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How pharmaceutical-grade gelatin improves tablet integrity, appearance, and patient acceptability

Gelatin has been a trusted ingredient in pharmaceutical manufacturing for more than a century. Beyond capsule shells, it plays a critical role in tablet coating and binding - two operations that directly affect product stability, appearance, and performance. This article reviews how pharmaceutical-grade gelatin functions as a binder and coating agent,and the quality and documentation requirements formulators should consider when selecting a pharmaceutical grade.

Gelatin as a Tablet Binder

In tablet formulation, binders help particles form granules or compact into tablets with sufficient mechanical strength. Gelatin is an established binder in wet granulation, where it is typically prepared as an aqueous solution and distributed through the powder blend. Its suitability depends on gelatin concentration, solution viscosity, API and excipient compatibility, granulation conditions, and the required tablet properties.

• Improves tablet hardness and reduces friability.
• Supports uniform granule growth during wet granulation.
• Can be used at low inclusion levels.
• Suitable for moisture-sensitive actives when used as a dry binder.

Gelatin as a Tablet Coating Polymer

Gelatin-based coatings create smooth, glossy tablet surfaces that improve swallowability, mask unpleasant tastes, and protect the core from moisture and oxygen. Unlike some synthetic polymers, gelatin is protein-based and widely accepted in pharmaceutical and nutraceutical markets.

Sub-coating and seal coating

Gelatin has traditionally been used as an adhesive component in sub-coating systems, helping applied powders adhere to the tablet and supporting the build-up of a smoother surface before later coating stages.

Film coating

Gelatin can be formulated into aqueous film-coating solutions, often combined with plasticizers such as glycerin or sorbitol to improve flexibility. The result is a glossy, easy-to-swallow tablet with good visual appeal.

Sugar coating

In traditional sugar coating, gelatin may be used as part of an adhesive or sub-coating solution to help coating powders and syrup layers adhere to the tablet core.

Quality Attributes for Pharma Gelatin

Formulation Considerations

• Dissolve gelatin in warm deionized water and use promptly to prevent microbial growth.
• Where gelatin is used in a film system, select and optimize any plasticizer according to the required flexibility, coating composition, gelatin grade, and drying conditions.
• Control product temperature, drying conditions, spray rate, and other relevant coating parameters to avoid sticking, uneven films, or excessive drying.
• Reconfirm disintegration and, where applicable, dissolution after meaningful changes to the binder or coating system.

Regulatory and Sourcing Notes

Pharmaceutical gelatin should comply with the applicable pharmacopoeial monograph and the customer's approved specification for the destination market. Each supplied lot should be supported by an appropriate Certificate of Analysis, while documents such as animal-source statements, TSE/BSE documentation, allergen information, Halal or Kosher certificates, and quality-system certificates should be maintained according to their applicable validity and customer requirements.

Key Takeaways

Gelatin is a versatile, well-characterized excipient for tablet binding and coating. Its film-forming and adhesive properties make it suitable for both functional coatings and aesthetic finishes. Its suitability depends on gel strength, viscosity, concentration, formulation compatibility, process conditions, and the applicable pharmaceutical quality requirements.

About the author

Eric Ma

General Manager

Leveraging two decades of expertise in the gelatin and collagen manufacturing sector, Eric has directed strategic operations that consistently deliver robust business growth and global market expansion.