(3S-cis)-3,6-dimethyl-1,4-dioxane-2,5-dione

Endpoint summary

Description of key information

A sample of L-lactide was examined for acute oral toxicity in an experiment according to OECD guideline 423 with male and female rats (limit testing). A dose level of 2000 mg/kg body weight was examined. No mortality or distinct clinical signs were observed after treatment of 3 males and 3 females with the 2000 mg/kg dose level.
In an acute dermal toxicity study (limit test), a group of young adult Wistar rats (5 males and 5 females) was dermally exposed to L-lactide (purity 99%) in polyethylene glycol 400 for 24 hours to approximately 10% of body surface area at 2000 mg/kg bw. Animals were observed for 14 days. No mortality occurred. There were no treatment related clinical signs, necropsy findings or changes in body weight.
Lactic acid is used as a read-across partner for L-lactide and in an acute inhalation toxicity study in rats with lactic acid a LC50 of  > 7.94 mg/L air was determined.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998-06-23 to 1998-08-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

adopted in March, 1996

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Version / remarks:

dated 30 september 1996

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Specific details on test material used for the study:

- Batch no.: DA 778 FN
- Purity: >99.5%
- Labelling: L-lactide
- Bulk density: 0.8 kg/L
- Package: sealed plastic bags
- General appearance: white crystalline powder
- Storage conditions: at ca-20 °C.

Species:

rat

Strain:

other: Crl:(WI) WU BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

Males and females, 5-6 weeks old upon arrival, were individually ear marked. A maximum of five animals per cage (stainless steel cages, fitted with wire-screen floor and front). Lighting was a 12 hours light / 12 hours dark cycle. Temperature: 22±3°C. Humidity: 54-87.5% (upper limit higher than 70%, because of meteorological circumstances and/or wet cleaning of the animal room). Ventilation was ca 10 air changes/hour. Animals were fed standard laboratory rodent diet ad libitum. Each batch of this diet was analyzed by the supplier (SDS Special Diets services, Whitham, England) for the nutrients and contaminants and the results are available upon request. Tap water (N.V. Waterleidingbedrijf Midden-Nederland) ad libitum. Results of routine physical, chemical and microbiological examination of drinking water as conducted by the supplier are available upon request.

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

The study was started with treatment of three females with a 2000 mg/kg body weight dose level. Since all females survived the first 3 days after treatment, it was decided to continue treatment with 3 males dosed with the 2000 mg/kg dose level. The animals were dosed with a 10 mL/kg b.w. dosing-volume of a 200 mg/mL dilution of the test substance in maize oil to obtain the 2000 mg/kg dose level.
The exact amount of the test substance to be dosed was calculated for each animal individually and administered by means of a syringe, equipped with an oral gavage. Prior to dosing, the animals had fasted overnight. Approximately four hours after dosing, they had access to food again. The animals were observed for mortality up to 14 days after treatment.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: All visible reactions to treatment were recorded, including type, severity, onset and duration. Observations were made within 1 hour and within 4 hours after dosing, and subsequently at least once daily throughout the observation period. The body weight of each animal was recorded immediately before dosing on day 0, and of the surviving animals on days 3, 7 and 14 of the study.

- Necropsy of survivors performed: yes

- Other examinations performed: clinical signs, body weight, organ weights, histopathology. At the end of the observation period, on day 14 of the study, all surviving animals were killed with carbon dioxide and examined for external changes. Next, the abdomen and the thorax of each animal was opened and examined for gross pathological changes.

Statistics:

N.A.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Sex:

male/female

Dose descriptor:

LD0

Effect level:

2 000 mg/kg bw

Based on:

test mat.

Mortality:

ohtNone

Clinical signs:

other: None

Gross pathology:

Examination at autopsy of the males and females did not reveal treatment-relal:ed gross alterations.

Interpretation of results:

other: CLP criteria not met

Conclusions:

Since no mortality occurred during the 14-day observation period, the LD50 of L-lactide exceeds 2000 mg/kg bw in both male and female rats. Therefore, L-lactide is considered not harmful after oral ingestion.

Executive summary:

In an acute oral toxicity study (according to OECD guideline 423), group of male and female Wistar outbred rats; Crl:(WI) WU BRA (n = 3/sex) were given a single oral dose of L-lactide (purity: > 99.5%) at dose level of 2000 mg/kg body weight.

