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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meeting generally accepted scientific prinicples, acceptable for assessment.

Data source

Reference
Reference Type:
publication
Title:
Long-term toxicity of the surfactant alpha-olefin sulphonate (AOS) in the rat.
Author:
Hunter, B. and Benson, H.G.
Year:
1976
Bibliographic source:
Toxicology 5: 359-370

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Study was performed before actual guideline was established.
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: solid
Details on test material:
- Name of test material (as cited in study report): alpha-olefin-sulphonate
- Analytical purity: 97.93 % active ingredient
- Impurities (identity and concentrations): moisture 1.4 %, NaOH 0.01 %, inorganic salt 0.02 %, sultones/oil 10.6 % (mainly alkane-1,4-sultone)
- Composition of test material, percentage of components: mixture of alkenyl sulphonate and hydroxyalkane sulphonate (60.4 : 39.6 % w/w); Chain-length distribution C14:C16:C18 = 25:45:30
- Other: Source: Lion Fat and Oil Co. Ltd., Tokyo, Japan; pH 7.7 (1% solution)

Test animals

Species:
rat
Strain:
other: CFY (hysterectomy-derived from SD)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Anglia Laboratory Animals (formerly Carworth Europe), Huntingdon, England
- Weight at study initiation: Mean group weights males 113.5 g, females 107 g
- Housing: 5/cage
- Diet (e.g. ad libitum): Spratts Laboratory Diet No. 2 containing the test substance (except control group), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 50 ± 5
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
DIET PREPARATION
- Rate of preparation of diet (frequency): A premix of the diet containing 5000 ppm test substance was prepared each week; from this, various dietary concentrations were obtained by blending in appropriate amounts of unadulterated powdered Laboratory Diet.
- Mixing appropriate amounts with (Type of food): Spratts Laboratory Diet No. 2
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
104 weeks
Frequency of treatment:
continuously, in the diet
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
males: 39, 96, 195 mg/kg bw/day; females: 57, 132, 259 mg/kg bw/day
Basis:
actual ingested
Remarks:
Doses / Concentrations:
1000, 2500, 5000 ppm
Basis:
nominal in diet
No. of animals per sex per dose:
50
Control animals:
yes, plain diet
Details on study design:
- Dose selection rationale: based on information from other published studies (acute, long-term, prenatal development)

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: not specified
- Cage side observations included: clinical signs


DETAILED CLINICAL OBSERVATIONS: Yes, time of onset, dimensions and locations of all palpable tumors
- Time schedule: not specifed


BODY WEIGHT: Yes
- Time schedule for examinations: initially and weekly thereafter


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
Food consumption per cage determined weekly and mean daily diet consumption was calculated.
Weekly compound intake was calculated from the consumption and group mean body weight data. The mean daily intakes over the 2 years of treatment were calculated.


FOOD EFFICIENCY:
Food conversion ratios were calculated.


WATER CONSUMPTION: Assessed by inspection of the water bottles. Regular measurement was not performed as there was no evidence of a treatment-related effect.


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: initially and after 25, 51, 78 and 104 weeks
- Dose groups that were examined: control and 5000 ppm group


HAEMATOLOGY: Yes
- Time schedule for collection of blood: at 13, 25, 52, 78 and 103 weeks
- Anaesthetic used for blood collection: Yes (not specified)
- Animals fasted: No data
- How many animals: 10 male and 10 female animals from control and 5000 ppm groups
- Parameters examined: packed cell volume, haemoglobin, red cell count, total and differential white cell counts, mean corpuscular haemoglobin and mean cell volume


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at 13, 25, 52, 78 and 103 weeks
- Animals fasted: No data
- How many animals: 10 male and 10 female animals from control and 5000 ppm groups
- Parameters examined: plasma urea, plasma glucose, total serum proteins (with electrophoresis and AG ratio), serum alkaline phosphatase, serum glutamic pyruvic transaminase, electrolyte levels


URINALYSIS: Yes
- Time schedule for collection of urine: at 12, 25, 51, 77 and 103 weeks
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters examined: urine samples of 10 male and 10 female animals of the control and the 5000 ppm group wer tested for pH, specific gravity, protein, reducing substances, glucose, ketones, bile pigments, urobilin and blood pigments. In addition , the spun deposit was examined for the presence of various cell types.


NEUROBEHAVIOURAL EXAMINATION: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes (particular attention paid to any distortion, swelling or lesion suggestive of neoplasia; further brain, pituitary, thyroids, spleen, heart, liver, kidneys, adrenals, testes, ovaries, uterus of all animals were weighed; samples of these tissues and of lungs, cervical and mesenteric lymph nodes, thymus where present, pancreas, urinary bladder, glandular and non-glandular stomach were preserved in buffered 10% formalin; eyes were preserved in Davidson's fixative, and bone marrow smears were prepared and fixed in methanol; all nodules, tissue masses and macroscopically abnormal tissues were routinely preserved, with samples of adjacent tissue where appropriate; in addition, samples of salivary gland,trachea, oesophagus, aorta, second eye, tongue, mammary gland, jejunum, mid-colon, sciatic nerve, prostate, skeletal muscle, skin and bone were routinely preserved, but processed only if specifically required)

HISTOPATHOLOGY: Yes (adrenals, thyroids, ovaries, spleen, lymph nodes and pituitary gland performed routinely for every animal; bone marrow smears, and all macroscopically observed lesions suggestive of neoplasia were also examined; in addition, samples of important tissues from 10 male and 10 female control animals, and from 20 male and 20 female rats of the 5000 ppm group were examined for non-neoplastic changes; sections of liver and kidney from all animals examined for toxic changes were stained for fat deposits, glycogen, or basement membranes; macroscopically abnormal tissues from animals which died during the study were examined to confirm the cause of death)
Statistics:
Differences in tumour incidence were directly compared using Fisher's Exact Probability Test as a 1-tailed test. Student's t-test was employed to assess the significance of other intergroup differences.

