Fatty acids, C16-18, 2-hydroxyethyl esters

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions. No ophthalmology, no neurobehaviour and limited number of haematology and clinical chemistry examinations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1967

Report date:

1967

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

no ophthalmology, no neurobehaviour, limited number of haematology and clinical chemistry examinations

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Stearic acid, monoester with propane-1,2-diol

EC Number:

215-354-3

EC Name:

Stearic acid, monoester with propane-1,2-diol

Cas Number:

1323-39-3

Molecular formula:

C21H42O3

IUPAC Name:

2-hydroxypropyl stearate

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: internal colony continued from the colony of the Charles River Breeding Laboratories, Inc.
- Age at study initiation: 25-28 days
- Weight at study initiation: 74.0 - 75.2 g (males) and 67.3 - 68.5 g (females)
- Housing: individually housed on wire mesh in stainless steel cage 7 x 11 x 6“ high
- Diet: basal diet Purina Laboratory Chow
- Water: no details

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23.9 ± 1.1
- Humidity (%): 50-70

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): weekly
- Mixing appropriate amounts with (Type of food): basal diet of Purina Laboratory Chow
- Vitamin (oil and water soluble) supplements were added to the diets in amounts sufficient to replace the original vitamin content reduced by the additive.

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

daily, 7 days/week

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
1.5, 3.36 and 7.52 % (w/w)
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
1158, 2571 and 5657 mg/kg bw/day (males)
Basis:
other: calculated from reported mean body weights and food consumption

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1461, 3214 and 7355 mg/kg bw/day (females)
Basis:
other: calculated from reported mean body weights and food consumption

No. of animals per sex per dose:

24

Control animals:

other: yes, isocaloric control diet containing 7.52% (w/w) mono- and diglyceride

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption determined: Yes (for six male and six female rats assigned to each of the diets)
- Time schedule for examinations: weekly

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION : Yes (for six male and six female rats assigned to each of the diets)
- Time schedule for examinations: daily

HAEMATOLOGY ANd CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Week 0 and Week 13
- How many animals: six male and six female rats assigned to each of the diets
- Parameters checked: blood glucose, blood urea nitrogen, plasma cholesterol, plasma glutamic-pyruvic transaminase (final period only), haemoglobin, haematocrit, white blood cell count, differential white cell count, clotting time (final period only)

URINALYSIS: Yes
- Time schedule for collection of urine: samples were collected during Week 1 and 12
- Metabolism cages used for collection of urine: Yes
- Parameters checked: pH, qualitative sugar, qualitative acetone, qualitative albumin, occult blood, crystals (microscopic examination after centrifugation), uric acid, urate, phosphate, oxalate, epithelial cells (microscopic)

ORGAN WEIGHTS:
- Organ weights and organ to body weight ratios and organ to brain weight ratios were determined in all animals for the following organs: adrenals, brain, gonads, heart, kidneys, liver and spleen

Sacrifice and pathology:

GROSS PATHOLOGY: Yes. Adrenals, bladder, eye, gonads, heart, kidney, liver, lung, lymph nodes, pancreas, spleen, thymus, thyroid, trachea
HISTOPATHOLOGY: Yes. From 6 rats of each sex per group histopathological examinations of the following organs were performed: liver, kidney, heart, spleen, gonads, adreals. From 10 rats of each sex in the group the control and high-dose group histopathological examinations of the following organs were performed (The 10 rats included the 6 rats formerly mentioned.): liver, spleen, stomach, multiple sections of small and large intestines, pancreas, kidneys, bladder, adrenals, testes and prostate, or ovaries and uterus, thyroid, pituitary, thymus, salivary glands, lymph nodes, heart, lungs, marrow, muscle, spinal cord, and brain.

Statistics:

See details under "Any other information on materials and methods incl. tables".

