δ-valerolactone

Endpoint summary

Description of key information

Oral
NOAEL systemic parental toxicity: 1000 mg/kg bw/d
NOAEL local parental toxicity: 1000 mg/kg bw/d (males), 300 mg/kg bw/d (females)
NOAEL reproduction/fertility toxicity: 1000 mg/kg bw/d
NOAEL developmental toxicity: 1000 mg/kg bw/d
Inhalation - read across
NOAEC systemic toxicity: 45 ppm (203 mg/m³)
NOAEC local toxicity: 15 ppm (70 mg/m³)
Please refer to the read-across statement in section 13.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant study according to guideline.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Version / remarks:

(March 22, 1996)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3650: Combined Repeated Dose Toxicity Study With the Reproduction/Developmental Toxicity Screening Test (July 2000)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services GmbH, Sulzfeld, Germany
- Age at study initiation: about 11-12 weeks old
- Weight at study initiation:
- Housing: 1 animal per cage. Exceptions: during mating 1 male/1 female per cage, during rearing up to PND 4:1 dam with her litter
- Diet: ground Kliba maintenance diet mouse-rat “GLP”, meal, supplied by Provimi Kliba SA, Kaiseraugst, Switzerland, ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature: 20 - 24°C
- Humidity: 30 - 70%
- Air changes: 15 per hour
- Photoperiod: 12 h light / 12 h darkness (6:00 to 18:00 h)

IN-LIFE DATES: From: 04-Sep-2012 To: 05-Nov-2012

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Delta-Valerolactone was applied as an emulsion. To prepare this emulsion, the appropriate amount of test substance was weighed out depending on the desired concentration. Then, corn oil was filled up to the desired volume, subsequently released with a magnetic stirrer. During administration of the test substance, preparations were kept homogeneous by stirring with a magnetic stirrer. The test substance preparations were prepared daily. The administration volume was 4 mL/kg body weight.

VEHICLE
- Justification for use and choice of vehicle: standard vehicle for studies of this type
- Concentration in vehicle: 25, 75, 250 mg/mL
- Amount of vehicle: 4 mL/kg bw (dose volume)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The analytical investigations of the test substance preparations were carried out at the Analytical Chemistry Laboratory of Experimental Toxicology and Ecology of BASF SE, Ludwigshafen, Germany, as part of this study.

The stability of Delta-Valerolactone in corn oil at room temperature for a period of 7 days was demonstrated before the start of the study. To ensure the content of the test substance in the vehicle, the test substance preparations were prepared daily.

At the beginning of the study each 6 samples were taken from the lowest and highest concentration for homogeneity analyses. These samples were used as a concentration control at the same time. Sampling was done under administration conditions out of the Erlenmeyer flasks (each 2 samples from bottom, mid, and top of the beaker). Two samples from the mid concentration were taken for concentration control analysis. Each one sample was analyzed in the analytical laboratory, the other was kept frozen at the laboratory Subchronic/Chronic Tox. Rodents until finalization of the report.

Duration of treatment / exposure:

Males:
- 14 days premating
- up to 14 days mating
- sacrifice minimum 4 days after littering
The exposure duration was at least 36 days.

Females:
- 14 days premating
- up to 14 days mating
- gestation about 22 days
-sacrifice minimum 4 days after littering
The exposure duration was at least 56 days.

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
0, 100, 300 or 1000 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

10 males/ 10 females

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: The animals were checked daily for any abnormal clinical signs before the administration as well as within 2 hours and within 5 hours after the administration for any signs of morbidity, pertinent behavioral changes and signs of overt toxicity. Abnormalities and changes were documented daily for each affected animal.
The littering and lactation behavior of the dams was generally evaluated in the mornings in combination with the daily clinical inspection of the dams. Only particular findings (e.g. inability to deliver) were documented on an individual dam basis.
On weekdays (except public holidays) the parturition behavior of the dams was inspected in the afternoons in addition to the evaluations in the mornings.
The day of littering was considered the 24-hour period from about 15.00 h of one day until about 15.00 h of the following day.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Detailed clinical observations (DCO) were performed in all animals prior to the administration period and thereafter at weekly intervals.

BODY WEIGHT: Yes
- Time schedule for examinations: Body weight was determined before the start of the administration period in order to randomize the animals. During the administration period body weight was determined on study day 0 (start of the administration period) and thereafter once a week at the same time of the day (in the morning).
The body weight change of the animals was calculated from these results.
The following exceptions are notable for the female animals:
- During the mating period the parental females were weighed on the day of positive evidence of sperm (GD 0) and on GD 7, 14 and 20.
- Females with litter were weighed on the day of parturition (PND 0) and on PND 4.
- Females without a litter and without positive evidence of sperm in the vaginal smear were weighed weekly. These body weight data were solely used for the calculations of the dose volume.

FOOD CONSUMPTION: Yes
- Time schedule: Generally, food consumption was determined once a week for male and female parental animals, with the following exceptions:
- Food consumption was not determined during the mating period (male and female F0 animals).
- Food consumption of the F0 females with evidence of sperm was determined on GD 0-7, 7-14, 14-20.
- Food consumption of F0 females, which gave birth to a litter, was determined for PND 1-4.
Food consumption was not determined in females without positive evidence of sperm (during the mating period of dams used in parallel) and females without litter (during the lactation period of dams used in parallel).

