title: Importance of using complementary process analyzers for the process monitoring, analysis, and understanding of freeze drying.
abstract: The aim of the present paper is to demonstrate the importance of using complementary process analyzers (PAT tools) for the process monitoring, analysis, and understanding of freeze drying. A mannitol solution was used as a model system. Raman spectroscopic, near-infrared (NIR) spectroscopic, plasma emission spectroscopic, and wireless temperature measurements (TEMPRIS) were simultaneously performed in-line and real-time during each freeze-drying experiment. The combination of these four process analyzers to monitor a freeze-drying process is unique. The Raman and NIR data were analyzed using principal component analysis (PCA) and multivariate curve resolution (MCR), while the plasma emission spectroscopic and wireless temperature measurement data were analyzed using univariate data analysis. It was shown that the considered process analyzers do not only complement but also mutually confirm each other with respect to process step end points, physical phenomena occurring during freeze drying (process understanding), and product characterization (solid state). Furthermore and most important, the combined use of the process analyzers helped to identify flaws in previous studies in which these process analyzers were studied individually. Process analyzers might wrongly indicate that some process steps are fulfilled. Finally, combining the studied process analyzers also showed that more information per process analyzer can be obtained than previously described. A combination of Raman and plasma emission spectroscopy seems favorable for the monitoring of nearly all critical freeze-drying process aspects.
authors.affiliation: Laboratory of Drug Analysis, Department of Pharmaceutical Analysis, Ghent University, Harelbekestraat 72, B-9000 Gent, Belgium. Thomas.DeBeer@UGent.be
authors.forename: T R M
authors.initials: TR
authors.lastname: De Beer
authors.forename: M
authors.initials: M
authors.lastname: Wiggenhorn
authors.forename: R
authors.initials: R
authors.lastname: Veillon
authors.forename: C
authors.initials: C
authors.lastname: Debacq
authors.forename: Y
authors.initials: Y
authors.lastname: Mayeresse
authors.forename: B
authors.initials: B
authors.lastname: Moreau
authors.forename: A
authors.initials: A
authors.lastname: Burggraeve
authors.forename: T
authors.initials: T
authors.lastname: Quinten
authors.forename: W
authors.initials: W
authors.lastname: Friess
authors.forename: G
authors.initials: G
authors.lastname: Winter
authors.forename: C
authors.initials: C
authors.lastname: Vervaet
authors.forename: J P
authors.initials: JP
authors.lastname: Remon
authors.forename: W R G
authors.initials: WR
authors.lastname: Baeyens
mesh_terms: D005612:Freeze Drying / Q000295:instrumentation* / Q000379:methods; D008353:Mannitol / Q000737:chemistry*; D025341:Principal Component Analysis; D019265:Spectroscopy, Near-Infrared; D013059:Spectrum Analysis, Raman; D013696:Temperature
chemical_list: D008353:Mannitol