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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

Study period:

The study was conducted between 21 August 2018 and 18 September 2018.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: European Commission Guidance Document EUR 20268 ‘Determination of Particle Size Distribution, Fibre Length and Diameter Distribution of Chemical Substances’ (2002)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

other: Sieving and Cascade Imapactor

Type of distribution:

mass based distribution

Specific details on test material used for the study:

Identification: Reaction mass of crystalline magnesium silicate and crystalline silicon and synthetic amorphous silicon dioxide
Appearance/Physical state: black powder
Lot No: Y180510A
Purity: Mg-SiO 95 wt% Carbon 4.0 ± 2.0 %wt
Expiry date: 31 May 2019
Storage conditions: room temperature, in the dark

Remarks on result:

not determinable

Remarks:

Too few particles were of a size less than 10.0 μm to allow accurate assessment of the mass median aerodynamic diameter.

No.:

#1

Size:

< 100 µm

Distribution:

98.6 %

Remarks on result:

other: inhalable particle size

No.:

#1

Size:

< 10 µm

Distribution:

<= 5.1 %

Remarks on result:

other: thoracic particle size

No.:

#1

Size:

< 5.5 µm

Distribution:

<= 1.7 %

Remarks on result:

other: respirable particle size

Sieve Screening Test

The results of the sieving procedure are shown in the following table:

Measurement	Result
Mass of test item transferred to sieve (W1)	11.79 g
Mass of test item passed through sieve (W3– W2)	11.63 g
Percentage of test item less than 100 μm	98.6%

Cascade Impactor

The results of the cascade impactor procedure are shown in the following table:

Collection Stage	Particle Size Range Collected (μm)	Collected Mass (g)
		Det^n1	Det^n2	Det^n3	Det^n4
Artificial throat	n/a	0.21	0.37	0.27	0.27
Sample Cup 1	>10.0	2.7821	2.5093	2.5566	2.5237
Sample Cup 2	5.5 to 10.0	0.0048	0.0664	0.1010	0.0420
Sample Cup 3	2.4 to 5.5	0.0000	0.0040	0.0095	0.0000
Sample Cup 4	1.61 to 2.4	0.0000	0.0011	0.0066	0.0000
Sample Cup 5	0.307 to 1.61	0.0000	0.0323	0.0255	0.0000
Final Filter	<0.307	0.0000	0.0032	0.0086	0.0005
Total mass of collected test item		2.9969	2.9863	2.9778	2.8362
Mass of test item added		3.0208	3.0357	3.0448	2.8692

The cumulative amounts of test item collected in the three determinations for the individual particle size cut-points are shown in the following table:

Particle Size Cut Points (μm)	Cumulative Mass (g)				Cumulative Percentage (%)
	Det^n1	Det^n2	Det^n3	Det^n4	Det^n1	Det^n2	Det^n3	Det^n4
<10.0	0.0048	0.1070	0.1512	0.0425	0.160	3.58	5.08	1.50
<5.5	0.0000	0.0406	0.0502	0.0005	0.00	1.36	1.69	0.018
<2.4	0.0000	0.0366	0.0407	0.0005	0.00	1.23	1.37	0.018
<1.61	0.0000	0.0355	0.0341	0.0005	0.00	1.19	1.15	0.018
<0.307	0.0000	0.0032	0.0086	0.0005	0.00	0.107	0.289	0.018

 

Overall cumulative percentage with a particle size less than 10.0 μm: ≤5.1%

Overall cumulative percentage with a particle size less than 5.5 μm : ≤1.7%

Conclusions:

Particle size data acquired for the test item is shown in the following table:
Measurement Method Result
Percentage of test item with an inhalable particle size <100 μm Sieve 98.6%
Percentage of test item with a thoracic particle size <10.0 μm Cascade Impactor ≤5.1%
Percentage of test item with a respirable particle size <5.5 μm Cascade Impactor ≤1.7%

Executive summary:

Particle size data was acquired, using a procedure designed to be compatible with the European Commission Technical Guidance Document EUR 20268 Determination of Particle Size Distribution, Fibre Length and Diameter Distribution of Chemical Substances (2002). The results are as follows:

Measurement	Method	Result
Proportion of test item having an inhalable particle size <100 μm	Sieve	98.6%
Proportion of test item having a thoracic particle size <10.0 μm	Cascade Impactor	≤5.1%
Proportion of test item having a respirable particle size <5.5 μm	Cascade Impactor	≤1.7%

Description of key information

Particle size data was acquired, using a procedure designed to be compatible with the European Commission Technical Guidance Document EUR 20268 Determination of Particle Size Distribution, Fibre Length and Diameter Distribution of Chemical Substances (2002). The results are as follows:

Measurement	Method	Result
Proportion of test item having an inhalable particle size <100 μm	Sieve	98.6%
Proportion of test item having a thoracic particle size <10.0 μm	Cascade Impactor	≤5.1%
Proportion of test item having a respirable particle size <5.5 μm	Cascade Impactor	≤1.7%