Methyl (S)-(-)-lactate

Endpoint summary

Description of key information

No acute toxicity data is available for the target substance Methyl (S)-lactate itself. Therefore, available data from suitable read-across substances was used for the assessment of the potential of Methyl (S)-lactate to induce acute toxicity.

In acute oral toxicity studies conducted according to OECD guideline 401, groups of Wistar rats (5/sex) were exposed to the source substances Propyl (S)-lactate, Ethyl (S)-lactate and Butyl (S)-lactate as a single dose of 2000 mg/kg bw. In all studies, the oral LD50 value was established to exceed 2000 mg/kg bw.

In acute inhalation toxicity studies conducted according to OECD guideline 403, groups of Wistar rats (5/sex) were exposed to the source substances Ethyl lactate, Ethylhexyl (S)-lactate and Butyl (S)-lactate for 4 hours. No mortality occurred in any study.

In acute dermal toxicity studies conducted according to OECD guideline 402, groups of Wistar rats (5/sex) were exposed to the source substances Propyl (S)-lactate and L(+) lactic acid as a single dose of 2000 mg/kg bw. In both studies, the dermal LD50 value was established to exceed 2000 mg/kg bw.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

weight of evidence

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

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred.

Clinical signs:

other: The only clinical symptom observed was sluggishness 1 and 4 h post-treatment, in all rats.

Body weight:

other body weight observations

Remarks:

All animals gained weight during the 14-day observation period

Gross pathology:

No treatment-related gross alterations were observed.

Other findings:

No other findings were observed.

Interpretation of results:

other: CLP criteria not met

Conclusions:

Propyl (S)-lactate is not acutely toxic when administered to rats by gavage, at a single dose of 2000 mg/kg bw. The LD50 is greater than 2000 mg/kg bw for both sexes.

Executive summary:

In an acute oral toxicity study conducted according to OECD guideline 401, groups of Wistar rats (5/sex) were given propyl (S)-lactate (purity 99.5%) as a single oral dose of 2000 mg/kg bw. The animals were observed for 14 days after the single exposure. No mortalities and no further signs of toxicity occurred. Therefore, the oral LD50 is greater than 2000 mg/kg bw, both in male and female 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.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

weight of evidence

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

Preliminary study:

A prelimary study was carried out to find the general level of acute toxicity of the test substance; data of this preliminary study were not presented in the report.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occcurred

Clinical signs:

other: At 1, 4 and 24 hours after treatment all animals showed moderate signs of piloerection. These signs of intoxication were not observed 48 hours after treatment and thereafter.

Gross pathology:

Macroscopic examination at the end of the observation period did not reveal any treatment-related gross alteration.

Interpretation of results:

other: CLP criteria not met

Conclusions:

In an acute oral toxicity study in rats conducted according to OECD Test Guideline 401, no mortality occurred at the limit dose of 2000 mg/kg bw. Based on the results and in accordance with OECD Guideline 401, the oral LD50 was determined to be greater than 2000 mg/kg bw in both male and female rats.

Executive summary:

In an acute oral toxicity study conducted according to OECD Test Guideline 401, groups of Wistar rats (n= 5/sex) were given a single oral dose of Ethyl (S)-lactate (purity: 99.5%) in water at a dose of 2000 mg/kg bw and were observed for 14 days. All animals survived until the end of the study. At 1, 4 and 24 hours after treatment all animals showed moderate signs of piloerection. These signs of intoxication were not observed 48 hours after treatment and thereafter. All animals gained weight after 3 days and thereafter. At necropsy, no treatment-related macroscopic findings were observed in any animal.

Based on the results the LD50 value was determined to be greater than 2000 mg/kg bw. Therefore, classification for acute oral toxicity according to the CLP Regulation 1272/2008 is not warranted.

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.

Reference 3

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

weight of evidence

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

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality was observed.

Clinical signs:

other: At 1, 4 and 24 h after treatment all animals showed moderate piloerection, which was not observed 48 h afterwards. At 4 h post treatment all animals showed moderate signs of diarrhoea, which were not observed 24 h after treatment.

Gross pathology:

No treatment-related gross lesions were observed.

