Docosyl methacrylate

Repeated dose toxicity: oral

Administrative data

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

CD rats were administered Docosan-1-ol (Behenyl alcohol) by oral gavage for 26 weeks at doses of 0, 10, 100, or 1000 mg/kg bw/day.

GLP compliance:

yes

Remarks:

Huntingdon Life Sciences Ltd (Suffolk, England)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Docosan-1-ol

EC Number:

211-546-6

EC Name:

Docosan-1-ol

Cas Number:

661-19-8

Molecular formula:

C22H46O

IUPAC Name:

docosan-1-ol

Test animals

Species:

rat

Strain:

other: CD

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Limited (Margate, Kent, England)
- Age at study initiation: 21 to 28 days
- Housing: stainless-steel cages, male and female rats were separated and housed 5 per cage
- Diet: expanded rodent diet without added antibiotic or other chemotherapeutic or prophylactic agent, ad libitum
- Water: tap water, ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21°C
- Humidity (%): 55%
- Photoperiod (hrs dark / hrs light): 12 hours/12 hours

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 1% w/w aqueous Tween 80

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
The required amount of test item was weighed into a glass container and heated (approximately 80°C) until molten using an electric mantle.
An appropriate volume of vehicle (1% Tween 80) was heated in a water bath to at least 75°C and then combined with the molten behenyl alcohol under continuous magnetic stirring, to a concentration of 20% behenyl alcohol. The resulting suspension was slowly cooled, with homogenization to a temperature of below 60°C, and then further cooled in a water bath to a temperature of 30°C. The 20% suspension was prepared once each week. Lower concentrations were prepared on the day of use by dilution of the 20% suspension with 1% w/w aqueous Tween 80.

VEHICLE
- aqueous Tween 80
- Amount of vehicle (if gavage): 1%

Animals received the test material or vehicle control formulations by gavage, at a volume-dosage of 5 mL/kg bw, using an 8 or 10 choke rubber catheter. The volume administered was calculated from body weights measured immediately before each administration.

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

26 weeks

Frequency of treatment:

7 days a week

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

10 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

20 male and 20 female per dose (main study)
10 male and 10 female per dose (toxicokinetic study)

Control animals:

yes, concurrent vehicle

Positive control:

none

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: prestudy, weekly for the duration of the study, and at necropsy

FOOD CONSUMPTION
- calculated weekly throughout the treatment periods

FOOD EFFICIENCY:
- Weekly group mean food conversion efficiencies were calculated for the first 14 weeks of the study

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: prestudy, and during weeks 12 and 25 of the study

HAEMATOLOGY: Yes
- Time schedule for collection of blood: during weeks 14 and 26
- Anaesthetic used for blood collection: Yes, anesthetized with halothane/nitrousoxide at time of sampling
- Animals fasted: Yes
- How many animals: 10 rats/sex/dose
- Parameters checked: hemoglobin concentrations, erythrocyte count, total and differential leukocyte count, platelet count, mean cell hemoglobin concentration, mean cell hemoglobin, morphology and unusual cell types, including normoblasts, anticoagulant and prothrombin time was measured
Blood samples were obtained from 6 (3 males and 3 females) nonfasted satellite rats on Day 1 and during Weeks 13 and 26 at 0.5, 1, 2, 4, 8, and 24 h after dosing

CLINICAL CHEMISTRY: Yes
- Parameters checked: alkaline phosphatase activity, alanine amino-transferase, aspartate amino-transferase,gamma-glutamyl transpeptidase, glucose, total bilirubin, total cholesterol, urea, total triglyceride, total protein,and electrolyte levels: Na, K, Cl, and C, inorganic phosphorus and electrophorectic protein, creatine

URINALYSIS: Yes
- Time schedule for collection of urine: during weeks 12 and 25
- Metabolism cages used for collection of urine: No
- Animals fasted: nonfasted waterdeprived
- Parameters checked: urine pH and protein, glucose, ketones, bilirubin, urobilinogen, blood, urine-specific gravity, the appearance and volume of urine

NEUROBEHAVIOURAL EXAMINATION: No

IMMUNOLOGY: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
- detailed examination of the external features and orifices, the neck and associated tissues, and the cranial, thoracic, abdominal, and pelvic cavities, and their viscera