WATER CONSUMPTION: Yes
- Time schedule for examinations: Drinking water consumption was monitored by daily visual inspection of the water bottles for any changes in volume.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: In the morning blood was taken from the retro-bulbar venous plexus from fasted animals. The blood sampling procedure and subsequent analysis of blood and serum samples were carried out in a randomized sequence.
- Anaesthetic used for blood collection: Yes, the animals were anaesthetized using isoflurane (Isoba, Essex GmbH, Munich, Germany).
- Animals fasted: Yes
- How many animals: Examinations were carried out in the first 5 surviving parental males and the first 5 surviving females with litter (in order of delivery) per group.
- Parameters examined. Leukocyte count (WBC), Erythrocyte count (RBC), Hemoglobin (HGB), Hematocrit (HCT), Mean corpuscular volume (MCV), Mean corpuscular hemoglobin (MCH), Mean corpuscular hemoglobin concentration (MCHC), Platelet count (PLT), Differential blood count, Reticulocytes (RET), Prothrombin time (HQT). In addition clotting tests were performed.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: In the morning blood was taken from the retro-bulbar venous plexus from fasted animals. The blood sampling procedure and subsequent analysis of blood and serum samples were carried out in a randomized sequence.
- Animals fasted: Yes
- How many animals: Examinations were carried out in the first 5 surviving parental males and the first 5 surviving females with litter (in order of delivery) per group.
- Parameters examined: Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Alkaline phosphatase (ALP), γ-Glutamyltransferase (GGT), Sodium (NA), Potassium (K), Chloride (CL), Inorganic phosphate (INP), Calcium (CA), Urea (UREA), Creatinine (CREA), Glucose (GLUC), Total bilirubin (TBIL), Total protein (TPROT), Albumin (ALB), Globulins (GLOB), Triglycerides (TRIG), Cholesterol (CHOL), Bile acids (TBA).

URINALYSIS: Yes
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters examined: pH, Protein, Glucose, Ketones, Urobilinogen, Bilirubin, Blood, Specific gravity, Sediment, Color, Turbidity, Volume

NEUROBEHAVIOURAL EXAMINATIONS
FUNCTIONAL OBSERVATION BATTERY: Yes
- Time schedule: A functional observational battery (FOB) was performed in all animals at the end of the administration period starting at about 10:00 h. At least one hour before the start of the FOB the rats were transferred to single-animal polycarbonate cages. Drinking water was provided ad libitum, but no food was offered during the measurements. The FOB started with passive observations without disturbing the rats, followed by removal from the home cage, open field observations in a standard arena and sensory motor tests as well as reflex tests. The findings were ranked according to the degree of severity, if applicable. The observations were performed at random.

MOTOR ACTIVITY ASSESSMENT: Yes
- Time schedule: Motor activity (MA) was also measured from 14:00 h onwards on the same day as the FOB was performed. The examinations were performed using the TSE Labmaster System supplied by TSE Systems GmbH, Bad Homburg, Germany. For this purpose, the rats were placed in new clean polycarbonate cages with a small amount of bedding for the duration of the measurement. Eighteen beams were allocated per cage. The number of beam interrupts was counted over 12 intervals for 5 minutes per interval. The sequence in which the rats were placed in the cages was selected at random. On account of the time needed to place the rats in the cages, the starting time was "staggered" for each animal. The measurement period began when the 1st beam was interrupted and finished exactly 1 hour later. No food or water was offered to the rats during these measurements and the measurement room was darkened after the transfer of the last rat.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

ORGAN WEIGHTS
- Organ weights: epididymides, testes (all male animals); adrenals, brain, heart, kidneys, liver, spleen, thymus (5 animals/sex and test group (females with litters, same animals as used for clinical pathology examinations)).

PRESERVATION OF TISSUES
Tissues preserved: adrenals, aorta, bone marrow (femur), brain, cecum, cervix, coagulating gland, colon, duodenum, epididymides, esophagus, eyes with optic nerve, extraorbital lacrimal glands, female and male mammary gland, femoral bone with articulation, heart, ileum, jejunum (with Peyers patches), kidneys, larynx, liver, lungs, lymph nodes (axillary and mesenteric), nose (nasal cavity), ovaries, oviducts, pancreas, parathyroid gland, pharynx, pituitary gland, prostate, rectum, salivary glands (sublingual and mandibular), sciatic nerves, seminal vesicles, skeletal muscle, spinal cord (cervical, thoracic and lumbar), spleen, sternum with bone marrow, stomach with forestomach and glandular stomach, target organs, testes, thymus, thyroids, trachea, urinary bladder, uterus, vagina, all gross lesions

HISTOPATHOLOGY: Yes, Mainly 5 animals/dose group from the control and high dose group, except all gross lessions and liver (all dose groups).
- Organs examined: adrenals, bone marrow (femur), brain, cecum, cervix, coagulating gland, colon, duodenum, epididymides, heart, ileum, jejunum (with Peyers patches), kidneys, liver, lungs, lymph nodes (axillary and mesenteric), ovaries, oviducts, prostate, rectum, sciatic nerves, seminal vesicles, spinal cord (cervical, thoracic and lumbar), spleen, stomach with forestomach and glandular stomach, testes, thymus, thyroids, trachea, urinary bladder, uterus, vagina, all gross lesions

Statistics:

Clinical examinations:
Food consumption (parental animals), body weight and body weight change (parental animals and pups; for the pup weights, the litter means were used), gestation days, implantation sites, pups delivered, life pups day x: DUNNETT-test (two-sided).
Male and female mating indices, male and female fertility indices, gestation index, females delivering, females with liveborn pups, females with stillborn pups, females with all stillborn pups: FISHER'S EXACT test (one-sided).
Mating days until day 0 pc, Viability Index: WILCOXON test (one-sided+) with BONFERRONI-HOLM adjustment
Feces, rearing, grip strength of forelimbs and hindlimbs, landing foot-splay test, motor activity: KRUSKAL-WALLIS test (two-sided), WILCOXON-test (two-sided).

