Fatty acids C16-18 (even numbered), mono and di esters with Sucrose

Endpoint summary

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Objective of study:

metabolism

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Sucrose esters were added to artificial gastric juice at a concentration or 0.4 or 1.25 mg/mL and incubated for up to 5 hrs. HPLC was then used to analyze the amount of sucrose esters degraded by the artificial gastric juice.
- Short description of test conditions: The artificial gastric juice had a pH of 1.2, and the incubation was done at 37 degrees C.
- Parameters analysed / observed: HPLC was then used to analyze the amount of sucrose esters degraded by the artificial gastric juice.

GLP compliance:

yes

Radiolabelling:

no

Species:

other: artificial gastric juice

Details on test animals or test system and environmental conditions:

Artificial gastric juice with a pH of 1.2.

Dose / conc.:

0.4 other: mg/mL artificial gastric juice

Remarks:

Sucrose monopalmitate and sucrose monostearate

Dose / conc.:

1.25 other: mg/mL artificial gastric juice

Remarks:

S-1170

Type:

metabolism

Results:

Very little of the test substance was broken down by artificial gastric juice with 81.7-99.8% of the sucrose ester remaining after 5 hrs.

81.7% of sucrose monopalmitate remained after 5 hrs incubation in the artificial gastric juice, and 85% of sucrose monostearate remained after 5 hrs incubation. In the experiment done with S-1170, the compound most broken down by the artificial gastric juice was sucrose monopalmitate at 82.7% remaining, and the compound least broken down by artificial gastric juice was sucrose diester with 99.8% remaining after 5 hrs of incubation.

Conclusions:

Small amounts of sucrose esters are digested by the stomach, but most is transported to the duodenum and small intestine without being degraded.

Executive summary:

Sucrose esters were added to artificial gastric juice at a concentration or 0.4 or 1.25 mg/mL and incubated for up to 5 hrs. HPLC was then used to analyze the amount of sucrose esters degraded by the artificial gastric juice. 81.7 -99.8% of the test substance was not degraded by the artificial gastric juice, thus indicating that most of the sucrose esters pass into the duodenum and small intestine unchanged.

Reference 2

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Objective of study:

absorption

excretion

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: The absorption of sucrose esters was determined in a study using dogs.
- Short description of test conditions: Three male dogs were given a single dose of 50 mg/kg bw of test substance. Seven days later, they were given a single dose of 250 mg/kg bw. Twelve days after that, they were given a single dose of 1250 mg/kg bw. All doses were given orally in a gelatin capsule.
- Parameters analysed / observed: Blood was drawn at specified intervals before and after dosing to determine the absorption kinetics of the test substance.

GLP compliance:

yes

Radiolabelling:

no

Species:

dog

Strain:

Beagle

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Ridgian Farms, Inc.
- Age at study initiation: 10-12 months
- Weight at study initiation: 9.7-10.2 kg
- Diet: animals were fasted 15 hrs prior to dosage
- Water: tap water ad libitum

Route of administration:

oral: capsule

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: The appropriate amount of test substance was placed in a 1/2 oz gelatin capsule.

Duration and frequency of treatment / exposure:

A single dose of 50 mg/kg bw of test subtance was given. 7 days later a single dose of 250 mg/kg bw was administered, and 12 days after that a single dose of 1250 mg/kg bw was given.

Dose / conc.:

50 mg/kg bw/day (nominal)

Remarks:

8.82 mg/L sucrose monopalmitate
20.58 mg/L sucrose monostearate

Dose / conc.:

250 mg/kg bw/day (nominal)

Remarks:

44.1 mg/L sucrose monopalmitate
102.9 mg/L sucrose monostearate

Dose / conc.:

1 250 mg/kg bw/day (nominal)

Remarks:

220.5 mg/L sucrose monopalmitate
514.5 mg/L sucrose monostearate

No. of animals per sex per dose / concentration:

3

Control animals:

no

Details on dosing and sampling:

TOXICOKINETIC / PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: plasma
- Time and frequency of sampling: immediately before dosage, and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, and 48 hrs after
- Method type(s) for identification: GC

Type:

absorption

Results:

The highest blood plasma concentration for sucrose monopalmitate was 0.60 µg/mL, and the highest concentration of sucrose monostearate was 1.4 µg/mL.

Key result

Toxicokinetic parameters:

Tmax: 4.7 hrs for sucrose monopalmitate

Key result

Toxicokinetic parameters:

Tmax: 7.3 hrs for sucrose monostearate

Key result

Toxicokinetic parameters:

half-life 1st: 2.5-5.6 hrs sucrose monopalmitate

Key result

Toxicokinetic parameters:

half-life 1st: 7.2-7.3 hrs for sucrose monostearate

Key result

Toxicokinetic parameters:

AUC: 0.22 - 5.10 µg * hr/mL

Remarks:

sucrose monopalmitate

Key result

Toxicokinetic parameters:

AUC: 1.76-15.38 µg * hr/mL

Remarks:

sucrose monostearate

Metabolites identified:

not measured

Table of Results

	50 mg/kg bw	250 mg/kg bw	1250 mg/kg bw
Oral intake of sucrose monopalmitate (mg/kg bw/day)	8.82	44.1	220.5
Oral intake of sucrose monostearate (mg/kg bw/day)	20.58	102.9	514.5
Plasma concentation of sucrose monopalmitate 48 hrs after exposure	Not detected	Not detected	Not detected
Plasma concentation of sucrose monostearate 48 hrs after exposure (µg/mL)	0.02 +/- 0.01	0.01 +/- 0.02	0.02 +/- 0.01
Cmax of sucrose monopalmitate (µg/mL)	0.06 +/- 0.03	0.27 +/- 0.08	0.60 +/- 0.78
Cmax of sucrose monostearate (µg/mL)	0.12 +/- 0.07	0.52 +/- 0.16	1.14 +/- 0.78
Tmax of sucrose monopalmitate (hr)	3.3 +/- 2.3	4.0 +/- 3.5	4.7 +/- 1.2
Tmax of sucrose monostearate (hr)	3.3 +/- 2.3	4.7 +/- 3.1	7.3 +/- 0.9
T1/2 of sucrose monopalmitate (hr)	--	2.5 +/- 0.9	5.6 +/- 3.0
T1/2 of sucrose monostearate (hr)	--	7.2 +/- 3.6	7.3 +/- 0.9
AUC(0 -infinity) sucrose monopalmitate (µg*hr/mL)	0.22 +/- 0.10	1.37 +/- 0.59	5.10 +/- 1.80
AUC (0 -infinity) sucrose monostearate (µg*hr/mL)	1.76 +/- 1.00	5.03 +/- 2.13	15.38 +/- 8.60

Conclusions:

Only trace amounts of the test substance were absorbed unchanged from the gastrointestinal tract.

