Manganese oxalate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Between 02 May 2012 and 23 May 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well performed GLP and OECD guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Manganese oxalate, dihydrate

IUPAC Name:

Manganese oxalate, dihydrate

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Five male and five female Wistar (RccHan:WIST) strain rats were supplied by Harlan Laboratories UK Ltd., Oxon, UK. On receipt the animals were randomly allocated to cages. The females were nulliparous and non pregnant. After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card. At the start of the study the animals weighed at least 200 g, and were eight to twelve weeks of age. The weight variation did not exceed ±20% of the mean weight for each sex.

The animals were housed in suspended solid floor polypropylene cages furnished with woodflakes. The animals were housed individually during the 24 Hour exposure period and in groups of up to four, by sex, for the remainder of the study. Free access to mains drinking water and food (2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK) was allowed throughout the study. The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.

The temperature and relative humidity were set to achieve limits of 19 to 25°C and 30 to 70% respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

arachis oil

Details on dermal exposure:

The appropriate amount of test item, moistened with arachis oil BP, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area).

Duration of exposure:

24 hours

Doses:

2504 mg/kg bodyweight (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight)

No. of animals per sex per dose:

5 Male
5 Female

Control animals:

not required

Details on study design:

On the day before treatment the back and flanks of each animal were clipped free of hair.
In the absence of data suggesting the test item was toxic, one male and one female rat were initially treated with the test item at a dose level of 2504 mg/kg (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight).
The appropriate amount of test item, moistened with arachis oil BP, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area). A piece of surgical gauze was placed over the treatment area and semi occluded with a piece of self adhesive bandage. The animals were caged individually for the 24 hour exposure period. Shortly after dosing the dressings were examined to ensure that they were securely in place.
After the 24-hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with arachis oil BP to remove any residual test item.
As no mortalities were noted a further group of animals (four males and four females) was similarly treated with the test item at a dose level of 2504 mg/kg bodyweight (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight) to give a total of five males and five females. After the 24 hour contact period the bandages were carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with arachis oil BP to remove any residual test item. These animals were returned to group housing for the remainder of the test period.
The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days.
After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J H (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.31:

EVALUATION OF SKIN REACTIONS
Erythema and Eschar Formation Value

No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beef redness) to slight eschar formation (injuries in depth) 4

Oedema Formation

No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 millimetre) 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure) 4

Any other skin reactions, if present were also recorded.
Individual bodyweights were recorded prior to application of the test item on Day 0 and on Days 7 and 14.
At the end of the study the animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Statistics:

No statistical analysis was performed.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

other: the anhydrous form of the substance/kg bodyweight

Remarks on result:

other: equivalent to >2504 mg of the test item (= the dihydrous form) per kg body weight

Mortality:

There were no deaths.

Clinical signs:

There were no signs of systemic toxicity.

Body weight:

Individual bodyweights and weekly bodyweight changes are given in Table 1.
One female showed bodyweight loss during the first week but expected gain in bodyweight during the second week. One other female showed bodyweight loss during the first and second weeks. The remaining animals showed expected gains in bodyweight over the study period.

Gross pathology:

No abnormalities were noted at necropsy.

Other findings:

Dermal Reactions
Individual dermal reactions are given in Table 2 and Table 3.
Very slight erythema was noted at the test sites of six animals. Small superficial scattered scabs were also noted at the test site of one male. All signs of dermal irritation were fully reversible within 9 days. There were no signs of dermal irritation noted at the test sites of the remaining animals.

Any other information on results incl. tables

Table 1              Individual Bodyweights and Weekly Bodyweight Changes

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight Change (g) During Week
		0	7	14	1	2
2504*	1-0 Male	244	265	300	21	35
	3-0 Male	222	250	277	28	27
	3-1 Male	223	249	280	26	31
	3-2 Male	226	247	272	21	25
	3-3 Male	249	287	311	38	24
	2-0 Female	201	195	216	-6	21
	4-0 Female	200	201	204	1	3
	4-1 Female	201	196	195	-5	-1
	4-2 Female	202	211	225	9	14
	4-3 Female	204	208	211	4	3

*= Equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight

Table 2       Individual Dermal Reactions - Males

Dose Level mg/kg	Animal Number and Sex	Observation	Effects Noted After Initiation of Exposure (Days)
			1	2	3	4	5	6	7	8	9	10	11	12	13	14
2504*	1-0 Male	Erythema Oedema Other	0 0 0	1 0 0	1 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	3-0 Male	Erythema Oedema Other	1 0 0	1 0 0	1 0 0	1 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	3-1 Male	Erythema Oedema Other	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 Ss	0 0 Ss	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	3-2 Male	Erythema Oedema Other	1 0 0	1 0 0	1 0 0	1 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	3-3 Male	Erythema Oedema Other	1 0 0	1 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0



* = Equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight

0 = No reactions Ss = Small superficial scattered scabs

                                                                                       

Table 3       Individual Dermal Reactions – Females

Dose Level mg/kg	Animal Number and Sex	Observation	Effects Noted After Initiation of Exposure (Days)
			1	2	3	4	5	6	7	8	9	10	11	12	13	14
2504*	2-0 Female	Erythema Oedema Other	1 0 0	1 0 0	1 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	4-0 Female	Erythema Oedema Other	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	4-1 Female	Erythema Oedema Other	1 0 0	1 0 0	1 0 0	1 0 0	0 0 0	0 0 0	1 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	4-2 Female	Erythema Oedema Other	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
	4-3 Female	Erythema Oedema Other	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0

* = Equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight 0 = No reactions

Applicant's summary and conclusion

Interpretation of results:

other: The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2504 mg/kg bodyweight (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight).

Conclusions:

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2504 mg/kg bodyweight (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight).

Executive summary:

The study was performed to assess the acute dermal toxicity of the test item in the Wistar strain rat. The method was designed to be compatible with the following: OECD Guidelines for the Testing of Chemicals No. 402 "Acute Dermal Toxicity" (adopted 24 February 1987) Method B3 Acute Toxicity (Dermal) of Commission Regulation (EC) No. 440/2008. Initially, two animals (one male and one female) were given a single, 24 hour, semi‑occluded dermal application of the test item to intact skin at a dose level of 2504 mg/kg bodyweight (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight). Based on the results of the initial test, a further group of eight animals (four males and four females) was similarly treated. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

There were no deaths. There were no signs of systemic toxicity. Very slight erythema was noted at the test sites of six animals. Small superficial scattered scabs were also noted at the test site of one male. All signs of dermal irritation were fully reversible within 9 days. There were no signs of dermal irritation noted at the test sites of the remaining animals. One female showed bodyweight loss during the first week but expected gain in bodyweight during the second week. One other female showed bodyweight loss during the first and second weeks. The remaining animals showed expected gains in bodyweight over the study period. No abnormalities were noted at necropsy.

The acute dermal median lethal dose (LD₅₀) of the test item in the Wistar strain rat was found to be greater than 2504 mg/kg body weigh (equivalent to 2000 mg of the anhydrous form of the substance/kg bodyweight).