Gelatin choice critical to softgel production success
Gelita is warning formulators that incorrect gelatin selection can disrupt softgel production, causing defects such as weak seams, inconsistent ribbon formation, or complete manufacturing failure. During CPHI Milan 2026, the company’s specialists highlighted that standard gelatin grades often fail to meet the requirements of specific formulations, with issues surfacing only after production has begun.
Martin Junginger, Gelita’s global category manager for Pharma & Bioscience, explained that problems typically arise during manufacturing and drying stages. Gel strength, viscosity, and molecular-weight distribution directly influence ribbon formation, sealing quality, and drying efficiency. When these properties do not align with formulation or machine settings, manufacturers encounter defects like narrow processing windows, weak seams, capsule leaks, or deformation. Certain fill materials—particularly those containing reactive compounds such as aldehydes, polyphenols, or metal ions—can further destabilize gelatin over time, creating a hard, insoluble layer that impairs or blocks release entirely.
Junginger emphasized that gelatin selection affects both processing and long-term performance. A softgel designed for rapid release may degrade if the gelatin reacts with the fill during storage, while a formulation intended for delayed release could fail prematurely with the wrong grade. He noted that no single gelatin parameter, such as bloom strength or viscosity, can predict compatibility with every fill. Instead, formulators must consider gelatin as part of a broader system, balancing shell composition, fill reactivity, and storage conditions.
A frequent error, Junginger observed, is choosing gelatin based only on processing specifications like bloom or viscosity without testing its interaction with the complete fill over time. Issues may not appear until stability testing, when a product that performed well initially fails under real-world conditions. To reduce risks, he recommended early collaboration between procurement teams, formulators, and gelatin suppliers, sharing details on the fill, intended release profile, and storage environment to select the appropriate grade.
RXL Gelatin’s Role in Stabilizing Reactive Fills
Gelita has developed its RXL (Reduced Cross-Linking) gelatin portfolio to address these challenges, but Junginger stressed that no single grade works universally. The optimal level of protection depends on the formulation’s reactive substances, their concentration, and storage conditions. While gelatin selection improves robustness, it cannot replace proper fill design, process control, or stability testing. The company’s Pharma Institute now assists customers in modeling shell-fill interactions and translating product profiles into customized gelatin solutions.
Junginger argued that the focus should shift beyond overcoming dissolution challenges. Future formulations must prioritize designing precise release profiles, where gelatin, fill, and processing work together to meet performance goals. Early involvement from suppliers and manufacturers is critical to aligning these factors before production begins.
Aldehydes, Polyphenols, and Metal Ions Threaten Softgels
At CPHI Milan 2026, Gelita’s discussions with formulators revealed that reactive fill components often necessitate specialized gelatin grades. Junginger cited aldehydes, found in oxidized oils or vitamin formulations, as a common issue, explaining these compounds can cross-link with gelatin’s amino groups, forming insoluble networks that trap active ingredients. Polyphenols in herbal extracts or fruit-based supplements pose similar risks, particularly when concentrated or exposed to heat during processing.
Even trace metal ions, such as iron or copper, can accelerate oxidative reactions within the gelatin matrix, worsening pellicle formation over time. The severity of these interactions depends on the fill’s composition and physical state; for example, a liquid fill may distribute reactive species more evenly than a powder, altering cross-linking rates across the capsule shell.
Storage conditions further complicate gelatin-fill compatibility, as humidity and temperature accelerate unwanted reactions. Junginger noted that gelatin’s moisture balance, essential for maintaining flexibility, can shift under varying storage environments, leading to brittleness or cracking. High humidity may temporarily plasticize the shell, masking early cross-linking until stability tests reveal a hardened membrane. Low humidity, conversely, can concentrate reactive species at the shell interface, intensifying localized cross-linking. Gelita’s RXL portfolio adjusts molecular-weight distribution and functional-group availability to mitigate these issues, but Junginger cautioned that no single grade eliminates the need for controlled storage or reactive fill mitigation.
Tailoring Gelatin for Precision Release Profiles
Beyond preventing defects, gelatin selection now influences release kinetics, with formulators seeking precise dissolution profiles. Junginger described how gelatin’s gel strength and viscosity can be adjusted to achieve rapid, delayed, or pulsatile release, provided the fill remains chemically inert. For instance, high-viscosity gelatin may slow initial hydration, delaying release in extended-formulation softgels, while low-bloom grades could enhance disintegration in immediate-release products. However, these adjustments require balancing processing constraints; overly fluid gelatins may leak during sealing, while excessively rigid ones can fracture under filling pressure. The key challenge is aligning gelatin properties with the fill’s solubility and the intended biological target, ensuring the shell neither hinders nor unpredictably accelerates release.
This approach allows formulators to test virtual scenarios, such as adjusting plasticizer levels or gelatin bloom, before production. Junginger emphasized that the goal is to move beyond reactive problem-solving, instead designing formulations where gelatin and fill coexist without conflict. Despite advanced modeling, Junginger warned that real-world validation through accelerated stability studies remains essential, as some interactions, like slow oxidative degradation, may not appear until months of storage.
At CPHI Milan, Gelita demonstrated how its Pharma Institute collaborates with customers to analyze these interactions, offering material recommendations, process adjustments, and packaging strategies. Junginger cited a case where a vitamin D3 softgel formulation initially failed stability testing due to cross-linking with residual aldehydes in the oil phase. By switching to a higher-RXL gelatin and modifying the drying profile, the manufacturer eliminated pellicle formation while preserving the desired release profile. The key takeaway, Junginger said, is that gelatin selection is now part of a broader formulation strategy, where every component, from the fill to the storage environment, must be considered as an integrated system. The result is a product that performs consistently from manufacture to expiration, without unexpected failures.
