title: Micro-feeding and dosing of powders via a small-scale powder pump.
abstract: Robust and accurate powder micro-feeding (<100mg/s) and micro-dosing (<5 mg) are major challenges, especially with regard to regulatory limitations applicable to pharmaceutical development and production. Since known micro-feeders that yield feed rates below 5mg/s use gravimetric feeding principles, feed rates depend primarily on powder properties. In contrast, volumetric powder feeders do not require regular calibration because their feed rates are primarily determined by the feeder's characteristic volume replacement. In this paper, we present a volumetric micro-feeder based on a cylinder piston system (i.e., a powder pump), which allows accurate micro-feeding and feed rates of a few grams per hours even for very fine powders. Our experimental studies addressed the influence of cylinder geometries, the initial conditions of bulk powder, and the piston speeds. Additional computational studies via Discrete Element Method simulations offered a better understanding of the feeding process, its possible limitations and ways to overcome them. The powder pump is a simple yet valuable tool for accurate powder feeding at feed rates of several orders of magnitude.
authors.affiliation: Research Center Pharmaceutical Engineering (RCPE), 8010 Graz, Austria.
authors.forename: M O
authors.initials: MO
authors.lastname: Besenhard
authors.affiliation: Research Center Pharmaceutical Engineering (RCPE), 8010 Graz, Austria.
authors.forename: S
authors.initials: S
authors.lastname: Fathollahi
authors.affiliation: Research Center Pharmaceutical Engineering (RCPE), 8010 Graz, Austria.
authors.forename: E
authors.initials: E
authors.lastname: Siegmann
authors.affiliation: Research Center Pharmaceutical Engineering (RCPE), 8010 Graz, Austria.
authors.forename: E
authors.initials: E
authors.lastname: Slama
authors.affiliation: Research Center Pharmaceutical Engineering (RCPE), 8010 Graz, Austria.
authors.forename: E
authors.initials: E
authors.lastname: Faulhammer
authors.affiliation: Research Center Pharmaceutical Engineering (RCPE), 8010 Graz, Austria; Graz University of Technology, Institute of Process and Particle Engineering, 8010 Graz, Austria. Electronic address: khinast@tugraz.at.
authors.forename: J G
authors.initials: JG
authors.lastname: Khinast
mesh_terms: D002138:Calibration; D004867:Equipment Design / Q000379:methods; D010316:Particle Size; D011208:Powders / Q000737:chemistry*; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D011208:Powders
keywords: Cylinder piston; Feed rate robustness; Low dose; Micro-dosing; Micro-feeding; Powder feeding