Other findings:

No other findings

Table 1: Summary of dose applied, mortality and mean body weights on day 0, 3, 7 and 14 after exposure to butyl-S-lactate:

Sex	Test concentration [mg/kg]	Mean body weight [g] on day				Mortality per 5 animals
		0	3	7	14
Male	2000	174	324	238	267	0/5
Female	2000	131	156	163	172	0/5

Interpretation of results:

other: CLP criteria not met

Conclusions:

Butyl-S-lactate is not acutely toxic when administered to rats by gavage, at a single dose of 2000 mg/kg bw. The LD50 is greater than 2000 mg/kg bw for both sexes.

Executive summary:

In an acute oral toxicity study conducted according to OECD guideline 401, groups of Wistar rats (5/sex) were given butyl-S-lactate (min. 97 % purity) as a single oral dose of 2000 mg/kg bw in maize oil. The animals were observed for 14 days after the single exposure. No mortalities occurred. Therefore, the oral LD50 value is greater than 2000 mg/kg bw, both in male and female rats.

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

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw

Quality of whole database:

GLP guideline studies

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.4 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

None of the rats died during or after exposure.

Clinical signs:

other: See remarks

Remarks:

During the entire exposure dreased breathing frequency. Wet noses were seen after 30 minutes of exposure and piloerection after 60 minutes. Half-closed eyes and lachrymation were all observed only at 15 minutes after the start of the study

Body weight:

Body weight gain was not visibly affected by the exposure. All animals gained weight in a normal way.

Gross pathology:

Gross-examination at autopsy revealed pale lungs in one male and three females. In three females the lungs showed a few petechiae.

The decrease in breathing frequency together with the wet nares and lachrymation are indicative of irritational properties of the test material.

Interpretation of results:

other: CLP criteria not met

Conclusions:

In an acute inhalation toxicity study in rats conducted according to OECD Test Guideline 403, no mortality occurred at the concentration of 5.4 mg/L air. Based on the results and in accordance with OECD Guideline 403, the LC50 was determined to be greater than 5.4 mg/L air in both male and female rats.

Executive summary:

In an acute inhalation toxicity study conducted according to OECD Guideline 403, groups of SPF-reared, Wistar derived rats (n= 5/sex) were exposed to a concentration of approximately 5.4 mg ethyl lactate/L for 4 hours and were observed afterwards for 15 days. All animals survived until the end of the study. A decreased breathing rate was observed during exposure. Wet noses were seen after 30 minutes of exposure and piloerection after 60 minutes. Half-closed eyes and lachrymation were all observed only at 15 minutes after the start of the exposure. These signs had all disappeared the next day. All animals appeared normal for the remainder of the 15 day observation period and gained weight in a normal way. At necropsy, gross-examination revealed pale lungs in one male and three females. In three females the lungs showed a few petechiae. The level of 5.4 mg/L was the maximum attainable concentration due to the physical properties of the test material. Based on these results, the LC50 of ethyl lactate is determined to be greater than 5.4 mg/L. Therefore, classification for acute inhalation toxicity according to CLP Regulation 1272/2008 is not warranted.

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

Reference 2

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

supporting 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

Mass median aerodynamic diameter (MMAD):

µm

Duration of exposure:

min

Control animals:

no

Sex:

male

Dose descriptor:

other: RD50, rat

Effect level:

791 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

30 min

Sex:

male

Dose descriptor:

other: RD50, mouse

Effect level:

772 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

30 min

Mortality:

None of the animals died.

Clinical signs:

other: No abnormalities were observed before, during and after exposure. During the 7-day observation period, no abnormalities were observed except for alopecia in the neck region of one rat.

Body weight:

The day after exposure, slight body weight gain or slight body weight loss was observed in all animals, which was explained by stress induced by the exposure conditions. Seven days after exposure all rats had gained weight whereas most mice had gained weight too.

Gross pathology:

In both species there was no increace in relative lung weight with increasing concentration. Macroscopic changes at necropsy were limited to grey discoloured or irregular surfaced lungs, with grey stains and/or grey/black, white or red. somewhat swollen spots or specks. A concentration-response relationship was not observed.

