Diisodecyl sebacate

Endpoint summary

Description of key information

No standard skin or eye irritation data were available on DIDS, but relevant QSAR assessments predict that DIDS would not be irritating or corrosive to the skin or eyes.
Reliable skin and eye irritation studies have been conducted with DIDA, including a guideline in vitro human skin irritation (EPISKIN) study (Verbaan, 2010) and an in vivo eye irritation study in rabbits (van Otterdijk, 2010a). Supporting data is available from further in vivo skin (rabbits and rats) and eye irritation studies in rabbits. DIDA was not considered irritating to the skin or eyes in any of these investigations.
A lack of irritation potential for DEHS was seen in a reliable in vivo rabbit skin irritation study (EviC-CEBA, 1994b) and a reliable in vitro eye irritation study (MB Research Laboratories, 2003).
Although no data on respiratory irritation was identified on DIDS, it is reasonable to assume such effects are unlikely to occur due to the lack of irritation potential observed in the available skin and eye studies (and QSAR predictions) and its low volatility. In addition, no local toxicity was seen in the lungs of hamsters following an intratracheal administration of DEHS (Brain et al. 1996).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation / corrosion

Remarks:

other: in vitro

Type of information:

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

Adequacy of study:

key study

Study period:

12-Jul-2010 to 19-Jul-2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study on a structurally-related read-across compound has been performed according to OECD and/or EC guidelines and to GLP principles.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Guidelines for Testing of Chemicals, Guideline no. 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

human

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 µl [presumably undiluted]

NEGATIVE CONTOL:
- Amount(s) applied (volume or weight with unit): 10 µl Phosphate buffered saline

POSITIVE CONTROL
- Amount(s) applied (volume or weight with unit): 10 µl
- Concentration (if solution): 5% (aq) Sodium dodecyl sulphate

Duration of treatment / exposure:

Exposure: 15 minutes
Post incubation period: 42 hours

Details on study design:

TEST SITE
- Area of exposure: human epidermis model
- % coverage: 0.38 cm2

REMOVAL OF TEST SUBSTANCE
- Washing (if done): phosphate buffered saline
- Time after start of exposure: 15 minutes

POST INCUBATION PERIOD
- 42 hours

SCORING SYSTEM:
- After a 42 hour incubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT at the end of the treatment. Cell viability was calculated for each tissue as a percentage of the mean of the negative control tissues.

Irritation parameter:

other: percentage viability

Basis:

other: percentage of control

Time point:

other: 15 minutes

Score:

103

Remarks on result:

other: The score relates to the relative mean tissue viability, compared to the negative controls. As such, the maximum score is not applicable and no reversibility assessed.

The positive and negative controls were within the historical control data.

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

In a GLP study, conducted according to OECD Guideline 439, DIDA was not irritating in an in vitro human epidermis (EPISKIN) model

Executive summary:

In a GLP study, conducted according to OECD Guideline 439, the potential of DIDA, a compound that is structurally-related to DIDS, was investigated in vitro in human epidermal keratinocytes (EPISKIN Standard Model^TM).

 

The EPISKIN Standard Model^TM, a three-dimensional human epidermis model, was exposed to 10 μl of [presumably undiluted] DIDA for 15 minutes.

 

After treatment, relative mean tissue viability was 103% of that seen in the negative control. Positive and negative controls performed as expected.

Since the mean relative tissue viability for DIDA was above 50% of that seen for the negative control after 15 minutes treatment, DIDA was not considered to be irritating under the conditions of this test.

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:

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

Adequacy of study:

key study

Study period:

28 June 2010 to 22 July 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study on a read-across compound has been performed according to OECD and/or EC guidelines and to GLP principles.

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

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nousan, Notification No 8147, November 2000, including the most recent partial revisions.

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
- Source: Harlan, Belton, Leics, England
- Age at study initiation: Animals used within the study were at least 6 weeks old
- Weight at study initiation: body weights were at least 1.0 kg.
- Housing: labeled cages with perforated floors (Ebeco, Germany, dimensions 67 x 62 x 55 cm) and shelters (Ebeco, Germany, dimensions 40 x 32 x 23 cm).
- Diet (e.g. ad libitum): Pelleted diet for rabbits (Global Diet 2030 from Harlan Teklad®, Mucedola, Milanese, Italy) approximately 100 grams per day. Hay (TecniLab-BMI BV, Someren, The Netherlands) was provided at least three times a week.
- Water (e.g. ad libitum): Free access to tap water.
- Acclimatization period: at least 5 days before start of treatment under laboratory conditions.

