Registration Dossier

Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
29 NOV 1989 to 30 JAN 1990
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
The study was performed following OECD TG 401 in GLP conditions. T

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report Date:
1990

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
yes (incl. certificate)
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Betaine anhydrous, chemically pure (>97% pure)

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
male/female
Details on test animals and environmental conditions:
Animals: young adult CD strain female rats, supplied by Charles River (UK) Ltd. Margate, Kent, England, 4 weeks old upon arrival.
Housing: The animals were bred and housed under barriered conditions in a limited access facility. The housing conditions were under daily monitoring (T = 18-25C, relative humidity 40-70%). 12 hours light cycle was employed.
Diet: commercially-available complete pelleted diet (Laboratory animal diet No1, from Biosure, Manea, Cambridgeshire, England) without restrictions, except removal of food 18 hours before administration of test material.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
Single oral administration
Doses:
5000, 10000, 12500, 15000 and 20000 mg/kg bodyweight
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
Pre-exposure period: Clean cages were prepared the day before delivery of the animals. On arrival, each animal was inspected before being aceepted. All animals were weighed on arrival and the range of bodyweight was recorded. Five animals of the same sex were non-selectively allocated to each cage. Tail tattoos identifying each individual within the cage were made within one day of delivery. The sex of each animal was checked at the same time.An acclimatisation period of atleast six days was allowed. A daily check of the condition of the animals was made. Food was removed at approx 1700 hours on the day before dosing. Each cage was labelled with details of the schedule number, unique cage reference number, treatment regime, animal identification numbers and sex of occupants, Project License umber and responsible licensee. Pre-fasted bodyweight was recorded on the day prior to dosing and ranged for male s107-139g and for females 102-128g.
Administration: given betaine anhydrous dose was dissolved 40 ml /kg bodyweight. Flexible catheter (8-choke) was passed down the oesophagus allowing instillation of the dose into the lumen of the stomach.
Observation period: three separate inspections were made during the first hour after dosing and two further inspections during the remainder of day 1. From day 2 onwards, the animals were inspected twice daily (morning, afternoon). The type, time of onset and duration of reactions to treatment and circumstances of any death were recorded. The bodyweight was recorded at days 1,8 and 15, the test was terminated on day 15.
Necropsy: carcases were stroed at +4C until trained necropsy staff were available. Necropsy was thoroughly studied, all abnormalitites were described or the normal appearance or major organs was confirmed.
Statistics:
Probit analysis was employed to determine the acute median lethal dosage, 95% confidence interval and slope of the dose response curve of the test material for both sexes. The calculations were performed by the GLIM statistics program using a special macro program.

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LD50
Effect level:
>= 11 204 mg/kg bw
95% CL:
>= 8 616 - <= 13 792
Remarks on result:
other: Slope (degrees) 88
Sex:
female
Dose descriptor:
LD50
Effect level:
> 11 148 mg/kg bw
95% CL:
> 9 929 - < 12 367
Remarks on result:
other: Slope (degrees) 83
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 11 179 mg/kg bw
95% CL:
> 10 454 - < 11 904
Remarks on result:
other: Slope (degrees) 85
Mortality:
Dosage (mg/kg), male, female, combined
5000, 0/5, 0/5, 0/10
10000, 0/5, 1/5, 1/10
12500, 5/5, 4/5, 9/10
15000, 5/5, 5/5, 10/10
20000, 5/5, 5/5, 10/10
Clinical signs:
Following symptoms were recorded per dose per time per animal: lethargy, decreased motor activity, prone posture, ataxia,musculature - tremor, bradypnoea, hyperpnoea, piloerection, ungroomed appearance, hunched posture and death.
With 5000 mg/kg: decreased motor activity, ataxia, ungroomed appearance, hunched posture which all disappeared within 2-4 days.
With 10000 mg/kg: lethargy, decreased motor activity, ataxia, ungroomed appearance, bradypnoea, hyperpnoea, hunched posture which all disappeared within 5-6 days.One female presented all symptoms and died on day 2.
With 12500 mg/kg: all symptoms present and died on day 1-3. One female survived and appeared normal by day 3.
With 15000 mg/kg: all symptoms present and died within 5 hours.
With 20000 mg/kg: all symptoms present and died within 3 hours.
Body weight:
All survived animals achieved expected bodyweight gains. Body weight gain or decrease per dose group:
5000 mg/kg: males +100%, females 65%
10000 mg/kg: males +100%, females 60%
12500 mg/kg: all dead
15000 mg/kg: all dead
20000 mg/kg: all dead
Gross pathology:
Necropsy observations per dose group:
5000 mg/kg: no significant lesions
10000 mg/kg: no significant lesions, one dead female yellow ventral staining, yellow serous fluid in stomach, small intestine and caecum
12500 mg/kg: dead individuals exhibit externally yellow/brown muzzle and perianal staining, internalyl yellow ventral staining, yellow serous fluid in stomach, small intestine and distented caecum
15000 mg/kg: mainly no significant lesions
20000 mg/kg: dead individuals exhibit externally yellow/brown muzzle and perianal staining, internalyl yellow ventral staining, yellow serous fluid in stomach, small intestine, distented caecum and darkened brain.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The defined LD50-value for betaine is 11179 mg/kg (female/male), and it can be considered as practically nontoxic. The LD50-value is well above of the limit for classification (2000 mg/kg).
Executive summary:

An acute oral toxicity study was perfomed according to OECD Guideline 401. Male and female rats (5/sex) were administered single oral doses of 5000, 10000, 12500, 15000, or 20000 mg/kg. The defined LD50-value for the test substance is 11179 mg/kg (female/male).