Clinical pathology:
Blood parameters: bidirectional changes: KRUSKAL-WALLIS test, WILCOXON-test (two-sided); unidirectional changes: WILCOXON-test (one-sided).
Urinalysis parameters (apart from urine color and turbidity): WILCOXON-test (one-sided).
Urine pH, volume, specific gravity, color and turbidity: KRUSKAL-WALLIS test, WILCOXON-test (two-sided)

Pathology: weight parameters: KRUSKAL-WALLIS test (two-sided), WILCOXON test (two-sided)

Details on results:

CLINICAL SIGNS, DETAILED CLINICAL OBSERVATIONS AND MORTALITY
Almost all animals of both sexes in test group 3 (1000 mg/kg bw/d) showed slight salivation within 2 hours after the test substance administration on several days of the study. In male animals, salivation was observed beginning on pre-mating day 12 (in-life day 12) as well as during the mating period and the post-mating period. In female animals, salivation started on pre-mating day 12 (in-life day 12) and was observed during the mating, gestation and lactation periods. In test group 2 (300 mg/kg bw/d) one male animal showed slight salivation within 2 hours after the test substance administration on several days of the study, beginning on day 1 of mating phase (study day 14) to day 7 of post-mating phase (study day 21). Two female animals of test group 1 (100 mg/kg bw/d) showed salivation within 2 hours after the test substance administration on several days during the lactation phase (study days 40 to 58). From the temporary, short appearance immediately after dosing it could be assumed that salivation was induced by a bad taste of the test substance or local affection of the upper digestive tract. The effect was related to the test substance but assessed as being non-adverse.

One female animal of test group 2 (300 mg/kg bw/d) showed reduced nutritional condition and piloerection on lactation days 4 to 6 (study days 45 to 47). The finding was assessed as being incidental but caused by local pathological findings in the glandular stomach.

One female animal of test group 0 (control) showed palpable masses at both mammary lines >1.5 cm on lactation days 6 to 9 (study days 46 to 49). Later, the same animal showed encrusted palpable masses at the left mammary line (>3cm) and an additional palpable mass at the right mammary line (<1.5 cm) from study days 50 to 52. The same animal showed a poor general condition and piloerection from lactation day 6 (study day 46) onwards. This animal was sacrificed in a moribund condition on day 12 of the lactation period (study day 52). One female animal of test group 3 (1000 mg/kg bw/d) showed a dorsal skin lesion from lactation day 8 onwards (study day 48). The findings in these 2 animals were assessed as being spontaneous in nature.

FUNCTIONAL OBSERVATION BATTERY
Deviations from "zero values" were obtained in several rats. However, as most findings were equally distributed between test-substance treated groups and controls, were without a dose-response relationship or occurred in single rats only, these observations were considered to have been incidental.
The following examinations were performed during FOB and assessed individually:
Home cage observations: No test substance-related effects were observed.
Open field observations: One female animal of test group 3 (1000 mg/kg bw/d) showed a dorsal skin lesion. The finding was assessed as being spontaneous in nature and not related to treatment.
Sensorimotor tests/reflexes: No test substance-related effects were observed.
Quantitative parameters: No test substance-related effects were observed.

MOTOR ACTIVITY MEASUREMENT
Regarding the overall motor activity as well as the single intervals, no test substance-related deviations were noted for male and female animals of test groups 1-3 (100, 300 and 1000 mg/kg bw/d). Single interval No. 4 in female animals of test group 1 (100 mg/kg bw/d) was significantly lower. This deviation to the control values was regarded as being incidental and not related to treatment as the overall activity was not significantly altered and no dose response-relationship was observed.

BODY WEIGHT
The body weight change was significantly lower in male animals of test group 3 (1000 mg/kg bw/d) between study days 7 to 13 (-48.2%). As no significant differences were observed in mean body weight or during other study periods than between study days 7 to 13 the finding was assessed as being spontaneous in nature and not related to treatment.

FOOD CONSUMPTION
No test substance-related changes with regard to food consumption were observed in most animals of test groups 0-3.
However, one female animal of test group 2 (300 mg/kg bw/d) and of test group 3 (1000 mg/kg bw/d) showed severely reduced food consumption during the lactation period. For the animal of test group 2, the finding was assessed as being incidental but caused by local pathological findings in the glandular stomach. For the animal of test group 3 the finding was assessed as being treatment-related and caused by local pathological findings in the forestomach.

WATER CONSUMPTION
No test substance-related changes with regard to water consumption were observed.

HAEMATOLOGY
No treatment-related changes among hematological parameters were observed.
In male animals of test group 3 (1000 mg/kg bw/d), relative large unstained cell (LUC) counts were increased. This was the only differential cell count fraction which was increased. Absolute LUC counts were not significantly increased and no alteration of the cell counts occurred in female animals. Therefore, this change was regarded as incidental and not treatment-related.

CLINICAL CHEMISTRY
No treatment-related changes among clinical chemistry parameters were observed.

URINALYSIS
No treatment-related changes among urinalysis parameters were observed.
In male animals of test group 3 (1000 mg/kg bw/d) the urine pH value was decreased. This altered parameter could not be related to any pathophysiological finding and, therefore, it was regarded as maybe treatment-related but not adverse.

ORGAN WEIGHTS
Absolute weights
When compared to control group 0 (set to 100%), the mean absolute weights of following organs were significantly increased: kidneys (females, test group 2 and 3 - 300 and 1000 mg/kg bw/d). Following organ weights were significantly decreased: adrenal glands (males, test group 2 - 300 mg/kg bw/d) and brain (female, test group 1 - 100 mg/kg bw/d). All other mean absolute weight parameters did not show significant differences when compared to test group 0 (control).