Other findings:

Respiratory irritation:
The RD50 was calculated using the maximum decreases, in this case the mean of the tree last measurements during exposure (viz. at 23, 26 and 29 min). The regression line through the mean response of the four exposure groups at 23, 26 and 28 min was R = 1.5663 - 0.3693 logC, with a correlation coefficient of -0.9047. From this regression equation for mice a RD50 of 772 mg/m³ was calculated. In view of the monotonic, asymptotic decrease during almost the entire exposure period, the RD50 value was also calculated using the mean of the reactions through the exposure period, after the first 5 minutes. An RD50 value of 886 mg/m³ was obtained which was slightly higher (as could be expected) than that obtained using the three last measurments, showing the maximum responses. According to a method described by Bos et al. (1992), it was checked whether a concentration-response-relationship was present which could point at other (toxic) actions but sensory irritation. In this study in mice with ethyl lactate there was no concentration-response relationship. After exposure to the three lowest levels, relative breathing frequencies increased and almost reached pre-exposure values (up to 95%); the recovery ion relative breathing rate after the first exposure to 3000 mg/m³ reached a highest level of 70% only.
For rats, maximal responses were observed at about 7, 8 and 9 minutes after the start of the exposure; thereafter increases in breathing rate were noted. The RD50 value was therefore calculated using the mean of the trhee measurements at 7, 8 and 9 minutes. The regression line was: R = 1.8160 - 0.4541 logC (C in mg/m³) with a correlation coefficient of 0.8981. From this regression equation an RD50 value of 791 mg/m³ was estimated which turned out to be in good agreement with that observed in mice. The Bos method again did not show any concentration-response relationship. After exposure, relative breathing frequencies increased and reached highest values of up to 80-87%.

Interpretation of results:

study cannot be used for classification

Conclusions:

The RD50 values of Ethyl (S)-lactate were 772 mg/m³ in mice and 791 mg/m³ in rats. In the same study an RD50 of 760 mg/m³ in mice and 701 mg/m³ in rats was found for n-butyl-L-lactate. The similarity in the results supports the conclusion, that the effects on breathing rate can be attributed to irritating effects from the lactic acid formed at hydrolysis of the substances, which is a rapid process during and after uptake in the organism. The sensory irritating effect is thus a pH effect and not a toxic effect.

Executive summary:

The airway irritating properties of Ethyl (S)-lactate were studied by exposing four groups of male rats and mice for a single period of 30 minutes. All groups consisted of four animals. Concentrations of ethyl lactate were between 0.333 and 4.020 g/m³. Animals were necropsied seven days after exposure. No abnormalities were observed before, during and after exposure, and during the 7-day observation period, no treatment-related abnormalities were observed. None of the animals died. The day after exposure, slight body weight gain or slight body weight loss was observed in all animals. Seven days after exposure all rats had gained weight whereas most mice had gained weight too.

In both species after exposure there was no increase in relative lung weight with increasing concentration. Macroscopic changes at necropsy were limited to grey discoloured or irregular surfaced lungs, with grey stains and/or grey/black, white or red, somewhat swollen spots or specks. A concentration-response relationship was not observed.

From the results of the present study, it was concluded that RD50 values of Ethyl (S)-lactate were 772 mg/m³ in mice and 791 mg/m³ in rats. In the same study an RD50 of 760 mg/m³ in mice and 701 mg/m³ in rats were found for n-butyl-L-lactate. The similarity in the results supports the conclusion, that the effects on breathing rate can be attributed to irritating effects from the lactic acid formed at hydrolysis of the substances, which is a rapid process during and after uptake in the organism. The irritating effect on breathing is thus a pH effect and not a toxic effect.

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.

Reference 3

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.6 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

Two females were found dead or sacrificed for ethical reasons on day 2 after exposure. No further mortality occurred (see Table 3 in attached background material).

Clinical signs:

other: No clinical signs were noted during exposure. Lethargy, hunched posture, rales and/or piloerection were shown by the surviving animals between days 1 and 4 after exposure. Rales were also noted among two animals at later time points during the observation

Body weight:

Reduced body weight gain and body weight loss was noted among the surviving animals during the first week post-exposure. All surviving animals regained weight during the second week (see Table 5 in attached background material).

Gross pathology:

No abnormalities were found at macroscopic post mortem examinantion of the surviving animals and the animal found dead. Macroscopic examination of the animal sacrificed for ethical reasons during the study revealed pale discolouration of the liver (see Table 6 in attached background material).
Incidental finding included pelvic dilation of the right kidney of one male. This finding is occasionally seen among rats ot this age and strain and was therefore considered not related to treatment.

Interpretation of results:

other: CLP criteria not met

Conclusions:

Based on these results, the LC50 of ethylhexyl (S)-lactate is greater than 5.6 mg/L.

