Isopentylamine

Endpoint summary

Description of key information

In valid acute toxicity rat studies, the LD50 was 341 and 427 mg/kg bw (oral) and 2000 mg/kg bw (dermal), respectively. The inhalation LC50(rat, 4 hr) was 11,500 mg/m³. Toxicity and mortality was closely related to the corrosivity of isopentylamine on either route of exposure.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

341 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

11 500 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

The acute oral toxicity of 3-methylbutylamine was tested in male and female Wistar rats (n=5/sex and dose; dose levels 63, 100, 160, 250, 315, 400, and 630 mg/kg bw (each 5 % (w/v) in water); oral gavage) in a study that was conducted according to OECD TG 401 and under GLP conditions. Mortality occurred within few days. Necropsy revealed corrosion of the GI tract (stomach, gut) and corrosion and adhesion of inner organs (liver, pancreas, kidneys).The LD₅₀ was 427 mg/kg bw in male and female rats in this study (Hoechst, 1985). In another study (Wistar rats, 5/sex; doses 215, 464, 1000 mg/kg bw) a slightly lower LD50 value (341 (range 251 -460) mg/kg bw) was determined (BASF, 1987).

The acute inhalation toxicity of isopentylamine was examined in male and female rats (n=5 per sex and dose) that were exposed to isopentylamine (duration 4 hours; 5.2, 9.9, and 17.4 mg/L; analytical monitoring) in a guideline study under GLP conditions. The observation period was 14 days.

Signs of eye and respiratory irritation were seen during exposure at all concentrations. Mortalities occurred at all dose levels on the day of exposure. Body weight of survivors was reduced in the first week after treatment, but was comparable to historical controls at the end of the second week. Gross pathology revealed general congestion and hyperemia of the lungs at all dose levels. The combined male and female LC_{50(rat, 4 hr)}was 11.5 mg isopentylamine/L (11,500 mg/m³) in this study. Local irritation (includes respiratory tract) was considered to cause toxicity and mortality (BASF, 1989).

The acute dermal toxicity was tested according to the OECD TG 402 and under GLP conditions. 5 male and female Sprague-Dawley rats received 2000 mg/kg bw of 3-methylbutylamine (50% in water), and the animals were observed until the end of the 14-day observation period. No systemic toxicity was seen in any rat. However, 5 of 10 animals were killed for humane reasons (one male on day 10; four females on days 7-10), based on the poor state of the skin. In the preliminary study, skin corrosion had been seen in all animals treated with the neat substance at 2000 mg/kg bw. In an attempt to reduce the local effects, a 50% solution of the amine in water was used in the definitive study, which, however, resulted also in skin corrosion.

 

Based on the above, the acute dermal LD₅₀ value is 2000 mg/kg bw in the rat (Safepharm, 1985).

 

 

 

Justification for classification or non-classification

Acute toxic properties of isopentylamine require classification as tabulated below.

Route	Effect level	value	Regulation 67/548/EC	Regulation 1272/2008/EC
oral	LD50, rat	341 mg/kg bw	Xn, R25	Acute tox, cat 4
inhalation	LC50, rat, 4 hrs	11.5 mg/L	Xn, R20	Acute Tox, cat 4
dermal	LD50, rat	2000 mg/kg bw	Xn, R 21	Acute Tox, cat 4