Relative organ weights
When compared to the control group 0 (set to 100%), the mean relative weights of the liver and kidneys were significantly increased in all test groups.
All other mean relative weight parameters in females and all mean relative weight parameters in male animals did not show significant differences when compared to the control group 0. The mean absolute or relative kidney and liver weights in females of all treatment groups were within the range of historical control data, whereas in control females the kidney and liver weights were clearly below the historical data. Therefore, the significantly increase in liver and kidney weights in treated females was considered to be incidental. Because there was no dose-response relationship, the significantly decreased mean absolute adrenal weight in males of test group 2 (300 mg/kg bw/d) as well as the decreased mean absolute brain weight in females of test group 1 (100 mg/kg bw/d) were considered to be incidental.

GROSS PATHOLOGY
One female animal of test group 3 (1000 mg/kg bw/d) showed few erosions/ ulcers (diameter 4mm) in the forestomach that were assessed as being related to treatment.
Few erosions/ ulcers in the glandular stomach were noted in one female of test group 2 (300 mg/kg bw/d). Because few erosions/ ulcers occurred also in the control group in one male animal, the occurrence of erosions in the glandular stomach was considered to be incidental and not related to treatment.
All other findings were considered to be incidental or spontaneous in origin and without any relation to treatment.

Fertility:
All female animals were pregnant.

HISTOPATHOLOGY: NON-NEOPLASTIC
Liver: The number of males with peripheral fatty change was increased in test group 3 (1000 mg/kg bw/d).
For the increased number of males with minimal peripheral fatty change in test group 3 (1000 mg/kg bw/d), a treatment-related effect could not be ruled out. The occurrence of peripheral fatty change in females did not show dose-response relationship and was therefore considered to be incidental. The macroscopically diagnosed erosions/ ulcers in the forestomach of one female animal of test group 3 (1000 mg/kg bw/d) correlated with a moderate focal squamous cell hyperplasia. Histopathologically the finding was interpreted as reactive rim surrounding the erosions/ ulcers. The erosions/ ulcers in the glandular stomach of one female animal of test group 2 (300 mg/kg bw/d) and of the one control male animal was confirmed histopathologically. The one control female animal that was sacrificed moribund showed a massive necrotizing, abscess-forming inflammation in the region of the mammary gland. All other findings occurred either individually or were biologically equally distributed over control and treatment groups. They were regarded to be incidental or spontaneous in origin and without any relation to treatment.

Dose descriptor:

NOAEL

Remarks:

general systemic toxicity

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No effects were observed.

Dose descriptor:

NOAEL

Remarks:

local effects

Effect level:

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

Based on:

test mat.

Sex:

male

Basis for effect level:

other: No local effects were observed in males.

Dose descriptor:

NOAEL

Remarks:

local effects

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Based on findings in the forestomach noted at 1000 mg/kg bw/day in a single female rat.

Critical effects observed:

not specified

Stability analyses

The stability of the test substance in corn oil was demonstrated over a period of 7 days at room temperature. As the mixtures were stored no longer than this time period, the stability was guaranteed.

Homogeneity control analyses

Considering the low relative standard deviation in the homogeneity analysis, it can be concluded that Delta-Valerolactone was distributed homogeneously in corn oil.

Concentration control analyses

The concentration control analyses of all concentrations revealed that the values were in the expected range of the target concentrations, i.e. were always in a range of 90-110% of the nominal concentrations. Taken together, the results demonstrate the correctness of the concentrations of Delta-Valerolactone.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

1990-10-29 to 1991-01-31

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Proprietary study conducted to GLP, similar to guidelines.

Justification for data waiving:

other:

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

68 male and 65 female Sprague-Dawley rats, 34 days of age were obtained from Harlan Sprague-Dawley. A pretest health screen was conducted on 5 animals per sex, randomly selected. Blood samples of 3 sacrificed rats were collected for serologic evaluation and the major organs were fixed and examined microscopically.
Rats were housed individually in wire cages. All animals were separated by sex and treatment group. Room temperature and relative humidity were monitored constantly; 19.4-23.3oC and 45-59% respectively. The photoperiod was 12 hour light/dark. Individuals were identified by tail tattoos. Body weights and physical condition of the rats were monitored for 2 weeks prior to group placement. During non-exposure periods, food and water were provided ad libitum, food and water were withheld during exposure periods. During exposured rats were individually housed and separated by sex and exposure group in wire cages.

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: Not relevant: exposure to vapour

Details on inhalation exposure:

e-Caprolactone was delivered as a vapour at 0, 15 or 45ppm concentrations: liquid e-Caprolactone was metered from a syringe pump and a piston pump for the 15 and 45 ppm concentrations respectively, into a glass evaporator. The syringe pump was equipped with a 10ml syringe for the 15ppm exposure, and the piston pump was equipped with a 1/8inch piston for the 45ppm exposure. The temperature in the evaporator was maintained at a level sufficient to vaporise the test substance.
The inhalation chambers were constructed from stainless steel with glass windows for animal observations. The volume of the chamber was approximately 900l, and the airflow rate was approximately 200L/min (13-14 air changes per hour). Air rate was calibrated with a trasnducer and flow computer. A pressure gauge was used to monitor airflow. Temperature and relative humidity were monitored at least 12 times per exposure. The daily mean temperature values were 23, 24 and 24oC for the 0, 15 and 45ppm concentrations respectively. The daily mean relative humidity values were 45, 51 and 47% for the 0, 15 and 45ppm concentrations respectively.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentrations of e-Caprolactone vapour were analysed 6 times during each daily 6 hour exposure period by sampling the chamber atmosphere using sorbent tubes. The samples were desorbed with carbon disulfide and analysed by flame ionisation gas chromatography. The control chamber was analysed once during each exposure period.

Duration of treatment / exposure:

Rats (now 49 days of age) were exposed 5 days a week for 13 weeks, in the last week the rats were exposed for 3 days. Each exposure period lasted 6 hours. An additional group underwent a post-exposure recovery period of 4 weeks.

Frequency of treatment:

Rats were exposed 5 days a week for 13 weeks, in the last week the rats were exposed for 3 days.

