Pentane-1,2-diol

Repeated dose toxicity: dermal

Administrative data

Endpoint:

sub-chronic toxicity: dermal

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: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,2 hexane diol

IUPAC Name:

1,2 hexane diol

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories; Kingston, NY
- Age at study initiation: 5-6 weeks
- Weight at study initiation: 200-300 grams
- Housing: individually in suspended cages
- Diet (e.g. ad libitum): ad libitum except during fasting prior to blood sample collection and necroscopy
- Water (e.g. ad libitum): ad libitum
- Acclimation period: for a minimum of 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/-3°C
- Humidity (%): 50% +/-20%
- Air changes (per hr): at least 10 air changes per hr
- Photoperiod: 12 hrs dark / 12 hrs light

Administration / exposure

Type of coverage:

open

Vehicle:

water

Details on exposure:

TEST SITE
- Area of exposure: dorsal trunk area including the shoulder region to the wing region of the ileum and halfway down the flank on each side of the animal (ca. 16 cm²)
- % coverage: 10%

REMOVAL OF TEST SUBSTANCE: no

TEST MATERIAL
- Amount(s) applied: 2 ml/kg bw

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

Beginning on study day 1, and for at least 91 consecutive days, the dose solution was applied daily as a single dermal dose.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0 mg/kg bw
Basis:
nominal per unit body weight

Doses / concentrations 2

Remarks:

Doses / Concentrations:
350 mg/kg bw
Basis:
nominal per unit body weight

Doses / concentrations 3

Remarks:

Doses / Concentrations:
700 mg/kg bw
Basis:
nominal per unit body weight

Doses / concentrations 4

Remarks:

Doses / Concentrations:
1000 mg/kg bw
Basis:
nominal per unit body weight

No. of animals per sex per dose:

15

Control animals:

yes

Details on study design:

- Dose selection rationale:
The dose regimen is designed to demonstrate a gradient of limited toxic effeck. The high dose is not expected to cause lethality, but may produce signs of toxicity such as decreased body weight The intermediate dose level was selected for the purposes of evaluating any potential toxicological effects. The low dose is not expected to produce signs of toxicity.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
Animals will be observed twice daily for moribidity and mortality. Any overt signs of toxicity, if obsewed, will also be recorded during these obsenrations. However, clinical signs obsewed during mortality checks or at collar removal which are related to the stressof collaring will not be documented.

DETAILED CLINICAL OBSERVATIONS: Yes
Routine detailed clinical observations will be performed and recorded prior to dosing on study day 1 and concurrent with body weights weekly. These obsenrations will include but not be limited to changes in: skin and fur, eyes and mucous membranes, morbidity,posture, respiratory System, salivation, and behavior. All routine clinical observations or a finding of normal will be recorded during routine detailed dinical observation sessions.
Any overt signs of toxicity obsetved during dosing sessions will also be recorded. Animals exhibiting a clinical sign On study day 91 will also be examined prior to their assigned necropsy day on either study day 92, 93, or 94.

DERMAL IRRITATION (if dermal study): Yes
Animals will be examined for erythema and edema prior to dosing on study day 1 and concurrent with body weights weekiy. Skin grading will be perforrned according to the Macroscopic Dermal Grading System based on Draize. Animals exhibiting a positive finding on skidy day 91 will also be examined for erythema and ederna prior to their assigned necropsy day om either study day 92, 93,or 94.

BODY WEIGHT: Yes
Individual body weights will be obtained at receipt and prior to randomization. Body weights will be obtained for all surviving animals weekly, beginning with the first weight collection on study day 1. In addition, a final in-life unfasted body weight will be collected prior to dosing on study day 91, For surviving animals, a terminal body weight will also be collected immediately prior to necropsy. For animals found dead or euthanized during study, a final body weight will be collected at the time the animal is found or immediateiy prior to euthanasia.

FOOD CONSUMPTION: YES
Individual food consumption will be recorded for all surviving animals weekly, beginning with the first food consumption recording on study day 1. In addition, individual food consumption will be collected prior to dosing on study day 91. Sufficient food will be offered to each animal to ensure ad Iibitum feeding.

WATER CONSUMPTION: No data

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: once within 10 days prior to necroscopy

HAEMATOLOGY: Yes
- Time schedule for collection of blood: immidiatly prior to necroscopy
- Anaesthetic used for blood collection: Yes (carbon dioxide)
- Animals fasted: Yes (vernight => 16-24 hours)
- the following Parameters were examined: total leucocyte count; erythrocyte count; hemoglobin concentration; Platelat count; blood smear evaluation; hematocrit; white blood cell differential; reticulocyte count; mean corpscular volume; mean corpuscular hemoglobin; mean corpuscular hemoglobin concentration


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: immidiatly prior to necroscopy
- Animals fasted: Yes (vernight => 16-24 hours)
- the following Parameters were examined: glucose; urea nitrogen; total protein; albumin; albumin/globulin ratio; Ssodium; potassium; chloride; calcium; phosphorus; alanine aminotransferase; total cholesterol; triglycerides; creatinine; globulin; total bilirubin; aspartate aminotransferase; alkaline phosphatase; gamma glutamyltransferase; sorbitol dehydrogenase; total bile acids; serum protein electrophoresis

URINALYSIS: Yes
- Time schedule for collection of urine: prior to necroscopy
- Metabolism cages used for collection of urine: Yes
- the following Parameters were examined: macroscopic evaluations - appearance, color, volume; microscopic evaluations - examination of sediment; specific gravity -via an automated refractometer; urine electrolytes (chloride, sodium, potassium); test strip analysis (including glucose, bilirubin, blood, pH, protein, ketones, Urobilinogen)

