Pregnenolone

Particle size distribution (Granulometry)

Administrative data

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 24 August 2017 to 12 February 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

ISO 13320 (Particle size analysis - Laser diffraction methods)

Version / remarks:

2009

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: CIPAC MT 187 (Particle size analysis by laser diffraction)

Version / remarks:

Handbook K, 2007

Principles of method if other than guideline:

According to REACH Article 13(3) tests on substances shall be conducted in accordance with the test methods laid down in a Commission Regulation or in accordance with other international test methods recognised by the Commission or the Agency as being appropriate. No particle size distribution test method is laid down in regulation (EC) No 440/2008. OECD 110 TG ‘Particle Size Distribution/FibreLength and Diameter Distributions’ dates from 1981 and describes two methods in detail; both methods have restrictions and are not applicable to the entire size range. ECHA’s Guidance on information requirements and Chemical Safety Assessment-Chapter R.7a stipulates that many methods are available for particle size measurements but none of them is applicable to the entire size range. The guidance mentions Laser scattering/diffraction as a method for particles of all kind and makes reference to ISO 13320:2009.
According to Guidance document EUR 20268 (2002), the laser diffraction technique is applicable to particles of respirable and inhalable size. The MMAD can be calculated.

GLP compliance:

yes (incl. QA statement)

Type of method:

Laser scattering/diffraction

Type of particle tested:

primary particle

Type of distribution:

volumetric distribution

Test material

Test material information

Constituent 1

Reference substance name:

Pregnenolone

EC Number:

205-647-4

EC Name:

Pregnenolone

Cas Number:

145-13-1

Molecular formula:

C21H32O2

IUPAC Name:

3-hydroxypregn-5-en-20-one

Test material form:

solid: particulate/powder

Details on test material:

- Physical appearance: white crystalline powder
- Storage conditions: at room temperature

Specific details on test material used for the study:

Relative density: 1.18

Results and discussion

Mass median aerodynamic diameter:

46.458 µm

Geometric standard deviation:

>= 1.83 - <= 1.832

Remarks on result:

other: The MMAD above is the average of 5 runs. GSD was calculated from d50/d15.78. The min. and max. GSD values of 5 runs are provided above. The St.dev. in the table below is the population standard deviation [µm].

Particle size

Particle size 1

Key result

Percentile:

D10

Mean:

19.41 µm

St. dev.:

0.075

Particle size 2

Key result

Percentile:

D50

Mean:

42.768 µm

St. dev.:

0.151

Particle size 3

Key result

Percentile:

D90

Mean:

82.01 µm

St. dev.:

0.322

Particle size distribution at different passages

No.:

#1

Size:

< 10 µm

Distribution:

2.03 other: vol%

Any other information on results incl. tables

Coefficient of variation for D50 is < 3%; D10 and D90 are < 5%. These values are within the acceptable limits mentioned in the ISO 13320 standard.

VISUAL OBSERVATION

The substance was observed to be a fine white crystalline powder with some clusters.

Under a microscope using 3.2 objective lens, the particles appeared to be irregular shaped crystals. The smallest individual particle size was approximately 6 μm and the largest individual size was approximately 64 μm.

Under a microscope using 40 objective lens, the sample was observed to be made up of single crystalline particles.

Applicant's summary and conclusion

Conclusions:

Particle size distribution of the substance: D10= 19.410 µm, D50= 42.768 µm and D90= 82.010 µm. 2.03% by volume was determined to be smaller than 10 µm. The MMAD was calculated to be 46.458 µm.

Executive summary:

The particle size distribution of the substance was determined using laser diffraction analysis (dry powder module) in a GLP study according to ISO 13320 and CIPAC MT 187. Each result is the average of five runs. D10= 19.410 µm, D50= 42.768 µm and D90= 82.010 µm. 2.03% by volume was determined to be smaller than 10 µm. The MMAD was calculated to be 46.458 µm.