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

3.36%: males were significantly heavier than the control group during Week 6 and 7, non-adverse

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Description (incidence and severity):

3.36% and 7.52%: more water consumed or spilled in comparison to the control group in Week 4 (males); 7.52%: more water consumed or spilled in comparison to the control group in Week 1 (females), non-adverse

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

7.52%: white blood cell count was higher in Week 13 (female), non-adverse

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

7.52%: urine specific gravity lowered in Week 1 (males); 1.5% and 7.52%: urine pH lowered in Week 12 (female), non-adverse

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

1.5%: lower gonads to body weight ration (males), non-adverse

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

high incidence of lung involvement in rats fed each diet (due to a mild respiratory infection of the pleuro-pneumonia-like organism type, which was present in the weanling rats), not test substance-related

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No mortality occurred during the study period. A mild respiratory infection of the pleuro-pneumonia-like organism type was present in the weanling rats when they were assigned to the diets but the majority of the animals showed no observable signs of infection after the first few weeks on test. No laxation or soft stool was evident in rats fed the diet containing propylene glycol monostearate or in those fed the diet containing mono- and diglycerides, the isocaloric control diet, or in either of the other two diets containing a mixture of these two.

BODY WEIGHT AND WEIGHT GAIN
No significant difference in growth rate was observed in females. The mean body weights of male rats fed 1.5% of the test substance in the diet was significantly higher than the weights of the controls (p < 0.05) during Weeks 6 and 7 (see Table 1 and 2 under "Any other information on results incl. tables").

FOOD EFFICIENCY
When the efficiency of caloric utilization ratio for each experimental group was compared separately with the control group by the t-test, no statistical difference was observed for any period of time for either male or female rats.

WATER CONSUMPTION
The t-test values showed no statistically significant difference between water consumed by rats fed an isocaloric control diet and that consumed by rats fed the experimental diet for any period of test, except for male rats fed 1.5% and 7.52% for Week 4 (p < 0.05) and females fed 7.52% in Week 1. More water was consumed, or spilled, than was consumed by the respective control rats.

HAEMATOLOGY AND CLINICAL CHEMISTRY
Blood chemical analyses and haematological determinations showed no finding in incidence or concentration considered to be dose-related, or to be outside a normal control range except for one borderline statistically significant value: the white blood cell count for female rats fed 7.52% of the test material in the diet was higher than that for the control group at Week 13 (p < 0.05, see Table 5 under “Any other information on results incl. tables”).

URINALYSIS
There were no significant differences observed for urinary output. Urine analyses showed no finding in incidence or concentration considered to be dose-related or to be outside a normal control range except for the few scattered statistically significant differences listed: the urine specific gravity of male rate fed 7.52% was lower than that of the control group at Week 1 (p < 0.05). The urine values for female rats fed 1.5% and 7.52% were significantly lower than that of the control group at Week 12 (p < 0.05) (see Table 7 under "Any other information on results incl. tables"). Qualitative values for urinary sugar, acetone, albumin and microscopic examination of centrifuged urine, for occult blood, crystals and epithelial cells were made. Scattered incidences of qualitative urinary sugar and albumin show no relation to diet, period of sampling or to sex. No urinary acetone was observed at any time. Occult blood was demonstrated at a minimum level in only four rats (one control male, one low- and high-dose male and one female high-dose); all other urine samples were free of red blood cells. Occasional epithelial cells at a minimum level appear unrelated to diet, sampling period or to sex.
Occasional uric acid, urate, phosphate, and oxalate crystals were seen in the urine sediment but these appear in incidence and concentration to be unrelated to any diet, period of sample or sex and are considered to be within a normal control range.

ORGAN WEIGHTS
When organ to body weight ratios for each experimental group of rats were compared separately with the control group by the t-test, no statistical differences were shown in male rats for the following ratios: adrenals, brain, heart, kidneys, liver and spleen to body weight ratios. Male rats fed 1.5% of the test material in the diet had a lower gonads to body weight ratio (p < 0.05) than did the control group (see Table 6 under "Any other information on results incl. tables"). For female rats no statistical differences were shown for any of the organ to body weight ratios. According to the author the difference in the gonads to body weight ratio found in male rats fed 1.5% is considered to be incidental and not dose related since no pattern of response is seen at other levels or in the other sex.
Organ to brain weight ratios for each experimental group of rats showed no statistical differences for any of the organ to brain weight ratios.

