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Description of key information

Acute Toxicity:
- oral: LD50: 495 mg/kg bw (rat);
- dermal: 925 mg/kg bw (rat);
- inhalation: 4.4 mg/L air (rat);

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
Value:
495 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
LC50
Value:
4 400 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
Value:
925 mg/kg bw

Additional information

Oral:

In a study which was in large parts equivalent to methods described in OECD guideline 401, the LD50 for oral acute toxicity in rats was calculated as 495 mg/kg bw (BASF AG, 1969; Val. 2). Doses of 290, 370, 474 and 592 mg/kg bw of an 4% aqueous solution were applied by gavage followed by a post dose period of 7 days. Main clinical signs observed were intermittent respiration, dyspnoe, ruffled fur, squatting posture, trembling gait and watery mouth discharge. At necropsy no abnormalities were noted.

 

In a further acute toxicology study dose levels of 125, 250, 500, 1000, 2000 mg/kg bw were administered to 4 female animals and a similar result was obtained (LD50 = 500 mg/kg bw; Dow Chemical 1973; Val 2). A slightly lower LD50 of 300 mg/kg bw was found in a study where only female animals were tested (Eli Lilly, 1980; Val. 2). Additionally the results of the study indicated that dipropylamine may cause CNS effects such as hyperactivity and leg weakness. When tested as a 5% solution a LD50 of 933 mg/kg bw and at necropsy congestion of internal organs was observed (Union Carbide, 1980; Val. 2). In the same report it is mentioned that dipropylamine was found to be more toxic undiluted as rats were killed by a dosage of only 125 ml/kg bw. As it is usual with corrosive materials, apparent toxicity is less upon dilution.

Acute systemic toxicity was evaluated in groups of 5 mice administered a gavaged oral dose of 10% dipropylamine in corn oil at doses ranging from 100-1600 mg/kg bw. The LD50 was 800-1600 mg/kg bw with time to death of a solitary high-dose mouse occurring at 13 minutes post-gavage. Symptoms of toxicity exhibited during 2 weeks post-treatment observation included weakness, ataxia, and convulsions at the highest dosage (Eastman Kodak, 1955; Val. 2).

Inhalation:

In an acute inhalation toxicity study after 1 h of exposure no mortality occurred and the LC50 was set to be over the calculated dose of 8.22 mg/L air (Eli Lilly, 1979; Val. 2). The animals were ataxic and hypoactive the first hour following exposure and several animals exhibited tremors. Other observations included bloody nasal discharge, labored respiration and wheezing. A LC50 of 4.4 mg/L air (4h) is stated in a Russian study from 1982 with unclear validity (Izmerov, Val. 4).

 

Additional data were available from an inhalation risk test (IRT) which meets generally accepted scientific principles (BASF AG, 1969; reliability score 2). The inhalation of a saturated vapor-air mixture for 3 minutes caused mortality. Clinical signs were escape attempts, dyspnoea, trembling, anaemia. At necropsy, distended lungs were observed. A second IRT study was conducted with 4 Sprague-Dawley rats receiving whole body exposure to a saturated atmosphere of dipropylamine in a gas environment chamber for 15 minutes. Ten to twelve minutes into the exposure, all rats were observed with labored breathing to the point of gasping, loss of equilibrium, and forced movements. After 15 minutes of exposure, some of the animals became prostrate and the exposure was terminated. All animals survived the exposure and subsequent 14 day observation period. Necropsy did not revealed any gross alterations (DOW, 1973; Val. 2). In a third IRT no mortality occurred after a 15 min exposure of concentrated vapor (Union Carbide, 1957; Val. 2).

Dermal:

In an acute dermal toxicity study the LD50 was found to be 925 mg/kg bw (Union Carbide, 1957, Val. 2.). Dipropylamine was applied to the skin of groups of 4 male rats at doses of 462.5, 925 and 1850 mg/kg bw for 24 hours. Following treatment, rats were observed daily and a gross necropsy examination was performed at the time of scheduled euthanasia (day 14). Necrosis of the skin resulted from the covered application. Internal organs of victims appeared pale or opaque and the lung among the 6 animals that died had hemorrhaged. In a second report with very limited data only a LD50 of 3700-7400 mg/kg bw is stated (East Kodak, 1980; Val. 4)

Justification for classification or non-classification

EU classification according to Annex I of Directive 67/548/EEC: Xn, R22

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