Vinyl 2-ethylhexanoate

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Very well experimentally designed study that was audited to ensure accuracy of the method used and that the results accurately reflect the raw data of the study. The source and specifications of the vinyl neodecanoate used in this study was very well documented. However, analytical verification of test substance stability and concentration were not conducted.

Data source

Reference

Reference Type:

other: Unpublished report

Title:

Unnamed

Year:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

Deviations:

not specified

GLP compliance:

not specified

Remarks:

The study was audited for compliance with the study protocol accuracy of the study report.

Test material

Test material information

Constituent 1

Reference substance name:

Vinyl neodecanoate

EC Number:

256-905-8

EC Name:

Vinyl neodecanoate

Cas Number:

51000-52-3

Molecular formula:

C12H22O2

IUPAC Name:

vinyl neodecanoate

Details on test material:

As per Vinyl Neodeconate IUCLID Data Set 2007 with characterization.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Male and female albino rats derived from the Wistar strain and bred under specific pathogen—free conditions were used at 10 to 11 weeks of age. The body weights of these animals were in the range males 335 to 461 g and females 204 to 324 g. Animals were identified by ear marking. Animals were housed three per cage, in two layers of cages with a total of twelve cages per chamber. Paper lined catch trays for excreta were placed between each layer of cages and changed daily. Food was provided by means of a top loading food hopper and water by means of water bottles. The food (LAD 1 (Spillers Spratts Ltd)) was removed during exposure and the hoppers replenished daily after each exposure. Untreated drinking water from the public supply was available ad libitum. The bottles were changed for clean ones twice weekly. The animals remained in the exposure chambers between exposures.

Administration / exposure

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: No data

Details on inhalation exposure:

Each exposure chamber was made from aluminum with a volume of 1 m³ and was ventilated with air drawn from laboratory through dust filters. Exhaust duct was connected to common exhaust duct connected to a fan located on the roof of the laboratory. Efficient mixing of the test atmosphere was achieved by recirculation part of the atmosphere. Flow rate through main duct was monitored continuously during the test. The liquid test material was introduced to chamber by means of micrometering pump connected to heated vaporizer which completely evaporates liquid into a stream of ventilating air entering the chamber. The temperature of the vaporizer was monitored and adjusted as needed. The nominal concentrations of Vinyl Neodeconoate were: 0.25. 0.50 and 1 g/m³. The concentrations of test substance in the three test atmospheres were kept normally within 10% of theirnominal value. When the concentration deviated from the nominal by more than 10% of this value for longer than approximately 36 mm (10% of a daily exposure) the extent of the deviation was recorded.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Atmosphere of chambers was monitored continuously using hydrocarbon analyzer connected to flame-ionization detector. Each analyzer was calibrated weekly against atmosphere containing a known concentration of vinyl neodecanoate. Traces of the vinyl neodecanoate concentration in the chamber were also measured daily to assure that its concentration remain within 10% of the nominal value. Any deviation more than 10% of the daily exposure was recorded. The control chamber atmosphere was monitored continuously during the exposure by a way similar to that of treatment chamber.

Duration of treatment / exposure:

6 hour/day, 5 days/week for 13 weeks

Frequency of treatment:

Five days per week.

Doses / concentrations

Remarks:

Doses / Concentrations:
0.25. 0.50 and 1 g/m³ or approximately: 0, 15.5, 31 and 62 ppm.
Basis:
nominal conc.

No. of animals per sex per dose:

18

Control animals:

yes, sham-exposed

Details on study design:

