Ammonia, anhydrous

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline and GLP compliant proprietary study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Diammonium phosphate

IUPAC Name:

Diammonium phosphate

Constituent 2

Reference substance name:

Diammonium hydrogenorthophosphate

EC Number:

231-987-8

EC Name:

Diammonium hydrogenorthophosphate

Cas Number:

7783-28-0

IUPAC Name:

diammonium hydrogen phosphate

Details on test material:

Diammonium phosphate (DAP), 17.93% NH4 and 46.86% P2O5 equivalent.

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

Male and female Crl:CD(SD)IGS BR rats

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: water purified by reverse osmosis

Details on oral exposure:

The substance was administered daily via gavage.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

No information

Duration of treatment / exposure:

The exposure period for the toxicity subgroup was 35 days, while the exposure period for the reproductive subgroup was at most 28 days among male and 53 days among females.

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

250 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

750 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

1 500 mg/kg bw/day (nominal)

No. of animals per sex per dose:

There were 5 males and 5 females per dose group in the toxicity group, and 5 males and 10 females per dose in the reproductive toxicity group.

Control animals:

yes, concurrent vehicle

Details on study design:

Doses were selected based on parameters assessed in a range-finding study at concentrations up to 1,000 mg/kg/day.

Animals comprising the toxicity subgroup (5 males and 5 females per dose group) were administered Diammonium Phosphate (DAP) for 5 weeks (7 days/week) via gavage administration. Animals comprising the reproductive subgroup (5 males and 10 females) were administered DAP for a period encompassing approximately 53 continuous days via oral gavage: 14 days of initial treatment, plus a maximum of 14 days of cohabitation to ensure mating, and among females, at least 25 days to litter and rear their young until day 4 of age.

Positive control:

Not required for this study type.

Examinations

Observations and examinations performed and frequency:

Toxicity subgroup:

Functional observations (sensory reactivity, grip strength, motor activity) and bleeds for haematology and blood chemistry were conducted during week 5 of treatment (see below).

Histology for reproductive subgroup animals was restricted to retained reproductive organs (and any other abnormalities observed at necropsy).

Sacrifice and pathology:

In the toxicity subgroup: organ weights (adrenals, brain, epididymides, heart, kidney, liver, ovaries, pituitary, prostate, seminal vesicles, spleen, testes, thymus, thyroids (with parathyroids) and uterus with cervix) were recorded at termination during Week 6. The following organs and tissues (and any other abnormalities observed at necropsy) were processed for microscopic examination: adrenals, aorta, brain, caecum, colon, duodenum, epididymides, eyes, heart, ileum, jejunum, kidneys, liver, lungs, lymph nodes, mammary area, oesophagus, ovaries, pancreas, pituitary, prostate, rectum, salivary glands, sciatic nerves, seminal vesicles, skin, spinal cord, spleen, sternum (bone marrow), stomach, testes, thymus, thyroid, trachea, urinary bladder, uterus and vagina.

Other examinations:

No information

Statistics:

No information

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

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:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

Toxicity subgroup:
There were no treatment-related deaths and no signs of overt clinical toxicity. Bodyweight gain and food consumption appeared to be suppressed among males at 1,500 mg/kg/day (bw 78% of control). The only treatment-related change evident in haematology was a reduction in activated partial thromboplastin time for males at 750 or 1,500 mg/kg/day (74 and 76% of control, resp.). There was a slightly greater variability in blood chemistry parameters, and the following were blood chemistry changes for males that may represent an effect of treatment: a non dosage-dependant elevation of alkaline phosphatase levels at 750 and 1,500 mg/kg/day (132 and 131% of control, resp.); reduced glucose and phosphorous levels at 1,500 mg/kg/day (79 and 82% of control, resp.); a dosage-dependant reduction in total protein at 750 and 1,500 mg/kg/day (93 and 91% of control, resp.) with a slightly elevated albumin/globulin ratio at the high dose (117% of control). Changes in females were limited to a decrease in phosphorous levels and a non-significant increase in alkaline phosphatase levels at 1,500 mg/kg/day (81 and 122% of control, resp.). No effect was observed on functional observations. Reddening of the extremities during the first week of dosing was observed in all doses, including 250 mg/kg/day but reduced as the treatment period progressed. Histological examination of the stomachs revealed some submucosal inflammation at all doses (0/5, 3/5, 4/5 and 2/5 for males and 0/5, 2/5, 4/5 and 4/5 for females at 0, 250, 750 and 1500 mg/kg bw), but this change was not dose dependent and was not statistically significant at the low dose.

Reproductive subgroup: There were no treatment-related deaths and no signs of overt clinical toxicity. Bodyweight gain for reproductive subgroup females receiving 1,500 mg/kg/day was reduced during the first week of gestation (82% of control), after which they returned to levels comparable to the controls for the remainder of the study. Mating performance and fertility were unaffected by treatment, and parental treatment had no apparent effect on the offspring to day 4 of age.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: General toxicity

2

Dose descriptor:

NOAEL

Effect level:

1 500 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: Reproduction/developmental toxicity

3

Dose descriptor:

LOAEL

Effect level:

750 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: General toxicity

4

Dose descriptor:

LOAEL

Effect level:

> 1 500 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

other: Reproduction/developmental toxicity

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

NOAEL: 250 mg/kg/day (general toxicity); 1,500 mg/kg/day (reproduction/developmental toxicity)

LOAEL: 750 mg/kg/day (general toxicity); >1,500 mg/kg/day (reproduction/developmental toxicity)

Applicant's summary and conclusion

Conclusions:

Diammonium phosphate NOAEL: 250 mg/kg/day (general toxicity); 1,500 mg/kg/day (reproduction/developmental toxicity)
Diammonium phosphate LOAEL: 750 mg/kg/day (general toxicity); >1,500 mg/kg/day (reproduction/developmental toxicity)

Executive summary:

The toxicity of diammonium phosphate (DAP) was assessed in a combined repeated dose toxicity study with a reproduction / developmental toxicity screening test in rats. The NOAEL was found to be: 250 mg/kg/day (general toxicity); 1,500 mg/kg/day (reproduction/developmental toxicity). The LOAEL was found to be: 750 mg/kg/day (general toxicity); >1,500 mg/kg/day (reproduction/developmental toxicity)