in other regions where authorities do not accept read-across data.

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Version / remarks:

25 June 2018

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

The Sprague Dawley SD rat was the species and strain of choice because it is accepted by many regulatory authorities and there are ample experience and background data on this species and strain.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Italia S.p.A., Calco (Lecco), Italy
- Females (if applicable) nulliparous and non-pregnant: [yes/no]
- Age at study initiation: 27-29 days
- Weight at study initiation: 90.7-109.2 g (males), 89.3-104.1 g (females)
- Housing: The animals were housed up to 5 of one sex to a cage, in clear polysulfone solid bottomed cages.Nesting material was provided inside suitable bedding bags and changed at least twice a week.
- Diet (e.g. ad libitum): laboratory rodent diet (4 RF 21,Mucedola S.r.l., Via G. Galilei, 4, 20019, SettimoMilanese (MI), Italy, ad libitum)
- Water (e.g. ad libitum): drinking water (ad libitum)
- Acclimation period: 13 days

DETAILS OF FOOD AND WATER QUALITY:

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C±2°C
- Humidity (%): 55%±15%
- Air changes (per hr): 15 to 20
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 04.09.2019 To: 12.12.2019

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
The required amount of test item was suspended in the vehicle. The preparations were made weekly.

VEHICLE
- Concentration in vehicle: 20, 60 and 200mg/mL
- Amount of vehicle (if gavage): 5 mL/kg body weight

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The technique used was gas chromatography (GC) with flame ionisation detection (FID).
Linearity was successfully assessed in the range from 0.05215 to 0.2086mg/mL of the test item, since the correlation coefficient, r, was found to be 0.9999 (acceptability criterion >0.98).
Accuracy and precision were assessed at 1 and 200mg/mL of the test item in corn oil. Suspensions were prepared at these levels and six samples were taken from each (two from the top, two from the middle and two from the bottom). The acceptability criteria for accuracy (between 85 and 115% of the theoretical values) and precision (CV < 10 %) were met.
The stability of the preparations at 1 and 200mg/mL was assessed after 28 hours at room temperature and after 8 days at +2-8 °C. The acceptability criteria for concentration and homogeneity (85 to 115% of the theoretical concentration, with a CV<10 %) were fulfilled, indicating that the suspensions were stable, under these conditions.
Samples of the preparations prepared in Weeks 1 and 13 of the current study were analysed to check the homogeneity (in the case of suspensions) and concentration.

Duration of treatment / exposure:

All animals will be dosed once a day, 7 days a week, for a minimum of 13 consecutive weeks. All animals were dosed up until the day before necropsy.

Frequency of treatment:

daily

Dose / conc.:

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

Dose / conc.:

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

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

Dose selection rationale: Dose levels were selected based on data from structurally similar substances (i. e. octyldodecan-1-ol, docosan-1-ol).

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Once before commencement of treatment and once per week during the study from the start of treatment

BODY WEIGHT: Yes
- Time schedule for examinations: Each animal was weighed on the day of allocation to treatment group, on the day that treatment commenced, weekly thereafter and just prior to necropsy.

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: prior to the commencement of treatment and during Week 13 of treatment
- Dose groups that were examined: all (prior commencement), control and high dose group (during week 13 of treatment)

HAEMATOLOGY: Yes
- Time schedule for collection of blood: During the necropsy procedure
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: Not specified
- How many animals: all
- Parameters checked: Haematocrit, Haemoglobin, Red blood cell count, Reticulocyte count, Mean red blood cell volume, Mean corpuscular haemoglobin, Mean corpuscular haemoglobin concentration, White blood cell count, Differential leucocyte count (Neutrophils, Lymphocytes, Eosinophils, Basophils, Monocytes, Large unstained cells) Platelets, Prothrombin time, Total triiodothyronine (total T3), Total thyroxine (total T4) and Thyroid stimulating hormone (TSH)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: During the necropsy procedure
- Animals fasted: Not specified
- How many animals: all
- Parameters checked: Alkaline phosphatase, Alanine aminotransferase, Aspartate aminotransferase, Gamma-glutamyltransferase, Bile acids, Urea, Creatinine, Glucose, Triglycerides, Inorganic phosphorus, Total bilirubin, Total cholesterol, Total protein, Albumin, Globulin, A/G Ratio, Sodium, Potassium, Calcium, Chloride

URINALYSIS: No
- Time schedule for collection of urine: during the last week of treatment
- Metabolism cages used for collection of urine: No
- Animals fasted: Yes

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: once during Week 12 of treatment
- Dose groups that were examined: all
- Battery of functions tested: sensory activity, grip strength, motor activity

OTHER: Vaginal smears were taken from all females before despatch to necropsy and the oestrous cycle phase recorded.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table)