Remarks:

Doses / Concentrations:
0, 15, 45 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

10 rats per sex per dose plus 10 additional males and females in the 0 and 45ppm groups for 4 week recovery observations.

Control animals:

yes, concurrent no treatment

Details on study design:

Test substance concentrations were determined by the sponsor prior to study initiation.
A pretest health screen was carried out on 5 rats per sex to test for parasites, and for microscopic evaluation of the major organs. Rats were assigned to 2 test groups and 1 control group using a computer-based randomisation program. Only rats with body weights within 2 standard deviations of the mean weight were selected. There were an extra 10 males and females in each of the 0ppm and 45ppm groups; these rats were not euthanased after 13 weeks' exposure and instead were monitored for 4 weeks for recovery.

Positive control:

No positive control was used.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS/DETAILED CLINICAL OBSERVATIONS/BODY WEIGHT:
- All rats were weighed on the morning prior to the first exposure. They were then weighed weekly throughout the exposure regimen and immediately prior to sacrifice. The animals that were held for a 4 week recovery period were weighed weekly and immediately prior to sacrifice.
- During non-exposure days the rats were examined once a day for overt clinical signs and twice a day for mortality. All rats were individually observed for signs of toxic effects except during exposure. During the exposures, observations were made on a group basis. Preceeding and following each exposure, observations were recorded for animals exhibiting overt clinical signs. Detailed observations were performed on all animals at the time of body weight determination and immediately prior to sacrifice.
OPHTHALMOSCOPIC EXAMINATION:
- Ophthalmic examinations took place 1 week before the exposure regimen began, and following the last exposure. The recovery animals were examied at the end of the 4 week recovery period.
FOOD CONSUMPTION/WATER CONSUMPTION:
- Food and water consumption measurements were obtained on a weekly basis during the first 4 weeks of exposure.
URINALYSIS:
- Urine was collected from individually housed animals using metabolism cages following day 64 for the males and day 65 for the females. Urine was also collected from the rats in the 4 week recovery group.
HAEMATOLOGY/CLINICAL CHEMISTRY:
- Haematology and serum clinical chemistry evaluation was performed on blood samples collected from all rats at the end of the exposure regimen and in the recovery groups after the 4 week recovery period. Blood was collected from the orbital sinuses of anaesthetised rats. Food was removed from the cages prior to the start of the blood collection period, whilst water was provided ad libitum.

Sacrifice and pathology:

GROSS PATHOLOGY/HISTOPATHOLOGY:
After sacrifice weights were recorded of the brain, liver, lungs, kidneys, testes and ovaries from all animals at sacrifice. Organ weights were recorded as absolute weights and relative weights. Complete necropsy was performed on each animal; gross examinations were performed on all animals and selected tissues were fixed in 10% formalin. Microscopic evaluations were performed on a large number of tissues in the control and high dose groups only (excluding the recovery groups);

Other examinations:

No further examinations were made.

Statistics:

Continuous parametric variables were analysed by Levene's test, ANOVA and t-tests. Frequency data were compared using Fisher's exact test. p<0.05 was considered significant.

Details on results:

CLINICAL SIGNS AND MORTALITY
- No mortality occurred during the study. Swollen periocular tissues were observed in the control and 45ppm groups, but no exposure relationship was evident.

OPHTHALMOSCOPIC EXAMINATION
- No lesions were observed in the ophthalmic examinations.

BODY WEIGHT AND WEIGHT GAIN
- The mean values for the body weight and body weight gain values were lower, but not statistically significantly lower, than control values for males and females at the 14 week sacrifice, and for males and the 18 week sacrifice.

FOOD CONSUMPTION
- On week 4, males exposed to 45ppm showed a significantly decreased food consumption.

WATER CONSUMPTION
- No decreased water consumption was observed during the course of the study.

ORGAN WEIGHTS
- At the 14 week sacrifice there were no significant differences in organ weights between treatment groups. At the 18 week sacrifice, the absolute and relative lung weights for males in the 45ppm group were significantly increased. The relative (as a percentage of brain weight) lung weight for the females in the 45 ppm group was significantly increased. The relative (as a percentage of brain weight) kidney weight for the males in the 45ppm group was significantly decreased. The absolute ovary weight in the 45ppm group was significantly decreased, however, one control animal had an ovarian cyst which doubled in weight and therefore increased the mean weight in the controls.

HAEMATOLOGY AND CLINICAL CHEMISTRY
- At the 14 week sacrifice, female rats had no significant differences in the haematologic and serum chemistry results. Male rats in the 45ppm group had a significant decrease in eosinophil counts and a significant increase in serum calcium values. At the 18 week sacrifice, female rats in the 45 ppm group had significant decreases in MCV and MCH values, significant increases in glucose, total protein, albumin and globulin, and a significant decrease in serum phosphorous. Male rats in the 45ppm group had a significant decrease in platelet counts, and no changes in the serum chemistry results were recorded.

URINALYSIS
- At the 14 week sacrifice there were no significant differences in urinalysis in male or female rats in the 15 and 45ppm groups. At the 18 week sacrifice female rats in the 45ppm group had a significant decrease in urine pH. A decrease in urine volume and an increase in osmolality were noted in the female rats in the 45ppm group.

HISTOPATHOLOGY: NON-NEOPLASTIC
- The only e-Caprolactone exposure-related lesions at the 14 week sacrifice were perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45ppm group.

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

15 ppm

Based on:

test mat.

Sex:

male

Basis for effect level:

other: The only e-Caprolactone exposure-related lesions at the 14 week sacrifice were perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45ppm group.

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

45 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

other: The only e-Caprolactone exposure-related lesions at the 14 week sacrifice were perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45ppm group.

