Temperature effects on ribbon characteristics in soft gelatin capsule manufacture

• Verfasst von: Polyak, Fabian [VerfasserIn]
• Verfasst von: Pugliese, Sonia [VerfasserIn]
• Verfasst von: Reinelt, Constantin [VerfasserIn]
• Verfasst von: Reich, Gabriele [VerfasserIn]
• Titel: Temperature effects on ribbon characteristics in soft gelatin capsule manufacture
• Verf.angabe: Fabian Polyak, Sonia Pugliese, Constantin Reinelt, Gabriele Reich
• E-Jahr: 2024
• Jahr: October 2024
• Umfang: 8 S.
• Illustrationen: Diagramme
• Fussnoten: Online verfügbar: 22. August 2024, Artikelversion: 01. September 2024 ; Gesehen am 12.05.2025
• Titel Quelle: Enthalten in: European journal of pharmaceutics and biopharmaceutics
• Ort Quelle: New York, NY [u.a.] : Elsevier, 1997
• Jahr Quelle: 2024
• Band/Heft Quelle: 203(2024) vom: Okt., Artikel-ID 114465, Seite 1-8
• ISSN Quelle: 1873-3441
• DOI: doi:10.1016/j.ejpb.2024.114465
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Coil-helix transition
• Sach-SW: FTIR spectroscopy
• Sach-SW: Gel elasticity
• Sach-SW: Gel network structure
• Sach-SW: Gelatin
• Sach-SW: Soft gelatin capsules
• Sach-SW: Ultimate tensile strength
• K10plus-PPN: 1925346722

Abstract

In the manufacture of soft gelatin capsules using a rotary-die encapsulation machine, the formation of ribbons at the cooling drums and their subsequent mechanical performance are key attributes for a smooth machinability. In this paper we present the results of a comprehensive investigation of the intricate impact of the cooling drum temperature in the range between 5 and 25 °C on the mechanical and the microstructural properties of a highly concentrated gelatin formulation (40% w/w) typically used in soft capsule manufacture. The study demonstrates that the temperature at the cooling drums strongly affects the gelation kinetics, the gel elasticity and the tensile strength of the ribbons. The temperature correlates linearly with the storage modulus G′ under low shear deformation, i.e. the lower the temperature of the gel, the higher the gel elasticity. A reverse linear relationship was found for the temperature-dependent ultimate tensile strength (UTS) of the gelatin ribbons, i.e. a higher drum temperature leads to a higher UTS. This inverse effect of the ageing temperature on G′ and UTS can be explained by temperature-induced microstructural differences within the gel network, as indicated by FTIR spectroscopy and Differential Scanning Calorimetry (DSC) measurements. Lower ageing temperatures result in a higher number of triple helical junction zones with fewer and/or weaker hydrogen bonds, which translate into a higher gel elasticity under low shear deformation, but a lower resilience of the ribbons against rupture in tensile testing. At higher temperatures, fewer but longer and/or more thermostable triple helical links in the gel network enhance the stability of the ribbons against tensile stress. In summary, the results clearly reveal that a detailed understanding of the complex relationship between the drum temperature, the gel network structure and the mechanical properties of gelatin ribbons is essential for process optimization.