Quorum q150r s sputter coater

Particle morphology was studied by scanning electron microscopy (SEM). Samples of selected nano spray-dried powder materials were coated with gold using a Quorum Q150R S sputter coater (Quorum Technologies Ltd., Laughton, UK) at 20 mA for 90 s. The samples were then visualized using a ZEISS EVO LS 10 scanning electron microscope (Carl Zeiss Microscopy GmbH, Jena, Germany). Images were captured using the ZEISS SmartSEM version 5.05 software and analyzed using the JMicroVision version 1.3.4 software (Roduit, N., Geneva, Switzerland). For each of the selected nano spray-dried powder materials, the maximum Feret’s diameters of 300–900 particles, which were randomly selected from 2–3 images, were determined. Grubbs’s test was used at a significance level of 0.001 to determine outliers. After removing outliers, the number-weighted ( $D_{\mathrm{N}}$ ) and the volume-weighted ( $D_{\mathrm{V}}$ ) particle size distributions were constructed. The mean diameter ( $D_{\mathrm{mean}}$ ), the 10th percentile ( $D_{10}$ ) of the cumulative undersize particle diameter distribution, the median diameter ( $D_{50}$ ), the 90th percentile ( $D_{90}$ ) of the cumulative undersize particle diameter distribution, and the $\mathrm{Span}$ ( $\mathrm{Span}=\left(D_{90}-D_{10}\right)/D_{50}$ ) were calculated.

Samples were directly sprayed onto aluminium foil. A small square (~1 × 1 cm) was cut from the foil and mounted onto an aluminium stub (TAAB Laboratories, Aldermaston, UK) with carbon-coated double-side adhesive tape, prior to sputter coating with gold for 60 s (10 nm gold layer) using a Quorum Q150RS sputter coater (Quorum Technologies, Laughton, UK). The coated samples were then analysed using a Phenom Benchtop SEM (ThermoFisher, Eindhoven, Netherlands) with applied voltage of 10 kV. The size of the particles was determined using the Image J software version 1.53c (National Institutes of Health, Bethesda, MD, USA). For each formulation the size of 100 particles from three different frames each was determined. The size distributions were plotted using Prism version 8.4.0 (GraphPad Software, San Diego, CA, USA).

Particle shape was studied by scanning electron microscopy using a ZEISS EVO LS 10 scanning electron microscope (Carl Zeiss Microscopy GmbH, Jena, Germany). For this purpose, the particles were coated with gold using a Quorum Q150R S sputter coater (Quorum Technologies Ltd., Laughton, United Kingdom) at 20 mA for 90 s.