Three groups of rats (18 male and 18 female per group) were used in the test. Groups were exposed - whole body - to vinyl neodecanoate at concentrations of approximately: 0.25, 0.5 and 1 mg/m³ (0. 15.5, 31, and 62 ppm) for 6 hour/day, 5 days/week for 13 weeks. Groups of 18 male and 18 female rats place in similar chambers were exposed to air only, and served as control. Laboratory temperature, pressure and humidity were measured and recorded during the test. Chamber temperature was measured daily at noon by Ni-Cr/Ni-Al thermometer mounted inside the chamber. Urine samples were collected from all animals the night before exposure, 6 weeks and 12 weeks after exposure. Urine was analyzed for glucose, nitrite, protein, ketones, bilirubin, pH and blood pigments. Specific gravity of urine was measured only before exposure and at the end of 12 weeks. Blood sample were collected from the tail veins at the end of the experiment for glucose estimation and cell fragility tests. Blood samples were also collected by cardiac puncture following intraperitoneal injection of pentobarbitone. Blood was analyzed for total protein, urea nitrogen, alkaline phosphatase, chloride, sodium, potassium, glucose, alkaline amino transferase and aspartate amino transferase. Blood samples for hematological examination were collected by cardiac puncture following intraperitoneal injection of sodium pentobarbitone. Total leucocyte count, erythrocyte count, hemoglobin and mean cell volumes were measured. Hematocrit, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were computed from the measured values. Differential leucocyte count and reticulocyte count were conducted on stain blood smears. Prothrombin and kaolin cephalin clotting times were measured in citrated plasma. The total leucocyte count or white blood cell (WBC), erythrocyte count or red blood cell (RBC), hemoglobin (Hb), and mean cell volume (MCV) were measured by Coulter Counter Model S. Hematocrit (Hct), mean corpuscular hemoglobin, and mean corpuscular concentrations were generated by computation. Prothrombin time and kaolin cephalin clotting time were measured by Warner 'Coag-a-pet' 200. Differential leucocyte count and reticulocyte count were measured by Leitz Dialux microscope. At the end of the exposure, animals were sacrificed by large dose of sodium pentobarbitone and brain, heart, kidney liver, spleen and testes were collected and weighed. Samples were collected from all abnormal tissues for microscopic examination and also from mammary gland, mesenteric lymph node, pancreas, stomach, intestine at 5 levels, caecum, liver, adrenals, kidneys, ovaries or testes, uterus or prostate, seminal vesicles, urinary bladder, thyroids with esophagus and trachea, heart, lungs, nasal cavity, thymus, eye and lacrimal glands, salivary gland, brain, spinal cord, pituitary, tongue, sciatic nerves, muscle (femoral), knee joint and femur. All samples were fixed in 10% neutral formalin and then examined for histopathologic signs when necessary. Tissues, were processed to paraffin wax blocks from which 5 i.an sections were cut. The paraffin sections stained with haematoxylin and eosin (HE), were examined microscopically.

Positive control:

None

Examinations

Observations and examinations performed and frequency:

The animals were observed daily for general health and clinical signs. Body weights were recorded weekly.

Sacrifice and pathology:

At the end of the exposure period, all animals received a lethal dose of sodium pentobarbitone and were then subjected to a detailed post—mortem examination. The following organs were weighed at necropsy: brain liver, heart, spleen, kidneys, and testes. The organs of all animals from the two upper dose groups and the control group were examined histologically. Samples were collected from all abnormal tissues for microscopic examination and also from mammary gland, mesenteric lymph node, pancreas, stomach, intestine at 5 levels, caecum, liver, adrenals, kidneys, ovaries or testes, uterus or prostate, seminal vesicles, urinary bladder, thyroids with esophagus and trachea, heart, lungs, nasal cavity, thymus, eye and lacrimal glands, salivary gland, brain, spinal cord, pituitary, tongue, sciatic nerves, muscle (femoral), knee joint and femur. All samples were fixed in 10% neutral formalin. Tissues, were processed to paraffin wax blocks from which 5 i.an sections were cut. The paraffin sections were stained with haematoxylin and eosin (HE), and examined microscopically.

Statistics:

Body and organ weights were analysed by covariance analysis using initial body weight as the covariate. Organ weights were further examined by covariance analysis using terminal body weight as the covariate. Clinical chemical and hematological parameters were examined using analysis of variance. The significance of any difference between treated and control group means was tested using the William's t-test and Dunnett's test was used when monotonic dose response could not be assumed.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

The concentration of vinyl neodecanoate was monitored daily for each chamber. The overall means of the daily concentrations were as follows: nominal concentrations were 1.0, 0.5, and 0.25 g/m³ and the measured concentrations were 1.0, 0.50, and 0.25 g/m³. Any deviations more than 10% of the daily exposure duration and for a period greater than 36 min were also recorded. On three occasions concentrations in excess of 1% of the lowest treatment level were captured in the control atmosphere.

No death was reported during the test and the general health condition of animals remained normal throughout the exposure time. No clinical signs of toxicity related to the test substance were seen during the exposure period.

