Registration Dossier

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study summary report
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
review article or handbook
Title:
ROBUST SUMMARY OF INFORMATION ON LUBRICATING OIL BASESTOCKS
Author:
American Petroleum Institute
Year:
2003
Bibliographic source:
ROBUST SUMMARY OF INFORMATION ON LUBRICATING OIL BASESTOCKS pag 25-27

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
not specified
GLP compliance:
not specified
Test type:
other: APi method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
not specified
Vehicle:
air
Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
ca. 4 h
Concentrations:
1, 1.5, 2.5, 3.5 and 5 mg/l
No. of animals per sex per dose:
5
Control animals:
yes

Results and discussion

Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
ca. 2.18 mg/L air
Based on:
not specified
95% CL:
> 1.8 - < 2.55
Exp. duration:
4 h

Any other information on results incl. tables

Actual exposure concentrations and mortalities were as follows:

 Target level  Actual concentration   Mortality  
 mg/l  mg/l  +/- SD male   female
 0  0.02  0.01  0/5 0/5 
 1  1.04  0.1  1/5 1/5 
 1.5  1.51  0.15  0/5  0/5
 2.5  2.37  0.31  3/5 3/5 
 3.5  3.49  0.36   5/5 5/5 
 5  5.05  0.18   5/5  5/5 

Particle size measurements confirmed that mass median aerodynamic diameter and geometric standard deviation values were in the ranges 1.7 to 2.5 mµ and 1.5 to 1.61 respectively. These measurements confirm that the particles were within the respirable range. The LC50 for combined sexes was estimated to be 2.18 with 95% confidence limits of 1.80 to 2.55 mg/l. Body weight differences did not show a consistent dose related pattern. At the highest concentration, the animals were obscured by a dense aerosol and observations could not be made during the exposure period. In other groups, there was a decreased activity, wet inguinal area, eyes partially closed, wet coat, loose stool and oily coat during exposure. During the first week post-exposure, similar signs were observed as well as signs of poor condition, respiratory distress and some deaths occurred. During test week 2, most survivors were considered to be of normal appearance. The signs that were observed occurred in a dose related manner.

At histology, affected animals exhibited diffuse pulmonary congestion and perivascular edema that were mostly moderate or marked in degree. Less consistently spotty alveolar edema was also seen. There was widespread damage to alveolar walls resulting in fibronecrotic debris resembling hyaline membranes in more marked cases and extravasation of RBCs and PMNs. Necrosis and inflammation were seen in the walls of small blood vessels and there was spotty epithelial necrosis in small bronchioles, but the most severe damage seemed to be centroacinar. The larger airways were relatively unaffected. None of the surviving animals exhibited the above acute changes. However, most of the surviving animals exposed to 2.5 or 1.0 mg/l and above exhibited chronic inflammatory changes that were not seen in the controls and only occasionally in animals exposed at the 1.5 mg/l level, and then to a lesser degree of severity. Other findings were considered sporadic or unrelated to exposure to the test material.

Applicant's summary and conclusion