Executive summary:

In an acute inhalation toxicity study conducted according to OECD TG 403 groups of young adult Wistar rats (5/sex) were exposed by inhalation route nose-only to ethylhexyl (S)-lactate (purity 99%) for 4 hours at a concentrations of approximately 5.6 mg/L (limit test). Animals then were observed for 14 days.

Two females were found dead or sacrificed for ethical reasons on day 2 after exposure. No further mortality occurred. No clinical signs were noted during exposure, excpet lethargy, hunched posture, rales and/or piloerection by the surviving animals between days 1 and 4 after exposure. Rales were also noted among two animals at later time points during the observation period. The two females found dead or sacrificed showed lethargy, ventro-lateral recumbency, hunched posture, slow breathing, laboured respiration and/or piloerections prior to death.

Reduced body weight gain and body weight loss was noted among the surviving animals during the first week post-exposure. All surviving animals regained weight during the second week. No abnormalities were found at macroscopic post mortem examination of the surviving animals and the animal found dead. Macroscopic examination of the animal sacrificed for ethical reasons during the study revealed pale discolouration of the liver.

Based on these results, the LC50 of ethylhexyl (S)-lactate is greater than 5.6 mg/L and in accordance with CLP Regulation 1272/2008 no classification for acute inhalation toxicity is warranted.

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

Reference 4

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

weight of evidence

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

Duration of exposure:

h

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.14 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality occured.

Clinical signs:

other: During exposure, visually decreased breathing frequency and wet nose and head were observed in all animals to the same extent. Immediately after exposure, visually decreased breathing frequency and wet head were still present. A wet fure was observed in a

Body weight:

Normal body weight gain was observed in all rats during the observation period (see Table 2 in box "Any other information on results incl. tables").

Gross pathology:

No treatment-related lesions were detected after the examination.

Analytical results:

Mean actual concentration (and standard deviation) turned out to be 5.14 (0.13) g/m³. Particle size distribution is given below in Table 1.

Table 1: Aerodynamic particle size distribution of n-butyl-S-(-)-lactate test atmosphere

Aerodynamic diameter (µm)	Distribution in % total mass
< 1.0	0.0
1.0	0.3
1.4	1.1
1.8	1.5
2.4	6.5
2.8	20.0
3.1	20.7
3.4	31.2
3.8	9.0
4.2	2.4
> 4.2	7.2

Body weight:

Normal body weight gain was observed in all rats during the observation period.

Table 2: Individual and mean body weights of male and female rats exposed to n-butyl-S-(-)-lactate aerosols for 4 h.

	Body weight (g)
	Males			Females
	Day 0^a	Day 7	Day 14	Day 0^a	Day 7	Day 14
	209	235	272	169	176	192
	222	234	265	167	177	191
	213	239	270	167	170	183
	221	238	271	160	163	174
	193	209	239	153	157	169
Mean	212	231	263	163	168	182

^a: just before exposure

Interpretation of results:

other: CLP criteria not met

Conclusions:

In an acute inhalation toxicity study in rats, conducted in accordance with OECD test guideline 403, no mortality occurred. Based on the results, the 4 h inhalative LC50 for n-butyl-S-(-) lactate can be considered to be greater than 5.14 mg/L in rats.

Executive summary:

In an acute inhalation toxicity study, young adult Wistar rats (5/sex), were exposed by nose-only inhalation to aerosols of n-butyl-S-(-)-lactate (> 97% purity) at a concentration of 5.14 mg/L in air, one single time for a period of 4 hours. Animals were observed for 14 days. No mortality occurred. Clinical observations revealed visually decreased breathing frequency, wet head and/or fur, during and shortly after exposure. No abnormalities were observed during the 14-day observation period. All rats showed normal body weight gain during the observation period. No gross lesions were detected at necropsy. Since no mortality occurred during the entire observation period, the LC₅₀ can be considered to be greater than 5.14 mg/L.

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

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

> 5 140 mg/m³ air

Physical form:

inhalation: aerosol

Quality of whole database:

Guideline studies

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occured during the 14-day observation period.

Clinical signs:

other: Encrustation of the nose, on day 1 or at 72 h or day 3 recorded in some of the animals. In the skin site treated with the test substance, only slight encrustation was observed in 2 males and 1 female on day 1 of the study. No other clinical symptoms obser

Body weight:

other body weight observations

Remarks:

no adverse effects on bodyweight gain were noted

Gross pathology:

No treatment-associated changes were detected in the animals.

