Hydrocarbons, C18-C24, iso-alkanes <2% aromatics

Endpoint summary

Description of key information

In guideline in vitro and in vivo studies conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics, the substance was not irritating to rabbit skin or eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21-Jul-2014 to 28-Jul-2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 µl water

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 / corrosion parameter:

% tissue viability

Run / experiment:

Time point: 15 minutes

Value:

79

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Remarks:

Basis: percentage of control.

Interpretation of results:

GHS criteria not met

Conclusions:

In vitro and in vivo skin irritation studies were conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GS310) in accordance with OECD test guidelines 439 and 404, respectively, and in compliance with GLP. The in vitro assay did not indicate any skin irritation potential. In the in vivo study, 4-hour dermal exposure to the test substance resulted in very slight erythema in the treated skin areas of the three rabbits which had resolved within 24 hours in two animals and within 72 hours in the other animal. The results of the studies indicated that the substance does not require classification for skin irritation according to the relevant EC and GHS criteria.

Executive summary:

Skin irritation is expressed as the remaining cell viability after exposure to the test substance. The relative mean tissue viability obtained after 15 minutes treatment with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics compared to the negative control tissues was 79%. Since the mean relative tissue viability for the test substance was above 50% after 15 minutes treatment the test substance is considered to be non-irritant.

 

The positive control had a mean cell viability of 21% after 15 minutes exposure. The absolute mean OD₅₇₀(optical density at 570 nm) of the negative control tissues was slightly below laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was less than 7%, indicating that the test system functioned properly.

Reference 2

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

31 July - 10 August 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal Irritation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Japanese Ministry of Agriculture, Forestry and Fisheries (JMAFF), 12 Nohsan, Notification No 8147, April 2011, including the most recent partial revisions.

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

- Source: Charles River France, L’Arbresle Cedex, France
- Age at study initiation: Animals used withihn the study were between 12 and 24 weeks old.
- Weight at study initiation: Body weights were at least 1.5 kg.
- Housing: Animals were housed individually in cages with perforated floors.
- Diet: Free access to pelleted diet for rabbits (Global Diet 2030 from Harlan Teklad, Italy). Hay and wooden sticks were available during the study period.
- Water: Free access to tap water.
- Acclimation period: At least 5 days

Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, approximately 15 room air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study.

IN-LIFE DATES: From: 31 July - 10 August 2014

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

other: Adjacent areas of the untreated skin of each animal served as controls.

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 mL

Duration of treatment / exposure:

Single application.

Observation period:

72 hours.

Number of animals:

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 skin irritation observed in the first animal.

TEST SUBSTANCE PREPARATION
The test substance was applied undiluted as delivered by the sponsor.

TEST SITE
Approximately 24 hours before treatment, the dorsal fur was clipped with electric clippers, exposing an area of approximately 150 square centimeters (10x15 cm). To facilitate scoring, treated skin areas were re-clipped at least 3 hours before the observations.

The test substance was applied to the skin of one flank, using a patch of 2x3 cm.

REMOVAL OF TEST SUBSTANCE
Four hours after the application, the dressing was removed and the skin cleaned of residual test substance using tap water.

OBSERVATIONS
- Mortality/Viability: Twice daily.
- Toxicity: At least once daily.
- Body Weight: Day of treatment (prior to application) and after the final observation.
- Necropsy: No necropsy was performed according to protocol.
- Irritation: The skin reactions were assessed at approximately 1, 24, 48 and 72 hours after the removal of the dressings and test substance. Readings were done under true light using Philips Master TL-5 HO 49 watt/840. The irritation scores and a description of all other (local) effects were recorded. Adjacent areas of the untreated skin of each animal served as controls.

SCORING SYSTEM:
The irritation was assessed according to the numerical scoring system according to OECD 404.

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.66

Max. score:

4

Reversibility:

fully reversible within: 72 h

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Irritation: Four hours exposure to 0.5 mL of Hydrocarbons, C18-C24, isoalkanes, <2% aromatics resulted in very slight erythema in the treated skin areas of the three rabbits. The skin irritation resolved within 24 hours in two animals and within 72 hours in the other animal.

Corrosion: There was no evidence of a corrosive effect on the skin.

Other effects:

Coloration/remnants: No staining of the treated skin by the test substance was observed and no test substance remnants were seen.