Body weights of animals were recorded weekly. With exception of males of the high concentration group, no significant differences form the controls were seen in any other group. Body weights of male rats exposed to high concentration of 1000 mg/m3 were significantly lower than those of controls from week 3 onwards. The high dose mean male rat body weight decrement was approximately 5% lower than the control value from week three to week twelve. Generally, with exception of liver and kidney, organ weights as adjusted for initial and terminal body weight did not change significantly from the controls after 13 week of exposure to low, medium, and high concentration of vinyl neodecanoate. The mean weight of female liver was significantly higher than the controls in rats exposed to 0.50 and 1.01 g/m³ for 13 weeks reaching a value that was approximately 9% greater than the control value based on mean relative liver weight at 1000 mg/m3. The significance remained the same when liver weight was adjusted for terminal body weight. Similarly, liver and kidney weights of male rats were slightly, but significantly higher than that of controls in the high dose group exposed to 1.0 g/m³. The relative mean male rat liver weight was increased approximately 8.5% at 1000 mg/m3 and the mean relative kidney was increased 6.6% at the hign dose level.

No differences were seen in urine pH, nitrite, protein, glucose, ketone, bilirubin, blood and specific gravity of male and female and males rats exposed to vinyl neodecanoate when compared to control before exposure and 6 and 12 weeks after exposure. No significant changes in the clinical chemical results were observed in female rats treated with Vinyl Neodeconoate. The male rats in the high dose 1.0 gm/m3 group showed a slight significant increase in plasma alkaline phosphatase activity of 14% However, all male rat mean alkaline phosphatase values were well within historical control values. No other significant clinical chemistry changes were observed.

With the exception of the decreased corpuscular hemoglobin in male rats exposed to 0.50 and 1.0 g/m³, there were no significant changes in other hematology markers. In male rats at the high dose level the mean corpuscular henoglobin (MCH) was increase 2% relative to the control value. However this MCH Value was well within the 95% Confidence Limits of the concurent control MCH value. The osmotic fragility measurements showed that the erythrocytes of male and female rats exposed to 1.0 g/m³ were 100% and 50% and 100% lysed at a slightly higher concentration of buffered saline than the controls.

No exposure-related difference were seen in treated and control rats upon macroscopic examination. No macroscopic abnormalities were seen in liver that could have caused the increase in liver weight seen in male and females at the high dose level. Histologigal examination of respiratory systemdid not show signs of exposure-related abnormalities. There was an increase in few pulmonary lesions in exposed groups, but they were not treatment related lesions. Hypertrophy of pulmonary arteries was seen in 11% and 39% in male rates exposed to 1.0 g/m³ and 0.50 g/m³ vinyl neodecanoate, respectively. In addition, 2 males (1 from the 0.5 and 1 from the 1.01 g/m³ groups, respectively) showed interstitial pneumonitis. While these lesions appear to be exposure-related, they showed no dose related severity (an inverse relationship with exposure concentration), and this is not considered significant. Mild bile hypertrophy was seen in male livers of group treated with 1.0 g/m³ (28% of animals of this group). However, the incidence of this lesion varied from 5.5 to 11% (only 1 or 2 animals in each group) in the three groups of female rats, and was not dose related. There were no microscopic lesions observed in male rat kidneys. In other organs there were sporadic observations, but none of these exhibited a dose/exposure response relationship, and were not consistent in males and females. These sporadic observations were not considered to be significant.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

500 mg/m³ air

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: The only adverse finding from this study was an increase in mean male rat kidney weight at the high dose level (1000mg/m3). The NOAEC for this study was the mid-dose level of 500mg/m3, or approximately 62 ppm.

2

Dose descriptor:

LOAEL

Effect level:

1 000 mg/m³ air

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: The only adverse finding from this study was an increase in mean male rat kidney weight at the high dose level (1000mg/m3). The NOAEC for this study was the mid-dose level of 500mg/m3, or approximately 62 ppm.

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Increases in mean liver weights are believed to be an adaptive response to the test substance, not an adverse effect. The increase in mean male rat kidney weight at the high dose level was not associated with any histopatological findings in this organ. The increase of male rat mean corpuscular hemoglobin at the 500 and 1000 mg/m3 dose levels was well within the concurent control value 95% Confidence Limits. Therefore this finding is considered to be not biologically relevant.

Applicant's summary and conclusion

Conclusions:

Exposure of rats to test atmospheres with vinyl neodecanoate vapour demonstrated that the No-Observed-Adverse-Effect-Concentration (NOAEC) for vinyl neodecanoate in this inhalation subchronic study was 0.50 g/m³ or approximately 62 ppm.

Executive summary:

Male and female rats were exposed up to a high dose level of 1000 mg/m3 Vinyl Neodecanoate vapor in an O.E.C.D. 413 "Subchronic Inhalation Toxicity 90 -Day" Testing Guideline study. The only adverse finding from this study was an increase in mean male rat kidney weight at the high dose level. The NOAEC for this study was the mid-dose level of 500mg/m3, or approximately 62 ppm.