Methoxyammonium chloride

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

according to GLP

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1984

Report date:

1984

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Bis(hydroxylammonium) sulphate

EC Number:

233-118-8

EC Name:

Bis(hydroxylammonium) sulphate

Cas Number:

10039-54-0

Molecular formula:

H3NO.1/2H2O4S

IUPAC Name:

bis(hydroxyammonium) sulfate

Details on test material:

- Name of test material (as cited in study report): Hydroxylamine Sulfate
- Analytical purity: 98 %
- Sample No.: 8185-40
- Shelf Life: greater than 1 year
- Stability under test conditions: stable at room temperature
- Storage condition of test material: room temperature

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Summit View Farms, Belvidere, USA
- Age at study initiation: 10 - 12 weeks
- Weight at study initiation: males: 2.12 to 3.06 kg; females: 2.41 to 3.21 kg
- Fasting period before study:
- Housing: single unit suspended, stainless steel, wire mesh cages with deotized animal cage board (DACB) as bedding material
- Diet: Purina Laboratory Chow 5321 (W. Fisher and Son), ad libitum except during actual dose administration
- Water: ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 20 +/-2 °C
- Humidity: 55 +/- 5 %
- Air changes: Air conditioned room
- Photoperiod: 12 hrs dark / 12 hrs light

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

Substance was moistened with equivalent weight of distilled water.
The test material was administered topically to the skin (clipped free of hair) of each test animal, as per SOP GTX-019.
A measured amount of the test material was placed on a gauze strip and was then applied to the skin of the rabbits. The animals were weighed immediately prior to dosing and the doses were based on that weight.

Duration of exposure:

under gauze cover for 24 h

Doses:

Dose levels tested: 0.5, 1.0, 1.5, and 2.0 g/kg bw

No. of animals per sex per dose:

male/female: 5 per group for 0.5, 1.5, and 2.0 g/kg bw
male: 5 per group for 1.0 mg/kg bw

Control animals:

yes, concurrent vehicle

Details on study design:

The animals were weighed on days -7, -1, 0, 1, 4, 7 and 14 (with day 0 being the day of dosing). The animals were observed for morbidity and mortality at least twice a day, and clinical signs were taken at least once a day. On day -1, pre-study clinical signs were taken. Morbidity, mortality and clinical signs were recorded immediately after observations were made. The Irwin neurobehavorial screen was performed on days 0, 1, 7 and 14. On day 14 the animals were sacrificed by suritol i.v. injection.
Necropsy was performed with each animal. The gross examination included an external (external inspection and palpation of the rabbit and examination of all external orifices and of skin at test and control sites) as well as an internal (examination of neck contents, all body cavities and their contents, all major viscera including cranial cavity with exterior and interior surfaces of the brain; thoratic, abdominal and pelvic cavities, interior lining of the stomach and portions of the bowel; weighing of the following organs: brain, lungs with trachea, liver, spleen, each kidney, each testis with epididymis and each ovary) examination. Bladder was expanded with fixative before removal and lungs were expanded with fixative before incision.
The following tissues were preserved in neutral buffered formalin: skin from test and control sites, brain and cervical cord, lungs and trachea, heart, thymus, thyrois with parathyroids and larynx, mesenteric and cervical lymph nodes, portions of stomach and bowel incl. duodenum, ileum and colon, liver, spleen, pancreas, adrenals, kidneys, urinary bladder, testes, epididymes, ovaries, tubes and uterus, portion of sternum with marrow.
Due to the striking degree of skin irritation and inflammation seen, special observations were made at 24, 48 and 72 h post-dosing to evaluate the degree of irritation.
Due to the clinical observations made during the course of the study blood was collected from all surviving animals on study day 14. The following determinations were made on this samples: WBC, RBC, Hemoglobin, Hematocrit, Reticulocytes, MCV, MCH, MCHC, PLT.

Statistics:

Statistical analysis was based on a decision-tree scheme for selecting statistical procedures.
Analysis of variance; Bartlett´s test; F max test; Student´s t-test; Cochran t-test:
Duncan (1955) Biometrics 11: 1 - 42
Snedecor GW and Cochran WG (1980) Statistical Methods; Iowa State University Press, Ames; Iowa, 7th edition

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 1 500 - < 2 000 mg/kg bw

Mortality:

7 animals which had received the highest dose died (4f/3m). It was not possible to calculate the LD50 from these data, but is possible to state that the LD50 is between 1.5 and 2.0 g/kg bw.

