Estradiol

Particle size distribution (Granulometry)

Link to relevant study record(s)

Reference

Endpoint:

particle size distribution (granulometry)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 110 (Particle Size Distribution / Fibre Length and Diameter Distributions)

Deviations:

no

Principles of method if other than guideline:

In considersation of the relevance of granulometry on toxicological assessment, only the size distribution of the sieved fraction <100 µm were studied in detail.

GLP compliance:

no

Type of method:

determination of fibre length and diameter distributions

Type of distribution:

counted distribution

Mass median aerodynamic diameter:

74.8 µm

Key result

Percentile:

D50

Mean:

74.8 µm

Remarks on result:

other: spherical volume(migrated from fields under 'Mass median diameter' as D50 percentile. No source field for Standard deviation.)

No.:

#1

Size:

3 - 5 µm

Distribution:

23.32 %

Remarks on result:

other: of the sieve fraction < 100 µm

No.:

#2

Size:

5 - 100 µm

Distribution:

76.28 %

Remarks on result:

other: of the sieve fraction < 100 µm

Result: Sieve Fraction (<100µm):

- weighted sample: 0.8641 g

- weight fraction <100µm: 0.6855 g

- mass fraction <100µm: 79.33 %

The mass fraction <100µm was 79.33 %, and was investigated by scanning electron microscopy. The mean diameter (median) was 7.22 µm with 19.18µm standard deviation. The median aspect ratio (median) was 1.50 with 0.71 as standard deviation.

The median diameter (mass fraction) of the particle size is given for the fraction <100µm. The value 74.8µm was calculated for spherical and the value 59.83µm was calculated for cubical particles.

Particle Size  Spherical Volume [%]  Cubical Volume [%]  <4 µm (respirable)  0.01  0.02  4-10 µm (thoracic)  0.36 0.74  10-100 µm (inhalable)  87.55  93.84  >100 µm  12.09 5.40  Median (diameter µm) 74.80  59.83

Conclusions:

The MMAD (Mass Median Aerodynamic Diameter < 100µm) has a value of 74.8 µm as spherical particles.

Executive summary:

According to OECD guideline 110 the particle size distribution was determined by scanning electron microscopy method for the sieved fraction (<100µm was 79.33% of the total sample) and presented on the basis of calculated mass fractions.

The mean diameter (median) was 7.22 µm with 19.18µm standard deviation. The median aspect ratio (median) was 1.50 with 0.71 as standard deviation. The median diameter (mass fraction) of the particle size is given for the fraction <100µm. The value 74.8µm was calculated for spherical particles and hence the tested particles with sieved size smaller than 100 µm are mainly dominated by inhalable fraction as defined in EU 481.

Description of key information

The MMAD (Mass Median Aerodynamic Diameter < 100µm) has a value of 74.8 µm as spherical particles.

Additional information

According to OECD guideline 110 the particle size distribution was determined by scanning electron microscopy method for the sieved fraction (< 100 µm, 79.33 % of total sample) and presented on the basis of calculated mass fractions. The median diameter was 74.8µm with the main fraction of 69.45 % spherical volume distributing in the range of 10 -100 µm and hence the tested particles with sieved size smaller than 100 µm are mainly dominated by inhalable fraction as defined in EU 481.