Effects of powder flow properties on capsule filling weight uniformity

Juan G. Osorio, Fernando J. Muzzio

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Filling capsules with the right amount of powder ingredients is an important quality parameter. The purpose of this study was to develop effective laboratory methods for characterizing flow properties of pharmaceutical powder blends and correlating such properties to weight variability in filled capsules. The methods used for powder flow characterization were bulk and tapped density, gravitational displacement rheometer (GDR) flow index, Freeman Technology V.4 (FT4) powder rheometer compressibility, FT4 basic flow energy (BFE), and cohesion parameters [cohesion, (C) and flow factor (ffc)] measured in a shear cell also using the FT4. Capsules were filled using an MG2-G140 continuous nozzle dosator capsule-filling machine. Powder flow properties were the most predominant factors affecting the weight and weight variability in the filled capsules. Results showed that the weight variability decreased with increasing bulk and tapped density, ffc and BFE, while the weight variability increased with increasing compressibility, cohesion and GDR flow index. Powder flow properties of the final blends were significantly correlated to the final capsule weight and weight variability of the filled capsules.

Original languageEnglish (US)
Pages (from-to)1464-1475
Number of pages12
JournalDrug Development and Industrial Pharmacy
Issue number9
StatePublished - Sep 2013

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Pharmaceutical Science
  • Drug Discovery
  • Organic Chemistry


  • Bulk density
  • Capsule filling
  • Cohesion
  • Dosing systems
  • Flow energy
  • Flow factor
  • Particle processing


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