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Administrative data

Description of key information

Piperazine has shown low toxicity in acute oral and dermal toxicity tests: LD50 oral, rat = 2600 mg/kg bw and LD50 dermal, rabbit = 8300 mg/kg bw. In acute inhalation toxicity tests (inhalation hazard tests) rats were exposed to the vapour; no LC50 was determined. At 1.61 mg/l exposure for 7 h slight mucosal irritation was noted. No clinical signs were noted at inhalation exposure of 0.57 mg/l for 7 h.

 

 

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 600 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LC0
Value:
> 2 mg/L
Physical form:
inhalation: vapour

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
8 300 mg/kg bw

Additional information

Acute oral toxicity:

Three reliable acute oral toxicity studies with very similar results are available. The key study was selected based on the lower acute oral LD50 value and the reporting date.
In an acute toxicity study Sprague Dawley rats were dosed with piperazine by gavage. Groups with 5 males and 5 females in each group recevied doses of 1000, 1210, 1780, 2610 or 3830 mg/kg. The LD50 value was 2600 mg/kg bw (BASF, 1980). In support, in an acute toxicity study acccording to OECD401, 5 male and 5 female rats in five dose groups were exposed to piperazine by oral gavage. The LD50 value for male and female rats was 3200 mg/kg bw (Mallory, 1981). In an acute toxicity study, rats were exposed to piperazine by gavage in six dose groups with 5 animals per sex per dose. The LD50 was 2500 mg/kg bw (BASF, 1964).

Acute inhalation toxitiy:

In an Inhalation Hazard Test, no mortality was observed when 6 rats were exposed for 8 hours to an atmosphere saturated at room temperature; the calculated concentration was 1.61 mg/L. Slight mucosal irritaion was noted. Extrapolation using Haber´s law results in a LC0 for 4h of 2 mg/l (BASF, 1964). In support, no mortality was observed in an Inhalation Hazard Test, when 6 rats were exposed for 7 hours to a saturated atmosphere at room temperature; the calculcated concentration was 0.57 mg/L. No clinical signs were noted. Extrapolation using Haber´s law results in an LC0 for 4 h of 0.8 mg/L (BASF, 1980). Thus, inhalation of an enriched/saturated vapour-air-mixture represents an unlikely acute hazard.

Acute dermal toxicity:

In an acute dermal toxicity study in rabbits performed according to OECD402, but with deviations in number of animals used and abrasion of the skin, an LD50 value of 8300 mg/kg was found (Pharmakon Laboratories, 1981).

Other data:

Data on human exposure for piperazine as an anti-helmintic agent has shown neurotoxic effects for which a LOAEL of 110 mg/kg can be set.

 

 

 

 

Justification for classification or non-classification

Piperazine does not meet the criteria for classification for acute toxicity according to the CLP regulation (EU-GHS).