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 350 attendees 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. Ulrich 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 emphasized that gelatin type significantly influences crosslinking susceptibility, with Type B gelatin showing better resistance than Type A. While aldehydes are the most widely recognized crosslinking inducers, Dr. Mach identified other critical functional groups that pose crosslinking risks and demonstrated how Gelita's specialized anti-crosslinking gelatins effectively protect vulnerable formulations.
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Yanitsa Miteva: Formulation Development Strategies
Next up was our very own Yanitsa Miteva. She covered everything to do with formulation aspects, highlighting that cross-linking is challenging because of the following:
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
Yanitsa also shared practical strategies for preventing crosslinking, including using purified excipients with lower aldehyde content, and control of process factors.
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Samir Haddouchi: Analytical Testing
Samir Haddouchi 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. However, prevention must be paired with robust analytical methods to detect crosslinking early in development, enabling timely formulation adjustments before stability issues compromise product quality.
This webinar was made possible through collaboration between Gelita Pharma Institute, SOTAX Pharma Services, and Trias Pharma.
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