title: Experimental investigation of granule size and shape dynamics in twin-screw granulation.
abstract: A twin-screw granulator (TSG), a promising equipment for continuous high shear wet granulation (HSWG), achieves the desired level of mixing by a combination of the appropriate screw configuration and a suitable set of process settings (e.g. feed rate, screw speed, etc.), thus producing a certain granule size and shape distribution (GSSD). However, the primary sizing and shaping mechanism behind the resulting distribution is not well understood due to the opacity of the multiphase system in the granulator. This study experimentally characterised the GSSD dynamics along the TSG barrel length in order to understand the function of individual screw modules and process settings, as well as their interaction. Particle size analysis of granules collected at the outlet of the TSG suggested significant interaction between the process and screw configuration parameters influencing the heterogeneity in the GSSD. By characterising the samples collected along the screw length, a variable influence of the screw modules at different process conditions was observed. At low liquid-to-solid ratio (L/S), the first kneading module seemed to play a significant role in mixing, whereas the second kneading module was found to be more involved in reshaping the granules. At high L/S and high throughput, aggregation mainly took place in the second kneading module changing the GSSD. The results obtained from this study will be further used for the calibration and validation of a mechanistic model and, hence, support future development of a more detailed understanding of the HSWG process in a TSG.
authors.affiliation: BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium; Laboratory of Pharmaceutical Process Analytical Technology, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium. Electronic address: ashish.kumar@ugent.be.
authors.forename: Ashish
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Laboratory of Pharmaceutical Technology, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium. Electronic address: jurgen.vercruysse@ugent.be.
authors.forename: Jurgen
authors.initials: J
authors.lastname: Vercruysse
authors.affiliation: BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: giacomo.bellandi@ugent.be.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bellandi
authors.affiliation: CAPEC-PROCESS, Department of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark. Electronic address: kvg@kt.dtu.dk.
authors.forename: Krist V
authors.initials: KV
authors.lastname: Gernaey
authors.affiliation: Laboratory of Pharmaceutical Technology, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium. Electronic address: chris.vervaet@ugent.be.
authors.forename: Chris
authors.initials: C
authors.lastname: Vervaet
authors.affiliation: Laboratory of Pharmaceutical Technology, Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium. Electronic address: jeanpaul.remon@ugent.be.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Remon
authors.affiliation: Laboratory of Pharmaceutical Process Analytical Technology, Department of Pharmaceutical Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat 72, B-9000 Ghent, Belgium. Electronic address: thomas.debeer@ugent.be.
authors.forename: Thomas
authors.initials: T
authors.lastname: De Beer
authors.affiliation: BIOMATH, Department of Mathematical Modelling, Statistics and Bioinformatics, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: ingmar.nopens@ugent.be.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Nopens
mesh_terms: D007785:Lactose / Q000737:chemistry; D010316:Particle Size; D011205:Povidone / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D011205:Povidone; D007785:Lactose
keywords: Continuous pharmaceutical production; Granule size and shape analysis; Twin-screw granulation