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

45 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No effects indicative of systemic toxiicty were seen in this study

Critical effects observed:

not specified

Analysis of e-Caprolactone performed prior to and following the exposure regimen showed no significant compositional change, the purity was >99%. The target exposure concentrations were 15 and 45 ppm of e-Caprolactone vapour. GC analysis of the chamber atmosphere resulted in mean concentrations (±SD) of 14.2±1.13 and 42.4±4.02 ppm. e-Caprolactone was not detected in the control chamber. The mean analytical-to-nominal concentrations were 0.86 and 0.73 for the 15 and 45 ppm groups respectively.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

203 mg/m³

Study duration:

subchronic

Species:

rat

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

1990-10-29 to 1991-01-31

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Proprietary study conducted to GLP, similar to guidelines.

Justification for data waiving:

other:

Qualifier:

equivalent or similar to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

68 male and 65 female Sprague-Dawley rats, 34 days of age were obtained from Harlan Sprague-Dawley. A pretest health screen was conducted on 5 animals per sex, randomly selected. Blood samples of 3 sacrificed rats were collected for serologic evaluation and the major organs were fixed and examined microscopically.
Rats were housed individually in wire cages. All animals were separated by sex and treatment group. Room temperature and relative humidity were monitored constantly; 19.4-23.3oC and 45-59% respectively. The photoperiod was 12 hour light/dark. Individuals were identified by tail tattoos. Body weights and physical condition of the rats were monitored for 2 weeks prior to group placement. During non-exposure periods, food and water were provided ad libitum, food and water were withheld during exposure periods. During exposured rats were individually housed and separated by sex and exposure group in wire cages.

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Remarks on MMAD:

MMAD / GSD: Not relevant: exposure to vapour

Details on inhalation exposure:

e-Caprolactone was delivered as a vapour at 0, 15 or 45ppm concentrations: liquid e-Caprolactone was metered from a syringe pump and a piston pump for the 15 and 45 ppm concentrations respectively, into a glass evaporator. The syringe pump was equipped with a 10ml syringe for the 15ppm exposure, and the piston pump was equipped with a 1/8inch piston for the 45ppm exposure. The temperature in the evaporator was maintained at a level sufficient to vaporise the test substance.
The inhalation chambers were constructed from stainless steel with glass windows for animal observations. The volume of the chamber was approximately 900l, and the airflow rate was approximately 200L/min (13-14 air changes per hour). Air rate was calibrated with a trasnducer and flow computer. A pressure gauge was used to monitor airflow. Temperature and relative humidity were monitored at least 12 times per exposure. The daily mean temperature values were 23, 24 and 24oC for the 0, 15 and 45ppm concentrations respectively. The daily mean relative humidity values were 45, 51 and 47% for the 0, 15 and 45ppm concentrations respectively.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentrations of e-Caprolactone vapour were analysed 6 times during each daily 6 hour exposure period by sampling the chamber atmosphere using sorbent tubes. The samples were desorbed with carbon disulfide and analysed by flame ionisation gas chromatography. The control chamber was analysed once during each exposure period.

Duration of treatment / exposure:

Rats (now 49 days of age) were exposed 5 days a week for 13 weeks, in the last week the rats were exposed for 3 days. Each exposure period lasted 6 hours. An additional group underwent a post-exposure recovery period of 4 weeks.

Frequency of treatment:

Rats were exposed 5 days a week for 13 weeks, in the last week the rats were exposed for 3 days.

Remarks:

Doses / Concentrations:
0, 15, 45 ppm
Basis:
nominal conc.

No. of animals per sex per dose:

10 rats per sex per dose plus 10 additional males and females in the 0 and 45ppm groups for 4 week recovery observations.

Control animals:

yes, concurrent no treatment

Details on study design:

Test substance concentrations were determined by the sponsor prior to study initiation.
A pretest health screen was carried out on 5 rats per sex to test for parasites, and for microscopic evaluation of the major organs. Rats were assigned to 2 test groups and 1 control group using a computer-based randomisation program. Only rats with body weights within 2 standard deviations of the mean weight were selected. There were an extra 10 males and females in each of the 0ppm and 45ppm groups; these rats were not euthanased after 13 weeks' exposure and instead were monitored for 4 weeks for recovery.

Positive control:

No positive control was used.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS/DETAILED CLINICAL OBSERVATIONS/BODY WEIGHT:
- All rats were weighed on the morning prior to the first exposure. They were then weighed weekly throughout the exposure regimen and immediately prior to sacrifice. The animals that were held for a 4 week recovery period were weighed weekly and immediately prior to sacrifice.
- During non-exposure days the rats were examined once a day for overt clinical signs and twice a day for mortality. All rats were individually observed for signs of toxic effects except during exposure. During the exposures, observations were made on a group basis. Preceeding and following each exposure, observations were recorded for animals exhibiting overt clinical signs. Detailed observations were performed on all animals at the time of body weight determination and immediately prior to sacrifice.
OPHTHALMOSCOPIC EXAMINATION:
- Ophthalmic examinations took place 1 week before the exposure regimen began, and following the last exposure. The recovery animals were examied at the end of the 4 week recovery period.
FOOD CONSUMPTION/WATER CONSUMPTION:
- Food and water consumption measurements were obtained on a weekly basis during the first 4 weeks of exposure.
URINALYSIS:
- Urine was collected from individually housed animals using metabolism cages following day 64 for the males and day 65 for the females. Urine was also collected from the rats in the 4 week recovery group.
HAEMATOLOGY/CLINICAL CHEMISTRY:
- Haematology and serum clinical chemistry evaluation was performed on blood samples collected from all rats at the end of the exposure regimen and in the recovery groups after the 4 week recovery period. Blood was collected from the orbital sinuses of anaesthetised rats. Food was removed from the cages prior to the start of the blood collection period, whilst water was provided ad libitum.