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

Interpretation of results:

GHS criteria not met

Conclusions:

In vitro and in vivo skin irritation studies were conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GS310) in accordance with OECD test guidelines 439 and 404, respectively, and in compliance with GLP. The in vitro assay did not indicate any skin irritation potential. In the in vivo study, 4-hour dermal exposure to the test substance resulted in very slight erythema in the treated skin areas of the three rabbits which had resolved within 24 hours in two animals and within 72 hours in the other animal. The results of the studies indicated that the substance does not require classification for skin irritation according to the relevant EC and GHS criteria.

Executive summary:

Primary skin irritation/corrosion study with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics in the rabbit (4-hour semi-occlusive application).

 

The study was carried out based on the guidelines described in:

OECD No.404, "Acute Dermal Irritation/Corrosion" (2002)

EC, No 440/2008; B4: "Acute Toxicity: Dermal Irritation/Corrosion"

US EPA, OPPTS 870.2500 (1998), Acute Dermal Irritation 

JMAFF Guidelines (2000), including the most recent revisions.

 

Three rabbits were exposed to 0.5 mL of Hydrocarbons, C18-C24, isoalkanes, <2% aromatics, by application onto clipped skin for 4 hours using a semi-occlusive dressing. Skin reactions were assessed 1, 24, 48 and 72 hours after exposure.

 

Exposure to Hydrocarbons, C18-C24, isoalkanes, <2% aromatics resulted in very slight erythema in the treated skin areas of the three rabbits which had resolved within 24 hours in two animals and within 72 hours in the other animal.

 

Based on these results Hydrocarbons, C18-C24, isoalkanes, <2% aromatics does not have to be classified and has no obligatory labelling requirement for skin irritation according to the:

- Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011)(including all amendments),

- Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 July - 08 August 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study has been performed according to OECD and/or EC guidelines and according 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 Nohsan, Notification No 8147, April 2011, including the most recent partial revisions.

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

- Source: Charles River France, L’Arbresle Cedex, France
- Age at study initiation: Animals used withihn the study were between 12 and 24 weeks old.
- Weight at study initiation: Body weights were at least 1.5 kg.
- Housing: Animals were housed individually in cages with perforated floors.
- Diet: Free access to pelleted diet for rabbits (Global Diet 2030 from Harlan Teklad, Italy). Hay and wooden sticks were available during the study period.
- Water: Free access to tap water.
- Acclimation period: At least 5 days

Environmental controls for the animal room were set to maintain 18 to 24°C, a relative humidity of 40 to 70%, approximately 15 room air changes/hour, and a 12-hour light/12-hour dark cycle. Any variations to these conditions were maintained in the raw data and had no effect on the outcome of the study.

IN-LIFE DATES: From: 14 July - 08 August 2014

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 applied: 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. Immediately after fluorescein examination on Day 2, in order to provide a continued level of systemic analgesia, buprenorphine 0.01 mg/kg and meloxicam (Metacam®, Boehringer Vetmed GmbH, Ingelheim/Rhein, Germany) 0.5 mg/kg were administered by subcutaneous injection. 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: 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. Readings were done under true light using Philips Master TL-5 HO 49 watt/840. The irritation scores and a description of all other (local) effects were recorded.

SCORING SYSTEM:
The irritation was assessed according to the numerical scoring system according to OECD 405.

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

3

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Irritation: Instillation of 0.1 mL of Hydrocarbons, C18-C24, isoalkanes, <2% aromatics into one eye of each of three rabbits resulted in irritation of the conjunctivae, which consisted of redness and discharge in all animals. The irritation had 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.

Corrosion: There was no evidence of ocular corrosion.

Other effects:

Colouration/Remnants: No staining of (peri) ocular tissues by the test substance was observed and no test substance remnants were seen.

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

Interpretation of results:

GHS criteria not met

Conclusions:

In vitro and in vivo eye irritation studies were conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GS310) in accordance with OECD test guidelines 437 and 405, respectively, and in compliance with GLP. The BCOP test did not indicate an irritancy potential based on either the opacity or permeability endpoints. In the in vivo study, a single instillation of the test substance in three rabbits resulted in redness and discharge in all animals one hour after dosing. The effects were fully resolved 24 hours post-instillation. The results of the studies indicated that the substance does not require classification for skin irritation according to the relevant EC and GHS criteria.

