Potassium (S)-lactate

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Publication in Japanese; the tested substance calcium lactate is the calcium salt of lactic acid. As the target substance isobutyl-R-lactate hydrolyses into isobutanol and lactic acid, calcium lactate is a suitable read-across partner to assess the toxicity of isobutyl-R-lactate.

Data source

Reference

Reference Type:

publication

Title:

Subchronic oral toxicity study of calcium lactate in F344 rats.

Author:

Matsushima, Y., Onodera, H., Nagaoka, T., Todate, A., Shibutani, M., Maekawa, A., Kurokawa, Y. and Hayashi, Y.

Year:

1989

Bibliographic source:

Eisei Shikenjo Hokuku 107: 78-83

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:

not specified

Principles of method if other than guideline:

13 week feeding study with calcium lactate.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Calcium dilactate

EC Number:

212-406-7

EC Name:

Calcium dilactate

Cas Number:

814-80-2

IUPAC Name:

calcium bis(2-hydroxypropanoate)

Test animals

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

Animals: Five week-old SPF male and female F344/DuCrj rats (Charles River Laboratories Japan, Inc.) were fed and acclimated for 1 week and then divided into 2 groups.
Feeding conditions: White flakes were used as bedding in a plastic cage. The animals were fed in a animal feeding room of a semi-barrier system.

Administration / exposure

Route of administration:

other: both feed and water

Details on oral exposure:

Experiment I
Calcium lactate was dissolved in ion-exchanged water at concentrations of 5, 2.5, 1.25, 0.6, and 0.3% since it was water-soluble and stable. Each experimental group was given ad libitum one of these solutions as the drinking water for 13 weeks. The control group was similarly given only ion-exchanged water. Each group was given ad libitum elemental diet (CRF-1 manufactured by Oriental Yeast Co., Ltd.). The highest dose was set based on the fact that the maximum solubility of this product in water was 5%. Each 5 male and female rats from each group were used, and all the surviving animals were sacrificed for autopsy in the 13th week.

Experiment II
Ten male and ten female were used. Calcium lactate was mixed at 30, 20, 10, 5, and 0% in the standard blend of purified diet [B-blend powder diet (Oriental Yeast Co., Ltd.)] and given ad libitum to the animals for 20 weeks. Each 5 male and female rats from each group were autopsied in the 8th week after the start of the experiment, and the remaining rats were sacrificed for autopsy in the 20th week.

Experiment III
Twenty male rats were divided into 2 groups. One group was given the B-blend powder diet, while the other group was given at libitum the CRF-1 solid diet. The rats in both groups were given ad libitum ion-exchanged water as the drinking water. Five rats from each group were sacrificed in the 4th week after the start of the experiment and the remaining rats were sacrificed for autopsy in the 8th week.

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

ad libitum

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0.3 other: %

Remarks:

dissolved in water

Doses / concentrations 2

Dose / conc.:

0.6 other: %

Remarks:

dissolved in water

Doses / concentrations 3

Dose / conc.:

1.25 other: %

Remarks:

dissolved in water

Doses / concentrations 4

Dose / conc.:

2.5 other: %

Remarks:

dissolved in water

Doses / concentrations 5

Dose / conc.:

5 other: %

Remarks:

dissolved in water

Doses / concentrations 6

Dose / conc.:

0 other: %

Remarks:

in food

Doses / concentrations 7

Dose / conc.:

5 other: %

Remarks:

in food

Doses / concentrations 8

Dose / conc.:

10 other: %

Remarks:

in food

Doses / concentrations 9

Dose / conc.:

20 other: %

Remarks:

in food

Doses / concentrations 10

Dose / conc.:

30 other: %

Remarks:

in food

No. of animals per sex per dose:

10

Control animals:

yes

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Minimal

BODY WEIGHT: Yes

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

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: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 8 wks / end of study

CLINICAL CHEMISTRY: Yes

URINALYSIS: Yes

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: No data

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

All observed effects could be attributed to calcium overload/imbalance. No lactate toxicity was observed.

Effect levels

Dose descriptor:

NOAEL

Effect level:

50 000 mg/L drinking water

Sex:

male/female

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

5% Calcium lactate in drinking water or diet does not result in adverse effects attributable to lactate.

Executive summary:

In a subchronic toxicity study (similar to OECD 408), Calcium lactate was administered to Fischer 344/DuCrj rats.

In Experiment I, Calcium lactate was mixed at 5, 2.5, 1.25, 0.6, and 0.3 % in the drinking water and the rats were given this solution ad libitum for 13 weeks. As a result, the inhibition of body weight gain in the 5 % group fell within 10 % of that in the control group. Some examination values showed variations in the hematological and hematobiochemical studies, but no controversial findings were obtained in the pathohistological search. Since the highest solubility of Calcium lactate is 5%, experiments II and III were carried out by giving blended diet in order to study the toxicity at higher doses. In experiment II, Calcium lactate was mixed at concentrations of 30, 20, 10, and 5 % in the B-blend powder diet and then the rats were given this diet ad libitum for 20 weeks. In experiment III, the rats were given the CRF-1 or the B-blend powder diet ad libitum for 8 weeks. As a result, in experiment II, nephrocalcinosis was observed in all the groups including the control group. The degree of the lesion was in reverse correlation with the administered concentrations of calcium and the lesion was seen more intensely in female rats. In experiment III, nephrocalcinosis resulting from the administration of the B-blend diet was already observed in the 4th week. Nephrocalcinosis as observed in experiments II and III was attributable to the small Ca/P value in the B-blend diet.

From the above results, the optimal dose for a long-term toxicity/carcinogenicity study has been determined to be 5 and 2.5 % based on the values obtained from experiment I.