No mortality or distinct clinical signs were observed after treatment of 3 males and 3 females with the 2000 mg/kg dose level. Macroscopic examination of the animals at the end of the observation period did not reveal any treatment-related gross changes. Since no mortality occurred during the 14-day observation period, the oral LD50 of L-lactide is considered to exceed 2000 mg/kg body weight, in both male and female rats. L-dilactide is considered to be not harmful after oral ingestion.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw

Quality of whole database:

Guideline study

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 7.94 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

1 female died.

Clinical signs:

other: Please refer to box "Any other information on results incl. tables".

Body weight:

At the beginning of the study, mean body weicihts for individual groups were within 20% of the overall mean for each sex. All groups of male rats gained weight within the first week after exposure in comparison to pre-exposure weights (3% for sham-exposed, 2< for L(+)-lactic acid,respectively). Female rats in the sham group gained weight during the first week after exposure (less than 1%). Female rats in the treated group lost weight during the first week after exposure (7%). After 14 days, all surviving animals had gained weight in comparison to pre-exposure weights (14% for males, 7% for females). No significant differences were observed in body weight between treated and control groups.

Gross pathology:

All surviving animals were necropsied at the termination of the study. The animal that died during the study was necropsied immediately. No gross lesions were observed at necropsy.

Clinical signs:

Rapid breathing and eye tearing were observed during exposure. At one and three hours after exposure, all animals (including the sham controls) had a hunched posture, ruffled and ungroomed fur, brown stained fur and red-stained fur surrounding the eyes (tearing). By 24 hours, female treated rats had ruffled and stained coats. All other animals appeared normal at 24 hours and for the remainder of the 14 day observation period. Several treated female rats continued to have ruffled fur up to 4 days after exposure.

Mass Median Diameter:

The Mass Median Diameters ranged from 2.03 to 2.14 microns and averaged 2.09.

Interpretation of results:

other: CLP criteria not met

Conclusions:

Based on these results, the LC50 of L(+)-lactic acid is greater than 7.94 mg/L.

Executive summary:

In an acute inhalation toxicity study according to OECD 403, groups of young adult F344 rats (5/sex/dose) were exposed by inhalation route to L(+)-lactic acid in a concentration of approximately 7.94 mg/L for 4 hours.

Rapid breathing and eye tearing were observed during exposure. At one and three hours after exposure, all animnals (including the sham controls) had a hunched posture, ruffled and ungroomed fur, brown stained fur and red-stained fur surrounding the eyes (tearing). After 24 hours, female treated rats had ruffled and stained coats. All other animals appeared normal at 24 hours and for the remainder of the 14 day observation period. Several treated female rats continued to have ruffled fur up to 4 days after exposure. One female rat from the treated group died on day 9. All other animals survived until the end of the study. At gross pathology no adverse lesions were observed.

Based on these results, the LC50 of L(+)-lactic acid is greater than 7.94 mg/L.

This acute inhalation study is classified as acceptable. It does satisfy the guideline requirement for an acute inhaltion study (OECD TG 403) in rats.

This information is used in a read-across approach in the assessment of the target substance. For details and justification of read-across please refer to the read-across report attached to IUCLID section 13.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

7 940 mg/m³ air

Physical form:

inhalation: aerosol

Quality of whole database:

Guideline study

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-05-28 to 2010-09-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

adopted in 1987

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

adopted in 2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Version / remarks:

adopted in August 1998

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: JMAFF Guidelines (2000), including the most recent revisions

Version / remarks:

adopted in November 2000

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): L-Lactide
- batch: 0911001952
- purity: 99%
- Expiration date of the lot/batch: 2010-11-23
- Stability under test conditions: stable
- Storage condition of test material: in refrigerator (2-8°C) in the dark under nitrogen

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: approximately 10 weeks old.
- Weight at study initiation: Body weight variation did not exceed +/- 20% of the sex mean (males: 297 g, females: 201 g).
- Fasting period before study: not applicable.
- Housing: Individually housed in labeled Macrolon cages (MIII type; height 18 cm) containing sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom).
- Diet (e.g. ad libitum): Free access to pelleted rodent diet (SM R/M-Z from SSNIFF@Spezialdiäten GmbH, Soest, Germany).
- Water (e.g. ad libitum): Free access to tap water.
- Acclimation period: At least 5 days before start of treatment under laboratory conditions. During the acclimatization period the animals were group housed in Macrolon cages (MIV type).

