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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
sub-chronic toxicity: oral
Remarks:
combined repeated dose and reproduction / developmental screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
51 days
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: valid without restriction; GLP guideline study conducted according to guideline OECD 422 Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test
Cross-reference
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
Details on test material:
-Test article name (as reported): Propanoic Acid, 2-Methyl-, Monoester with 2,2,4-Trimethyl-1,3-Pentanediol; 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate
-Physical State and Appearance: Colorless liquid
-Date received: May 9, 1991
-Purity at start of study: 98.8%
-Purity at end of study: 98.7%
-Analytical laboratory: purity analysis was conducted by the Chemicals Quality Services Laboratory at Eastman Kodak Company
-Stability: Based on purity analysis at start and end of study, test material is considered stable.

Test animals

Species:
rat
Strain:
other: Sprague-Dawley (CD®(SD)BR/VAF Plus™)
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS:
-Source: Charles River Laboratories (Kingston, NY)
-Condition at receipt: animals were isolated upon arrival and were judged healthy prior to testing
-Age at Study Initiation: 8 weeks
-Weight at Study Initiation: 270 ± 8g
-Method of Animal Identification: uniquely numbered metal ear tag
-Method of Animal Distribution: animals were randomly assigned to each test group
-Housing: Starting at study initiation and continuing throughout premating, animals were housed singly in suspended, stainless-steel wire mesh cages. During the mating period, animals were housed one male with one female. Following mating, males were housed singly. Cages were washed once a week and absorbent paper under the cages was changed daily.
-Diet: Agway® Prolab™ Animal Diet (RMH 3200) certified ground chow was available ad libitum. Feed containers were cleaned weekly.
-Water: city water (Monroe County NY Water Authority) was supplied ad libitum through an automatic watering system. Water was analyzed four times per year and analysis reports maintained on file with the testing laboratory.

ENVIRONMENTAL CONDITIONS:
-Temperature (°F): 70-76
-Relative Humidity: 44-56%
-Air changes per hour: no information
-Photoperiod (hrs dark/ hrs light): 12 hours dark/light

IN-LIFE DATES:
-Date of First Dose: May 13, 1991
-Date of Last Dose: July 2, 1991
-Duration of Dosing: 51 Days
-Experimental Termination Date: April 27, 1992

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
All male rats were treated for 51 doses over 51 days; all male rats were euthanized the following day. Dose levels were 0, 100, 300, or 1000 mg/kg bw/day of the test material; the test material was administered as received by oral gavage to 12 rats/dose group. Animals were dosed seven days per week including holidays. Dosing volumes were calculated weekly so that animals from each dose group received volumes on a per kilogram body weight basis. Controls received a dose of distilled water equal in volume to that administered to the highest test group.
Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
Not applicable, the test material was administered undiluted.
Duration of treatment / exposure:
51 days
Frequency of treatment:
Daily
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
100 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
300 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
1000 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
12 males
Control animals:
other: Controls dosed with distilled water.
Details on study design:
Dose selection rationale – In a subacute oral gavage study in which the undiluted test material was administered to groups of male and female rats for 11 doses over a 15-day period at dose levels up to 1000 mg/kg bw/day, the NOAEL was 1000 mg/kg bw/day. Although slight increases in absolute and relative liver weights were seen in both sexes given 1000 mg/kg bw/day, no treatment-related lesions or changes in clinical chemistry suggestive of target organ damage were observed at necropsy.

51-Day Study - Twelve male rats were randomly assigned to each test group. Animals were approximately 8 weeks of age at the start of treatment and were treated for a total of 51 days. Dose levels were 0, 100, 300, or 1000 mg/kg bw/day; animals were dosed 7 days a week. Information on a comparably-dosed group of female rats is reported in the section on Developmental/Reproductive Toxicity.

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes; included, but not limited to, examination of the hair, skin, eyes, motor activity, feces, and urine
-Time schedule: immediately after dosing and again in the afternoon

DETAILED CLINICAL OBSERVATIONS: Yes
-Time schedule: every workday morning, each rat was removed from its cage and examined by a trained technician

BODY WEIGHT: Yes
-Time schedule: Days 0, 4, 7, 14, 21, 28, 35, 42, and 49

WATER CONSUMPTION: no data

FOOD CONSUMPTION: Yes
-Time schedule: Days 4, 7, 14, 35, 42, and 49

HEMATOLOGY: Yes
-Time schedule: blood from fasted rats collected prior to necropsy from the posterior vena cava while animals were under CO2 anesthesia.
-Number of animals: all males
-Parameters examined: hemoglobin concentration, hematocrit, red blood cell count, nucleated red blood cell count, white blood cell count, differential cell count
-Method: assays conducted by the EK Clinical Biochemistry Group, using a Becton-Dickinson ELT 8/ds hematology analyzer