Executive summary:

Acute eye irritation/corrosion study with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics in the rabbit.

The study was carried out based on the guidelines described in:

OECD No.405 (2012) "Acute Eye Irritation / Corrosion"

EC, No 440/2008, B5: "Acute Toxicity: Eye Irritation/Corrosion"

EPA, OPPTS 870.2400 (1998): "Acute Eye Irritation"

JMAFF Guidelines (2000), including the most recent revisions.

 

Single samples of 0.1 mL of Hydrocarbons, C18-C24, isoalkanes, <2% aromatics were instilled into one eye of each of three rabbits. Observations were made 1, 24, 48 and 72 hours after instillation.

 

Instillation of the test substance resulted in irritation of the conjunctivae, which consisted of redness and discharge in all animals. The irritation had completely resolved within 24 hours in all animals.

 

Based on these results, Hydrocarbons, C18-C24, isoalkanes, <2% aromatics does not have to be classified and has no obligatory labelling requirement for eye irritation according to the:

- Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011)(including all amendments),

- Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08-Jul-2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU method B.47 (Bovine corneal opacity and permeability test method for identifying ocular corrosives and severe irritants)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): approx. 750 µl per cornea

NEGATIVE CONTROL
- Amount(s) applied (volume or weight with unit): 750 µl of physiological saline per cornea

POSITIVE CONTROL
Amount(s) applied (volume or weight with unit): 750 µl per cornea
Concentration (if solution): 10% (w/v) Benzalkonium Chloride

Duration of treatment / exposure:

10 minutes

Details on study design:

TEST SITE
- Isolated bovine cornea

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 10 minutes

SCORING SYSTEM:
- After exposure the cornea was thoroughly rinsed to remove the test substance and incubated for 2 hours with fresh medium followed by opacity measurement and the permeability of the corneas was determined after a 90 minutes incubation period with sodium fluorescein.

- The mean opacity and mean permeability values (OD490) were used for each treatment group to calculate an in vitro score:

In vitro irritancy score (IVIS) = mean opacity value + (15 x mean OD490 value).


TOOL USED TO ASSESS SCORE:
- opacitymeter and microplate reader

DATA EVALUATION:
In vitro score range UN GHS
≤ 3 No Category
> 3; ≤ 55 No prediction can be made
>55 Category 1

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean at 10 minutes

Value:

-1.2

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Interpretation of results:

GHS criteria not met

Conclusions:

In vitro and in vivo eye irritation studies were conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GS310) in accordance with OECD test guidelines 437 and 405, respectively, and in compliance with GLP. The BCOP test did not indicate an irritancy potential based on either the opacity or permeability endpoints. In the in vivo study, a single instillation of the test substance in three rabbits resulted in redness and discharge in all animals one hour after dosing. The effects were fully resolved 24 hours post-instillation. The results of the studies indicated that the substance does not require classification for skin irritation according to the relevant EC and GHS criteria.

Executive summary:

The negative control responses of the opacity and permeability values were less than the upper limits of the laboratory historical range indicating that the negative control did not induce irritancy on the corneas.The mean in vitro irritancy score of the positive control (10% (w/v) Benzalkonium Chloride) was 141 and within the historical positive control data range. It was therefore concluded that the test conditions were adequate and that the test system functioned properly.

The test substance did not induce ocular irritation through both endpoints, resulting in a mean in vitro irritancy score of -1.2 after 10 minutes of treatment.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin and eye irritation studies are available for the substance itself and for a number of related substances in the relevant carbon number range.

Skin irritation

In vitro and in vivo skin irritation studies were conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GS310) in accordance with OECD test guidelines 439 and 404, respectively, and in compliance with GLP (WIL Research, 2014a and WIL Research, 2014b). The in vitro assay did not indicate any skin irritation potential. In the in vivo study, 4-hour dermal exposure to the test substance resulted in very slight erythema in the treated skin areas of the three rabbits which had resolved within 24 hours in two animals and within 72 hours in the other animal. The results of the studies indicated that the substance does not require classification for skin irritation according to the relevant EC and GHS criteria.

