Film coating application for Soft Gel Capsules

Soft capsules are oral solid forms where the active principal ingredient (inner fill) is usually placed inside a solid capsule (outer shell). Soft gelatin capsules (SGC) are often coated with a film layer for different reasons, such as protection against degradation, functionality, masking bad taste, and patient compliance.

Challenges the industry faces during gelatin capsule film coating- Romaco

Your challenges

Special roughness of the SGC surface
Low solubility of the capsule shell in organic solvents as carriers do not adhere properly to the shell
Defects on the film coating, such as peeling or cracking of the film layer
Swelling or sticking together of the capsules during the process due to plasticity effect of water when using aqueous or hydroalcoholic suspensions

Our solution

Proposing initial process parameters for the film coating of SGCs with a 100% aqueous suspension:

The key point of the coating process is to stabilize the equilibrium between the amount of energy provided by the inlet air flow and inlet temperature versus the amount of coating suspension provided.
The coating of 50 kg of SGCs was carried out in a TPR 100 OPT coating machine.
The coating formulation is shown in Table 1. The SGCs were mainly composed of sunflower oil and gelatin.
Process parameters were adjusted in such way that whole spraying time was 90 minutes to achieve a 3% weight gain. Process parameters used during this trial are listed in Table 2.

Table 1. Coating Composition

Coating suspension components
Purified water	83.0 %
Vivacoat® A	17.0 %
Red iron oxide	0.05 %

Table 2

Phase	Heating	Spraying	Drying
Drum speed (rpm)	3	8	3
Inlet air Flow (m3/h)	1600	1600	1000
Underpresure (Pa)	250	250	250
Inlet air T (°C)	48	48	32
Product temperature (°C)	37	37	33
Outlet air T (°C)	42	40	33
Spray rate (g/min)	-----	100	-----
Atomization pressure (bar)	-----	2.0	-----
Spray pattern pressure (bar)	-----	2.0	-----
Nozzle (mm)	1.2 (2 guns)	1.2 (2 guns)	1.2 (2 guns)
Gun distance from tablets (mm)	160	160	160
Batch size (kg)	50	50	50
Coater drum filling (%) Bulk density 0.6 Kg/L	55%	55%	55%
Sprayed solution (kg)	-----	8.8	-----
Process time (min)	20	90	15
Appearance quality	Acceptable	Acceptable	Acceptable

Conclusion - gelatin capsule film coating- Romaco

Our Conclusions

The film coating of a 50 kg batch (around 55% capacity of a TPR OPT 100) of soft gelatin capsules has been carried out. The challenge of performing an aqueous coating process while maintaining the process temperature below the melting point of the gelatin capsules has been successfully achieved. The TPR 100 OPT managed to keep all process parameters stable throughout the whole process, which was the main factor for the success of the trial.

Suitable Products

Tecpharm

TPR OPT Tablet Coater

Applications

Maximum output (liters)

7.5–900

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Tecpharm

TPR Standard tablet coater

Applications

Maximum output (liters)

3.5–900

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Application Note

Film coating application for Soft Gelatine Capsules

The film coating of a 50 kg batch (around 55% capacity of a TPR OPT 100) of soft gelatin capsules

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Do you have the challenge of coating SCG?

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FAQ

Can I use different film coating formulations with the Romaco machine?

At Romaco Tecpharm, our coating machines are designed to handle a variety of film coating formulations. Our emphasis on flexibility, particularly for soft gelatin capsule coating, demonstrates our commitment to adapting to diverse film coating materials. We pride ourselves on providing customized solutions, working closely with our clients to tailor the coating process to their specific formulation requirements. The range of coating types we support, including enteric, sustained release, and aesthetic coatings, further underscores this capability, as each requires distinct formulations. Therefore, it's highly likely that your desired film coating formulation is compatible with our machines designed for soft gelatin capsules. However, the specific formulations compatible with a given machine will depend on the machine's configuration and the properties of the coating material. We encourage you to contact us directly to confirm compatibility with your particular formulation so we can ensure optimal results.

How do I ensure optimal process parameters for my specific soft gelatin capsule formulation?

Ensuring optimal process parameters for your specific soft gelatin capsule formulation requires a collaborative approach. Romaco's focus on customized solutions suggests they provide expert support in developing and optimizing coating processes designed to meet your needs. This likely involves understanding key parameters like airflow, temperature, drum speed, spray rate, and product temperature, and then using a process of trial and error to fine-tune these settings. Ultimately, developing robust coating recipes is crucial for consistent and repeatable results. Direct consultation with Romaco's experts is the best way to achieve optimal coating performance for your unique formulation.

What kind of maintenance does the TPR OPT Coating Machine require?

Maintaining the TPR OPT Coating Machine involves a combination of regular, preventive, and corrective maintenance. Regular maintenance likely includes frequent cleaning of key components like the coating drum and spray nozzles, along with periodic inspections for wear and tear. Proper lubrication and timely filter replacements are also important. Preventive maintenance, likely scheduled by Romaco, may involve more detailed inspections and component replacements. Keeping the control system software updated is also a key aspect of preventive care. Finally, corrective maintenance addresses any unexpected issues or malfunctions. However, for the specific maintenance requirements of the TPR OPT, it's essential to consult Romaco directly. We can provide detailed procedures, schedules, and information on any specialized tools or training needed, and may also offer service contracts for ongoing support. It is very important to use original Romaco Tecpharm spare parts to ensure the correct functioning of the equipment.

Can the coating machine handle different capsule sizes and batch volumes?

Romaco Tecpharm's TPR OPT coating machines are designed with scalability in mind, handling batches from 10% to 100% of the machine's capacity. This inherent flexibility allows for a range of batch sizes within a given machine. However, while the TPR OPT can accommodate this range, it's important to understand that the specific capsule sizes and types it can process will still depend on the machine's configuration. Different capsule sizes might require adjustments to process parameters, and some capsule types might not be suitable for all machines. Therefore, while the TPR OPT offers excellent scalability for batch volume, consulting with Romaco directly is crucial to determine its compatibility with your specific capsule sizes and types. We can provide detailed information about the machine's capabilities and recommend the appropriate setup for your needs. It is very important to note that the volume-to-weight ratio is conditioned by a calculated and determined tablet density (approximately 0.66 g/ml).

Can the coating machine handle aqueous suspensions without damaging the capsules?

Whether Romaco Tecpharm coating machines can handle aqueous suspensions without damaging capsules depends on several factors, including the specific capsule type (soft gelatin, hard gelatin, etc.), the formulation of the aqueous suspension, and the machine's configuration. While aqueous film coating is a common practice, certain capsule types might be more sensitive to moisture than others. The coating machine's drying system and process parameters must be carefully controlled to prevent capsule swelling, sticking, or other damage. It is absolutely essential to contact Romaco Tecpharm directly to discuss your specific capsule type and aqueous suspension formulation. We can advise on the feasibility of using aqueous coatings with your capsules and recommend the appropriate machine configuration and process parameters to ensure product integrity. They can also provide guidance on any necessary pre-treatments or specialized equipment required.