Performance Evaluation of a High-Precision Low-Dose Powder Feeder

Area of Science:

• Pharmaceutical Engineering
• Materials Science
• Process Engineering

Background:

• Accurate low-dose powder feeding is critical in pharmaceutical manufacturing, especially for highly potent active pharmaceutical ingredients (APIs) and low-density excipients.
• Existing commercial technologies struggle to reliably handle powders with diverse particle sizes and flow characteristics, leading to dosing inaccuracies.

Purpose of the Study:

• To present and evaluate a novel micro-feeder system designed for precise low-dose powder feeding.
• To characterize the feeding performance of various pharmaceutical powders using the micro-feeder system.
• To introduce and validate the 'displacement-feed factor' as a tool for system calibration and performance prediction.

Main Methods:

• A micro-feeder system combining volumetric feeding with an outlet weighing balance was employed.
• Six different pharmaceutical powders (lactose grades, di-calcium phosphate, croscarmellose sodium, silicon dioxide, spray-dried intermediate, and an API) were tested.
• Powder density variations during feeding were characterized using a 'displacement-feed factor' derived from mass and volume measurements.

Main Results:

• The micro-feeder system demonstrated capability in feeding low-dose rates across a range of powder properties.
• A 'displacement-feed factor' profile was established for each powder, revealing density variations during feeding.
• Finer particles and higher compressibility led to powder densification, while larger particles and lower compressibility exhibited both densification and powder bed expansion.

Conclusions:

• The 'displacement-feed factor' provides a method for calibrating the micro-feeder system to ensure accurate, constant feed rates.
• This factor enables prediction of feeding performance for specific materials across different feed rates.
• The developed micro-feeder system and characterization method offer a solution for precise low-dose material handling in pharmaceutical production.