Webinar Recap: Crosslinking in Softgel Capsules
A month ago, we hosted a webinar on crosslinking in softgel capsules that drew an impressive audience of over 650 registrants from across the pharmaceutical industry. This remarkable turnout demonstrates that crosslinking remains a critical challenge worthy of attention for softgel manufacturers and formulation scientists.
Introduction to Crosslinking
Crosslinking poses a significant challenge because it affects dissolution and stability of softgel capsules, yet typically appears only during stability testing—often when it's too late to make fundamental formulation changes. Our webinar brought together three industry experts to share insights on understanding, preventing, and testing for this phenomenon.
Dr. Ulrich Mach: Understanding Crosslinking Mechanisms
Dr. Mach from Gelita Pharma Institute provided a clear explanation of what crosslinking is and why it matters. He highlighted two main types of crosslinking that affect softgels:
Self-crosslinking between gelatin molecules
Pellicle formation at the shell-fill interface
He explained that several factors influence crosslinking susceptibility, with gelatin type being particularly important. Type B gelatin (especially lime bone gelatin) typically shows better resistance to crosslinking than Type A. Dr. Mach shared impressive results demonstrating how Gelita's specialized anti-crosslinking gelatins can effectively protect formulations at risk of crosslinking.
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Yanitsa Miteva: Formulation Development Strategies
Our very own Yanitsa Miteva focused on formulation aspects, highlighting that cross-linking is challenging because:
It's typically observed only during stability testing
Accelerated condition results don't always predict real-time stability
Time pressure often leads companies to proceed with suboptimal formulations
She identified critical fill materials that commonly trigger crosslinking, particularly polyoxythylated excipients like PEG and natural products such as omega-3 derivatives and essential oils.
Yanitza shared practical strategies for preventing crosslinking:
Using purified excipients with lower aldehyde content
Incorporating suitable antioxidants
Optimizing shell composition and plasticizer systems
Controlling water content in the shell
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Samir Haddouchi: Analytical Testing
Samir from SOTAX Pharma Services rounded out the webinar by discussing how to test for crosslinking in softgel capsules. He explained the pharmacopoeial testing methods and what they mean from a regulatory perspective.
An important insight from his presentation was that while standard testing methods exist for crosslinked capsules, regulatory authorities may still request additional in vivo data even when products pass these tests—particularly for certain types of drug compounds.
Final Thoughts
The key takeaway was clear: prevention through thoughtful formulation development and material selection is far better than relying on analytical workarounds after problems emerge. Understanding what causes crosslinking in your specific formulation is essential for implementing effective prevention strategies.
For those who missed this informative session, the recording is available to all registrants.
This webinar was made possible through collaboration between Gelita Pharma Institute, SOTAX Pharma Services, and Trias Pharma.
Stay tuned for our next webinar! Follow us on LinkedIn or subscribe to our newsletter to be the first to know about our upcoming expert sessions on softgel capsule development.
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+ Solutions to common quality issues like leakage and crosslinking
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