Sacrifice and pathology:

GROSS PATHOLOGY/HISTOPATHOLOGY:
After sacrifice weights were recorded of the brain, liver, lungs, kidneys, testes and ovaries from all animals at sacrifice. Organ weights were recorded as absolute weights and relative weights. Complete necropsy was performed on each animal; gross examinations were performed on all animals and selected tissues were fixed in 10% formalin. Microscopic evaluations were performed on a large number of tissues in the control and high dose groups only (excluding the recovery groups);

Other examinations:

No further examinations were made.

Statistics:

Continuous parametric variables were analysed by Levene's test, ANOVA and t-tests. Frequency data were compared using Fisher's exact test. p<0.05 was considered significant.

Details on results:

CLINICAL SIGNS AND MORTALITY
- No mortality occurred during the study. Swollen periocular tissues were observed in the control and 45ppm groups, but no exposure relationship was evident.

OPHTHALMOSCOPIC EXAMINATION
- No lesions were observed in the ophthalmic examinations.

BODY WEIGHT AND WEIGHT GAIN
- The mean values for the body weight and body weight gain values were lower, but not statistically significantly lower, than control values for males and females at the 14 week sacrifice, and for males and the 18 week sacrifice.

FOOD CONSUMPTION
- On week 4, males exposed to 45ppm showed a significantly decreased food consumption.

WATER CONSUMPTION
- No decreased water consumption was observed during the course of the study.

ORGAN WEIGHTS
- At the 14 week sacrifice there were no significant differences in organ weights between treatment groups. At the 18 week sacrifice, the absolute and relative lung weights for males in the 45ppm group were significantly increased. The relative (as a percentage of brain weight) lung weight for the females in the 45 ppm group was significantly increased. The relative (as a percentage of brain weight) kidney weight for the males in the 45ppm group was significantly decreased. The absolute ovary weight in the 45ppm group was significantly decreased, however, one control animal had an ovarian cyst which doubled in weight and therefore increased the mean weight in the controls.

HAEMATOLOGY AND CLINICAL CHEMISTRY
- At the 14 week sacrifice, female rats had no significant differences in the haematologic and serum chemistry results. Male rats in the 45ppm group had a significant decrease in eosinophil counts and a significant increase in serum calcium values. At the 18 week sacrifice, female rats in the 45 ppm group had significant decreases in MCV and MCH values, significant increases in glucose, total protein, albumin and globulin, and a significant decrease in serum phosphorous. Male rats in the 45ppm group had a significant decrease in platelet counts, and no changes in the serum chemistry results were recorded.

URINALYSIS
- At the 14 week sacrifice there were no significant differences in urinalysis in male or female rats in the 15 and 45ppm groups. At the 18 week sacrifice female rats in the 45ppm group had a significant decrease in urine pH. A decrease in urine volume and an increase in osmolality were noted in the female rats in the 45ppm group.

HISTOPATHOLOGY: NON-NEOPLASTIC
- The only e-Caprolactone exposure-related lesions at the 14 week sacrifice were perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45ppm group.

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

15 ppm

Based on:

test mat.

Sex:

male

Basis for effect level:

other: The only e-Caprolactone exposure-related lesions at the 14 week sacrifice were perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45ppm group.

Dose descriptor:

NOAEC

Remarks:

local

Effect level:

45 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

other: The only e-Caprolactone exposure-related lesions at the 14 week sacrifice were perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45ppm group.

Dose descriptor:

NOAEC

Remarks:

systemic

Effect level:

45 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No effects indicative of systemic toxiicty were seen in this study

Critical effects observed:

not specified

Analysis of e-Caprolactone performed prior to and following the exposure regimen showed no significant compositional change, the purity was >99%. The target exposure concentrations were 15 and 45 ppm of e-Caprolactone vapour. GC analysis of the chamber atmosphere resulted in mean concentrations (±SD) of 14.2±1.13 and 42.4±4.02 ppm. e-Caprolactone was not detected in the control chamber. The mean analytical-to-nominal concentrations were 0.86 and 0.73 for the 15 and 45 ppm groups respectively.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEC

70 mg/m³

Study duration:

subchronic

Species:

rat

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

Oral

In a combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (BASF SE, 2013) Delta-Valerolactone was administered orally by gavage to groups of 10 male and 10 female Wistar rats (F0 animals) at dose levels of 0 mg/kg bw/day (test group 0), 100 mg/kg bw/d (test group 1), 300 mg/kg bw/d (test group 2) and 1000 mg/kg bw/d (test group 3). The animals of the control group were treated in the same way with the vehicle only (corn oil). Fourteen days after the beginning of treatment, males and females from the same test group were mated. The duration of treatment covered a 2-week pre-mating and mating period in both sexes, approximately 3 week post-mating in males, and the entire gestation period as well as 4 days of lactation in females followed by an additional treatment until one day before sacrifice. Clinical and detailed clinical signs, food and water consumption as well as body weight development and gain were determined repeatedly during the study period. Towards study end, clinicochemical and haematological examinations, urinalysis and a functional observation battery incl. motor activity measurements were performed. After sacrifice, parent animals were examined by gross pathology. Selected organs were weighed and a histopathological examination was performed. Pups were sexed and macroscopically examined on PND0. Viability was recorded. They were weighed on PND1 and PND4. Necropsy was performed on PND4. All pups were examined macroscopically for external and visceral findings.

Results:

Parental animals:

Clinical examinations:

Signs of toxicity were observed in one female parental animal of test group 3 (1000 mg/kg bw/d) towards the end of the lactation period as indicated by reduced food consumption and secondary effects of maternal toxicity on pup weight, impaired nutritional condition and cannibalism in the litter of this female animal. These findings were considered to be adverse and toxicologically relevant effects. This animal was sacrificed in a moribund condition on day 12 of the lactation period (study day 52). Salivation after treatment was seen in several animals of test groups 1-3 (100, 300 as well as 1000 mg/kg bw/d). From the temporary, short appearance immediately after dosing it is likely, that this finding was induced by a bad taste of the test substance or local affection of the upper digestive tract. This finding was considered not to be an adverse and toxicologically relevant effect.