Executive summary:

The absorption of sucrose esters was determined in a study using dogs. Three male dogs were given a single dose of 50 mg/kg bw of test substance. Seven days later, they were given a single dose of 250 mg/kg bw. Twelve days after that, they were given a single dose of 1250 mg/kg bw. All doses were given orally in a gelatin capsule. Blood was drawn at specified intervals before and after dosing to determine the absorption kinetics of the test substance. Maximum blood plasma concentrations were noted at 4.7 -7.3 hrs after dosing. Only trace amounts of the test substance were absorbed unchanged from the gastrointestinal tract.

Reference 3

Endpoint:

basic toxicokinetics in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Objective of study:

absorption

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: In order to assess which part of the digestive tract degrades sucrose esters, an in vitro study was performed in which 5, 25, or 50 mg sucrose esters/ 10 mL of intestinal flora culture were incubated at 37 degrees C for 5 hours.
- Parameters analysed / observed: The residual amount of sucrose esters was determined by HPLC.

GLP compliance:

yes

Radiolabelling:

no

Species:

other: Human intestinal flora

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Intestinal Flora Laboratory, The Calpis Food Industry Co., Ltd., Kanagawa, Japan

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 37

Duration and frequency of treatment / exposure:

5 hrs

Dose / conc.:

5 other: mg/ 10 mL human intestinal flora culture

Remarks:

0.05% w/v

Dose / conc.:

25 other: mg/ 10 mL human intestinal flora culture

Remarks:

0.25% w/v

Dose / conc.:

50 other: mg/ 10 mL human intestinal flora culture

Remarks:

0.5% w/v

Type:

absorption

Results:

The residual amount of sucrose ester was 31.5-48.1%

Details on absorption:

Only 15-19% of sucrose monopalmitate was retained, whereas 35-47% of sucrose monostearate was retained. 30-55% of the sucrose triester was retained, whereas 35-66% of sucrose triester was retained. These results show that palmitate esters are more easily metabolized than the stearate esters, and that the higher the degree of esterification, the less metabolization there is. These results suggest the intestinal flora is highly involved in the degradation of sucrose esters.

Residue after Incubation (%)

	Pre-incubation	0.05%	0.25%	0.50%
Sucrose Monopalmitate	100.0	18.9	15.1	15.1
Sucrose Monostearate	100.0	46.8	35.2	38.2
Sucrose Diester	100.0	65.8	34.6	35.9
Sucrose Triester	100.0	52.7	36.6	30.3
Total	100.0	48.1	31.5	32.5

Conclusions:

Sucrose esters are mostly degraded by the intestinal flora.

Executive summary:

In order to assess which part of the digestive tract degrades sucrose esters, an in vitro study was performed in which 5, 25, or 50 mg sucrose esters/ 10 mL of intestinal flora culture were incubated at 37 degrees C for 5 hours. The residual amount of sucrose esters was then determined by HPLC. Results show that sucrose esters are mostly degraded by the intestinal flora (50 -70%).

Reference 4

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Objective of study:

absorption

distribution

excretion

metabolism

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: The absorption, distribution, metabolism, and excretion of sucrose stearate esters were studied in a radiolabeled study.
- Short description of test conditions: A single oral dose of sucrose monostearate or sucrose distearate was given to male rats.
- Parameters analysed / observed: Blood plasma, urine, feces, and expired air were collected from the test animals. Organ tissues were also analyzed for the amount of radiolabeled substance absorbed.

GLP compliance:

yes

Radiolabelling:

yes

Species:

rat

Sex:

male

Route of administration:

oral: unspecified

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Sucrose was reacted with 1-14C methyl stearate to produce sucrose monostearate and sucrose distearate which was then purified.

Duration and frequency of treatment / exposure:

Single dose

Dose / conc.:

100 mg/kg bw (total dose)

No. of animals per sex per dose / concentration:

3

Control animals:

no

Details on study design:

- Dose selection rationale: Based on previous rat metabolism study

Details on dosing and sampling:

TOXICOKINETIC / PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine, faeces, blood, plasma, expired air, bile; tissues - cerebrum, cerebellum, hypophysis, harderian gland, eyeball, parotid gland, submaxillary gland, thyroid, thymus, heart, lung, liver, adrenal, kidney, spleen, pancreas, mesenteric lymph node, fat, brown fat, muscle, skin, prostate gland, testis, stomach, small intestine, caecum, large intestine
- Time and frequency of sampling: blood - 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 24, 48, 72, 120, 168 hrs after dosing; expired air - 4, 8, 24, 48, 72, 120, 168 hrs after dosing; urine - 8, 24, 48, 72, 120, 168 hrs after dosing; feces - 24, 48, 72, 120, 168 hrs after dosing; tissues - 168 hrs after dosing

Statistics:

Mean and standard deviation

Type:

excretion

Results:

Total excretion of sucrose monostearate in the urine feces and air was 60.9% in 24 hrs.

Type:

excretion

Results:

Total excretion of sucrose distearate in the urine, feces and air was 76.9% in 24 hrs.

Type:

absorption

Results:

17.9% of sucrose monostearate was retained in the carcass.

Type:

absorption

Results:

9.2% of sucrose distearate was retained in the carcass.

Details on absorption:

The peak absorption was 12. 0 µg eq./mL for sucrose monostearate, and 8.36 µg eq./mL for sucrose distearate at 3 hrs after dosing.

Details on distribution in tissues:

Radioactivity levels in the harderian gland, eyeball, parotid gland, submaxillary gland, liver, and pancrease peaked at 4 hrs after dosing. The radioactivity in the mesenteric lymph node peaked at 2 hrs. By contrast, the radioactivity in the white fat tissue increased after administration and peaked at 168 hrs after dosing. Higher radioactivity than the plasma was noted in the mensenteric lymph node, liver, brown fat, heart, pancreas, and adrenal tissues 2 hrs after dosing. The amount of radioactivity in the organs was higher than in the blood plasma in all organs tested by 168 hrs after dosing. Peak concentration in the organs was at 24 hrs after dosing, with the liver, skin, muscle, white fat, blood, and kidney having high levels of radioactivity.

