Palm oil, epoxidized

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

key study

Study period:

January 22, 1981 - February 4, 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

[May not be GLP compliant. Control animals were not mentioned. As no signs of toxicity were seen in 10 rats it is safe to assume that Soybean oil, epoxidised is not toxic therefore this deviation should not be an issue.] This read-across is based on the hypothesis that source and target substances have similar toxicological properties because of their structural similarities and they are assumed to have similar toxicokinetic profiles i.e. they are expected to be metabolised in a similar fashion. The target substance Epoxidized Palm Oil (EPO) and source substance Epoxidized Soybean Oil (ESBO) are derived respectively from their raw materials, palm oil and soybean oil, and are of variable composition consisting of fatty acid triglycerides. Both EPO and ESBO are organic UVCB sub-type 1: substances of biological nature that have been modified in chemical processing. Both are manufactured by the reaction of the respective oils with an epoxidizing agent (50-60% hydrogen peroxide at 60-75°C). The olefinic bonds of the oils are converted to epoxy oxirane groups. As Palm oil has lower unsaturated bonds than Soybean Oil, less of the epoxidizing agent hydrogen peroxide is required and thus EPO has a lower epoxidized adduct content than ESBO and is therefore expected to be less chemically reactive. The % epoxidation in ESBO is 6-8% while the % epoxidation in EPO is 2.5-3.5%. The target substance (EPO) and source substance (ESBO) have a structurally similar backbone which is an epoxidized triglyceride structure derived from one glycerol molecule and three fatty acid molecules. Therefore, the source and the target substances share structural similarities with common functional groups and side chains varying in their length and the amount of epoxide groups. The target substance contains 8 fatty acids with the largest components being C16:0 palmitic acid (44%), C18:1 oleic acid (39.2%) and C18:2 linoleic acid (10.1%). The source substance contains 5 fatty acids with the largest components being C16:0 palmitic acid (11.3%), C18:1 oleic acid (39.2%) and C18:2 linoleic acid (55.8%). ESBO does not contain lauric (C12), myristic (C14) and arachidic (C20) acids while they are present in very low amounts in EPO (0.2, 1.1 and 0.3% respectively). Stearic acid (C18:0) is present in both substances at similar levels (4.5% in EPO and 3.4% in ESBO) while α-linolenic acid (C18:3) is present at 0.4% in EPO and 6.4% in ESBO. So, the main component of the triglyceride structure of both EPO and ESBO is C16 (44%; 11.3%) and C18 (54.2%; 88.7%). The data gap for the target substance EPO is an acute oral toxicity study (Annex VII, 8.5.1). No reliable data on acute oral toxicity of EPO is available. Therefore, read-across from an existing acute oral toxicity study of the source substance, ESBO, is considered as an appropriate adaptation to the standard information requirements of Annex VII 8.5.1 of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

no guideline available

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

Conduct of the study predates formal adoption of the test guideline but in principle the OECD 401 limit method was followed. No vehicle control animals were included. The vehicle, designated PAG in the report, was not tested separately.

Principles of method if other than guideline:

Although pre-dating the formal guideline, the study was conducted in general concordance with a limit test as described in OECD method 401. The vehicle selected was described as PAG with no elucidation. It is assumed that it was polyethylene glycol (PEG), which was comonly used for acute gavage administration and this would explain the absence of a separate vehicle control group.

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Soybean oil, epoxidized

EC Number:

232-391-0

EC Name:

Soybean oil, epoxidized

Cas Number:

8013-07-8

IUPAC Name:

8013-07-8

Details on test material:

- Name of test material (as cited in study report): TK 11278
- Physical state: Liquid
- Lot/batch No.: prod. Oct. 80


Before treatment the suspension was homogeneously dispersed with an Ultra-Turrax and during treatment it was kept stable with a magnetic stirrer.
The test material was dispersed in PAG - probably polyethylene glycol (PEG) and administered in a dose volume of 20 mL/kg bw.