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):
not 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):
no effects observed
Ophthalmological findings:
no effects observed
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
No treatment-related clinical signs observed. Highest mortality occurred in the 2500 ppm group, but not significantly different from control group. No indication of a treatment-related effect. The apparent causes of death were those usually seen in this strain of rats; the more common conditions included renal and respiratory infections and tumours of the subcutaneous tissues and pituitary gland, which were distributed evenly between the groups.

BODY WEIGHT AND WEIGHT GAIN
During the first 13 weeks there were no adverse changes in growth rate. Between weeks 14 and 26, however, both males and females receiving 5000 ppm showed a slight depression of bodyweight gain.the low and mid-dose groups were not affected in this way, and between weeks 26 and 96 all treated groups achieved weight gains comparable with those of the control group.
Males of all groups showed some loss of weight during the last 2 months of the study which was probably attributable to ageing , although treated males showed greater loss than did the controls.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
During the first year of treatment a minor depression of food intake was recorded in female rats receiving 5000 ppm in the diet which was not apparent during the second year. Food intake of rats receiving 1000 or 2500 ppm remained comparable (within ±5%) with that of the control group throughout the study.

FOOD EFFICIENCY
Food conversion ratios were not affected by treatment.

WATER CONSUMPTION
Not examined on a regular basis as there seemed to be no treatment-related effects.

OPHTHALMOSCOPIC EXAMINATION
No treatment-related abnormalities.

HAEMATOLOGY
No significant abnormalities.

CLINICAL CHEMISTRY
No significant abnormalities.

URINALYSIS
No significant abnormalities.

ORGAN WEIGHTS
No treatment-related changes. The few statistically significant differences between controls and treated groups were considered to occur by chance or to be attributable to bodyweight differences.

GROSS PATHOLOGY
Pathological conditions seen at post mortem examination in rats sacrificed at 104 weeks were those commonly seen in old rats. Chronic respiratory disease, renal pallor and cortical scarring, pituitary enlargement, ovarian cysts and subcutaneous masses were particularly noted and were commonly seen in some rats from all groups. No treatment-related effects on the reproductive organs were observed.

HISTOPATHOLOGY: NON-NEOPLASTIC
No treatment-related changes were observed. Histopathology of macroscopically abnormal tissues from animals dying during the study did not revael any condition which could be attributed to treatment.

HISTOPATHOLOGY: NEOPLASTIC (if applicable)
There were no significant intergroup differences in the overall incidence of benign tumours, malignant tumours or tumours of any type:
Pancreatic islet cell tumours in male rats were confined to the treated groups, with the highest incidence (4 rats) occurring in the 1000 ppm group. However, the similarity to the historical controls and the absence of any dose-related trend suggests a random distribution in the present study.

Adrenal tumours were found in a total of 8 males receiving 2500 ppm. However, only 2 males were affected in the high dose group, the same amount as in the control group. Therefore, the high occurrence of adrenal tumours in the 2500 ppm males was not considerd to be treatment-related.

The highest incidence of thyroid tumours occurred among females at 2500 ppm. Again, this was not considerd to be treatment-related as the incidence of thyroid tumours in the high dose group was identical to that of the control females.

Pituitary tumours were common in both control and treated rats, with the lowest incidence among males of the high dose group.

Mammary gland tumours were very common in females of all groups, there were no significant intergroup differences. The number of females bearing multiple mammary gland tumours (2 or more) were 14/30 (47%) in the controls, 17/33 (52%) in the low-, 16/38 (42%) in the mid-, and 18/35 (51%) in the high-dose group. The apparent group mean induction periods (the average time taken for the first mammary tumour in each rat to appear) for the female groups were 84 wks for the control and low-dose groups, 83 wks for the mid- and 85 wks for the high-dose group.

HISTORICAL CONTROL DATA (if applicable)
Incidences of islet cell tumours as high as those seen in the present study have been recorded among male control CFY rats used in other studies carried out in the same laboratory.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
>= 195 mg/kg bw/day (nominal)
Sex:
male
Basis for effect level:
other: corresponding to 5000 ppm in the diet over 2 years
Dose descriptor:
NOAEL
Effect level:
>= 259 mg/kg bw/day (nominal)
Sex:
female
Basis for effect level:
other: corresponding to 5000 ppm in the diet over 2 years
Dose descriptor:
NOEL
Effect level:
96 mg/kg bw/day (nominal)
Sex:
male
Basis for effect level:
other: body weight gain; corresponding to 2500 ppm in the diet over 2 years
Dose descriptor:
NOEL
Effect level:
132 mg/kg bw/day (nominal)
Sex:
female
Basis for effect level:
other: body weight gain; corresponding to 2500 ppm in the diet over 2 years

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Group mean changes in body weight:

Group

Initial weight (g)

Increase in body weight (g)

Wks 0-13

Wks 14-26

Wks 27-52

Wks 53-104

Males

Control

114

390

108

144

132

1000 ppm

113

385

112

149

69

2500 ppm

113

390

107

146

56

5000 ppm

114

376

91*

138

69

Females

Control

107

170

64

83

143

1000 ppm

107

170

55

76

155

2500 ppm

107

186**

59

92

122

5000 ppm

107

180

46***

91

157

*p<0.05

** p<0.01

***p<0.001

Applicant's summary and conclusion