Dioctyltin dilaurate

Endpoint summary

Description of key information

SKIN
Warren (2013a) OECD 431, EU Method B.40, Not corrosive (in vitro, Reconstructed Human Epidermis (RHE) model).
Warren (2013b), OECD 439, EU Method B.46, Not irritating (in vitro, Reconstructed Human Epidermis (RHE) model).
EYE
Sanders (2013) OECD 405, EU Method B.5, Non-irritant (Rabbit, male).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 October 2012 to 08 October 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to valid guidelines and the study was conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Amount / concentration applied:

10 µL of test material was applied topically.

Duration of treatment / exposure:

15 minutes.

Irritation / corrosion parameter:

other: other: Relative viability (%)

Value:

101.8

Remarks on result:

other:

Remarks:

Basis: mean. Time point: 15 minutes. Max. score: 100.0. (migrated information)

Direct MTT Reduction

The MTT solution containing the test material did not turn blue which indicated that the test material did not directly reduce MTT.

Main Test - Results

The relative mean viability of the test material treated tissues was 101.8 % after a 15 minute exposure period.

Table 1: Results

Item	OD540 of tissues	Mean OD540 of triplicate tissues	± SD of OD540 (%)	Relative individual tissue viability (%)	Relative mean viability (%)	± SD of Relaive mean viability (%)
Negative control item	0.727	0.725	0.044	100.3	100*	6.1
	0.680			93.8
	0.768			105.9
Positive control item	0.070	0.053	0.015	9.7	7.3	2.1
	0.046			6.3
	0.043			5.9
Test material	0.785	0.738	0.110	108.3	101.8	15.2
	0.612			84.4
	0.816			112.6

SD = standard deviation

* = the mean viability of the negative control tissues is set at 100 %

Quality Criteria

The relative mean tissue viability for the positive control treated tissues was 7.3 % relative to the negative control treated tissues and the standard deviation value of the percentage viability was 2.1 %. The positive control criterion was therefore satisfied.

The mean OD540 for the negative control treated tissues was 0.725 and the standard deviation value of the percentage viability was 6.1 %. The negative control acceptance criterion was therefore satisfied.

The standard deviation calculated from individual percentage tissue viabilities of the three identically treated tissues was 15.2 %. The test material acceptance criterion was therefore satisfied.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the test, the test material was considered to be a non-irritant.

Executive summary:

The skin irritation potential of the test material was determined in vitro, in accordance with standardised guidelines OECD 439 and EU Method B.46 using the EPISKIN™ Reconstructed Human Epidermis (RHE) Model.

During the study triplicate tissues were treated with the test material for an exposure period of 15 minutes. At the end of the exposure period each tissue was rinsed before incubating for 42 hours. At the end of the post-exposure incubation period each tissue was taken for MTT-loading. The maintenance medium from beneath each tissue was transferred to pre-labelled micro tubes and stored in a freezer for possible inflammatory mediator determination. After MTT loading a total biopsy of each epidermis was made and placed into micro tubes containing acidified isopropanol for extraction of formazan crystals out of the MTT-loaded tissues.

At the end of the formazan extraction period each tube was mixed thoroughly and duplicate 200 µL samples were transferred to the appropriate wells of a pre labelled 96 well plate. The optical density (OD) was measured at 540 nm (OD540).

Under the conditions of the study, the relative mean viability of the test material treated tissues was 101.8 % after the 15 minute exposure period. The quality control criteria required for acceptance of results were satisfied and the test material was concluded to be a non-irritant to the skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 November 2012 to 22 November 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to valid guidelines and the study was conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Age at study initiation: 12 - 20 weeks
- Weight at study initiation: 2.53 - 2.59 kg
- Housing: individually in suspended cages.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 - 23 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): at least 15 air changes per hour.
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light.

IN-LIFE DATES: From 12 November 2012 - 22 November 2012

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL

Duration of treatment / exposure:

- Dose administration: 0.1 mL of the test material was placed into the conjunctival sac of the right eye of one rabbit by gently pulling the lower lid away from the eyeball. The upper and lower eyelids were then held together for about 1 second immediately after treatment, to prevent loss of the test material, and then released. The left eye remained untreated and was used for control purposes. After consideration of the initial pain reaction (see Table 2) in the first treated animal, a second animal was treated.

Observation period (in vivo):

Animals were observed up to 72 hours post administration.

Number of animals or in vitro replicates:

One male initially, followed by a further male once the irritation potential was fully assessed in the first animal.

Details on study design:

REMOVAL OF TEST SUBSTANCE
Washing: Irrigation was not performed.

SCORING SYSTEM:
The reactions observed were scored in accordance with the criteria of Draize (1977).

TOOL USED TO ASSESS SCORE:
Examination of the eye was facilitated by the use of the light source from a standard ophthalmoscope.

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 24, 48 and 72 hours

Score:

1.67

Max. score:

110

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.66

Max. score:

3

Reversibility:

fully reversible within: 72 hours

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 24 hours

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 24 hours

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.33

Max. score:

4

Reversibility:

fully reversible within: 24 hours

Remarks on result:

other: Mean at 24, 48 and 72 hours

Irritant / corrosive response data:

No corneal or iridial effects were noted during the study. Moderate conjunctival irritation was noted in both treated eyes one hour after treatment. Minimal conjunctival irritation was noted in both treated eyes at the 24 hour observation and persisted in one treated eye at the 48 hour observation. One treated eye appeared normal at the 48 hour observation and the other treated eye appeared normal at the 72 hour observation.