A skin irritation study was conducted with limited range GTL Kerosine (C8-C12) in accordance with OECD 404 and GLP (Huntingdon Life Sciences Ltd, 1997c). 4-hour semi-occlusive application of undiluted test material caused very slight erythema (Grade 1) in all six animals during the first 72 hours after patch removal, persisting in one animal until day 7. Very slight oedema (Grade 1) was apparent in one animal only, during the first 72 hours after patch removal. The observed effects were not sufficient to require classification for skin irritation according to EC criteria.

A skin irritation study was conducted with full range GTL Paraffin Waxes (C15-C50) in accordance with OECD 404 and GLP (SafePharm, 2008a). 5-hour semi-occlusive application of undiluted test material caused an isolated incident of mild erythema (Grade 1) at the 48-hour observation. The effects were fully resolved by the 72-hour observation and were not sufficient to require classification for skin irritation according to EC criteria.

A skin irritation study was conducted with GTL Base Oil Distillates (C18-C50) in accordance with OECD 404 and GLP (SafePharm 2008b). A 4-hour semi-occluded application of the test material to the intact skin of three rabbits produced no evidence of skin irritation. The test material is classified as a not irritant to rabbit skin according to the Draize classification scheme, and in accordance with EC criteria.

Consideration of skin defatting

Repeated dermal contact with petroleum-derived hydrocarbons causes skin dryness and cracking, and  Hydrocarbons, C18-C24, isoalkanes, <2% aromatics was classified for skin defatting from repeated skin contact: EUH066, based on precaution. To establish whether this classification was justified, a study has been conducted with volunteers to investigate the hydrating efficacy and the skin barrier integrity efficacy of a number of substances in a double-blind, randomised study. The test substances included Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GTL Solvent GS310). The volume applied was 2 µl/cm². A total of ten test substances were tested at two different concentrations, 5% (emulsion in water) and 100%.

Healthy adult volunteers were split into four groups. Five test substances, a placebo, a negative control and, for the skin capacitance measurement, a positive control were applied to eight separate sites, four on each forearm, of each volunteer in the group. Each group had a different set of test substances.

The skin hydration was assessed by measurement of skin capacitance compared with a placebo (Span 80 (0.65%) and Tween 80 (0.20%) in water), a negative control (water), and a positive control. The positive control was an aqueous solution of glycerine at 85%, glycerine is a known moisturiser (Lodén, 2002; Milani, 2017) and not classified for skin defatting from repeated skin contact. Measurement of skin capacitance is a standard method for the assessment of skin hydration (Qassem, 2019).

The skin barrier integrity efficacy was assessed by measurement of the skin transepidermal water loss (TEWL) compared with a placebo (Span 80 (0.65%) and Tween 80 (0.20%) in water) and a negative control (water). Measurement of TEWL is a standard method for the assessment of skin barrier function, increase in TEWL indicates skin irritation (Kovács et al., 2020). A decrease in TEWL indicates enhancement of the barrier function of the skin (Kottner et al., 2015).

Skin hydration and TEWL are related but not co-related indirect measurements for barrier function, where the common denominator is the water content in the corneocytes. TEWL is an indirect measurement for skin defatting, as removal of lipids from the stratum corneum increases water evaporation. Skin hydration, measured by skin capacitance, is improved when alkanes of a certain structure and length integrate withing the fatty acids and ceramides (Uchiyama et al., 2016). A skin emollient cannot be skin defatting at the same time, as these effects are mutually exclusive.

The skin hydration measurements were performed at each test site, in triplicate, before application of the test and control substances, and at 2 hours, 4 hours, 8 hours and 24 hours after application.

The skin transepidermal water loss (TEWL) measurements were performed at the same test sites and time intervals as the skin hydration measurements.

Application of Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (Shell GTL Solvent GS310) resulted in a statistically significant increase in the skin hydration relative to the placebo up to 8 hours after application at concentrations of 5% (emulsion in water) and 100%. 24 hours after application the hydration level had decreased to be close to the baseline level.

Application of Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (Shell GTL Solvent GS310) decreased the TEWL relative to the placebo up to 24 hours after application at a concentration of 100%, indicating an improvement of the skin barrier condition. The TEWL was unchanged after application at a concentration of 5% (emulsion in water).

