Nanosmearing due to process shear – Influence on powder and tablet properties

• Investigated influence of process shear on nanosmearing and its subsequent powder and tablet properties.
• Experimental techniques were developed to interpret % nanosmearing.
• Applied process shear on powder particles had a significant effect on powder and tablet properties.
• Nanosmeared structures influenced the powder hydrophobicity and drug release rate.
• Drug release rate dropped with an increase in the amount of nanosmear on particle surface.

The objective of the study was to investigate the influence of process shear, blend composition and mixing order on thin film nanosmearing of lubricant and glidant on particle surfaces as a function of powder and tablet properties. Multiple pharmaceutical blends containing avicel 200 and micronized acetaminophen were prepared at three different mixing orders at a shear rate of 80 rpm and a shear strain of 640 rev. Chemical analysis such as inductively coupled plasma mass spectroscopy (ICPMS), scanning electron microscopy with X-ray microanalysis/energy dispersive spectroscopy (FESEM/EDS) and focused ion beam (FIB) were done for sheared powder samples. Powder hydrophobicity and tablet dissolution were carried out to test for powder and finished product properties. Experimental techniques were developed to interpret the general aspects of % area nanosmearing distribution obtained from EDS mapping combined with cameo imaging. Their % area distributions on particle surfaces were quantified for the first time. Applied process shear on powder particles had a significant effect on powder and tablet properties. The nanoscale investigation measured in terms of extent of nanosmearing (% area), amount and thickness of nanosmearing clearly showed that nanosmeared structures influenced the powder hydrophobicity and drug release rate.

Figure optionsDownload as PowerPoint slide