Other effects:

Both animals showed expected gain in bodyweight during the study.

Table 3: Results

Animal	No. 1				No. 2
Time after treatment	1 h	24 h	48 h	72 h	1 h	24 h	48 h	72 h
Cornea
Degree of opacity	0	0	0	0	0	0	0	0
Area of cornea involved	0	0	0	0	0	0	0	0
Iris
Iris	0	0	0	0	0	0	0	0
Conjunctivae
Redness	2	1	1	0	2	1	0	0
Chemosis	2	1	0	0	2	1	0	0
Discharge	1	0	0	0	1	0	0	0
Individual total scores	10	4	2	0	10	4	0	0

Initial pain reaction: When the test material was instilled in the eye, the animals were observed to blink a few times within one or two minutes. The initial pain reaction of 1 was given to each animal tested.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the test, the test material only elicited slight reactions in any of the animals during the course of the study that meant the test material does not require classification as an eye irritant.

Executive summary:

The eye irritation potential of the test material was determined in accordance with standardised guidelines OECD 405 and EU Method B.5, in vivo. During the study, 0.1 mL of test material was placed into one eye of each of two rabbits and assessed for up to 72 hours to determine the grade of ocular reaction. No corneal or iridial effects were noted during the study. Moderate conjunctival irritation was noted in both treated eyes one hour after treatment. Minimal conjunctival irritation was noted in both treated eyes at the 24 hour observation and persisted in one treated eye at the 48 hour observation. One treated eye appeared normal at the 48 hour observation and the other treated eye appeared normal at the 72 hour observation. Under the conditions of the test, the test material only elicited slight reactions in any of the animals during the course of the study that meant the test material does not require classification as an eye irritant.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin

A two tiered in vitro testing strategy was adopted to investigate skin irritation and corrosion, both of which are key to addressing this endpoint.

Warren (2013a) determined the potential for the test material to cause skin corrosion using the EPISKIN™ Reconstructed Human Epidermis (RHE) Model. Under the conditions of the test the relative mean viability of treated tissues after exposure for 240, 60 and 3 minutes were, 83.5%, 87.1% and 97.1, respectively. Since all values were ≥ 35% relative to the negative control the test material can be predicted to be non-corrosive.

Similarly, Warren (2013b) determined the potential for the test material to cause skin irritation using the EPISKIN™ Reconstructed Human Epidermis (RHE) Model. Under the conditions of the test, the relative mean viability of the treated tissue was 101.8 % after a 15 minute exposure period. Since the cell viability was > 50% relative to the negative control the test material can be predicted to be non-irritating to the skin.

Both studies were performed under GLP conditions and in line with standardise guidelines. Accordingly they have both been assigned a reliability score of 1 in accordance with the principles for assessing data quality as defined by Klimisch (1997).

Based on these results, it can be concluded that the test material does not cause corrosion or irritation when exposed to the skin. The data is sufficient in addressing this endpoint, negating the need for further in vivo testing.

Eye

The key study (Sanders, 2013) determined the potential for the test material to cause eye irritation in vivo in accordance with GLP and standardised guidelines. The study was assigned a reliability score of 1 in line with the principles for assessing data quality as defined in Klimisch (1997). Under the conditions of the test, the test material only elicited slight reactions in any of the animals during the course of the study, meaning the test material does not require classification as an eye irritant.

The supporting study (Warren, 2013c) determined the eye irritation potential of the test material in vitro, using the SkinEthic Reconstituted Human Corneal model. The study was assigned a reliability score of 2 in line with the principles for assessing data quality as defined in Klimisch (1997). Under the conditions of the study the relative mean viability of the test material treated tissues, after a 10 minute exposure period, was 86.8 %. In accordance with the criteria defined in the study the test material was considered to be a "non-irritant". The result was in good agreement with the findings of the key study and is sufficient to act as supporting data.

Justification for selection of skin irritation / corrosion endpoint:
A two tiered testing strategy was adopted to address this endpoint. Both the corrosivity and irritation studies are important in addressing this endpoint, however, skin irritation potential cannot be assessed on the basis of the information provided in the corrosion study alone. Therefore the skin irritation has been selected to represent this endpoint. Warren (2013b) was performed according to standardised guidelines and under GLP conditions, being assigned a reliability score of 1 in line with Klimisch (1997).

Justification for selection of eye irritation endpoint:
The key study (Sanders, 2013) was performed in vivo, according to standardised guidelines and under GLP conditions. It was assigned a reliability score of 1 in accordance with the criteria outlined in Klimisch (1997), and is considered suitable to be the key study for this endpoint.

Justification for classification or non-classification

Skin

In accordance with with criteria for classification and labelling as defined in Regulation (EC) No. 1272/2008 (CLP) and Directive 67/548/EEC (DSD), the test material does not require classification for skin irritation or corrosion.

Eye

In accordance with the criteria for classification and labelling as defined in Regulation (EC) No. 1272/2008 and Directive 67/548/EEC (DSD), the test material does not require classification for eye irritation.