A health inspection was performed prior to commencement of treatment, to ensure that the animals were in a good state of health. Special attention was paid to the eyes, which were free from any abnormality.

Results of analysis for diet (nutrients and contaminants), hay and water were assessed and did not reveal any findings that were considered to have affected the study integrity. All certificates and results of analysis are retained in the NOTOX archives.

Animal specifications (sex, age and body weight) are specified in the attached table.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.2ºC -21.6ºC
- Humidity (%): 43-80%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours darkness per day

IN LIFE DATES: From: 28 June 2010 to 22 July 2010

Vehicle:

unchanged (no vehicle)

Controls:

other: One eye of each animal remained untreated and served as the reference control.

Amount / concentration applied:

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

Duration of treatment / exposure:

Single instillation on Day 1.

Observation period (in vivo):

The eyes of each animal were examined approximately 1, 24, 48 and 72 hours after instillation of the test substance

Number of animals or in vitro replicates:

3 males

Details on study design:

STUDY DESIGN
The study was performed in a stepwise manner and was started by treatment of a single rabbit (sentinel). The two other animals were treated in a similar manner three weeks later, after considering the degree of eye irritation observed in the first animal.

TREATMENT
Each animal was treated by instillation of 0.1 mL of the test substance in the conjunctival sac of one of the eyes after gently pulling the lower lid away from the eyeball. The lids were then gently held together for about one second to prevent loss of the test substance. The other eye remained untreated and served as the reference control.

Immediately after the 24-hour observation, a solution of 2% fluorescein (Merck, Darmstadt, Germany) in water (adjusted to pH 7.0) was instilled into both eyes of each animal to quantitatively determine corneal epithelial damage. Any bright green stained area, indicating epithelial damage, was estimated as a percentage of the total corneal area.

After the final observation, the animals were sacrificed by intra-venous injection of Euthasol® 20% (AST Farma BV, Oudewater, The Netherlands).

REMOVAL OF TEST SUBSTANCE
-Washing (if done): No

OBSERVATIONS
- Mortality/Viability: Twice daily.
- Toxicity: At least once daily.
- Body Weight: Day of treatment (prior to instillation) and after the final observation.
- Necropsy: No necropsy was performed according to protocol.
- Irritation:
The eyes of each animal were examined approximately 1, 24, 48 and 72 hours after instillation of the test substance.
The irritation scores and a description of all other (local) effects were recorded.The irritation was assessed according to the following numerical scoring system. At each observation, the highest scores given were recorded:

CORNEAL IRRITATION
Opacity: degree of density (area most dense taken for reading)
0: No ulceration or opacity (may include slight dulling of normal luster)
1: Scattered or diffuse areas of opacity, details of iris clearly visible
2: Easily discernible translucent area, details of iris slightly obscured
3: Nacreous area, no details of iris visible, size of pupil barely discernible
4: Opaque cornea, iris not discernible through the opacity

Area of cornea involved:
0: No ulceration or opacity
1: One quarter or less but not zero
2: Greater than one quarter, but less than half
3: Greater than half, but less than three quarters
4: Greater than three quarters, up to whole area

IRIS
0: Normal
1: Markedly deepened rugae, congestion, swelling, moderate circumcorneal hyperaemia, or injection, any of these or combination thereof, iris still reacting to light (sluggish reaction is positive)
2: No reaction to light, hemorrhage, gross destruction (any or all of these)

CONJUNCTIVAL IRRITATION
Redness (refers to palpebrae and sclera, excluding cornea and iris):
0: Blood vessels normal
1: Some blood vessels definitely hyperaemic (injected)
2: Diffuse, crimson color, individual vessels not easily discernible
3: Diffuse beefy red

Chemosis (refers to lids and/or nictitating membranes):
0: No swelling
1: Any swelling above normal (includes nictitating membranes)
2: Obvious swelling with partial eversion of lids
3: Swelling with lids about half closed
4: Swelling with lids more than half closed