HISTOPATHOLOGY: Yes
- adrenals, brain, eyes and optic nerve, femur, heart, kidneys, liver, lungs, seminal vesicles, spinal cord, stomach, thyroid, and uterus

Statistics:

For organ weights and body weight changes, homogeneity of variance was evaluated by Bartlett’s test. Whenever this was found to be statistically significant, a Behrens-Fisher test was used to perform pairwise comparisons; otherwise, a Dunnett’s test was used. Fisher’s exact test was applied as a two-tailed test, where appropriate, to the distribution of macroscopic or microscopic pathological entities. Unless stated, group mean values or incidences for the treated groups were not significantly different from those for the controls (P>0.05). The significance of intergroup differences in hematology (excluding the incidence of morphological abnormalities evident on the blood smears for rats), blood chemistry, and urinalysis (volume, pH, and specific gravity only) was assessed by Student’s t test using a pooled error variance.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One male receiving 100 mg/kg/day died during Week 25.

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Details on results:

Toxikokinetic study:
Blood sample results were obtained from satellite animals on Day 1, and during Weeks 13 and 26 of the study. The maximum mean plasma concentration (Cmax) occurred 1 h after dosing in all males and in the majority of the females. During Week 13, females in the 100 and 1000 mg/kg bw/day dose level groups reached the Cmax at 0.5 h after dosing. 24 hours after dosing, plasma concentrations of behenyl alcohol in animals from the 10 and 100 mg/ kg bw/day dose group were generally below the limit of quantification (<10 ng/ml). In animals treated with 1000 mg/kg bw/day, mean plasma concentrations of behenyl alcohol were quantifiable on each sampling day, and these values ranged from 203.68 to 528.82 ng/mL throughout the duration of the study.
Area under the curve (AUC24) values ranged from 1043.8 to 3196.0 ng x h/mL in males and females treated with 1000 mg/kg bw/day during the study. Generally, no statistically significant sex-related differences occurred in any of the dose groups. However, statistically significant differences (P=0.040) in AUC24 values, 24 h after dosing, were observed between males and females treated with 10 and 1000 mg/kg bw/day on Day 1 and during Week 13 of the study, respectively. On Day 1, AUC24 values of 96.4 and 154.8 ng x h/mL were obtained in male and females treated with 10 mg/kg bw/day, respectively, while AUC24 values of 2797.0 and 1043.8 ng x h/ml were obtained in males and females treated with 1000 mg/ kg bw/day, respectively. The rate and extent of systemic exposure of rats to behenyl alcohol, characterized by the Cmax and AUC24, respectively, on Day 1 and during Weeks 13 and 26 of the study increased with increasing dose level; however, these increases were less than the proportionate dose increment, and there was statistically significant evidence of non-proportionality on each of the sampling days (P=0.056).

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: highest dose tested

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1: Maximum Mean Plasma concentrations of Behenyl Alcohol in rats and the areas under the mean plasma behenyl alcohol concentration time curves estimated up to 24 h postdose on Day 1 and during weeks 13 and 26 of the study

	Day 1		Week 13		Week 26
Dose level (mg/kg bw/day)	Males	Females	Males	Females	Males	Females
	Maximum mean plasma concentration (Cmax) (ng/mL)
10	31.16 (11.94)	49.00 (12.26)	53.28 (23.68)	42.66 (17 .44)	93.08 (49.06)	46.13 (23.26)
100	179.96 (109.07)	117.63 (25.88)	306.92 (207.29)	160.25 (83.92)	153.14 (34.42)	151.76 (40.43)
1000	292.74 (47.53)	203.68 (30.43)	525.72 (232.90)	414.91 (82.85)	526.40 (160.22)	528.82 (171.70)
	Area under the curve (AUC24)(ng x h/mL)
10	96.4 (21.0)	154.8 (19.2)	271.5 (64.6)	257.7 (71.4)	290.0 (73.0)	127.8 (55.7)
100	766.6 (89.7)	720.1 (161.0)	731.7 (180.6)	345.2 (106.9)	1072.7 (372.2)	378.9 (70.5)
1000	1858.0 (253.0)	1296.7 (186.6)	2797.0 (539.7)	1043.8 (102.9)	3196.0 (433.7)	2254.9 (442.7)

Numbers in parentheses represent standard deviations and standard errors of the Cmax and AUC24, respectively.