(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 an read-across partner for L-lactide and in an acute inhalation toxicity study in rats with lactid 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:

other: GLP study according to OECD guideline 423

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

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 earmarked. 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.

Sex:

male/female

Dose descriptor:

LD0

Effect level:

2 000 mg/kg bw

Mortality:

None

Clinical signs:

None

Body weight:

All animals gained weight during the 14-day observation period.

Gross pathology:

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

Other findings:

N.A.

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

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:

A sample of L-lactide was examined for acute oral toxicity 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. 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

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

1987-11-24 to 1988-01-08

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline 403. Lactic acid used as read-across partner to L-lactide.

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

1981

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

Male and female Fischer 344 rats were obtained from Charles River Breeding Laboratories, Raleigh, North Carolina. Upon arrival, animals were quarantined for approximately 21days. Stringent disease control procedures were followed during quarantine to assure the use of healthy animals. Rats were observed for signs of illness. The animals were judged to be healthy prior to utilization in this study and were 9-10 weeks old at initiation of exposure.
Animals were housed in an AAAIAC-accredited facility with a controlled environment. The temperature range was 71±5°F, while the humidity range was 50 ± 22 % with a brief excursion down to 18% during one day. The light cycle was maintained on a 12 hour light/dark cycle. Rats were individually housed in polycarbonate cages with filter tops and automatic watering devices. Corn-cob bedding was used and animals had free access to certified laboratory rodent chow which had been analyzed for environmental contaminants. Water and food were provided ad libitum, except during exposure.

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

Atmosphere Generation:
A collison nebulizer (BGI Industries) was used to generate the aerosol. Compressed air was attached to the generator and the output from the aerosol was directed into a 4 liter dilution jar. Room air was allowed to dilute the aerosol before it was drawn into the exposure module under vacuum. A continuous, dynamic exposure to aerosolized test material was achieved with the nose-only exposure units. The air flow in the exposure module was adjusted to approximately 5 L/min using a calibrated rotameter and was periodically monitored during exposure. The exposure module consisted of a 360 ml cylindrical chamber mounted horizontally with an inlet, outlet and sampling port. Sampling of the test atmosphere was done from a sampling port situated on the side of the exposure module. Samples from the exposure module were taken for gravimetric and particle size determinations. Determinations of oxygen content could not be performed due to a malfunction of the oxygen sensor.
Conditions for Animal Exposures:
Rats were held in cylindrical tubes which aligned the heads of the animals with the conical shaped openings on the exposure chamber. The nose of each animal protruded into the chamber for nose-only inhalation. The animals were held in place by a soft sponge which served as a plunger in the cylinder and prevented the animal from turning or backing out. Five rats were restrained on each side of the exposure module. All rats of each concentration level were exposed at the same time.

Determination of Aerosol Concentration and Particle Size Distribution:
Gravimetric determinations were made by pre-weighing a 24 mm diameter Whatman glass-fiber filter (GF/A), placing the filter in a filter holder, and connecting the filter to the sampling port of the exposure module. Air samples were drawn through the filter using a vacuum supply regulated by a flow meter. Flow rates were set 0.5 L/min and a sampling time of 4-8 min was used. The concentration of aerosol present in the chamber was calculated by the difference in weight of the filter divided by the volume of air sampled. Seven separate determinations were made and a time-weighted average was calculated for the total aerosol concentration.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Gravimetric, using a filter interception

Duration of exposure:

4 h

Concentrations:

7.94 mg/L

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

Five male and five female rats were exposed to a nominal concentration of 7.94 mg/L of aerosolized test material for 4 hours. Analysis of at least three filter samples was performed to determine the purity of test material in the exposure module. The exposure atmosphere was also sampled to determine particle size distribution. A sham control group of 5 male and 5 female rats was used and was exposed to air alone for 4 hours. Animals were weighed prior to treatment and at weekly intervals thereafter. The animals were observed for mortality and pharmacotoxic signs during exposure, at 1 and 3 hours following exposure and once daily thereafter for 14 days. Survival was recorded for each group. Complete necropsies were performed on all animals on day 15 of the study. At necropsy, all organs showing gross lesions, if any, were fixed in 10% buffered formalin. Histopathology was not performed.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 7.94 mg/L air

Exp. duration:

4 h

Mortality:

1 female died.

Clinical signs:

other: Animals were observed during exposure for signs of toxicity. Rapid breathing and eye tearing was observed in the treated group, while in the sham control group, respiration was calm and steady during exposure. One and three hours after exposure, the treat

Body weight:

Individual body weights for animals on test are given in Tables 4 and 5. At the beginning of the study, mean body weights 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 SY-83, 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.

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the test, the LC50 of SY-83 is greater than 7.94 mg/L

Executive summary:

SY-83 was tested for its acute inhalation toxicity. Male and female F344 rats were exposed to 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 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. One female rat from the treated group died on Day 9. All other animals survived until the end of the study. Based on these results, the LC50 of SY-83 is greater than 7.94 mg/L. Lactic acid (termed SY-83 in the study) is used as read-across partner to LL-lactide.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

7 940 mg/m³

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:

other: GLP study according to OECD guideline 402

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1200 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

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:

LD0

Effect level:

2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred

Clinical signs:

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

Body weight:

The changes noted in body weight gain in males and females were within the range expected for rats used in this type of study and were therefore considered not indicative of toxicity

Gross pathology:

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

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

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 (OECD 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

Additional information

After oral application of rats with L-lactide in accordance to OECD 423 an acute oral LD50 of L-lactide of > 2000 mg/kg bw was determined. After dermal application 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 in accordance to OECD guideline 403 a LC50 of > 7.94 mg/L air was determined.

Justification for selection of acute toxicity – oral endpoint
GLP guideline study

Justification for selection of acute toxicity – inhalation endpoint
In a GLP guideline study according to OECD 403 treated rats show signs of toxicity and one female rat from the treated group died on Day 9

Justification for selection of acute toxicity – dermal endpoint
GLP guideline study

Justification for classification or non-classification

Based on the available data L-lactide does not warrant classification for acute toxicity. LD50 values for all routes are above the limit values of the relevant OECD guidelines.