HISTOPATHOLOGY: Yes (see table)

Statistics:

Standard deviations were calculated as considered appropriate. For continuous variables the significance of the differences amongst groups was assessed by analysis of variance. Differences between each treated group and the control group were assessed by Dunnett’s test using a pooled error variance. The homogeneity of the data was verified by Bartlett’s test before Dunnett’s test. If the data were found to be inhomogeneous aModified t test (Cochran and Cox) was applied.
The mean values, standard deviations and statistical analysis were calculated from the actual values in the computer without rounding off. Statistical analysis of histopathological finding was carried out by means of a nonparametric Kolmogorov-Smirnov test.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Minor, not treatment-related clinical signs were observed in individual animals. The most relevant clinical signs were scabs, hairloss and abrasions in few male animals (Group 4) and few female animals (Group 2). One female animal in Group 2 showed a palpable mass.
Slight decreases or increases in the number of rearing, statistically significant, were occasionally observed in treated males and females, when compared to controls. Since these changes were minimal and only occasional, they were not considered to be toxicologically significant.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Two cases of unscheduled death occurred during the study. One low dose male was found dead on Study Day 39. At necropsy, this animal showed dark discoloration of mesenteric lymph nodes and multiple pinpoint red areas and dark discoloration in the thymus. At histopathology, several organs were autolytic and no treatment-induced changes were seen. All reported microscopic observations were considered to be an expression of spontaneous and/or incidental pathology and the cause of death could not be established.
One high dose male (No. A3602074) was found dead on Study Day 86. At necropsy, no macroscopic abnormalities were detected. At histopathology, no treatment-induced changes were seen. All reported microscopic observations were considered to be an expression of spontaneous and/or incidental pathology and the cause of death could not be established.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No difference of toxicological relevance was noted in body weight between treated and control animals.
The comparison between the control and the treated groups of both sexes revealed no treatment related differences in the terminal body weight. All terminal body weight variations were considered to be within the physiological range of Sprague Dawley SD rats of this age.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No difference at toxicological relevance was noted in food consumption between treated and control animals.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No ocular findings were detected before the start of treatment and during Week 13 of treatment, at the ophthalmoscopic examination performed on animals of the control and high dose group.

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Females dosed at 1000 mg/kg/day showed an increase of leucocytes (38% above controls). The increment involved almost all white cell subpopulations. This change was slight and data were within physiological values, therefore this finding was considered to be not adverse. The other statistically significant differences between control and treated males (mean corpuscular haemoglobin, eosinophils, large unstained cells) were not dose-related, therefore they were considered to be incidental.

Coagulation
Prothrombin time was statistically significantly higher than controls in females dosed at 1000 mg/kg/day. Due to the minimal severity (7% above controls), this finding was considered to be not adverse.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Fluctuations of liver markers were recorded in some treated animals, mainly those receiving 1000 mg/kg/day. Compared with controls, males dosed at 1000 mg/kg/day showed increases of alanine aminotransferase (45%) and aspartate aminotransferase (32%), and decreases of bile acids (57%) and chloride (2%). Those receiving 300 mg/kg/day showed similar findings, such as: increase of alanine aminotransferase (14%), decreases of bile acids (44%) and chloride (2%). Bile acids were also decreased in males dosed at 100 mg/kg/day (51%). Concerning females, those receiving 1000 mg/kg/day showed increases of alanine aminotransferase (36%), bilirubin (68%) and calcium (3%) and decreases of triglycerides (37%). Calcium was also increased in those treated at 300 mg/kg/day (3%). The severity of the findings observed was not considered to be suggestive of tissue/organ injury, therefore the above findings were considered to be not adverse. The other statistically significant differences between control and treated females (chloride and sodium) were recorded in animals dosed with 100 or 300 mg/kg/day, therefore considered unrelated to treatment.

Urinalysis findings:

no effects observed

Description (incidence and severity):

Diuresis was the only parameter analysed and no findings were observed.

Behaviour (functional findings):

effects observed, non-treatment-related

Description (incidence and severity):

At functional tests (sensory reactivity, landing footsplay, grip strength) performed at the end of the treatment period, a moderate and statistically significant increase in landing footsplay was recorded in female animals of the mid-dose group (Group 3). In absence of a dose relationship, this finding was considered incidental and of no toxicological relevance.
Motor activity measurements performed at the end of the treatment period did not show any toxicologically significant differences between treated animals and controls.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

The comparison between the control and the treated groups of both sexes revealed no treatment related differences in the absolute and relative organ weight parameters. All terminal organ weight variations were considered to be within the physiological range of Sprague Dawley SD rats of this age.