GROSS PATHOLOGY
All of the 192 test animals survived until termination of the study and were sacrificed. A very high incidence of demonstrable lung involvement was observed upon necropsy of the rats in this study. 163/192 rats showed gross lung pathology. These findings, mainly diffuse congestion and consolidation, were not related to any diet or sex but reflected a general condition of the entire group of rats. Limited, scattered incidental gross findings were observed in groups of rats, male and female, fed the control or the test material diets. The incidence of such findings in the control rats as well as the rats on the test diets in this experiment negated any significance to a dose related response in the experimental animals.

HISTOPATHOLOGY
The liver, kidneys, spleen, heart, gonads, and adrenals were examined in 48 rats consisting of six male and six female rats fed each of the 4 diets. Additionally, in 4 animals per sex of the control and high-dose group 21 tissues were examined including: liver, spleen, stomach, multiple sections of small and large intestines, pancreas, kidneys, bladder, adrenals, testes and prostate, or ovaries and uterus, thyroid, pituitary, thymus, salivary glands, lymph nodes, heart, lungs, marrow, spinal cord and brain.
In the kidneys of 2 females at the lowest level of the test substance in the diet there was some calcification at the corticomedullary junction. This finding was also present in two females of the control group. Hydropelvis was seen in one female fed of the high-dose group and increased hematopoiesis in the spleen of one male that received 3.32% of the test substance in the diet. These findings are considered to be incidental findings and unrelated to the dietary treatments.
In the control and high-dose group the findings were approximately the same in character and number. These consisted principally of a low grade of thyroid hyperplasia (predominately in males) and a widespread incidence ob various inflammatory changes in the lungs, i.e. focal chronic, interstitial, and/or peribronchial. Thyroid hyperplasia at the level observed is a common finding in rats. This is also true for the inflammatory responses in the lungs. These, as well as all other findings were considered incidental and none of them dose-related. In most instances, several pathological changes were found in the lungs of the same animal.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

>= 7.52 other: % in diet

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: appearance, growth, survival, efficiency of caloric utilization, water intake, blood chemistry, heamatology, urinary examinations, organ to body weight ratios and gross and microscopic pathology

2

Dose descriptor:

NOAEL

Effect level:

>= 7 355 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: calculated from mean body weights and food consumption

3

Dose descriptor:

NOAEL

Effect level:

>= 5 657 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: calculated from mean body weights and food consumption

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1. Body weight (g) males.

	Diet 1	Diet 2	Diet 3	Diet 4
	Males
	Propylene glycol monostearate (%)
Week	0	1.5	3.36	7.52
0	74.7	75.2	75.2	74
1	120.3	123	121.5	120.1
2	166.5	171.6	167.3	163.7
3	218.1	228.2	221	220.3
4	270.2	286.6	277.7	277
5	315.1	333.7	325.8	321.1
6	350.9	371*	362.2	356.8
7	379.8	403*	392	390.7
8	406.8	428.5	417.7	419.1
9	430	454.2	444.2	443.7
10	451.2	476.3	469.6	469.2
11	468.6	493.3	488.5	488.5
12	486.6	510.7	508.7	504.7
13	503.2	527.4	528.2	523.2
Mean body weight Week 0-13	331.6	348.8	342.8	340.9

* significance: p < 0.05

Table 2. Body weight (g) females.

	Diet 1	Diet 2	Diet 3	Diet 4
	Females
	Propylene glycol monostearate (%)
Week	0	1.5	3.36	7.52
0	67.9	67.6	68.5	67.3
1	104	103.6	105.3	104.1
2	136.6	135.8	138.2	136.9
3	164.8	166.9	169.5	166.9
4	191	191.9	195.5	189.8
5	209.9	213.2	216	211.3
6	225.1	225.8	231.2	227.2
7	239.4	241.3	243.9	241.2
8	251.8	251.4	256.2	251
9	262.1	264.6	266.7	261.8
10	271.1	272.9	276	273.2
11	278	281.9	283.6	280.5
12	284.6	288.7	290.5	283.7
13	294.2	299.9	298.2	295
Mean body weight Week 0-13	212.9	214.7	217.1	213.6

 

Table 3. Food consumption (g) males.

