Isovaleraldehyde

Endpoint summary

Description of key information

The oral LD50 of isovaleraldehyde was determined to be 5740 mg/kg bw in male and female rats (BASF, 1974).
The inhalation LC50 of isovaleraldehyde was determined to be 42.7 mg/L in rats (Carpenter, 1974).
The dermal LD50 of isovaleraldehyde was determined to be 2534 mg/kg bw in male rabbits (Carpenter, 1974).

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 740 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

42 700 mg/m³ air

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

2 534 mg/kg bw

Additional information

Acute toxicity: oral

 

For the assessment of the acute oral toxicity of isovaleraldehyde (3-methylbutanal, 3-methylbutyraldehyde), two valid studies are available (BASF 1974, Carpenter 1974; both RL 2). The LD50 values of the two studies are in the same order of magnitude. But the LD50 determined by BASF (5740 mg/kg bw) is lower than the value reported by Carpenter (7100 mg/kg bw). As conservative estimate, the LD50 of the BASF study is selected to represent the oral toxicity of isovaleraldehyde.

In the publication of Safronkina, only results are summarized. Thus the reliability of data cannot be assessed (RL3).

 

BASF (1974)

 

The acute oral toxicity of isovaleraldehyde was determined in groups of 5 male and 5 female Sprague-Dawley rats receiving the test material by oral gavage at doses of 160, 1275, 2550, 5100, 6376, and 7970 mg/kg bw. The observation period was 14 days. The LD50 was estimated using a graphical evaluation of the dose response curve on probability paper. Overall, the study was conducted in accordance with the recently retracted OECD test guideline 401.

 

The acute oral LD50 was determined to be 5740 mg/kg bw in rats (BASF, 1974).

 

 

Carpenter (1974)

 

The acute oral toxicity of isovaleraldehyde was determined in groups of 5 male Carworth-Wistar rats receiving the test material by oral gavage. The doses were spaced by a factor of 2 (logarithmically). The observation period was 14 days. The LD50 and a range of ± 1.96 SD was calculated according to the method of Thomson (1947). Overall the study was conducted in accordance with the recently retracted OECD test guideline 401.

 

The acute oral LD50 was determined to be 7100 mg/kg bw in rats (Carpenter, 1974).

 

Acute toxicity: inhalation

 

To assess the acute inhalation toxicity potential of isovaleraldehyde, only one valid study is available (Carpenter, 1974). In the publication of Safronkina, only results are summarized. Thus the reliability of data cannot be assessed (RL3). The test method of Salem (extended exposure period up to 10 h, only one concentration tested) is unsuitable to derive a LC50 value according to recent test guidelines (RL3).

 

Carpenter (1974)

 

For this acute inhalation toxicity study, a standard graduate dose test and an inhalation hazard test were performed. The observation period for both tests was 14 days.

 

Groups of six albino rats were exposed for 4 hours to graduate doses of isovaleraldehyde vapor in the breathing atmosphere of test animals. Doses were spaced in a logarithmic series with a factor of 2 (28.64 and 57.28 mg/L).

 

In the inhalation hazard test, test animals were exposed for various time periods starting from one forth hour up to 8 hours (if appropriate, spacing factor of 2) to an atmosphere saturated or close to saturation with vapor of isovaleraldehyde. Actual atmosphere concentrations were not measured but can be estimated to be saturated or close to saturation by the method, the atmosphere was generated. Saturated vapor concentration of isovaleraldehyde at 25°C in air is 233 mg/L (Auer Technikum, Edition 12, Auergesellschaft GmbH, Berlin, 1988).

 

In the standard test, a mortality of 0 and 5 animals was observed for the two concentrations tested. The LC50 was calculated as 42.7 mg/L.

 

In the inhalation hazard test (saturated vapor), the exposure time to death of half of the rats exposed (LT50) was determined to be 21.7 min.

 

The LC50 for isovaleraldehyde was determined to be 42.7 mg/L in rats (Carpenter 1974).

 

Acute toxicity: dermal

 

For assessment of the acute dermal toxicity of isovaleraldehyde, only one valid study is available (Carpenter, 1974).

 

Carpenter (1974)

 

The acute dermal toxicity of isovaleraldehyde was determined in groups of 4 male albino New Zealand rabbits receiving graduate single doses of test substance per group. Number and quantity of individual doses are not specified. The exposure time was 24 hours followed by an observation period of 14 days. Individual data on mortality, weight development, clinical signs, and gross necropsy findings are not reported. From mortality data, the LD50 and a range of ± 1.96 SD was calculated according to the method of Thomson (1947).

 

The acute dermal LD50 for isovaleraldehyde was determined to be 2534 mg/kg bw in rabbits (Carpenter, 1974).