Gross pathological findings:

no effects observed

Description (incidence and severity):

No treatment-related changes were noted, following gross pathology examination at final sacrifice. All observed changes were considered spontaneous and incidental, having a comparable incidence in control and treated groups and/or are characteristically seen in untreated Sprague Dawley SD rats of the same age. No morphological changes were detected when compared to each “estrous phase” in the ovaries, uterus, cervix and vagina.

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

At the end of the treatment, no treatment-related changes were detected in both males and females treated at 1000 mg/kg/day (high dose). All reported microscopic observations were considered to be an expression of spontaneous and/or incidental pathology. Seminiferous tubules were evaluated with respect to their stage in the spermatogenic cycle and to the integrity of the various cell types within the different stages. As regular layering in the germinal epithelium was noted, there was no treatment-related effect on the spermatogenic
cycle.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

Normal physiology of the oestrous cycle (estrous, metaestrous, diestrous and proestrous) was noted in control and treated females.

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical biochemistry

haematology

Critical effects observed:

no

Conclusions:

On the basis of the results of the oral subchronic toxicity study in rats, it could be concluded that No Observed Adverse Effect Level (NOAEL) for this study is 1000 mg/kg body weight/day.

Executive summary:

The toxicity of the test item Guerbet alcohols, C24-26, branched and cyclic in rats, following daily oral administration for 13 consecutive weeks, was investigated in this study. Three groups, each of 10 male and 10 female Sprague Dawley rats, received the test item by gavage at dosages of 100, 300 and 1000 mg/kg body weight/day. A fourth similarly constituted group received the vehicle alone (corn oil) and acted as a control.

Two cases of unscheduled death occurred during the study. One low dose male and one high dose male were found dead on Study Day 39 (Week 6) and Day 86 (Week 13), respectively. In both animals, gross and histopathology evaluations revealed no treatment-related changes. All reported macroscopic and microscopic observations were considered to be an expression of spontaneous and/or incidental pathology and the cause of death could not be established. No clinical signs related to treatment were recorded at the daily observations performed throughout the study. One female animal in Group 2 showed a palpable mass.

No toxicologically relevant changes were observed at the weekly detailed clinical signs.

No effect considered of toxicological relevance were noted in functional tests (sensory reactivity, landing footsplay, grip strength) and motor activity.

No difference of toxicological relevance was noted in body weight between treated and control animals.

No difference of toxicological relevance was noted in food consumption between treated and control animals.

No ocular findings were detected at the ophthalmoscopic examination performed at the end of treatment.

The increment of leucocytes showed in females dosed at 1000mg/kg/day was within physiological values, therefore considered to be not adverse as well as the other statistically differences noted in males.

Due to the minimal severity, the statistically significant increase of prothrombin time in females dosed at 1000 mg/kg/day was considered to be not adverse.

Fluctuations of liver markerswere recorded in some treated animals, mainly those receiving 1000mg/kg/day. The severity of these findings observed was not considered to be suggestive of tissue/organ injury, therefore considered to be not adverse.

Diuresis was the only parameter analysed in urine and no findings were observed.

No relevant findings were recorded in the thyroid hormone determination.

Physiological phases of the oestrous cycle were detected in all female groups at termination.

At the end of dosing, no treatment-related effects were noted in terminal body weight and organ weights, when compared to controls.

Gross pathology examination did not reveal any treatment-related changes in all dose animals.

Histopathology evaluation did not reveal any treatment-related effect.

Conclusion:

On the basis of these results, it could be concluded that No Observed Adverse Effect Level (NOAEL) for this study is 1000 mg/kg body weight/day

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The toxicity of the test item Guerbet alcohols, C24-26, branched and cyclic in rats, following daily oral administration for 13 consecutive weeks, was investigated according to OECD 408. Three groups, each of 10 male and 10 female Sprague Dawley rats, received the test item by gavage at dosages of 100, 300 and 1000 mg/kg body weight/day. A fourth similarly constituted group received the vehicle alone (corn oil) and acted as a control.

These data reflect the results of studies with two read-across substances, i. e. 2-octyldodecan-1-ol and docosan-1-ol:

A well documented 13 week subchronic toxicity study is available for the structurally related Guerbet alcohol 2-octyldodecan-1-ol (C20). Male and female rats received the substance daily by gavage. There were no indications that 2-octyldodecan-1-ol was toxic at the limit dose of 1 ml/kg bw/d.

Additional data are available for the linear C22-alcohol docosan-1-ol. In a repeated dose toxicity study conducted according to a Guideline similar to OECD Guideline 408 male and female rats received oral doses of up to 1000 mg/kg daily for 26 weeks. No effects were observed resulting in a NOEL of 1000 mg/kg bw.

Justification for classification or non-classification

Available data are conclusive but not sufficient for classfication of Guerbet alcohols, C24-26, branched and linear with regard to repeated dose toxicity.