Details on excretion:

Less than 0.1% of sucrose monostearate or sucrose distearate was excreted in the bile. The majority (30.8% for sucrose monostearate, and 63% for sucrose distearate) was excreted in the feces. A significant amount (28.7% for sucrose monostearate and 13.3% for sucrose distearate) was excreted via air. Only very small amounts (1.4% for sucrose monostearate and 0.7% for the sucrose distearate) were excreted in the urine. The radioactivity in the urine may have been due to contamination with feces. The principle pathway for excretion is the feces.

Key result

Toxicokinetic parameters:

half-life 1st: 33.2 hrs

Remarks:

sucrose monostearate

Key result

Toxicokinetic parameters:

half-life 2nd: 96.9 hrs

Remarks:

sucrose monostearate

Key result

Toxicokinetic parameters:

Tmax: 3 hrs

Remarks:

sucrose monostearate

Key result

Toxicokinetic parameters:

half-life 1st: 35.6 hrs

Remarks:

sucrose distearate

Key result

Toxicokinetic parameters:

half-life 2nd: 86.8 hrs

Remarks:

sucrose distearate

Key result

Toxicokinetic parameters:

Tmax: 3 hrs

Remarks:

sucrose distearate

Metabolites identified:

yes

Details on metabolites:

A high polarity metabolite was found in the urine. The principal metabolite was likely stearic acid, as it eluted at the same time as stearic acid. This implies the test substance is rapidly degraded to sucrose and stearic acid.

Cumulative Percent Excretion of Sucrose Esters at 168 hrs After Exposure

	Sucrose Monostearate (%)	Sucrose Distearate (%)
Expired Air	35.9 +/- 2.29	17.3 +/- 1.11
Urine	1.9 +/- 0.30	1.0 +/- 0.12
Feces	34.8 +/- 3.70	66.7 +/- 1.84
Total	72.5 +/- 1.60	84.9 +/- 0.85
Residue in Carcass and Tissues	17.9 +/- 1.43	9.2 +/- 1.16
Overall Recovery	90.5 +/- 0.31	94.2 +/- 0.38

Conclusions:

Blood radioactivity peaked at 3 hrs after administration, and decreased in a biphasic manner. The principle metabolite was likely stearic acid. The test substance was distributed extensively to organ tissues, but is also rapidly eliminated. The principle route of excretion was the feces, followed by air expiration.

Executive summary:

The absorption, distribution, metabolism, and excretion of sucrose stearate esters were studied in a radiolabeled study. A single oral dose of sucrose monostearate or sucrose distearate was given to male rats. Blood plasma, urine, feces, and expired air were collected from the test animals. Organ tissues were also analyzed for the amount of radiolabeled substance absorbed. Blood radioactivity peaked at 3 hrs after administration, and decreased in a biphasic manner.  The principle metabolite was likely stearic acid.  The test substance was distributed extensively to organ tissues, but is also rapidly eliminated.  The principle route of excretion was the feces, followed by air expiration.  

Reference 5

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July 9, 1992-October 31, 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Objective of study:

absorption

metabolism

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: The absorption of the test sustance was determined in a human oral dosing study.
- Short description of test conditions: Adult males were given 1-6 g/day of test substance in juice or in bread on various dosing schedules of one to three doses per day for up to seven days.
- Parameters analysed / observed:
History taking
Auscaltation
Percussion
Blood pressure
Pulse rate
Body temperature
12-lead ECG
Hematology: WBC, RBC, hemoglobin, hematocrit, platelet count
Blood biochemistry: Total bilirubin, direct bilirubin, GOT, GPT, ALP, LDH, gamma-GTP, Ch-E, total protein, albumin, A/G ratio, BUN, uric acid, creatinine, total cholesterol, triglycerides, blood sugar, Ca2 +, inorganic phosphorous, Na+, K+, Cl-
Urinalysis: Bilirubin, urobilinogen, ketones, sugar, protein, occult blood, pH

GLP compliance:

yes

Radiolabelling:

no

Species:

other: human

Details on species / strain selection:

The test substance is an additive in foods, and therefore testing needed to be performed in humans prior to introducing the substance into the wider market.

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: volunteers
- Age at study initiation: 20-29 years
- Weight at study initiation: 60 +/- 10 kg
- Diet: no restrictions on diet were placed on the test subjects
- Water: no restrictions on water intake were placed on the test subjects

Route of administration:

oral: feed

Vehicle:

other: orange juice or bread

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: For the juice study, enough test substance was added to create a solution containing 1, 2, or 3 g of test substance in 200 mL orange juice. For the bread study, enough test substance for a dose of either 1, 1.5, or 2 g of test substance per 50 g roll was added.

Duration and frequency of treatment / exposure:

In Experiments I-III of the juice study, a single dose of 1, 2, or 3 g of test substance in 200 mL of orange juice was given.
In Experiment IV of the juice study, test subjects were given 200 mL of orange juice containing 1 g of test subsance twice daily for 5 days.
In Experiments I-III of the bread study, test subjects were given 1, 1.5, or 2 g of test substance in a single dose.
In Experiment IV of the bread study, test subjects were given a dose of 1.5 g test substance 3 times in one day.
In Experiment V of the bread study, test subjects were given a dose of 1.5 g of test substance 3 times per day for seven days.
In Experiment VI of the bread study, test subjects were given a dose of 1 g of test substance 3 times per day for five days.
In Experiment VII of the bread study, test subjects were given a dose of 1 g of test substance 2 times per day for five days.

