Propan-2-ol

Endpoint summary

Description of key information

Isopropanol is associated with low acute oral toxicity. The oral LD50 was reported to be 5840 mg/kg body weight in rats administered the test article by gavage (Smyth and Carpenter, 1948). No other study details were provided. 
Isopropanol is associated with low acute dermal toxicity following dermal exposure. Smyth and Carpenter (1948)  reported a dermal LD50 for isopropanol of 16.4 mL/kg body weight in rabbits.
Isopropanol was reported to be well tolerated in rats at inhalation exposures up to 1500 ppm for 6 hours (Gill, 1991). At higher dose levels (5000 and 10000 ppm) a number of clinical signs were observed, including transient central system sedation and reversible narcosis. No mortalities were observed at exposures up to 10000 ppm.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Dose descriptor:

LD50

Value:

5 840 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Dose descriptor:

LC50

Value:

25 000 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion

Dose descriptor:

LD50

Value:

13 900 mg/kg bw

Additional information

Acute Toxicity: Oral

The potential acute oral toxicity of isopropanol was assessed in rats by Smyth and Carpenter (1948). Although this study is lacking in methodological details, the work of this group pre-dates range finding toxicity guidelines and provided much of the basis for their development. Their results are cited by many subsequent authoritative review bodies and are often found in SIDS and SIAR documents via secondary references. Therefore, the results reported by this group are deemed reliable. In their investigation, Smyth

and Carpenter (1948) determined the LD50 of isopropanol in rats to be 5840 mg/kg body weight as assessed following oral gavage administration of a range of isopropanol concentrations in acetone (vehicle) to groups of 6 Sherman rats (reported as 10, 1, 0.1, etc. g/kg body weight). Ispropanol was not classified as acutely toxic following oral exposure according to CLP.)

 

Acute Toxicity: Dermal

As described above, the work of Smyth and Carpenter (1948) lacks methodological details, but is deemed reliable. These authors examined the potential acute dermal toxicity of isopropanol in 6 rabbits after 24 hours of exposure and reported the LD50 as 16.4 mL/kg body weight. Isopropanol was not classified as acutely toxic following oral exposure according to CLP.

 

Acute Toxicity: Inhalation

The potential acute inhalation toxicity of isopropanol was assessed in Fischer 344 rats in a study similar in methodology to OECD Guidelines for the Testing of Chemicals No. 403 and in compliance with Good Laboratory Practice (Gill, 1991). Groups of 25 male and 25 female rats were exposed (whole-body) to vapor concentrations of 0, 500, 1500, 5000, or 10000 ppm for 6 hours. The animals were placed in steel chambers with glass doors and windows. The animals were observed for signs of toxicity twice daily and body weights were recorded prior to exposure and at 6 and 24 hours post exposure. No animals died during the study. There were no significant effects on body weight with the exception of a decrease in the 10000 ppm group. The authors reported that this decrease reflected the decrease in food consumption observed during times of prostration and narcosis. In the 5000 ppm group, transient central system sedation was reported in males and females and in the 10000 ppm group reversible narcosis was observed. In the 10000 ppm group, prostration, severe ataxia, decreased arousal, slowed or labored respiration, decreased neuromuscular tone, hypothermia, and loss of reflex function was observed 1 and 6 hours after exposure. Concentration-related decreases in mean motor activity were observed for males in the 1500, 5000, and 10000 ppm groups and females in the 5000 and 10000 ppm groups. Motor activity was severely depressed for males and females in the 10000 ppm group. Exposure-related behavioral changes were not observed in the 500 ppm group. The LD50 was > 10,000 ppm

Isopropanol was not classified as acutely toxic following oral exposure according to CLP.

Justification for classification or non-classification

The substance does not meet the criteria for classification and labelling for this endpoint, as set out in Regulation (EC) NO. 1272/2008.

Specific target organ, Neurotoxicity: According to CLP classification criteria, the substance does meet the criteria for classification and labelling for this endpoint (STOT single exposure category 3, H336 - may cause drowsiness and dizziness) as set out in Regulation (EC) No. 1272/2008.