Test animals

Species:

rat

Strain:

other: Tif: RAIf (SPF) Strain

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Healthy random bred rats of the Tif:RAIf (SPF) strain , which were raised on the Ciba-Geigy Ltd, Basle, laboratory premises
- Age at study initiation: 7 to 8 weeks old
- Weight at study initiation: male mean = 185g; female mean = 174g
- Fasting period before study: rats were fasted overnight prior to treatment
- Housing: in groups of 5 in Macrolan cages
- Diet (e.g. ad libitum): NAFAG, Gossau SG
- Water (e.g. ad libitum): potable water source not specified in report
- Acclimation period: 4 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 55 ± 10 %
- Air changes (per hr): Not specified
- Photoperiod (hrs dark / hrs light): 14/10

IN-LIFE DATES: From: 22 January 1981 To: 4 February 1981

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: PAG. Assumed to be PEG = polyethylene glycol

Details on oral exposure:

The report indicates PAG was used as a vehicle (it is assumed this is a typographical error and that PEG, polyethylene glycol was actually used).
The test material was dispensed at 20 ml/kg bw.

Animals were fasted overnight and treated by single oral intubation.

Doses:

5000 mg/kg

No. of animals per sex per dose:

5 animals per group

Control animals:

not specified

Details on study design:

Bodyweights were recorded immediately prior to dosing and after 7 and 14 days. Physical condition and mortality were monitored throughout the observation period.

Statistics:

LD50 including 95 % confidence limits are calculated by the logit model.

Results and discussion

Preliminary study:

Not relevant

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: No confidence intervals or median lethal dose calculated for the 5g/kg bw limit test

Mortality:

None of the rats died

Clinical signs:

other: See Table 2 below Evidence of slight dyspnoea, slightly ruffled fur, slight diarrhoea and a slightly curved body position were noted primarily on Day 1 (1-24 h after administration). Some cases of ruffled fur and curved body position persisted on days 2

Gross pathology:

No gross organ changes were observed

Other findings:

No further information supplied

Any other information on results incl. tables

Table 1: Bodyweight change

	Dose – 5000 mg/kg
	Mean (g)	Standard Deviation (g)
Day 1 (Male)	185	1.8
Day 1 (Female)	174	1.2
Day 7 (Male)	236	5.1
Day 7 (Female)	186	1.8
Day 14 (Male)	289	5.7
Day 14 (Female)	215	2.9

  

Table 2: Clinical Signs

Dose – 5000 mg/kg

Signs and Symptoms

Hours

Days

1

2

3

5

24

2

3

4

5

6

7

8

9

10

11

12

13

14

Sedation

Dyspnoea

+

+

Dacryorrhoea

Chromodacryorrhoea

Rinorrhoea

Epistaxis

Exophthalmos

Salivation

Ruffled fur

+

+

+

+

+

+

+

+

Pallor

Cyanosis

Diarrhoea

+

+

+

Body Position (ventral)

Body Position (lateral)

Body Position (curved)

+

+

+

+

+

+

Ataxia

Trismus

Tremor

Tonic clonic muscle spasms

Convulsions

 + = slight

Read-Across Justification: Full report is attached in study summary

3 Analogue approach justification

3.1. Physicochemical properties

Physicochemical data shows that the physicochemical properties of the target and source substances are similar as outlined in the data matrix (Table 3). Both are liquids and the structural differences in the side chains do not significantly influence the physicochemical properties of both substances, i.e. vapour pressure, water solubility and partition co-efficient (log Pow). Both substances are highly insoluble in water; <0.01 mg/L at 30°C for EPO and <0.02 µg/L at 20°C (calculated) for ESBO. Neither of the substances is volatile, with a vapour pressure of 0.5 kPa at 25°C for EPO and 8.4 x 10-8 Pa at 25°C for ESBO. Both substances are highly lipophilic; mean Log Pow >6.2 at 25°C for ESBO and log Pow >10 (calculated) for EPO.

3.2. Toxicokinetics

No specific experimental data on absorption, distribution, metabolism or excretion is available for the source or target substance. Read-across was performed for all human health toxicity endpoints to Epoxidised Soybean Oil (ESBO, CAS No. 8013-07-8). An OECD SIDS report is available that concluded on a proposed metabolic pathway for epoxidised fatty acid esters, including ESBO (OECD, 2006). The toxicokinetic analysis is based on physicochemical data from EPO, read-across ESBO data from in vivo animal models and the OECD SIDS report in the literature (OECD, 2006).

