Development and implementation of a pneumatic micro-feeder for poorly-flowing solid pharmaceutical materials

Area of Science:

• Pharmaceutical Manufacturing
• Powder Technology
• Process Engineering

Background:

• Consistent powder micro-feeding (<100 g/h) is vital for solid oral dosage form manufacturing, improving drug efficacy and reducing waste.
• Current micro-feeders struggle with cohesive pharmaceutical powders at flow rates below 20 g/h, exhibiting significant fluctuations.
• Addressing this limitation is key to enhancing drug product quality and process efficiency.

Purpose of the Study:

• To introduce an advanced pneumatic micro-feeder design for consistent powder delivery at very low flow rates.
• To evaluate the micro-feeder's performance with various pharmaceutical-grade powders, including cohesive materials.
• To investigate the impact of process parameters and equipment configurations on feeding consistency.

Main Methods:

• A novel pneumatic micro-feeder utilizing particle re-entrainment for powder conveying was designed and constructed.
• Experimental studies were conducted using pharmaceutical powders like microcrystalline cellulose (MCC), croscarmellose sodium (CCS), crospovidone (XPVP), and paracetamol (APAP).
• The influence of air pressure, air flow rate, insert size, and plug position on feeding performance was systematically analyzed.

Main Results:

• The developed micro-feeder successfully achieved consistent powder flow rates as low as 0.7 g/h with less than 20% variation.
• Excellent micro-feeding performance was demonstrated even for cohesive pharmaceutical powders.
• The system exhibited good repeatability and stability across different powders and operating conditions.

Conclusions:

• The novel pneumatic micro-feeder design effectively overcomes the limitations of existing technologies for low-flow, high-consistency powder feeding.
• The particle re-entrainment concept is a viable strategy for minimizing flow rate variations in micro-feeding applications.
• This advanced micro-feeder holds significant potential for improving the manufacturing of solid oral dosage forms, particularly for challenging cohesive powders.