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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
repeated dose toxicity: oral
Remarks:
other: Combined sub-chronic and developmental
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The published literature fulfilled basically scientific principles Without GLP compliance statement

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1984

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Iodide (in KI) was fed to male and female rats before and during breeding, to females only during gestation and lactation, and to their offspring after weaning (day 21 after birth) through to day 90, at levels of 0, 0.025, 0.05 or 0.1% (w/w) of the diet. The screening test battery of Cincinnati Psychoteratogenicity for rats as the method for assessing the psychotoxic potential of potassium iodide was used to investigate the hazard effects to parents and developmental toxic effects to embryo and offspring in 90 days.
GLP compliance:
no
Remarks:
Publication
Limit test:
no

Test material

Constituent 1
Reference substance name:
iodide in KI
IUPAC Name:
iodide in KI
Constituent 2
Reference substance name:
Potassium iodide
EC Number:
231-659-4
EC Name:
Potassium iodide
Cas Number:
7681-11-0
IUPAC Name:
potassium iodide
Details on test material:
Food grade potassium iodide (Mallinckrodt Inc.) was purchased from the Tab Chemical Company, Chicago, IL.

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
Parents (males and females): 14 days before mating; l-14 days during breeding.

Female only (mother): during gestation (22 days) and lactation (21 days)

Offspring: given dietary potassium iodide, at the level their parents had received, throughout the remainder of the experiment (up to 90 days of age for most animals and somewhat longer for those in avoidance testing).
Frequency of treatment:
Dietary treatments were given continuously to both males and females for 14 days before mating and for l-14 days during breeding, and to females only during gestation (22 days) and lactation (21 days). After weaning, the offspring were given dietary potassium iodide, at the level their parents had received, throughout the remainder of the experiment (up to 90 days of age for most animals and somewhat longer for those in avoidance testing).
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0 (two control groups) parents
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
0.025% (w/w)
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
0.05% (w/w)
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
0.1% (w/w)
Basis:
nominal in diet
No. of animals per sex per dose:
no data
Control animals:
yes, concurrent no treatment

Results and discussion

Effect levels

Dose descriptor:
NOAEL
Effect level:
0.5 ppm
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: 0.05% in diet.

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The concentration of 0.1% (w/w) of the diet of iodide, it just shows slight developmental toxicity to growing rats in 90 days, but these effects are not dose related.
Executive summary:

Potassium iodide (KI) was fed to male and female rats before and during breeding, to females only during gestation and lactation, and to their offspring after weaning (day 21 after birth) through to day 90, at levels of 0, 0.025, 0.05 or 0.1% (w/w) of the diet.

In rats killed on day 90 after birth KI reduced brain and body weight at a dose of 0.1% of the diet, and reduced body but not brain weight at a dose of 0.05% of the diet. No significant effect was found on absolute or relative thyroid weight at 90 days of age. Several additional behavioural effects were observed in the low-dose KI group, but because these effects were not dose-dependent, they were not regarded as reliable. 5-Azacytidine produced evidence of substantially greater developmental toxicity than KI. It was concluded that KI produced evidence of developmental toxicity consistent with a picture of impaired thyroid function. The inclusion of tests of functional development added useful evidence to the overall picture of KI developmental toxicity. No significant effect was found on absolute or relative thyroid weight at 90 days of age. Several additional behavioural effects were observed in the low-dose KI group, but because these effects were not dose-dependent, they were not regarded as reliable. 5-Azacytidine produced evidence of substantially greater developmental toxicity than KI. It was concluded that KI produced few evidence of developmental toxicity consistent with a picture of impaired thyroid function. The inclusion of tests of functional development added useful evidence to the overall picture of KI developmental toxicity.