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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
05.04. - 30.08.2004
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report date:
2004

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Qualifier:
according to guideline
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
GLP compliance:
yes (incl. QA statement)
Test type:
acute toxic class method

Test material

1
Chemical structure
Reference substance name:
2-aminopyridin-3-ol
EC Number:
240-886-8
EC Name:
2-aminopyridin-3-ol
Cas Number:
16867-03-1
Molecular formula:
C5H6N2O
IUPAC Name:
2-aminopyridin-3-ol

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
Number of animals: 6 females (nulliparous and non-pregnant) and 3 males. Each dose group consisted of 3 animals.
Age and body weight: Young adult animals (approx. 9 weeks old) were selected. Body weight variation did not exceed +/- 20% of the sex mean.
Conditions: Animals were housed in a controlled environment, in which optimal conditions were considered to be approximately 15 air changes per hour, a temperature of 21.0 ± 3.0°C (actual range: 18. 7 - 22.6°C), a relative humidity of 30-70% (actual range: 35 - 71 % ) and 12 hours artificial fluorescent light and 12 hours darkness per day.
Cleaning procedures in the room might have caused the temporary fluctuations above the optimal maximum level of 70% for relative humidity. Based on laboratory historical data, these fluctuations were considered not to have affected the study integrity.
Accomodation: Group housing of 3 animals per sex per cage in labelled Macrolon cages (type IV; height 18 cm.) containing purified sawdust as bedding material (Woody Clean bedding (Woody-Clean type 3/4; Tecnilab-BMI BV, Someren, The Netherlands).
Diet: Free access to standard pelleted laboratory animal diet (from Altrom in (code VRF 1 ), Lage, Germany).
Water: Free access to tap-water.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
propylene glycol
Details on oral exposure:
single dosage, on day 1
Doses:
300, 1000 mg/kg bw; dose volume: 10 ml/kg bw
No. of animals per sex per dose:
3
Control animals:
no
Details on study design:
Food was withheld overnight (for a maximum of 20 hours) prior to dosing. Food was given approximately 2-4 hours after dosage. The toxicity of the test substance was assessed by stepwise treatment of groups of 3 females. The first group was treated at a dose level of 1000 mg/kg. The absence or presence of mortality of animals dosed at one step determined the next step, based on the test procedure defined in the guidelines. The onset, duration and severity of the signs of toxicity were taken into account for determination of the time interval between the dose groups.

Results and discussion

Effect levels
Key result
Sex:
male/female
Dose descriptor:
LD50 cut-off
Effect level:
500 mg/kg bw

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Conclusions:
The oral LD50 value of A 132 in Wistar rats was established to be within the range of 300-1000 mg/kg body weight.
According to the OECD 423 test guideline the LD50 cut-off value is 500 mg/kg body weight.
Executive summary:

SUMMARY

Assessment of acute oral toxicity with A 132 in the rat (Acute Toxic Class Method).

The study was carried out based on the guidelines described in: "Acute Taxicity-Oral, Acute Toxic Class Method", OECD No.423 (2001); "Acute Oral Toxicity"; EC Commission Directive 96/54/EC, Part B.1 tris (1996); Environmental Protection Agency (EPA): Health Effects Test Guidelines OPPTS 870.1100 (2002), "Acute Oral Toxicity - Acute Toxic Class Method" and JMAFF Japanese test guidelines (2000).

lnitially, A 132 was administered by oral gavage to three female Wistar rats at 1000 mg/kg body weight. In a stepwise procedure an additional group of females and one additional group of males were dosed at 300 mg/kg body weight. All animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed on the day of death or after terminal sacrifice (day 15).

The incidence of mortality was as follows, presented in chronological order of treatment:

 Dose level  Mortality  Date of treatment
 Females 1000 mg/kg  3/3  25 May 2004
 Females 300 mg/kg  1/3  10 June 2004
 Males 300 mg/kg  0/3  16 June 2004

The decedents were found within several minutes post-treatment.

Clinical signs observed during the study period were as follows:

Females 1000 mg/kg b.w

tremor, cramped posture, hunched posture, abnormal gait, salivation, chromodacryorrhoea (left and right eye)

Females 300 mg/kg b.w

restless, lethargy, tremor, hunched posture, uncoordinated movements, flat gait, quick breathing, laboured respiration, rales, shallow respiration, piloerection, salivation, chromodacryorrhoea (left eye), pale, ptosis

Males 300 mg/kg b.w.

no clinical signs noted

The surviving animals had recovered from the symptoms between days 2 and 7. Except for one female showing chromodacryorrhoea between days 1 and 15 and rales between days 13 and 15

The body weight gain shown by the male animals over the study period was considered to be normal. The incidence of slight body weight loss or reduced body weight gain between days 8 and 15 in the females were considered not indicative of toxicity.

Macroscopic post martern examination of all females that were found dead after a dose of 1000 mg/kg bw. revealed enlarged lungs with many, dark red foci. In the female that died after a dose of 300 mg/kg reddish discolouration of mucosa in stomach was noted. In the male, which survived the study period, enlarged mandibular lymph nodes were noted.

The oral LD50 value of A 132 in Wistar rats was established to be within the range of 300-1000 mg/kg body weight.

According to the OECD 423 test guideline the LD50 cut-off value is 500 mg/kg body weight.

Based on these results and according to the:

-       OECD Harmonized lntegrated Hazard Classification System for Human Health and Environmental Effects of Chemical Substances (OECD, 1998), A 132 should be classified in Class 4 for acute toxicity by the oral route.

-       EC criteria for classification and labelling requirements for dangerous substances and preparations (Council Directive 67/548/EEC), A 132 should be labelled as: harmful if swallowed (R22).

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