Dose / conc.:

1 other: g/day

Dose / conc.:

2 other: g/day

Dose / conc.:

3 other: g/day

Dose / conc.:

4.5 other: g/day

No. of animals per sex per dose / concentration:

3-6

Control animals:

no

Details on study design:

- Dose selection rationale: Selection based on previous metabolism studies in rats, dogs, and humans

Details on dosing and sampling:

TOXICOKINETIC / PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: plasma
- Time and frequency of sampling: Bread study (Experiments I, and II): 0.5 hrs prior to dosing, 2, 4, 6, and 24 hrs after dosing
Bread study (Experiment III): 0.5 hrs prior to dosing, 2, 4, 6, 24, and 48 hrs after dosing
Bread study (Experiment IV): 0.5 hrs prior to dosing, 4, 10, 14, 24, 34, and 58 hrs after initial dose
Bread study (Experiment V): 0.5 hrs prior to dosing, 4, and 10 hrs after first dose on Day 1, on Days 2-6 at 0, 4, and 10 hrs after first dose of day, on Day 7, at 0, 4, 10, 14, 24, 34, 48, and 58 hrs after first dose of day.
Bread study (Experiment VI): 0.5 hrs prior to dosing, 4, and 10 hrs after first dose on Day 1, on Days 2-6 at 0, 4, and 10 hrs after first dose of day, on Day 7, at 0, 4, 10, 14, 24, 34, 48, and 58 hrs after first dose of day.
Juice study (Experiments I-III): 0.5 hrs prior to dosing, 2, 6, and 24 hrs after dosing
Juice study (Experiment IV): 0.5 hrs prior to dosing, 2 hrs after first and second dose on Days 1-5, 15 and 24 hrs after last dose on Day 6
- Method type(s) for identification: GC-MS, HPLC


METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled: urine, feces
- From how many animals: all (pooled)

Statistics:

Fisher statistical analysis program was used to test significant differences. The paired t-test was used to compare pre- and post- exposure values. Physical examinations were tested using ANOVA. <0.01 and <0.05 were used as the levels of significance. All data are expressed as mean and standard deviation.

Type:

absorption

Results:

The peak blood plasma levels of test substance occurred 6 hrs after dosing, with the highest concentration being 0.08 µg/mL. Blood plasma levels plateaued after 3 days of treatment, and declined to below detection limits within 48 hrs of dosing.

Details on absorption:

Absorption of test substance into the body is low as it is mostly broken down into sucrose and fatty acids.

Details on excretion:

No test substance was detected in any of the urine samples.

In the juice Experiment I, an average of 22% of the test substance was excreted in the feces in 0-48 hrs. In juice Experiment II, an average of 30.6% of the test substance was excreted in the feces in 0-48 hrs. In juice Experiment III, an average of 25.1% was excreted in the feces in 48 hrs. In Experiment IV, an average of 17.4% of the test substance was excreted in the feces in 0-48 hrs.

Key result

Toxicokinetic parameters:

Tmax: 6 hours

Metabolites identified:

yes

Details on metabolites:

Only monoesters were detected in blood plasma. No diesters or triesters were detected. The test substance is expected to breakdown into sucrose and fatty acids. Results of the urine and feces studies indicate that 70-80% of the test substance is metabolized in the gastrointestinal tract. The monoester is most digestible, followed by the di- and triesters. The palmitate esters were also more digestible than the stearate esters. The test substance is likely broken down by the enteric enzymes lipase and carboxylesterase.

Plasma Concentration of Sucrose Monopalmitate (ug/mL, last sampling of the day)

Day	Orange Juice (1 g twice daily)	Bread (1.5 g 3 times daily)
1	0.01 +/- 0.01	0.06 +/- 0.02
2	Not detected	0.14 +/- 0.09
3	0.02 +/- 0.01	0.13 +/- 0.05
4	0.02 +/- 0.01	0.08 +/- 0.04
5	0.02 +/- 0.01	0.09 +/- 0.05
6	Not detected	0.08 +/- 0.05
7	--	0.05 +/- 0.02
8	--	Not detected
9	--	Not detected

Plasma Concentration of Sucrose Monostearate (ug/mL, last sampling of the day)

Day	Orange Juice (1 g twice daily)	Bread (1.5 g 3 times daily)
1	0.02 +/- 0.02	0.10 +/- 0.04
2	0.02 +/- 0.01	0.33 +/- 0.14
3	0.05 +/- 0.01	0.29 +/- 0.15
4	0.05 +/- 0.02	0.20 +/- 0.11
5	0.06 +/- 0.02	0.23 +/- 0.15
6	0.02 +/- 0.01	0.22 +/- 0.14
7	--	0.19 +/- 0.10
8	--	0.03 +/- 0.05
9	--	Not detected

Conclusions:

The maximum blood plasma levels of the test substance in human were seen at 6 hrs after dosing. The blood plasma levels of the test substance plateaued after 3 days of exposure. Blood plasma levels of the test substance were below detection limits by 48 hrs after the final dosing.

Executive summary:

The absorption of the test sustance was determined in a human oral dosing study. Adult males were given 1-6 g/day of test substance in juice or in bread on various dosing schedules of one to three doses per day for up to seven days. Blood plasma levels of the test susbstance were determined. Abdominal side effects and laxation were noted. The maximum blood plasma levels of the test substance were seen at 6 hrs after dosing.  The blood plasma levels of the test substance plateaued after 3 days of exposure.  Blood plasma levels of the test substance were below detection limits by 48 hrs after the final dosing.

Description of key information

With respect to oral absorption, the available toxicokinetic data on sucrose esters in rats and human suggest that the substance is extensively hydrolysed in the gastrointestinal tract to the respective fatty acid and sucrose prior to absorption. Only small amounts of intact monoesters are absorbed. It is unlikely that diesters are absorbed intact. Based on physico-chemical parameters the dermal absorption is considered to be moderate and inhalative absorption potential is considered to be low.

There was no evidence of tissue accumulation of the absorbed monoesters that were completely metabolised to carbon dioxide or integrated into other endogenous constituents. The hydrolysis products fatty acids mainly are distributed into fat tissue, lymph nodes and liver, while sucrose is metabolised in the intestinal mucosa to glucose and fructose; these can then be incorporated in the standard metabolic pathways of glycolysis and gluconeogenesis. Fatty acids are degraded by mitochondrial β-oxidation and used for energy generation. Incompletely hydrolysed sucrose esters of Fatty acids C16-18 (even numbered), mono and diesters with sucrose are mainly excreted via the feces, whereas hydrolysis products are excreted via the feces or expired as CO2 as a result of metabolism.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

In accordance with Annex VIII, Column 1, Item 8.8.1, of Regulation (EC) 1907/2006 and with ‘Guidance on information requirements and chemical safety assessment Chapter R.7c: Endpoint specific guidance’ (ECHA, 2017), an assessment of the toxicokinetic behaviour of the test substance is conducted to the extent that can be derived from the relevant available information. This comprises a qualitative assessment of the available substance specific data on physico-chemical and toxicological properties according to the Chapter R.7c Guidance document (ECHA, 2017) and taking into account further available information from source substances. Additionally, there are studies in rats available evaluating the toxicokinetic properties of the substance.

Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS) is a UVCB substance covering mainly mono- and diesters of stearic and palmitic acid with sucrose at varying proportions and small proportions (<20% and <10%) of tri- and tetraesters. The substance is a white solid at room temperature and the molecular weight is between 580.7 and 1408.1 g/mol. The substance has an estimated water solubility of < 0.51 mg/L at 20 °C and an estimated vapour pressure of < 0.0001 Pa at 20 °C. The log Pow was estimated to be 3.4, 3.99, 11.06 and 12.63 for the 4 main constituents.

Absorption

The major routes by which the test substance can enter the body are via the lung, the gastrointestinal tract, and the skin. To be absorbed, the test substances must transverse across biological membranes either by active transport mechanisms or - as being the case for most compounds - by passive diffusion. The latter is dependent on compound properties such as molecular weight, lipophilicity, or water solubility (ECHA, 2017).

Oral

Generally the smaller the molecule the more easily it may be taken up. Molecular weights below 500 are favourable for absorption; molecular weights above 1000 do not favour absorption. The molecular weight of the test substance is between 580.7 and 1408.1 g/mol, thus a moderate oral absorption is presumed. However, the absorption of highly lipophilic substances (log Pow >4) may be limited by the inability to dissolve into gastrointestinal fluids and hence make contact with the mucosal surface. Lipophilic compounds may be taken up by micellar solubilisation by bile salts; this mechanism is important for highly lipophilic compounds (log Pow > 4), in particular for those that are poorly soluble in water (≤ 1 mg/L) as these would otherwise be poorly absorbed (Aungst and Chen, 1986; ECHA, 2017).

The available data on acute and repeated dose oral toxicity support a conclusion of no/low toxicity.

In an acute oral toxicity study conducted with the test substance in rats no signs of adverse effects were observed and no mortality occurred. Therefore, the LD50 is > 2000 mg/kg bw (Jensch, 1996).

In a 13-week feeding study conducted with source substance Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose (no CAS) in rats no mortality or clinical signs related to the test substance occurred. A significant increase in glutamic-pyruvic transaminase (GPT) in the medium and high dose male groups and high dose female groups was observed. The observed values were within the control range. Therefore, it is not clear if this effect is treatment related. As there were no definitive treatment related effects, the NOAEL for both males and females was the highest dose, 5% of feed (equivalent to 3240 and 3430 mg/kg bw/day for males and females, respectively) (Takeda, 1991).

In addition, toxicokinetic studies of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS) were conducted in rats, dogs and humans.

Kinetic studies were conducted in three male beagle dogs given of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS) in a single gelatin capsule at doses of 50, 250 and 1250 mg/kg bw in that order, separated by a washout period of 7 days between the low and mid doses and a period of 12 days between the mid and high doses. The increasing doses of the test substance contained 9, 44 and 221 mg/kg bw of sucrose monopalmitate (SMP) and 21, 103 and 515 mg/kg bw of sucrose monostearate (SMS). After administration of the test substance blood concentrations of SMP and SMS were intermittently followed during 48 hours. The time to peak plasma concentration increased with dose and was 3.3-4.7 hours for SMP and 3.3-7.3 hours for SMS. Plasma concentrations of SMP and SMS also increased dose dependently (0.06-0.60 μg/mL for SMP and 0.12-1.14 μg/mL for SMS). SMP and SMS at the 250 and 1250 mg/kg bw doses were eliminated from the plasma in a monophasic manner, with a half-life of 2.5 and 5.6 hours for SMP, respectively, and 7.2 and 7.3 hours for SMS, respectively The AUCo → infinity was 0.22, 1.37 and 5.10 μg x hr/mL for the increasing doses of SMP and 1.76, 5.03 and 15.38 mg x hr/mL for the increasing doses of SMS (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

Two human studies have been performed in order to evaluate the kinetic characteristics and safety of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS) in humans (Mitsubishi, 1994a; Mitsubishi, 1994b). In one of the studies (Mitsubishi, 1994b), the volunteers were additionally observed for clinical symptoms and subjected to physical examination and laboratory tests.

In the first study, the kinetics of the test substance, mixed in 200 mL of orange juice, was evaluated in healthy male volunteers (body weights ranged from 51.5 to 70 kg) after single- or multiple dose regimens. In the single-dose experiment 1, 2 or 3 g of the test substance was given to 3, 6 and 3 subjects, respectively. In the multiple-dose experiment 1 g of the test substance was administered to five subjects twice daily (2 g/day) for 5 days. At 2 and 6 hours after the single-dose administration, SMS and SMP were detected in the plasma (0.01-0.04 μg/mL) at levels close to the detection limit (0.01 μg/mL). At 24 hours SMS was still detectable in 50% of the subjects that received 2 g. No clinical symptoms were observed in the three persons who received a single dose of 1 g test substance in 200 mL orange juice, but after single doses of 2 g and 3 g test substance soft stools or diarrhoea were observed in 4/6 and 3/3 subjects, respectively. The incidence and severity of these symptoms increased with dose. When 5 individuals ingested 1 g twice daily (2 g/day) for 5 days no clinical symptoms developed.

In the multiple-dose experiment SMP showed the same pattern with daily levels below 0.03 μg/mL at 2 hours, and not detectable levels at 24 hours after the last dose. SMS was detected at slightly higher levels and the concentration seemed to increase with number of doses, i.e. the mean concentration after the second daily dose was 0.02, 0.02, 0.05, 0.05 and 0.06 μg/mL on days 1 to 5, respectively. The SMS levels at 15 and 24 hours after the last dose were 0.05 and 0.02 μg/mL, respectively (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004.