Discharge:
0: No discharge (may include small amounts observed in inner canthus of normal animals)
1: Any amount different from normal and/or lacrimation
2: Discharge with moistening of the lids and hairs just adjacent to lids
3: Discharge with moistening of the lids and hairs (considerable area around the eye)

Where standard lighting was considered inadequate for observing minor effects, eye examinations were performed using an ophthalmic examination lamp.
In cases of equivocal results when comparing the treated and untreated eyes, the illustrated guide from the Consumer Product Safety Commission, Washington, D.C. 20207 was used for additional control purposes.

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

mean

Time point:

other: 24, 48 and 72 hr.

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

iris score

Basis:

mean

Time point:

other: 24, 48 and 72 hr.

Score:

0

Max. score:

2

Reversibility:

fully reversible

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

mean

Time point:

other: 24, 48 and 72 hr.

Score:

0

Max. score:

3

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: 24, 48 and 72 hr.

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritant / corrosive response data:

Instillation of 0.1 mL of DIDA into one eye of each of three rabbits resulted in redness of the conjunctivae. The irritation completely resolved within 24 hours in all animals.

No iridial irritation or corneal opacity were observed, and treatment of the eyes with 2% fluorescein 24 hours after test substance instillation revealed no corneal epithelial damage.

Individual and mean eye irritation scores are specified in the attached table.

No staining of (peri) occular tissues by the test substance was observed and no test substance remnants were seen.

No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

0.1 ml of undiluted DIDA was not irritating to the eyes of rabbits in a guideline eye irritation study, performed to GLP.

Executive summary:

In a GLP study, conducted according to OECD Guideline 405, the potential for DIDA, which is structurally-related to DIDS, to irritate the eyes was investigated in New Zealand White rabbits.

 

Three males were given a single administration of 0.1 ml of undiluted DIDA to one eye (with the other, untreated, eye acting as a control). Eyes were examined approximately 1, 24, 48 and 72 hours after instillation of the test substance and graded for irritation of the cornea, iris or conjunctiva, discharge and chemosis.

 

Conjunctival redness was seen after administration, but this completely resolved within 24 hours in all animals. Under the conditions of this assay, DIDA was not considered irritating to the eyes of rabbits. Classification as an eye irritant is not warranted under DSD or CLP.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation

No standard skin irritation studies were available on DIDS.

 

A QSAR model (BfR skin irritation/corrosion, with no defined domain) applied using the OECD QSAR Toolbox (OECD, 2012) predicted DIDS to be "not irritating or corrosive to skin". Structural features considered suggestive of a lack of irritation potential included low water and lipid solubility, low vapour pressure, a log Kow above 9, a melting point above 55 °C, surface tension above 62 mN/m and a molecular weight greater than 350 g/mol.

 

Relevant read-across data:

In an in vitro study, conducted to GLP and according to OECD Guideline 439, 10 μl of [presumably 100%] DIDA had no significant adverse effect on the mean tissue viability of a three-dimensional human skin model (EPISKIN Standard Model^TM) following a 15-minute treatment. As the mean relative tissue viability was above 50% of that seen for the control, DIDA was not considered to be irritating under the conditions of this test (Verbaan, 2010).

In vivo, DIDA was not considered irritating following semi-occlusive application to the skin of three albino rabbits for 4 hr. In the 72 hr following treatment, no oedema was observed, and erythema scores [probably out of 4] ranged from 0-1 (and were fully reversible) (EviC-CEBA, 1994a). Similarly, DIDA was not considered irritating to rat skin over the course of a [presumably 12 -day] non-guideline study (pre-dating GLP) in which DIDA was applied under occlusion to the skin of three females on six alternate days (Conning, 1970).

 

DEHS and DOS have demonstrated a lack of skin irritation potential in vivo. In a reliable study, DEHS was not irritating when applied undiluted to the skin of three rabbits for 4 hr (EviC-CEBA, 1994b) and DOS was not irritating when applied undiluted to the skin of 15 to 30 human subjects for 48 hr (Mallette and Von Haam, 1952a,b).