Functional Observation Battery/Motor Activity Measurement:

No test substance-related effects were observed.

Reproductive performance:

Fertility indices for male and female animals were not impaired by test-substance administration even at dose levels of 1000 mg/kg bw/d. In addition, live birth indices of pups in all test groups were not influenced. The viability index as indicator for pup mortality was not impaired by test-substance administration even at a dose level of 1000 mg/kg bw/d taking into account that changes in comparison to the control were related to maternally toxic effects in the one individual female animal which was sacrificed in a moribund condition on day 12 of the lactation period.

Clinical pathology:

No test substance-related, adverse findings were observed in all test dose groups.

Pathology:

The macroscopically diagnosed erosions/ ulcers in the forestomach of the one female animal which was sacrificed in a moribund condition on day 12 of the lactation period (test group 3, 1000 mg/kg bw/d) correlated with a moderate focal squamous cell hyperplasia. Histopathologically the finding was interpreted as reactive rim surrounding the erosions/ ulcers. Its occurrence was regarded as consequence of irritant effects of the test substance and considered to be adverse. A minimal peripheral fatty change was observed in the liver of three control males, in two males of test group 1 (100 mg/kg bw/d), in two males of test group 2 (300 mg/kg bw/d), as well as in the liver of eight males in test group 3 (1000 mg/kg bw/d). For the increased incidence of peripheral fatty change in the liver in males of test group 3 (1000 mg/kg bw/d), a treatment-related effect could not be ruled out. But because the peripheral fatty change was only minimal and was also observed in control animals, its occurrence was regarded, if at all, as non-adverse. All other recorded findings were considered to be incidental in nature and not related to treatment.

Pups:

Clinical examinations and gross findings:

The viability index was decreased down to 99.3, which was related to the individual litter of the one female animal which showed as well a food consumption reduction and pathological findings and was sacrificed in a moribund condition on day 12 of the lactation period. In this litter, reduced nutritional condition and empty stomachs were observed in male and female pups. Pups were cannibalized and found dead. In all other test dose groups and litters no test substance-related, adverse findings were observed.

Conclusion:

Under the conditions of this study the oral administration by gavage of Delta-Valerolactone revealed local pathological findings in the forestomach of one female Wistar rat at a dose level of 1000 mg/kg bw/d. This finding was related to the corrosive potential of the test substance. No local pathological findings in the forestomach were observed in female Wistar rats at 300 mg/kg bw/d and male Wistar rats up to a dose level of 1000 mg/kg bw/d. Signs of systemic toxicity were observed in one female parental animal of test group 3 (1000 mg/kg bw/d) towards the end of the lactation period as indicated by reduced food consumption and secondary effects of maternal toxicity on the litter. Thus, the no observed adverse effect level (NOAEL) for general systemic toxicity was 1000 mg/kg bw/d for male and female animals. With regard to effects in the stomach the NOAEL for local effects was set to 300 mg/kg bw/d in female and 1000 mg/kg bw/d in male Wistar rats. The NOAEL for reproductive performance, fertility and developmental toxicity was set to 1000 mg/kg bw/d in male and female Wistar rats.

Inhalation - read across

In a 90 -day repeated dose inhalation toxicity study (Bushy Run Research Centre, 1992), two groups of rats were exposed to Epsilon-Caprolactone vapour for 6 hours per day, 5 days per week, for 13 weeks, at concentrations of either 15 or 45 ppm. A third group acted as the control group and was exposed to air only. The rats were sacrificed after the final exposure (14 week sacrifice). Two additional groups of rats were exposed (at the same time as the three groups sacrificed at week 14) to the 0 or 45 ppm concentrations for 6 hours per day, 5 days per week, for 13 weeks, then allowed a 4 week recovery period prior to sacrifice (18 week sacrifice). No evidence of a systemic effect was seen in this study. There were no mortalities during the study, and no effects were observed in opthalmology, water consumption or body weights at the 14 and 18 week sacrifices, or in organ weights and urinalysis parameters at the 14 week sacrifice. Significant changes in food consumption, haematologic and urinalysis values, and organ weights observed in the 45 ppm group were not considered to be exposure related, due to the delayed onset and nature of the changes. The only observations of local toxicity thought to be directly related to exposure were the instances of perinasal and periocular encrustation and eyelid swelling in a small number of males in the 45 ppm group at the 14 week sacrifice, however no histopathologic evidence of skin inflammation was noted in these regions. The NOAEC for systemic toxicity is therefore 45 ppm (203 mg/m³); some evidence of slight irritation was seen at this concentration, leading to a NOAEC for irritation of 15 ppm (70 mg/m³).

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
The key study was selected (GLP and guideline study).

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
As no subchronic study for Delta-Valerolactone is available, the repeated dose 90-day inhalation toxicity study in rats with Epsilon-Caprolactone was selected for read across, based on structural similarity.

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
As no subchronic study for Delta-Valerolactone is available, the repeated dose 90-day inhalation toxicity study in rats with Epsilon-Caprolactone was selected for read across, based on structural similarity.

Justification for classification or non-classification

Based on the results of the combined repeated dose toxicity study with the reproduction/developmental toxicity screening test, and with regard to the results of a subchronic inhalation toxicity study with the structural analogue Epsilon-Caprolactone, Delta-Valerolactone is not subject to classification and labelling according to Directive 67/548/EEC and Regulation 1272/2008/EC. No target organ of repeated dose toxicity was identified.