In a supplementary study, the kinetics of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS), mixed in bread, was studied in healthy male volunteers (age 20-29 years, body weights 60±10 kg) after single or multiple dosing regiments. In the single dose experiment 1, 1.5 or 2 g of the test substance was given to five subjects per dose group. In one of the multiple dose experiments, bread containing 1.5 g of the test substance was ingested by five subjects three times daily (4.5 g/day) for 1 day (total dose 4.5 g) or 7 days (total dose 31.5 g). In another multiple dose experiment, bread containing 1 g of the test substance was given to five subjects two or three times daily (total dose 2 or 3 g/day) for 5 days (total dose 10 or 15 g). In the single dose experiments SMP and SMS could be detected in the plasma at 2 hours (0.01-0.03 μg/mL) after ingestion of 2 g. The peak concentrations of SMP (0.02-0.04 μg/mL) and SMS (0.07-0.11 μg/mL) were detected at 6 hours after the intake. At 24 hours only SMS could be detected in plasma (0.01 μg/mL) and only in a few subjects given 2 g. In the multiple dose experiments plasma levels of SMP and SMS gradually increased during the first days, reaching a steady state from day 3 and onwards with levels in the range of 0.08- 0.14 μg/mL for SMP and 0.20-0.33 μg/mL for SMS. At 24 hours after the last dose SMS, but not SMP, could still be detected in plasma from 3 of 5 subjects (0.02-0.11 μg/mL).

After a single dose of 1.5 g or 2 g of test substance, administered in bread, treatment related soft stool or diarrhoea were observed in 1/5 or 3/5 of the subjects, respectively. No symptoms of laxation were observed in the volunteers who ingested 1 g of the test substance in bread. In the multiple-dose studies, treatment related increases in laxation were observed in 4/5 subjects receiving 1.5 g three times daily for 7 days (1-5 events), in 2/5 persons receiving 1 g three times daily for 5 days, and in 1/5 subjects receiving 1 g two times daily for 5 days. Treatment related clinical symptoms, besides laxation, were a feeling of enlarged abdomen, borborygmus, abdominal pain, flatus, suprapubic discomfort and nausea. These abdominal symptoms, noted during 1 to 10 h after the administration, were transient and slight and tended to subside by 24 hours. There were no treatment-related changes in the results of physical examinations or in haematology, clinical chemistry urinalysis parameters (Mitsubishi, 1994b; summarised in WHO, 1995 and EFSA, 2004).

The potential of a substance to be absorbed from the gastrointestinal tract may be influenced by several parameters, like chemical changes taking place in gastrointestinal fluids, as a result of metabolism by gastrointestinal flora, by enzymes released into the gastrointestinal tract or by hydrolysis. These changes will alter the physico-chemical characteristics of the substance and hence predictions based upon the physico-chemical characteristics of the parent substance may in some cases no longer apply (ECHA, 2017).

To study the hydrolysis of sucrose esters, Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS) at final concentrations of 0.05%, 0.25% or 0.5% was incubated with cultures of human intestinal flora at 37 °C for 5 hours. After the incubation period, analysis of the total remaining unchanged sucrose esters (SMP, SMS, SDE (sucrose distearate) and STE (sucrose tristearate)) showed that 52%, 68% and 67% had been hydrolysed to sucrose and free fatty acids following the incubations at concentrations of 0.05%, 0.25% and 0.5%, respectively (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

Degradation of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS), at a concentration of 1.25 mg/mL, was also studied in artificial gastric juice (pH 1.2) at 37 °C for 5 hours. After the incubation the residue levels of SMP, SMS, SDE and STE were 82.7%, 92.8%, 99.8% and 84.4%, respectively. When SMP and SMS were similarly incubated, at concentrations of 0.4 mg/mL, 82% of SMP and 85% of SMS remained (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

In the reviews/opinions prepared by the WHO, 1995, WHO, 1998 and EFSA, 2004 and the references therein, several absorption and distribution experiments in rats were conducted. These studies confirm that extensive hydrolysation of SE occurs in gastrointestinal tract prior to absorption and that only small amounts of intact monoesters are absorbed. Further it is shown from studies on oligoesters, that the degree of absorption is inversely related to the degree of esterification of the sucrose moiety (Noker, 1997; Shigeoka, 1984).

Overall, available studies indicate that the test substance is predicted to undergo hydrolysis in the gastrointestinal tract and absorption of the hydrolysis products sucrose and fatty acids rather than the parent substance is likely.

Dermal

The dermal uptake of solids is generally expected to be lower than that of liquid substances. Dry particulates will have to dissolve into the surface moisture of the skin before uptake can begin. Additionally, the substance must be sufficiently soluble in water to partition from the stratum corneum into the epidermis. Therefore if the water solubility of the substance is below 1 mg/L, dermal uptake is likely to be low. For substances with log Pow above 4 the rate of penetration may be limited by the rate of transfer between the stratum corneum and the epidermis, but uptake into the stratum corneum will be high (ECHA, 2017).

The dermal permeability constant Kp of the main constituents of the substance was estimated to be between 1.57 E-4 and 7.01 cm/h using DermwinTM (v.2.02) and taking into account determined log Pows of 3.4, 3.99, 11.06 and 12.63 and the molecular weights of 580.72, 608.77, 789.11 and 845.22 g/mol for the main constituents. Thus, the dermal absorption of the test substance is anticipated to range from very low to medium high for the main constituents.

If a substance shows skin irritating or corrosive properties, damage to the skin surface may enhance penetration. If the substance has been identified as a skin sensitiser then some uptake must have occurred although it may only have been a small fraction of the applied dose (ECHA, 2017).

The available data provide no indications for skin irritating effects of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS) in rabbits. No skin effects were noted in the acute dermal toxicity study at the limit dose of 2000 mg/kg bw and no sensitisation was observed in skin sensitisation tests (GMPT). Therefore, no enhanced penetration of the substance due to skin damage is expected. Taking all the available information into account, the dermal absorption potential is assumed to be moderate.

Inhalation

In humans, particles with aerodynamic diameters below 100 μm have the potential to be inhaled. Particles with aerodynamic diameters below 50 μm may reach the thoracic region and those below 15 μm the alveolar region of the respiratory tract. Granulometry revealed a mass median aerodynamic diameter of 50.6 µm, with D75 of 81.3 µm and D25 of 3.4 µm. Therefore, inhalation of particles is assumed with low percentage of particles reaching alveolar region of respiratory tract (ECHA, 2017).

For poorly water-soluble dusts, the rate at which the particles dissolve into the mucus will limit the amount that can be absorbed directly. Poorly water-soluble dusts depositing in the nasopharyngeal region could be coughed or sneezed out of the body or swallowed (Schlesinger, 1995). Such dusts depositing in the tracheo-bronchial region would mainly be cleared from the lungs by the mucocilliary mechanism and swallowed. However a small amount may be taken up by phagocytosis and transported to the blood via the lymphatic system. Poorly water-soluble dusts depositing in the alveolar region would mainly be engulfed by alveolar macrophages. The macrophages will then either translocate particles to the ciliated airways or carry particles into the pulmonary interstitium and lymphoid tissues (ECHA, 2017).