CLINICAL CHEMISTRY: Yes
-Time schedule: blood from fasted rats collected prior to necropsy from the posterior vena cava while animals were under CO2 anesthesia.
-Number of animals: all males
-Parameters examined: aspartate aminotransferase, alanine amino-transferase, glucose, urea nitrogen, gamma glutamyl transpeptidase, total bilirubin, creatinine, total protein, albumin, albumin/globulin ratio, potassium, sodium, chloride, calcium, phosphorus
-Method: assays conducted by the EK Clinical Biochemistry Group, using a Roche Cobas Bio serum chemistry analyzer

URINALYSIS: not examined

NEUROBEHAVIORAL EXAMINATION: not examined
Sacrifice and pathology:
GROSS PATHOLOGY: Yes. Rats were fasted overnight prior to necropsy. Rats were anesthetized with CO2 and exsanguinated by severing the posterior vena cava. Necropsies were performed on all animals. The heart, liver, kidneys, adrenal glands, thymus, spleen, brain, target organs, and gross lesions were fixed in 10% buffered formalin; testes and epididymides were fixed in Bouin’s fixative.

ORGAN WEIGHTS: Yes. The liver, kidneys, thymus, testes, and epididymides were weighed. Paired organs were weighed together.

HISTOPATHOLOGY: Yes. All tissues were examined microscopically from the control and high-dose group. Target organs (kidney and liver) and gross lesions were examined from other groups.
Statistics:
All mean data (body weight, feed consumption, organ weights, hematology, and clinical chemistries) were evaluated using the Bartlett’s test (p ≤ 0.01), one-way analysis of variance (ANOVA, p ≤ 0.05), and Duncan’s multiple range test (p ≤ 0.05) to indicate statistical significance. Ratios such as percent mortality were compared using Chi Square Tables. Transformations (ranking) to normalize distribution of the data were performed where appropriate. A Student's t-test was performed where Bartlett's test indicated a significant difference in variances among the groups.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
not examined
Details on results:
Clinical signs and mortality: No mortality. Clinical signs for all animals were limited to sialorrhea during the post-dose observation period in some animals in all treatment groups.

Body weight and body weight gain: No significant differences in body weight or body weight gain were noted.

Feed consumption: Mean feed consumption was significantly lower (8.4%) for high-dose group on Day 4 when compared to controls but from day 7 to study termination no differences in feed consumption were noted in any group.

Hematology: Mean hemoglobin concentrations in the mid- and high-dose rats were significantly lower than controls. No other differences were noted in any group for hematology parameters. Red blood cell morphological variations, including poikilocytosis, anisocytosis (found in all dose groups) and Howell-Jolly bodies (observed in low- and mid- dose groups) were graded minimal with the exception of poikilocytosis which was graded as minor in one low dose rat.

Clinical chemistry: Mean aspartate aminotransferase and alanine aminotransferase concentrations were significantly lower in all dose groups when compared to the controls. Mean glucose and chloride values were significantly lower in the high-dose group when compared to controls. Mean creatinine was significantly lower in the mid- and high-dose animals when compared to the controls.

Gross pathology: No treatment related changes were observed during the macroscopic examination in any animal.

Organ weights: All organ weights except the kidney and liver, were comparable between the treated and control groups. Mean absolute and relative kidney weights were significantly higher in the high-dose male rats. The mean absolute liver weights in the low-dose males and mean absolute and relative liver weights in the mid- and high-dose groups were significantly higher than controls.

Histopathology: Centrilobular hepatocytomegaly was observed in the livers of the rats at the mid- and high-dose levels. This was considered an adaptive response rather than a toxic response due to the absence of degenerative changes to the liver. Hyaline droplet formation, increased incidence of regenerative tubular epithelium, increased incidence of dilated tubules and the presence of granular casts at the cortico-medullary junction were identified in kidney sections from the male rats in the mid- and high-dose groups. The kidney lesions were typical of α2u globulin nephropathy although the droplets were not chemically defined.

Effect levels

Dose descriptor:
NOAEL
Effect level:
1 000 other: mg/kg bw/day (actual dose received)
Sex:
male
Basis for effect level:
other: see 'Remark'

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Organ weights

GROUP 0 100 300 1000
MG/KG MG/KG MG/KG MG/KG
F F F F
BODY WEIGHT (G) 317.5 315.0 324.2 317.8
19.4 15.7 14.3 19.3
9 7 10 9
KIDNEYS (G) 2.3362 2.4063 2.4769 2.4214
0.2508 0.1551 0.1912 0.1268
9 7 10 9
% 0.7350 0.7652 0.7641 0.7630
0.0556 0.0581 0.0503 0.0312
9 7 10 9
LIVER (G) 13.5971 14.5748 14.6530 16.4069*
1.2910 0.8718 1.3189 1.7729
9 7 10 9
% 4.2983 4.6281 4.5178 5.1516
0.5076 0.1984 0.343 0.3421
9 7 10 9
THYMUS                                            (G) 0.3568 0.3400 0.3690 0.3185
0.0982 0.0654 0.1333 0.1548
9 7 10 9
% 0.1117 0.1081 0.1133 0.1030
0.0264 0.0216 0.0380 0.0596
9 7 10 9
KEY: FOR EACH GROUP. VALUES ARE REPORTED AS - MEAN +/- STANDARD DEVIATION
Number PER GROUP