These results indicate that, after a single application, Hydrocarbons, C18-C24, isoalkanes, <2% is effective as a skin moisturiser and improves the skin barrier by decreasing the transepidermal water loss. Based on these results, it is concluded that the test substance does not require classification for skin defatting from repeated skin contact.

References:

Kottner J., Vogt A., Lichterfeld A., Blume-Peytavi U. (2015) Transepidermal Water Loss in Young and Aged Healthy Humans. In: Farage M., Miller K., Maibach H. (eds) Textbook of Aging Skin. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-27814-3_127-1

Kovács, A., Péter-Héderi, D., Perei, K., Budai-Szűcs, M., Léber, A., Gácsi, A., ... & Berkó, S. (2020). Effects of Formulation Excipients on Skin Barrier Function in Creams Used in Pediatric Care. Pharmaceutics, 12(8), 729.

Lodén, M., Andersson, A. C., Anderson, C., Bergbrant, I. M., Frodin, T., Ohman, H., ... & Lindberg, M. (2002). A double-blind study comparing the effect of glycerin and urea on dry, eczematous skin in atopic patients. Acta Dermato Venereologica, 82(1), 45-47.

Milani, M., & Sparavigna, A. (2017). The 24-hour skin hydration and barrier function effects of a hyaluronic 1%, glycerin 5%, and Centella asiatica stem cells extract moisturizing fluid: an intra-subject, randomized, assessor-blinded study. Clinical, cosmetic and investigational dermatology, 10, 311.

Qassem, M., & Kyriacou, P. (2019). Review of modern techniques for the assessment of skin hydration. Cosmetics, 6(1), 19.

Uchiyama, M., Oguri, M., Mojumdar, E. H., Gooris, G. S., & Bouwstra, J. A. (2016). Free fatty acids chain length distribution affects the permeability of skin lipid model membranes. Biochimica et Biophysica Acta (BBA)-Biomembranes, 1858(9), 2050-2059.

Eye irritation

In vitro and in vivo eye irritation studies were conducted with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GS310) in accordance with OECD test guidelines 437 and 405, respectively, and in compliance with GLP (WIL Research, 2014c and WIL Research, 2014d). The BCOP test did not indicate an irritancy potential based on either the opacity or permeability endpoints. In the in vivo study, a single instillation of the test substance in three rabbits resulted in redness and discharge in all animals one hour after dosing. The effects were fully resolved 24 hours post-instillation. The results of the studies indicated that the substance does not require classification for skin irritation according to the relevant EC and GHS criteria.

An eye irritation study was conducted with limited range GTL Kerosine (C8-C12) in accordance with OECD 405 and GLP (Huntingdon Life Sciences Ltd., 1997d). Instillation of undiluted test material into the rabbit eye produced slight conjunctival redness (Grade 1) in four out of six animals at one and 24 hours after instillation. Iritis (Grade 1) was also apparent in the treated eye of one animal at one hour after exposure. Ocular reactions were present in the remaining two animals. All eyes appeared normal by day 8. The test substance was found to be not irritating to eye. The observed effects were not sufficient to require classification for eye irritation according to EC criteria.

An eye irritation study was conducted with full range GTL Paraffin Waxes (C15-C50) in accordance with OECD 405 and GLP (SafePharm, 2008c). Instillation of undiluted test material into the rabbit eye produced minimal conjunctival irritation (Grade 1) in all treated eyes at the 1 and 48-hour observations. The treated eyes appeared normal at the 24 and 72-hour observations. The test substance was found to be not irritating to eye.

An eye irritation study was conducted with GTL Base Oil Distillates (C18-C50) in accordance with OECD 405 and GLP (SafePharm 2008d). A single application of the undiluted test material to the non-irrigated eye of the three rabbits produced minimal conjunctival irritation. One treated eye appeared normal after the 24 hour observation and the remaining two treated eyes appeared normal at the 48 hour observation. According to guideline (Regulation (EC) No. 1272/2008) the test material does not require classification for eye irritation.

Justification for classification or non-classification

On the basis of in vitro and in vivo data, Hydrocarbons, C18-C24, isoalkanes, <2% aromatics is not classified as irritant to skin, eyes or the respiratory tract.

On the basis of data for Hydrocarbons, C18-C24, isoalkanes, <2% aromatics from human volunteers, classification for skin defatting from repeated skin contact is not required.