Physicochemical data

The molecular weight of EPO and ESBO is > 500 g/mol and is not in the range for favourable oral absorption (<500 g/mol). The calculated log Pow of EPO (>10) and mean Log Pow >6.2 at 25°C for ESBO indicate they are highly lipophilic and water solubility (<0.01 mg/L at 30°C) for EPO and <0.02 µg/L at 20°C (calculated) for ESBO indicates they are both insoluble in water. These characteristics will not facilitate transport of EPO or ESBO via passive diffusion. Based on its high lipophilicity, absorption of EPO and ESBO via the lymphatic system through micellular solubilisation by bile salts is likely, similar to other vegetable oils. Insolubility in water of both EPO and ESBO indicates low dermal uptake while the high log Pow values for both are an indication for a high uptake into the stratum corneum but little or no penetration into the lower layers of the epidermis and dermis. Overall, the physical state, molecular weight, calculated log Pow and water insolubility indicate that dermal absorption of EPO and ESBO is unlikely. Due to the low vapour pressure of EPO (0.5 kPa at 25°C) and ESBO (8.4 x 10-8 Pa at 25°C) and physical state (liquid), exposure via the inhalation route of both is expected to be negligible. Based on the information available for the analogue ESBO in the OECD SIDS report (OECD, 2006; see ‘Other data in the literature’), during metabolism, breakdown products are produced that are more water soluble than the parent substance i.e. free fatty acids, so it is expected that any EPO metabolites will be excreted in the urine.

Other data in the literature

The OECD produced a report on Epoxidised Oils and Derivatives in 2006 (OECD, 2006), which included ESBO. The OECD SIDS concluded that epoxidised fatty acid esters, such as ESBO and therefore we assume EPO, produce metabolic products with similar primary constituents as other vegetable oils and are assumed to have similar metabolic pathways e.g. breakdown in the gastrointestinal tract by esterases (pancreatic lipase) to epoxidised fatty acids and glycerol which enter the normal nutritional pools (JECFA, 1974). Pancreatic lipase works at the oil/water interface since triglycerides are insoluble. During metabolism in the GI tract, pancreatic lipase preferentially hydrolyses triglycerides to release the free fatty acids from the SN-1 and SN-3 (terminal) positions of the glycerol backbone. The other products of metabolism are mono- and di-glycerides (OECD, 2006). The EFSA Panel on Contaminants in the Food Chain agreed with this assessment for ESBO in 2011 (EFSA, 2011). Overall, the proposed metabolic pathway for ESBO is enzymatic breakdown to epoxidised fatty acids and glycerol; a similar pathway is predicted for EPO. Based on the information available for the analogue ESBO in the OECD SIDS report, during metabolism, breakdown products are produced that are more water soluble than the parent substance i.e. free fatty acids, so it is expected that any EPO metabolites will be excreted in the urine.

Available in vivo toxicological data

The in vivo read-across data from ESBO indicate no adverse effects if oral absorption occurs (acute oral LD50 of >5,000 mg/kg (3), 2 year combined chronic/carcinogenicity toxicity study NOEL (male) of 1000 mg/kg bw/day and NOEL (female) of 1400 mg/kg bw/day (13), pre-natal developmental toxicity maternal/developmental NOAEL of 1000 mg/kg bw/day (14). The in vivo read-across data from ESBO indicates is poorly absorbed via the dermal route (slightly irritating in the in vivo skin irritation study in rabbits (6) and non-sensitising in Guinea pig maximization test (8)). Any significant dermal absorption is unlikely.

3.3. Comparison of data from human health endpoints

3.3.1 Toxicity data of the target and source substances

There is no existing human health toxicity data for the target substance, EPO. As is presented in the data matrix (Table 3), the dermal toxicity data (LD50 >20mL/kg bw) shows very low toxicity for the source chemical, ESBO, in rabbits. The source chemical is slightly irritating to skin and eye in rabbits. The source substance is not a skin sensitizer in the guinea pig maximization test. In the in vitro bacterial reverse mutation study (Ames test), in vitro chromosomal aberration study and in vitro gene mutation study in mammalian cells, the source substance ESBO was negative in the presence and absence of metabolic activation. The source substance ESBO is not genotoxic. In a 2 year combined chronic toxicity/carcinogenicity study in rats for 104 weeks, a NOEL value of 1000 mg/kg bw/day (male) and 1400 mg/kg bw/day (female) was derived. In a pre-natal developmental toxicity study in rats, the NOAEL (maternotoxic, embryofetal) was 1000 mg/kg bw/day with no adverse effects noted. In accordance with Column 2 of ANNEX IX of the REACH Regulation, a two generation reproductive toxicity study does not need not to be conducted as the existing read across combined chronic toxicity/carcinogenicity study from ESBO is available and does not indicate clear adverse effects on reproductive organs or tissues.

