Fluocortolone

Vapour pressure

Link to relevant study record(s)

Reference

Endpoint:

vapour pressure

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 Feb - 07 Feb 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

EU Method A.4 (Vapour Pressure)

Principles of method if other than guideline:

lt should be noted that the data provided in this report do not represent the results of a comprehensive study and do not suffice to satisfy data requirements according to EC or OECD guidelines for the testing chemicals

GLP compliance:

no

Other quality assurance:

other: Not specified

Type of method:

effusion method: Knudsen cell

Key result

Temp.:

25 °C

Vapour pressure:

< 0.001 Pa

Remarks on result:

other: The vapour pressure of 0.001 Pa equals an evaporation rate of 0.014 μg/s

The measured evaporation rate of the mixture (1.5*10^-3 μg/s) at 25 °C is significantly below the calculated value. Therefore, it can be assumed that the vapour pressure of the mixture and consequently of the test substance is lower than the lower limit of the measuring range recommended by the EC Testing Guideline. In addition the mass spectra of the vapour escaping from the Knudsen cell show only masses m/e.

 

Validity criteria for the measurement of the vapour pressure:

Target condition according to guideline:	Actual condition according to the study:	Validity criteria met:
At least two vapour pressure and temperature values - and preferably three or more – are required in the range 0 to 50 °C (or 120 to 150 °C).	Temperature tested:25 °C. One measurement was performed.	No
A log p versus 1 /T curve should be stated.	Raw data is not available	With restrictions
An estimate of the vapour pressure at 20 or 25 °C should be stated.	Values 25 °C are given.	Yes

 

Conclusions:

The vapour pressure of lower than 0.001 Pa was measured at 25°C.

Executive summary:

The vapour pressure was determined using a screening method based on the detection of the evaporation rate from a Knudsen cell of a vapour pressure balance at 25 °C. Since simplified experimental conditions are also acceptable within the scope of this project, the substance was mixed with four other compounds. From all five test substances low or very low vapour pressures were expected. For this reason the experiments consisted in the measurement of the evaporation rate of the mixture from a Knudsen cell a 25 °C. Since the evaporation rate of the mixture was below the value derived from the lower limit of the vapour pressure range recommended for the use of a vapour pressure balance (10^-3 Pa, EC Testing Guideline A.4) it can be assumed that the vapour pressure of the mixture is lower than 10^-3 Pa. Considering this this fact, the vapour pressure of the single compounds in the mixture has also to be lower than 10^-3 Pa.

Therefore, the vapour pressure can be estimated to be lower than 0.001 Pa at 25 °C.

Description of key information

The vapour pressure of lower than 0.001 Pa was measured at 25 °C.

 

Key value for chemical safety assessment

Vapour pressure:

0.001 Pa

at the temperature of:

25 °C

Additional information

Low or very low vapour pressure, based on the study director's experience was expected. For this reason the experiment consisted in the measurement of the evaporation rate of the mixture from a Knudsen cell at 25 °C. Since the evaporation rate of the mixture was below the value derived from the lower limit of the vapour pressure range recommended for use of a vapour pressure balance (10^-3 Pa, EU testing guideline A.4) it can be assumed that the vapour pressure of the mixture was lower than 10^-3 Pa. Considering this fact, the vapour pressure of the single compounds in the mixture has also to be lower than 10^-3 Pa. Therefore, the vapour pressure could be estimated to be lower than 0.001 Pa at 25°C.