Absorption after oral administration of the substance is mainly driven by enzymatic hydrolysis of the ester bond to the respective metabolites and subsequent absorption of the breakdown products. Therefore, for increased absorption in the respiratory tract enzymatic hydrolysis in the airways would be required, and the presence of esterases in the mucus lining fluid of the respiratory tract would be important. Due to the physiological function of enzymes in the gastrointestinal tract for nutrient absorption, esterase activity/expression in the lung is expected to be lower in comparison to the gastrointestinal tract. Therefore, hydrolysis within the respiratory tract comparable to that in the gastrointestinal tract and subsequent absorption in the respiratory tract is considered to happen at a lower rate. The molecular weight, log Pow and water solubility indicate that the substance may be absorbed across the respiratory tract epithelium by micellular solubilisation to a certain extent. However, low water solubility does restrict the diffusion/dissolving into the mucus lining before reaching the epithelium, and it is not clear which percentage of the inhaled aerosol could be absorbed as the ester. 

In conclusion, based on physicochemical properties of Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS), absorption via inhalation is assumed to be low. Further, spray application is not intended for the substance.

Distribution and Accumulation

Distribution of a compound within the body depends on the physico-chemical properties of the substance; especially the molecular weight, the lipophilic character and the water solubility. In general, the smaller the molecule, the wider is the distribution. If the molecule is lipophilic, it is likely to distribute into cells and the intracellular concentration may be higher than extracellular concentration, particularly in fatty tissues (ECHA, 2017).

As discussed for oral absorption, Fatty acids C16-18 (even numbered), mono and diesters with sucrose (no CAS), are hydrolysed in the gastrointestinal tract prior to absorption. Therefore, distribution and accumulation of the hydrolysis products is considered the most relevant.

After being absorbed, fatty acids are (re-)esterified along with other fatty acids into triglycerides and released in chylomicrons into the lymphatic system. Chylomicrons are transported in the lymph to the thoracic duct and subsequently to the venous system. On contact with the capillaries, enzymatic hydrolysis of chylomicron triacylglycerol fatty acids by lipoprotein lipase takes place. Most of the resulting fatty acids are taken up by adipose tissue and re-esterified into triglycerides for storage (Bloom et al., 1951; IOM, 2005; Johnson, 1990; Lehninger, 1998; NTP, 1994; Stryer, 1996). There is a continuous turnover of stored fatty acids, as these are constantly metabolised to generate energy and then excreted as CO2. Accumulation of fatty acids takes place only if their intake exceeds the caloric requirements of the organism. In contrast, sucrose is metabolised in the intestinal mucosa to glucose and fructose; these are transported by the portal vein to the liver where they are rapidly metabolised and incorporated into physiological pathways (Lehninger, 1998; Noker et al. 1995).

The absorption and distribution of SMS and sucrose distearate (SDS) was determined after administration of single oral doses of 100 mg/kg bw of 14C-SMS or 14C-SDS to male rats in groups of three. Radioactivity in the blood peaked 3 hours after the administration of 14C-SMS (equivalent to 12.0 μg SMS/mL) and 14C-SDS (equivalent to 8.36 μg SDS/mL), and thereafter declined in a biphasic manner. The elimination half-life for the first and second phase was approximately 33.2 hours (at 8 to 48 hours) and 96.9 hours (at 48 to 168 hours), respectively.

The tissue distribution of radioactivity was studied at 24 and 168 hours after administration of 14C-SMS or 14C-SDS. Each test compound was orally administered to three male rats at 100 mg/kg bw. The plasma peak concentration of 14C-SMS (equivalent to 16.9 μg SMS/mL) and 14C-SDS (equivalent to 7.66 μg SDS/mL) appeared in this study at 2 and 4 hours after the administration, respectively, thereafter declining with an elimination half-life of 34 hours and 40 hours, respectively, reaching 1.9% and 7.6% of the peak concentration at 168 hours, respectively. The number of tissues retaining radioactivity increased with time. At 24 hours after administration of 14C-SMS and 14C-SDS the highest level of radioactivity (% of dose) was found in the liver (8.50% and 3.70%, respectively), followed by skin, muscle, white fat, blood and kidney. At 168 hours the radioactivity of 14C-SMS was still high in white fat (6.11%), muscle (4.97%), skin (2.66%), liver (0.42%), kidney (0.18%) and pancreas (0.16%). At the same point in time, a corresponding high activity of 14C-SDS was found in white fat (2.87%), muscle (2.31%), skin (1.57%), liver (0.25%), and pancreas (0.09%). After 14C-SMS administration only low levels of unchanged SMS (less than 0.01% of the administered dose) were detected, with the highest concentrations found in the liver (0.051-0.060%) and lungs (0.01-0.02%) at 2 and 4 hours after administration. After 14C-SDS administration, unchanged SDS was not detected in these tissues or in the blood (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

Overall, available studies indicate that after being absorbed tissue distribution of small amounts of Fatty acids C16-18 (even numbered), mono and diesters with sucrose and/or their metabolites (not further specified) into white fat, muscle, skin, liver, kidney and pancreas was demonstrated. There is no evidence of tissue accumulation of the absorbed intact monoesters.

Metabolism

As discussed previously, Fatty acids C16-18 (even numbered), mono and diesters with sucrose is hydrolysed in the gastrointestinal tract prior to absorption, whereas the extent of absorption and metabolism is inversely related to the degree of esterification of the glucose molecule (Noker, et al. 1997; Shigeoka, 1984). Only small amounts of intact monoesters which escape hydrolysis are absorbed. Some hydrolysis occurs in the presence of blood esterase: however, the rate is extremely slow compared to the other enzyme systems like in the gastrointestinal tract (Shigeoka, 1979). Absorbed monoesters are completely metabolised to carbon dioxide or integrated into other endogenous constituents (Mitsubishi, 1994a, Mitsubishi, 1994b, Shigeoka, 1984, Noker, 1997; summarised in WHO, 1980, WHO, 1995, WHO, 1998 and EFSA, 2004).

