Butyl (S)-2-hydroxypropionate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-08-26 to 1996-10-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

adopted in July 1992

Deviations:

yes

Remarks:

The relative humidity of the animal room was higher than the upper limit mentioned in the guidelines

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Butyl (S)-2-hydroxypropionate

EC Number:

252-036-3

EC Name:

Butyl (S)-2-hydroxypropionate

Cas Number:

34451-19-9

Molecular formula:

C7H14O3

IUPAC Name:

butyl 2-hydroxypropanoate

Specific details on test material used for the study:

- Name: PURASOLV BL (n-butyl lactate)
- Chemical name: butyl-S-(-)-2-hydroxy propionate
- Package: Plastic bottle
- Batch No: BU-6001K
- CAS. Reg. No: 138-22-7 (although this is the CAS number for butyl lactate of unspecified stereochemistry, the substance is clearly identified as the S-enatiomer)
- Labelling: Butyl lactate PURASOLV BL
- General appearance: Clear, colourless liquid
- Storage conditions: Ambient temperature

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Broekman Institute, Someren, The Netherlands
- Age at study initiation: Young adults
- Weight at study initiation: 3350-3910 g
- Sex: Male
- Housing: Individually in stainless steel cages with perforated floor
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 54 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3
- Humidity (%): 60-87.5 % (upper limit higher than 70%, because of wet cleaning of the animal room and/or meteorological circumstances; the 87.5% peak occurred for some hours at most)
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: removal of hair with electric clippers so as to avoid abrasions

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

4 h

Observation period:

14 days

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: 2.5 × 2.5 cm

REMOVAL OF TEST SUBSTANCE
- Washing (if done): with a moistened tissue
- Time after start of exposure: 4 h

SCORING SYSTEM: Draize et al. (1944)

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

3.33

Max. score:

5

Reversibility:

not fully reversible within: 7 days

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 5

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1.67

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.67

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritant / corrosive response data:

The irritation scoring is presented in Table 1 below, section 'any other information on results incl. tables'. At 1 hour after treatment, very slight erythema was observed in the three rabbits. At 24 an 48 h post- treatment, well-defined erythema and slight oedema were observed in the three rabbits. One rabbit showed very slight incrustation and all three rabbits slight scaliness at 48 hours after treatment. At 72 hours after treatment, well-defined erythema and very slight or slight oedema were observed in the three rabbits. In addition, one rabbit showed very slight incrustation and all three rabbits slight scaliness. At 14 days after treatment all skin effects had cleared in the skin of all rabbits.

Any other information on results incl. tables

Table 1: Skin irritation scores for n-butyllactate after 4 -h dermal application in rabbits.

Rabbit No	1 h A B	24 h A B	48 h A B	72 h A B	7 d A B
8	1-0	2-2	4^2-2	4^2,3-2	4-0
10	1-0	2-2	2-2	2-1	0-0
12	1-0	2-2	2-2	2^3-1	0-0
Erytherma^1	1.0	2.0	3.0	3.0	n.r.
Oedema^1	0.0	2.0	2.0	1.5	n.r.

The average score is calculated for the two animals showing the strongest skin response

A: erythrema

B: oedema

¹ The average erythema and oedema score is calculated for the two animals showing the strongest skin response

² very slight incrustation in combination with well-defined erythema (erythema score = 4)

³ slight scaliness

⁴ very slight incrustation and slight scaliness (erythema score = 4), which had cleared completely at 14 days
after treatment

n.r. = not relevant; only scores 24-72 hours are used for classification

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

n-Butyl-S-lactate is moderately irritating to the skin of rabbits when applied for 4 h under semi-occlusive conditions.

Executive summary:

A sample of n-Butyl-S-lactate was tested for acute skin irritating/corrosive properties in an experiment with three albino rabbits. The dermal exposure period was 4 hours under semi-occlusive conditions. The test substance caused well-defined erythema, very slight incrustation, slight scaliness and slight oedema in the rabbits. The study design was in accordance with OECD guideline 404 (adopted in July 1992). At 14 days after treatment, the skin effects had cleared completely. On the basis of the results obtained it was concluded that, under the conditions of this study, n-Butyl-S-lactate is moderately irritating to the skin of rabbits after a 4-hour dermal contact period. According to the EC-standards n-butyl-S-lactate is irritating, but not corrosive to (human) skin and it shall be classified as irritant Category 2 (CLP, Regulation EC No 1272/2008).