NEUROBEHAVIOURAL EXAMINATION: Yes
For these expanded clinical observation testing sessions, the first ten male and female rats per dose group will be distributed evenly, but in random order, across two testing days to limit experimental bias. Weekly expanded clinical obsewation testing sessions will occur at approximately the same time of day (I2 hours) to limit the possible effects of diurnal variation. Random order will be determined using a cornputerized randomization procedure, and the procedure used will be documented in the study records. The same randomization scheme will be used throughout the study. All evaluations will be performed with the tester blind to treatment group.
a) Hand-Held and Open-Field Observations
Expanded clinical observations, which include both hand-held and Open field evaluations, will be perfomed weekly during the study. These evaluations will be performed on a day other than that scheduled for the weekly routine clinical observations described above.
b) Elicited Behaviors Observations
Animals evaluated weekly for expanded clinical obsetvations will also be evaluated for elicited behaviors (including forelimb and
hindlimb gripstrength and tail flick) once during the last week of study. Within weeks prior to ths elicited behaviors evaluations, the animals to be tested will acclimated to the gripstrength devices. This acclimation may be performed in day and does not need to be conducted in the random oder used for testing, the acclimation will be docurnented in the study records.

MALE REPRODUCTIVE ASSESSMENT: YES
All surviving males in each keatment group will be evaluated for reproductive capacity as follows:
- Sperm Motility Sample Collection and Evaluation
- Total SpermC ount Sample Collection and Determination
- Sperm Morphology

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Dermal irritation:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not specified

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

no effects observed

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 specified

Details on results:

CLINICAL SIGNS AND MORTALITY
Treatment-related clinical findings included rough coat and fur staining. Slight dermal irritation, dose responsive in nature, was observed during the study in all treatment groups.

BODY WEIGHT AND WEIGHT GAIN / FOOD CONSUMPTION
During some weekly measurement intervals, the study animals in the 1000 mg/kg bw/day treatment group exhibited statistically significant decreases in body weight gains per day and in cumulative absolute body weight gains, and they exhibited statistically significant increases in feed consumed per body weight per day (unrelated to decreased body weights).

OPHTHALMOSCOPIC EXAMINATION
Ophthalmology findings observed pre-necropsy were not toxicologically relevant, and reproductive assessment results indicated no biologically relevant differences between treated and control animals.

HAEMATOLOGY
Increased white blood cell Parameters in female animals from the 1000 mgikglday treatment group. The toxicological significance of these
changes cannot be determined since they were not associated with any histopathologic alterations.

CLINICAL CHEMISTRY
The clinical chemistry changes noted were minor deviations from control values and are not considered toxicologically relevant.

URINALYSIS
There were multiple changes from controls in urinalysis parameters evaluated in both male and and female animals. These changes included decreased urine pH, increased urine specific gravity, and decreased urine volume (except in low dose females) in all treated animals. Statistically significant increases in urine potassium and chloride, secondary to the increase in urine concentration, were dose-related in all treated female animals. These changes correlate with increased absolute kidney weights in all treated females, and with statistically significant increases in kidney-to-body weight ratios and kidney-to-brain weight ratios in females from the 1000 mg/kg bw/day treatment group. However, there were no histopathologic effects noted in
the kidneys. Therefore, changes from controls noted in these urinalysis parameters are considered to be treatment-related, but not adverse. Differences in urine potassium excretion between control and female rats were small in magnitude and were without a dose-response effect; therefore, these
changes were not clearly associated with test article administration. A mild increase in urine protein in females at 1000 mg/kg bw/day was observed but taken together with a mild increase in total leucocyte count this suggests rather a hidden infection than a test article-related effect at this dose level.

ORGAN WEIGHTS
Treated female animals exhibited increases in heart-to-body weight ratio, kidney-to-body weight ratio, and kidney-to-brain weight ratio when compared to wntrols, but there were no histopathologic alterations associated with the increased heart and kidney weight ratios in these animals.

GROSS PATHOLOGY / HISTOPATHOLOGY: NON-NEOPLASTIC
Treatment-related changes in anatomic pathology parameterc were Iimited to the treated Skin of mid and high dose animals and to some body weight changes in all treated females. Treated skin changes included a low incidence of slight focal erythema/demal thickening observed at necropsy and minimal epidermal hyperplasia and hyperkeratosis observed microscopically. The microscopic changes observed would not be expected to Progress to ulceration or chronic skin damage, however, and they are considered to be consistent with repeated topical applications. Treated female animals exhibited increases in heart-to-body weight ratio, kidney-to-body weight ratio, and kidney-to-brain weight ratio when compared to wntrols, but there were no histopathologic alterations associated with the increased heart and kidney weight ratios in these animals.

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

local

Effect level:

700 mg/kg bw/day (nominal)

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: local irritation

2

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Daily dermal administration of the test item to Sprague-Dawley rats for 91-93 days was associated with treatment-related rough coat, fur staining, and slight dermal irritation at 1000 mg/kg/day. Treated skin changes included a low incidence of slight focal erythema/demal thickening observed at necropsy and minimal epidermal hyperplasia and hyperkeratosis observed microscopically. The microscopic changes observed would not be expected to Progress to ulceration or chronic skin damage. A mild increase in urine protein in females at 1000 mg/kg bw/day and mild changes in other urine parameters were observed but taken together with a mild increase in total leucocyte count this suggests rather a hidden infection than a test article-related effect at this dose level. Not any adverse effect was reported from FOB or additional male fertility examination and histopathology. The systemic dermal NOAEL of this 90 day study is 1000 mg/kg as systemic effects describe above are not considered to be treatment related. The local dermal NOAEL is 700 mg/kg/day due to the local effects described above.