 

Eye irritation

No standard eye irritation studies were available on DIDS.

 

A QSAR model (BfR eye irritation/corrosion, with no defined domain) applied using the OECD QSAR Toolbox (OECD, 2012) predicted DIDS to be "not irritating or corrosive to [the] eye". Structural features suggesting a lack of irritation potential included low water and lipid solubility, a log Kow above 9, a melting point above 55 °C and a molecular weight greater than 350 g/mol.

 

Relevant read-across data:

In a GLP study, conducted according to OECD Guideline 405, the potential for DIDA to irritate the eyes was investigated in New Zealand White rabbits. Following an application of 0.1 ml of undiluted DIDA, only conjunctival redness was seen (which resolved within 24 hr). DIDA was not considered irritating (van Otterdijk, 2010a). A similar (pre-GLP) study on Dutch rabbits saw no irritation following treatment with a "drop" of undiluted DIDA (Conning, 1970).

A cream containing 1.2% DEHS was non-irritating in a reliable in vitro EpiOcular MTT viability assay. The ET₅₀ (time for tissue viability to be reduced by 50%) was 484.9 min (MB Research Laboratories, 2003).

Respiratory irritation

No data on respiratory irritation were identified on DIDS. However, it is reasonable to assume that such effects are unlikely to occur due to the lack of irritation potential predicted in QSAR for DIDS, and the reassuring available skin and eye studies (and QSAR predictions) on DIDA, DOS and DEHS. No adverse effects were seen in an acute in vivo inhalation study with DEHS (see below). In addition, DIDS is unlikely to vaporise due to its low volatility and high boiling point, limiting the possibility for respiratory exposure during normal conditions of use.

 

Relevant read-across data:

Three different samples of DEHS (one fresh, the second heated to 170 °C and collected from a boiler, and the third taken from a deposit of aerosolised DEHS) were instilled intratracheally at a concentration of 2.5% into the lungs of groups of 6 hamsters (resulting in a dose of about 37.5 mg/kg bw). The inhalation exposure of the treated and controls animals also contained about 13.3 mg/ml of surface-active material (SAM). About 24 hr later, animals were killed and assessed for markers of inflammation, oedema, bleeding, macrophage phagocytosis, cell injury and cell secretion. No significant changes were observed in the lungs of treated hamsters compared to those from controls given saline and SAM (Brain et al. 1996).

 

References

Brain JD, Blanchard JD, Heyder J, Wolfthal SF and Beck BD (1996). Relative toxicity of di(2-ethylhexyl) sebacate and related compounds in anin vivohamster bioassay. Inhalation Toxicology 8, 579-593.

 

EviC-CEBA (1994b). Attestation of biological significance (acute oral toxicity and dermal irritation) on diethylhexyl sebacate. Study ref. T 207/4072. Unpublished data submitted by the Council (2 pp). 4-7-1994 (cited in CIR, 2010).

 

Mallette FS and von Haam E (1952a). Studies on the toxicity and skin effects of compounds used in the rubber and plastics industries. I. Accelerators, activators, and antioxidants. AMA Archives of Industrial Hygiene and Occupational Medicine 5, 311-317.

 

Mallette FS and von Haam E (1952b). Studies on the toxicity and skin effects of compounds used in the rubber and plastics industries. II. Plasticizers. AMA Archives of Industrial Hygiene and Occupational Medicine 6, 231-236.

 

MB Research Laboratories (2003). EpiOcular MTT viability assay of a cream containing 1.2% diethylhexyl sebacate (cited in CIR, 2010).

Justification for selection of skin irritation / corrosion endpoint:
OECD guideline study conducted to GLP on a read-across compound.

Justification for selection of eye irritation endpoint:
OECD guideline study conducted to GLP on a read-across compound.

Justification for classification or non-classification

QSAR analysis predicted that DIDS is not irritating or corrosive to the skin or eyes. In addition, reliable in vitro and in vivo studies with DIDA show that it lacks skin and eye irritation potential, and a study on DEHS indicates a lack of local effects on the lungs. On this basis, DIDS does not require classification as a skin, eye or respiratory irritant according to EU CLP Regulation (EC) 1272/2008 or the DSD (67/548/EEC).