Gas-pressurized dispersive powder flow tester for low volume sample characterization

Area of Science:

• Pharmaceutical Technology
• Materials Science
• Chemical Engineering

Background:

• Conventional powder flow testers often require large sample volumes (>40g) and struggle with cohesive powders.
• Powder cohesion significantly impacts pharmaceutical manufacturing processes and product quality.
• Accurate measurement of powder flowability is crucial for process optimization and consistency.

Purpose of the Study:

• To design and validate a novel gas-pressurized dispersive powder flow tester.
• To assess the powder flow indices of various lactose grades using the new tester.
• To compare the performance of the new tester against traditional methods like Hausner ratio and Carr's index.

Main Methods:

• A gas-pressurized dispersive powder flow tester was designed using high-velocity air to disaggregate small powder samples (9g).
• Flow indices (distance, surface area, width, weight of dispersion) were determined for seven lactose grades.
• Results were correlated with Hausner ratio and Carr's index, and particle characteristics (size, shape, density).

Main Results:

• The new tester effectively eliminated powder cohesion and required minimal sample volume.
• Particle dispersion distance and surface area showed significant negative correlations with Hausner ratio and Carr's index.
• Flow indices correlated well with lactose particle size and shape, with elongation impacting orifice blockage.

Conclusions:

• The gas-pressurized dispersive tester is a viable alternative for measuring the flowability of low-volume and cohesive powders.
• This method provides a more sensitive assessment of powder flow compared to Hausner ratio and Carr's index.
• The tester's ability to detect subtle changes in particle properties like elongation offers enhanced characterization capabilities.