Sucrose is metabolised in the intestinal mucosa to glucose and fructose, which can then be incorporated in the standard metabolic pathways of glycolysis and gluconeogenesis. Fatty acids are degraded by mitochondrialβ-oxidation which takes place in most animal tissues and uses an enzyme complex for a series of oxidation- and hydration reactions, resulting in the cleavage of acetate groups in the form of acetyl-CoA. The alkyl chain length is reduced by 2 carbon atoms during eachβ-oxidation cycle. Alternative pathways for oxidation can be found in the liver (ω-oxidation) and the brain (α-oxidation). Each two-carbon unit resulting fromβ-oxidation enters the citric acid cycle as acetyl-CoA, through which they are completely oxidised to CO2 (CIR, 1987; IOM, 2005; Lehninger, 1998; Stryer, 1996).

Urine and feces were analysed for SMS, SDS and potential metabolites at 24 and 168 hours after administration of 14C-SMS or 14C-SDS to three male rats at 100 mg/kg bw. A small amount of the total radioactivity excreted at 24 hours in the urine (1.4% of dose) and faeces (2.0% of dose) was unchanged SMS. Similarly, after 14C-SDS administration unchanged SDS could be detected in the urine (2.2% of the administered radioactivity) and faeces (39% of the administered activity), as well as a minor amount of SMS in the faeces (4.3% of the administered activity). Altogether six metabolites were determined, but the structures were not elucidated. The major fecal metabolite (87% of the radioactivity) after 14C-SMS administration was identified as stearic acid. Similarly, stearic acid could be detected in the feces (50% of activity) after administration of 14C-SDS (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

The potential metabolites following enzymatic metabolism of the test substance were predicted using the QSAR OECD toolbox (v4.1, OECD, 2014). This QSAR tool predicts which primary and secondary metabolites of the test substance may result from enzymatic activity in the liver and in the skin, and by intestinal bacteria in the gastrointestinal tract. Up to 18 hepatic metabolites and up to 25 dermal metabolites were predicted for the 4 main constituents of the test substance. Primarily, the ester bond is broken both in the liver and in the skin, after which the hydrolysis products may be metabolised further. The resulting liver and skin metabolites are the products of alpha-, beta- or omega-oxidation (= addition of hydroxyl group). The ester bond may also remain intact, in which case a hydroxyl group is added to, or substituted with, a methyl group. In general, the hydroxyl groups make the substances more water-soluble and susceptible to metabolism by phase II-enzymes. The metabolites formed in the skin are expected to enter the blood circulation and have the same fate as the hepatic metabolites. Up to 184 metabolites were predicted to result from all kinds of microbiological metabolism. The high number includes many minor variations in the c-chain length and number of carbonyl- and hydroxyl groups; reflecting the diversity of microbial enzymes identified. Not all of these reactions are expected to take place in the human GI-tract. The results of the OECD toolbox simulation support the information on metabolism routes retrieved from the literature and data from metabolism studies.

There is no indication that Fatty acids C16-18 (even numbered), mono and diesters with sucrose is activated to reactive intermediates under the relevant test conditions. The experimental studies performed on genotoxicity (Ames test) using the test substance and QSAR predictions on the bacterial mutagenicity were negative, with and without metabolic activation. In addition, experimental studies on genotoxicity (gene mutation in mammalian cells in vitro and micronucleus test in vivo) performed with the source substance Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose (no CAS) were consistently negative. The results of the skin sensitisation studies (GPMT) performed with the target substance were likewise negative.

Excretion

The excretion of SMS and SDS was determined after administration of single oral doses of 100 mg/kg bw of 14C-SMS or 14C-SDS to male rats in groups of three. Within 24 hours after dosing 1.4%, 30.8% and 28.7 of 14C-SMS were excreted in urine, faeces and expired air, respectively. The corresponding percentages for 14C-SDS were 0.7%, 63.0% and 13.3%. Thus, at 24 hours after administration the total excretion of 14C-SMS and 14C-SDS was 60.9% and 76.9%, respectively. After 168 hours the total cumulative excretion by these routes had increased to 72.6% for 14C-SMS and 84.9% for 14C-SDS. At 168 hours the radioactivity retained in the carcass was 17.9% of the administered 14C-SMS and 9.2% of the administered 14C-SDS (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

The contribution of biliary excretion of to elimination of sucrose mono- and diesters after oral single dose administration of 14C-SMS or 14CSDS at 100 mg/kg bw was studied in groups of three bile-duct cannulated male rats. For both compounds, the cumulative biliary excretion during 48 hours was 0.1% or less of the dose. The corresponding urinary and fecal excretions were 0.5% and 8.9% for 14C-SMS, and 0.1% and 15.5% for 14C-SDS, respectively (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

In previously described human studies, the excretion pattern of Fatty acids C16-18 (even numbered), mono and diesters with sucrose, mixed in 200 mL of orange juice, was evaluated in healthy male volunteers (body weights ranged from 51.5 to 70 kg) after single- or multiple-dose regimens. In the single-dose experiment 1, 2 or 3 g of the test substance was given to 3, 6 and 3 subjects, respectively. In the multiple-dose experiment 1 g of the test substance was administered to five subjects twice daily (2 g/day) for 5 days. Twelve-hour urine samples were analysed for SMP, SMS, SDE and STE, but these unchanged compounds could not be detected in urine after single or repeated oral administration. The total 48-hour fecal excretion (% of dose) of these sucrose esters was 22%, 25% and 31% at single doses of 1, 2 and 3 g, respectively. The total 120 hour fecal excretion (% of dose) of these sucrose esters after the repeated dose administration was 17%. These results indicate that following ingestion about 70-80% of the sucrose esters are hydrolysed in the gastro-intestinal tract of humans (Mitsubishi, 1994a; summarised in WHO, 1995 and EFSA, 2004).

In general, the hydrolysis products sucrose and fatty acids are catabolised entirely by oxidative physiologic pathways, ultimately leading to the formation of carbon dioxide and water. Small amounts of ketone bodies resulting from the oxidation of fatty acids may be excreted via the urine; however, the major part of the fatty acids will enter an oxidative pathway as described above under ‘Metabolism’ (Lehninger, 1998; IOM, 2005; Stryer, 1996).

In conclusion, incompletely hydrolysed sucrose esters of Fatty acids C16-18 (even numbered), mono and diesters with sucrose are mainly excreted via the feces, whereas hydrolysis products are excreted via the feces or expired as CO2 as a result of metabolism.

A detailed reference list is provided in the technical dossier (see IUCLID 6, section 13) and within the CSR.

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