Gelatine for softgel capsule production

Selecting the Ideal Gelatin for Softgel Capsule Production

The quality of a softgel capsule is largely determined by its shell composition, where gelatin serves as the primary polymer. Choosing the right gelatin is a balance of science and functionality, affecting everything from the encapsulation speed to the final product's shelf life. Here are the critical factors to consider when selecting gelatin for softgel production:

1. Bloom Strength (Gel Strength)

Bloom strength measures the firmness of the gel. For softgels, the standard range is typically between 150 and 200 Bloom.

·         Higher Bloom (e.g., 180-200): Provides a tougher, more elastic shell, which is essential for high-speed encapsulation and preventing leakage.

·         Lower Bloom: May result in a shell that is too soft, leading to deformation or sticking during the drying process.

2. Viscosity

Viscosity determines how the gelatin mass flows through the encapsulation machine. The ideal viscosity for softgels usually falls between 35 and 45 mps (millipascal-seconds).

·         If the viscosity is too high, the gelatin ribbon becomes difficult to cast at a uniform thickness.

·         If too low, the ribbon may lack the structural integrity required to form a proper seal around the fill material.

3. Raw Material Source (Bovine vs. Porcine vs. Fish)

The origin of the gelatin impacts the product's marketability and physical properties:

·         Bovine Bone/Skin: The most common choice, offering excellent thermal stability and cost-effectiveness.

·         Porcine Skin: Known for high clarity and quick dissolution, but limited by religious dietary restrictions (Halal/Kosher).

·         Fish Gelatin: Growing in popularity for premium or "marine-based" supplements, though it often has a lower melting point and requires specific machine adjustments.

4. Particle Size (Mesh Size)

The particle size affects the dissolution rate during the preparation of the gelatin mass. Finer mesh sizes (e.g., 8–30 mesh) dissolve faster and more uniformly, reducing the risk of "fish eyes" (undissolved gel lumps) that can cause defects in the capsule wall.

5. Chemical Compatibility and pH

The gelatin must be compatible with the fill material.

·         Type A Gelatin (Acid processed): Usually derived from porcine skin.

·         Type B Gelatin (Alkali processed): Usually derived from bovine bones.
Standard softgel production often utilizes Type B or a blend to ensure a stable pH (typically 5.0–7.0), preventing cross-linking—a reaction that makes the capsule shell insoluble over time.

6. Microbial Purity and Compliance

Ensure the supplier provides documentation for BSE/TSE-free certification, and compliance with pharmacopeia standards such as USP, EP, or ChP. Low microbial counts are non-negotiable to ensure the safety and longevity of the finished supplement or medication.

Conclusion

Selecting the right gelatin requires a deep understanding of your fill material and encapsulation equipment. By optimizing Bloom strength, viscosity, and sourcing, manufacturers can produce softgels that are durable, visually appealing, and highly bioavailable.