title: Multi-methodological investigation of the variability of the microstructure of HPMC hard capsules.
abstract: The objective of this study was to analyze differences in the subtle microstructure of three different grades of HMPC hard capsule shells using mechanical, spectroscopic, microscopic and tomographic approaches. Dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), vibrational spectroscopic, X-Ray scattering techniques as well as environmental scanning electron microscopy (ESEM) and optical coherence tomography (OCT) were used. Two HPMC capsules manufactured via chemical gelling, one capsule shell manufactured via thermal gelling and one thermally gelled transparent capsule were included. Characteristic micro-structural alterations (associated manufacturing processes) such as mechanical and physical properties relevant to capsule performance and processability were thoroughly elucidated with the integration of data obtained from multi-methodological investigations. The physico-chemical and physico-mechanical data obtained from a gamut of techniques implied that thermally gelled HPMC hard capsule shells could offer an advantage in terms of machinability during capsule filling, owing to their superior micro- and macroscopic structure as well as specifically the mechanical stability under dry or humid conditions.
authors: Research Center Pharmaceutical Engineering, Inffeldgasse 13, 8010, Graz, Austria.
authors: E
authors: E
authors: Faulhammer
authors: Institute for Chemistry and Technology of Materials, Graz University of Technology, NAWI Graz, Stremayrgasse 9, A-8010 Graz, Austria; Kompetenzzentrum Holz GmbH (Wood K Plus), Altenberger Strasse 69, A-4040 Linz, Austria.
authors: A
authors: A
authors: Kovalcik
authors: Research Center Pharmaceutical Engineering, Inffeldgasse 13, 8010, Graz, Austria.
authors: V
authors: V
authors: Wahl
authors: Research Center Pharmaceutical Engineering, Inffeldgasse 13, 8010, Graz, Austria.
authors: D
authors: D
authors: Markl
authors: Institute for Chemistry and Technology of Materials, Graz University of Technology, NAWI Graz, Stremayrgasse 9, A-8010 Graz, Austria.
authors: F
authors: F
authors: Stelzer
authors: GlaxoSmithKline (GSK), New Frontiers Science Park, Harlow, Essex CM19 5AW, UK.
authors: S
authors: S
authors: Lawrence
authors: Research Center Pharmaceutical Engineering, Inffeldgasse 13, 8010, Graz, Austria.
authors: J G
authors: JG
authors: Khinast
authors: Research Center Pharmaceutical Engineering, Inffeldgasse 13, 8010, Graz, Austria. Electronic address: amrit.paudel@rcpe.at.
authors: A
authors: A
authors: Paudel
mesh_terms: D002214:Capsules / Q000737:chemistry*; D055598:Chemical Phenomena; D065347:Hypromellose Derivatives / Q000737:chemistry*; D055595:Mechanical Phenomena; D014867:Water / Q000032:analysis
chemical_list: D002214:Capsules; D014867:Water; D065347:Hypromellose Derivatives
keywords: DMA-RH; HPMC capsules; Material characterization; Microstructural properties; Physicochemical properties; Processability