The data gap for the target substance EPO is an acute oral toxicity study (Annex VII, 8.5.1). No reliable data on acute oral toxicity of EPO is available. Therefore, read-across from an existing acute oral toxicity study of the source substance, ESBO, is considered as an appropriate adaptation to the standard information requirements of Annex VII 8.5.1 of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation. The read-across oral acute toxicity study (RL2) was conducted according to a guideline that was equivalent or similar to OECD 401. In the study, ESBO was administered to male and female Tif: RAIf (SPF) rats (5/group) at 5000 mg/kg bw in a limit test. There were no mortalities. Mild clinical signs were noted (slight dyspnoea, slightly ruffled fur, slight diarrhoea and a slightly curved body position) on Day 1 with some cases of ruffled fur and curved body position persisting on days 2 to 4. No gross organ changes were noted. The LD50 (male/female) > 5000 mg/kg bw. An LD50 of >5000 mg/kg bw is also predicted for EPO.

3.3.2 Effect of structural differences between target and source chemical

The target substance consists of 8 fatty acids with the largest components being C16:0 palmitic acid (44%), C18:1 oleic acid (39.2%) and C18:2 linoleic acid (10.1%). The source substance consists of 5 fatty acids with the largest components being C16:0 palmitic acid (11.3%), C18:1 oleic acid (39.2%) and C18:2 linoleic acid (55.8%). ESBO does not contain lauric, myristic and arachidic acids while they are present in very low amounts in EPO (0.2, 1.1 and 0.3% respectively). Stearic acid is present in both substances at similar levels (4.5% in EPO and 3.4% in ESBO) while α-linolenic acid is present at 0.4% in EPO and 6.4% in ESBO. So, the main component of the triglyceride structure of both EPO and ESBO is C16 (44%; 11.3%) and C18 (54.2%; 88.7%). When these epoxidized fatty acid products are released during metabolism (see Section 3.2) they are not expected to have any adverse effects in the body as all are naturally occurring fatty acids and they are all ‘Not Classified’ in the ECHA Classification and Labelling (C&L) inventory (checked 24-08-15). The only exception is α-linolenic acid which is indicated as a skin sensitizer but this is not relevant to ESBO and EPO as the former is negative in the guinea pig maximization test and EPO is also predicted to be negative also. The main structural difference is that palm oil has lower unsaturated bonds than soybean oil therefore less of the epoxidizing agent hydrogen peroxide is required to produce the epoxidized derivatives. EPO has a lower epoxidized adduct content than ESBO and is therefore expected to be less chemically reactive. The % epoxidation in ESBO is 6-8% while the % epoxidation in EPO is 2.5-3.5%.

3.3.3 Classification and labelling

According to the ECHA Classification and Labelling (C&L) inventory, the source substance, ESBO, is ‘Not Classified’ (647 notifiers, joint entry; checked 24-08-15). The target substance, EPO, is not listed in the C&L inventory (checked 24-08-15). Based on the read-across acute oral toxicity study presented for the source substance, EPO does not need to be classified for acute toxicity or STOT-SE when the criteria outlined in Annex I of 1272/2008/EC are applied.

4. Conclusion

The structural similarities between the source and the target substances and estimated similar toxicokinetics presented above support the read-across hypothesis. The structural differences between the target and source substance are not expected to have an impact on the prediction. Adequate, reliable and available scientific information indicates that using the source substance for read across to the target substance is acceptable.

Therefore, based on the considerations above, it can be concluded that the acute oral toxicity study conducted in rats with ESBO is likely to predict the acute oral toxicity of EPO and is considered as adequate to fulfill the information requirement of Annex VII 8.5.1.

The data matrix is in Section 5 of the full report attached in the study summary.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute oral LD50 of TK 11'278 in rats of both sexes observed over a period of 14 days is greater than 5000 mg/kg. The test material is therefore practically non toxic to the rat by this route of administration. According to Directive 67/548/EEC, no classification is warranted. According to Regulation (EC) No. 1272/2008, no classification is warranted.

Executive summary:

The acute oral LD50 of TK 11'278 in rats of both sexes observed over a period of 14 days is greater than 5000 mg/kg. The test material is therefore practically non toxic to the rat by this route of administration. According to Directive 67/548/EEC, no classification is warranted. According to Regulation (EC) No. 1272/2008, no classification is warranted.