Clinical signs:

other: There were scattered incidences of a number of signs that were not clearly associated with treatment with the test material. Clearly associated with exposure were a number of signs. These included marked skin irritation (all doses), cyanosis (all doses),

Gross pathology:

Gross necropsy observations:
A number of observations occured in a scattered and random manner and were not related in any manner to treatment. However, several observations were seemingly clearly associated to treatment. In all cases these were in high dose animals, and included lung, liver and heart discolourations, the stomaches containing blood and mucoid-like material, enlarged and discoloured spleen, discoloured and congested kidneys with pronounced vascularization, blood in the bladder, discoloured/brown blood and necrotic areas of the skin.

Organ weights and organ/body weight ratios:
Numerous statistically significant alterations occured in the organ weights and organ to body weight ratios of both sexes. Lung weights and -ratios were significantly increased in the 1.5 g/kg bw male group only. Liver weights were increased in all male groups, but only statistically significant in the 1.0 g/kg bw group. The liver to body weight ratio was significantly decreased in the 0.5 g/kg bw male group, while this ratio was increased in all other male treatment groups (only statistically significant in the 1.0 g/kg bw animals). In females liver weights were significantly decreased in all dose groups. Spleen weights were increased in the three highest male dose groups while no clear pattern of alteration occured in females. Kidney weights and ratios were significantly altered in the single surviving female of the highest dose group. Testes weights were significantly depressed in the 1.0 g/kg bw males and significantly increased in the 1.5 mg/kg bw males. Ovarian weights and ratios likewise showed no clear pattern in the alterations which occured. Brain weights and ratios were depressed in the surviving high dose animals of both sexes. The overall pattern of organ weight effects was one which indicated no specific target organ from acute exposure, but rather generallized systemic toxicity.

Other findings:

Neurobehavioral Screen:
The signs observed in the neurobehavioral screen were limited to few scattered random observations (unrelated to either treatment or control) and to cyanosis and hypothermia in treatment groups.
Histopathology:
An acute hemorrhagic dermatitis was present in each of the 7 rabbits that died. The skin lesion was characterized by hemorrhage, edema, vascular congestion and massive heterotrophilic infiltrates. It appeared that the deaths may have been related to circulatory collapse (shock) brought on by neurogenic pain reflexes associated with skin lesions. Lesions in the liver and kidneys supported this contention.
Few compound-associated changes were present in the survivors: The skin contained residual but healing changes in 1/3 survivors at the high dose level 1/10 at the mid-level and in 1/5 at the low intermediate dose level. The spleens of 3/3 high and 4/10 mid-dose terminated rabbits contained increased amounts of hemosiderin pigment. Whether the red cell damage was associated with the single administration of the compound is not known, however, the compound is known to produce methemoglobinemia.
Other tissue alterations wer judged to have been unrelated to the treatment with the test material.

Hematology:
White blood cell counts were significantly depressed in a dose-related fashion in the 1.5 and 2.0 g/kg bw groups. A dose-related trend in the male RBC was evident at the lowest dose tested.
Hemoglobin levels were significantly depressed in surviving high-dose animals of both sexes. Hematocrit was also significantly depressed in the high dose female and in the 1.5 and 2.0 g/kg bw males. Mean corpuscular volume and mean corpuscular hemoglobin were significantly increased in the 1.5 and 2.0 g/kg bw groups of both sexes.
MCHC was significantly increased in the 1.0, 1.5 and 2.0 g/kg bw males annd in the 1.5 and 2.0 g/kg bw females.
Platelets were depressed in the 2.0 g(kg bw males As such an effect showed up in no oher dose group and there was no dose trend, this result would seem to be unrelated to treatment.
Reticulocyte counts were elevated in the males, though significancy only in the 2.0 g/kg bw group was seen. A similar pattern of elevation also occured in the females, with the increase being significant only in th 1.5 g/kg bw group.

Applicant's summary and conclusion

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

Under the conditions of the test (similar to OECD guideline 402) for acute toxicity after dermal application, the LD50 was > 1500 < 2000 mg/kg body weight for male and female rabbits.

Executive summary:

The acute dermal toxicity associated with 24 h skin exposure to the test material was evlauated in rabbits at dose levels 0.5, 1.0, 1.5 and 2.0 g/kg bw. The LD50 of the test material was found to be between 1.5 and 2.0 g/kg bw for male and female rabbits under the experimental conditions chosen. Therefore the test material has to be classified as Xn R21 according to EU criteria and as Category 4 according to GHS criteria. Effects were also seen which are indicative of the blood being the primary systemic target organ. These included cyanosis, hypothermia, reductions in red blood cell counts, increases in reticulocyte counts and enlarged spleen. Effects extended down to the lowest doses tested. Additionally, a severe skin irritation response was seen in all test levels evaluated.