GROUP 0 100 300 1000
MG/KG MG/KG MG/KG MG/KG
M M M M
BOOY WEIGHT (G) 450.4 468.1 453.5 450.3
14.0 24.2 27.0 33.8
12 12 12 12
KIDNEYS (G) 3.3740 3.4807 3.5094 4.1283*
0.1945 0.2221 0.2670 0.3976
12 12 12 12
% 0.7492 0.7439 0.7758 0.9179*
0.0367 0.0379 0.0693 0.0725
12 12 12 12
LIVER              (G) 13.3655 14.6095* 14.7002* 17.9233*
1.1264 1.24 1.2853 1.7580
12 12 12 12
% 2.9673 3.1175 3.2387 3.9780*
0.2293 0.1485 0.1599 0.1975
12 12 12 12
THYMUS 0.4823 0.5368 0.5085 0.5228
0.1142 0.0678 0.0947 0.1307
12 12 12 12
% 0.1069 0.1149 0.112 0.1159
0.0244 0.0151 0.019 0.0272
12 12 12 12
TESTES                (G)       3.4047 3.3996 3.6637 3.4507
0.1776 0.2647 0.2909 0.2924
12 12 12 12
% 0.7561 0.7283 0.8115 0.7676
0.0335 0.0718 0.0913 0.0581
12 12 12 12
EPIDIDYMIDES       (G)   1.2666 1.2867 1.3828 1.3143
0.1217 0.0993 0.1802 0.1274
12 12 12 12
% 0.2817 0.2749 0.3057 0.2926
0.0311 0.0176 0.0412 0.0283
12 12 12 12
KEY: FOR EACH GROUP. VALUES ARE REPORTED AS - MEAN +/- STANDARD DEVIATION
Number PER GROUP

Applicant's summary and conclusion

Conclusions:
The NOAEL following oral gavage treatment of male rats with Texanol Ester-alcohol for 51 consecutive days was 1000 mg/kg bw/day.

There were no significant treatment-related effects on mortality, clinical signs, body weight and body weight gain, feed consumption, or gross pathology in male rats exposed to up to 1000 mg/kg bw/day Texanol® Ester-Alcohol by oral gavage for 51 days. Although there was an increase in absolute and relative liver weights in all dose groups, no treatment-related changes were observed during the macroscopic examination. Microscopically, centrilobular hepatomegaly was observed in the livers of rats in the mid- and high-dose groups but this was considered an adaptive metabolic response rather than a toxic response due to the absence of degenerative changes to the liver. Certain clinical chemistry parameters, i.e., mean aspartate aminotransferase and/or alanine aminotransferase levels, which would be expected to rise when liver damage occurs, were both significantly lower in all dose groups when compared to the controls. The only other significant effect noted in male rats was an increase in absolute and relative kidney weights in the high-dose group and the presence of hyaline droplet formation, increased incidence of regenerative tubular epithelium, increased incidence of dilated tubules and the presence of granular casts at the corticomedullary junction in the kidneys of mid- and high-dose animals. Mean creatinine levels, which would be expected to rise when kidney function is impaired, were significantly lower in the mid- and high-dose groups. The kidney lesions were typical of alpha 2-μ globulin nephropathy, a common spontaneous lesion in male rats and frequently exacerbated by chemical exposure. The significance of increased hyaline droplet degeneration and lesions suggestive of alpha 2-μ globulin nephropathy is unclear since these effects have not been observed in humans or other species. Based on this information, Texanol® Ester-Alcohol is not classified for “Specific Target Organ Toxicity – Repeated Exposure” in male rats according to the GHS guidelines.
Executive summary:

In a combined repeated dose and reproductive/developmental toxicity study, undiluted test material was administered to 12 male rats/dose by oral gavage at dose levels of 0, 100, 300 and 1000 mg/kg bw/day for 51 days.  Controls received distilled water.  Organ weight differences included statistically significant increases in absolute and relative kidney weights in the high-dose group and absolute and relative liver weights in all dose groups. Centrilobular hepatocytomegaly was observed in the livers of the rats at the mid- and high-dose levels.  Hyaline droplet formation, increased incidence of regenerative tubular epithelium, increased incidence of dilated tubules and the presence of granular casts at the corticomedullary junction were identified in kidney sections from the male rats in the mid- and high-dose group.  In the absence of degenerative changes, the liver changes suggest increased metabolic activity resulting from test article administration.  The kidney lesions were typical of α2u globulin nephropathy although the droplets were not chemically defined.  The significance of hyaline droplet degeneration is unknown since this is a species/sex specific effect common to male rats. Due to heavier mean liver weights in all dose groups, a no-observed-effect level (NOEL) was not determined in this study. However, since the liver weight differences suggest metabolic alterations rather than a toxicological effect and the hyaline droplet accumulation was not considered a significant effect, the no-observed-adverse-effect level (NOAEL) for this study was 1000 mg/kg bw/day.