Week	Diet 1	Diet 2	Diet 3	Diet 4
	Males
	Propylene glycol monostearate (%)
	0	1.50	3.32	7.52
1	106.1	115	119.1	110.8
2	127.3	144.5	148.8	132
3	162.6	162.8	159.6	149.5
4	168.6	188.6	182.6	175.3
5	183.3	203.6	199	187.1
6	185.1	201.5	195.8	191
7	192.1	202	203	198.6
8	200	210.5	197	199.8
9	184.1	203.3	192.1	198.6
10	186	204.6	206	200.8
11	186.1	204.3	193	199
12	188.3	211.6	198.1	196.5
13	187.3	197.5	193.3	194.5
Mean food consumption/week (g)	173.6	188.4	183.6	179.5
Mean food consumption/day (g)	24.8	26.9	26.2	25.6

Table 4. Food consumption (g) females. 

Week	Diet 1	Diet 2	Diet 3	Diet 4
	Females
	Propylene glycol monostearate (%)
	0	1.50	3.32	7.52
1	94.0	98.8	107	102.1
2	112.1	114.6	126.5	122.8
3	120.1	134.3	119.8	123.5
4	129	137.5	132.8	136.6
5	134.1	150	147.3	145.6
6	137.6	137.6	145	159.3
7	143.3	151.8	159	162.6
8	145.6	167.8	174.6	160.3
9	150.8	152.8	158.1	157.8
10	137	171.6	152.8	155.3
11	140	159.6	150.3	156.5
12	133.1	158	165.8	157.8
13	137	169	151	160.8
Mean food consumption/week (g)	135.8	159.0	140.5	146.2
Mean food consumption/day (g)	19.5	22.7	20.1	20.9

Table 5. Heamatology results white blood cell count (1000/cu. mm).

Week	Diet 1	Diet 2	Diet 3	Diet 4
	Females
	Propylene glycol monostearate (%)
	0	1.5	3.32	7.52
	Blood WBC (1000/cu. mm)
0	9.70	9.90	9.80	9.70
13	9.90	10.80	11.00	11.9*

* significance: p < 0.05

 Table 6. Average organ to body weight ratios (males).

Organ	Diet 1	Diet 2			Diet 3	Diet 4
	Propylene glycol monostearate (%)
	0		1.5	3.32		7.52
	Grams of Organ Weight/100 Grams of Body Weight
Gonads	0.701	0,641*			0,663	0,668

 * significane: p < 0.05

Table 7. Results of urine analyses.

Parameter	Diet 1	Diet 2	Diet 3	Diet 4
	Propylene glycol monostearate (%)
	0	1.5	3.32	7.52
Urine specific gravity Week 1, Males Week 1, Females	1.056 ± 0.002 1.051 ± 0.004	1.052 ± 0.005 1.053 ± 0.004	1.059 ± 0.002 1.048 ± 0.004	1.043 ± 0.003* 1.045 ± 0.001
Urine pH Week 1, Males Week 1, Females Week 12, Females	5.167 ± 0.167 5.00 ± 0.00 8.00 ± 0.3365	5.00 ± 0.00 5.00 ± 0.00 6.833 ± 0.307*	5.00 ± 0.00 5.00 ± 0.00 7.667 ± 0.333	5.00 ± 0.00 5.00 ± 0.00 6.833 ± 0.307*

 * significane: p < 0.05

Table 8. Summary table body weight and food consumption (g).

	Diet 1	Diet 2	Diet 3	Diet 4
	Propylene glycol monostearate (%)
	0	1.5	3.36	7.52
Mean body weight Week 0-13
Males	331.57	348.76	342.83	340.86
Females	212.89	214.68	217.09	213.56
Mean food consumption/week
Females	135.80	159.00	140.50	146.20
Males	173.61	188.45	183.65	179.50
Mean food consumption/day
Females	19.50	22.70	20.10	20.90
Males	24.80	26.92	26.24	25.64
Calculated mean dose value Week 0-13
Males	-	1.16	2.57	5.66
Females	-	1.46	3.21	7.36