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.0 ± 3.0°C (actual range: 19.9 - 21.5°C).
- Humidity (%): relative humidity of 40-70% (actual range: 39-72%).
- Air changes (per hr): approximately 15 air changes per hour.
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours darkness per day.

IN-LIFE DATES: From: 17 June 2010 To: 01 July 2010

Type of coverage:

occlusive

Vehicle:

polyethylene glycol

Details on dermal exposure:

TEST SITE
- Area of exposure: Approximately 10% of the total body surface, i.e. approximately 25 cm² for males and 18 cm² for females.
- % coverage: Approximately 10% of the total body surface.
- Type of wrap if used:The test substance formulation was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1D, Laboratoires Stella s.a., Liege, Belgium), successively covered with aluminium foil and Coban elastic bandage (3M, St. Paul, Minnesota, U.S.A. (Coban & Micropore)).

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The skin was cleaned of residual test substance using tap water.
- Time after start of exposure: 24 hours.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg (10 ml/kg) body weight.

VEHICLE
Polyethylene glycol 400 (Merck, Darmstadt, Germany) (specific gravity 1.125). The vehicle was dehydrated before the formulation was prepared. The formulation (w/w) was prepared within 4 hours prior to dosing. Homogeneity was accomplished to a visually acceptable level. Adjustment was made for specific gravity of the vehicle. In order to obtain homogeneity, the test substance formulation was heated in a water bath with a temperature of 49°C for 31 minutes. The test substance formulation was allowed to cool down below 40°C prior to dosing.

Duration of exposure:

24 hours

Doses:

2000 mg/kg (10 ml/kg) body weight

No. of animals per sex per dose:

5

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Mortality/viability: Twice daily
Body weights: Days 1 (pre-administration), 8 and 15
- Necropsy of survivors performed: yes
- Other examinations performed:
clinical signs: At periodic intervals on the day of dosing (Day 1) and once daily thereafter, until Day 15. The time of onset, degree and duration were recorded and the symptom graded according to fixed scales.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Sex:

male/female

Dose descriptor:

LD0

Effect level:

2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred

Clinical signs:

other: Chromodacryorrhoea (snout) was noted for one male on Day 1. No further clinical signs were observed

Gross pathology:

Reddish discolouration of the uterine adipose tissue in the abdominal cavity was observed for one female.

Interpretation of results:

other: CLP criteria not met

Conclusions:

The dermal LD50 value of L-lactide in Wistar rats was established to exceed 2000 mg/kg body weight.

Executive summary:

In an acute dermal toxicity study (according to OECD guideline 402, limit test), a group of young adult Wistar rats (5 males and 5 females) was dermally exposed to L-lactide (purity 99%) in polyethylene glycol 400 for 24 hours to approximately 10% of body surface area at 2000 mg/kg bw. Animals were observed for 14 days. No mortality occurred. There were no treatment related clinical signs, necropsy findings or changes in body weight. The dermal LD50 value of L-lactide in Wistar rats was established to exceed 2000 mg/kg body weight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw

Quality of whole database:

GLP-compliant guideline study

Additional information

After oral application of rats with L-lactide (study conducted in accordance to OECD 423) an acute oral LD50 of L-lactide of > 2000 mg/kg bw was determined. After dermal application (study conducted in accordance to OECD guideline 402), the LD50 of L-lactide was determined with > 2000 mg/kg bw.

Lactic acid is an acceptable read-across partner as lactide is rapidly converted by hydrolysis into lactic acid under aqueous conditions.

In an acute inhalation toxicity study in rats with lactic acid conducted in accordance to OECD guideline 403 a LC50 of > 7.94 mg/L air was determined.

Justification for classification or non-classification

Based on the available data according to CLP Regulation 1272/2008, L-lactide does not warrant classification for acute toxicity. LD50 values for all routes are above the limit values of the relevant OECD guidelines.