Interpretation of results:

other: CLP criteria not met

Conclusions:

Propyl (S)-lactate is not dermally toxic and the LD50 is >2000 mg/kg bw.

Executive summary:

In an acute dermal toxicity study conducted according to OECD TG 402 groups of young adult Wistar rats (5/sex) were dermally exposed to n-propyl-lactate (purity 99.5%) for 24 hours to at least 10% of the total body surface area at a dose of 2000 mg/kg bw. Animals were observed for 14 days. No mortality was observed among the animals. The only clinical symptom detected was encrustation of the nose on days 1 or 3 of the study. All animals gained weight day during the 14-day observation period, except for a slight dip in the body weight of all males and 4 females, recorded on day 3. No treatment-associated changes were detected in the animals during the gross pathology examination.

Based on the results, the dermal LD50 of the substance for both male and female rats can be considered to be greater than 2000 mg/kg bw.

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

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

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

Adequacy of study:

weight of evidence

Justification for type of information:

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

Reason / purpose for cross-reference:

read-across source

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals survived the 14-day duration of the study.

Clinical signs:

other: No abnormal clinical signs were observed during the study.

Gross pathology:

Brown, crusted, and raised discolorations of the treated skin were observed during necropsy of 3 males and 3 females. Multiple depressions in the treated skin were observed during necropsy of one of the same males, of 2 other males, and of one other female. A dark red focus was also observed on the lung of one male. No other abnormalities were observed during necropsy of all males and 4 females, and no abnormalities were observed during necropsy of one female.

Skin reactions:

Severe erythema and severe edema were observed for all animals after test article removal on day 1. Erythema decreased in severity (to well defined or very slight) for 2 males on day 14 and for one female on day 12. Edema decreased in severity (to moderate, slight, or very slight) for all males and 3 females as early as day 2. No erythema was observed on day 14, and no edema was observed on days 12 to 14 for one female. Also, no edema was observed on day 14 for one male. Other dermal reactions observed at test sites included:

- Blanching: all animals on day l and as late as days 2, 3, or 4 for 6 animals.

- Necrosis (brown-green discoloration): all animals on days l and 2, as late as days 3, 5, or 6 for 3 males, and to day 11 for 4 females.

- Eschar formation: all animals on days 2 to 11, and for 7 animals to day 14. Eschar was present along the abrasion lines only of one female on days 7 to 11.

- Eschar peeled off: one female on day 12, and 2 males on day 14.

- Atonia: all males and 3 females from days 3 or 4 to days 11 or 14.

- Desquamation: all animals from days 10 or 11 to day 14.

- Fissures: one male and 4 females as early as day 5 and as late as day 14.

- Denuded areas along abrasion lines: one female on day 14. No other dermal reactions were observed during the study.

Interpretation of results:

other: CLP criteria not met

Conclusions:

L(+)-lactic acid is not dermally toxic and the LD50 is >2000 mg/kg bw.

Executive summary:

In an acute dermal toxicity study conducted according to EPA OPP 81-2, young adult New Zealand White rabbits (5/sex) were dermally exposed to L(+)-lactic acid for 24 hours to 10% of the body surface area at a dose of 2000 mg/kg bw. Animals then were observed for 14 days.

All animals survived the 14-day duration of the study and gained body weight. No abnormal clinical signs were observed during the study. Severe erythema and severe edema were observed at the test sites of all animals after removal on day 1. Other dermal reactions observed at test sites included: Blanching, necrosis, eschar formation, eschar along abrasion lines, eschar peeled off, atonia, desquamation, fissures and denuded areas along abrasion lines. No other dermal reactions were observed during the study. Based on the results the dermal LD50 is > 2000 mg/kg bw.

This acute dermal study is classified as acceptable. It does satisfy the guideline requirement for an acute dermal study (EPA OPP 81 -2) in the rabbits.

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

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw

Quality of whole database:

Guideline studies

Justification for classification or non-classification

Based on the available data, the target substance Methyl (S)-lactate does not warrant classification for acute toxicity in accordance with CLP Regulation 1272/2008. The derived LD50 values from suitable read-across substance for the oral and dermal route (OECD TG 401, 402) are above the limit value of the relevant OECD guidelines and in acute inhalation toxicity studies (OECD TG 403) conducted with suitable read-across substances no mortality occurred at the maximum achievable concentrations.