Coating High-Viscosity Formulations: Challenges and Solutions
Share
As oral dissolvable films (ODFs) and transdermal patches evolve with multi-component, sustained-release, and functional ingredients, more clients are requesting coating solutions for high-viscosity, high solid content, and non-Newtonian fluids. These formulations place higher demands on coating systems. Conventional equipment often struggles with issues such as thickness variations, film breakage, bubbling, and misalignment. Overcoming these challenges requires systematic optimization across liquid supply, die design, and tension control.
Coating high-viscosity ODF and patch formulations (above 10,000 cps) typically fails through poor fluidity, thickness instability, foaming and edge leakage.
1. Common Coating Challenges with High-Viscosity Formulations
- Poor fluidity: Difficult to spread evenly, leading to buildup or film breakage in the coating zone.
- Thickness instability: Sensitive to temperature and pressure, resulting in uneven thickness across batches.
- Foaming: Entrapped air bubbles are harder to release, causing rough film surfaces after drying.
- Edge leakage: Wide-width coating may cause material to overflow at die edges, contaminating rollers or destabilizing tension.
2. HUANGHAI’s Solutions for High-Viscosity Coating
To handle complex formulations with viscosities above 10,000 cps, HUANGHAI equipment integrates the following innovations:
- Closed liquid supply system: Minimizes shear force and air intake while stabilizing pressure output.
- Intelligent tension control: Real-time feedback with auto web-guiding to maintain film stability.
- Optional foam elimination module: Supports inline degassing or optimized pre-mixing for bubble-prone formulations.
Recommended Model:
3. Application Scenarios for High-Viscosity Coating
- Nutritional films / sugar-loaded ODFs: High sweetener or thickener content.
- Sustained-release drug films: High-viscosity polymers to control release profiles.
- Traditional medicine ODFs: Extract-based formulations with sticky concentrates.
- Industrial topical patches: Muscle or joint patches often containing viscous matrix materials.
Conclusion
High-viscosity formulations bring both higher value and greater technical complexity. Only coating systems that optimize liquid handling, die precision, and process control can truly meet the demands of these challenging applications. HUANGHAI delivers not just coating equipment, but production-ready systems engineered for high-viscosity ODF formulations.
*The MJ150 production line's patented hot-air drying tunnel (Academician Hou Huimin's patent CN201668734U).
Related product
MJ150 ODF & Transdermal Patch Film Making Machine
Doctor-blade coating, 0.2–5 m/min running speed, drying from room temperature up to 120 °C.
Frequently Asked Questions
What is the difference between an ODF film and a transdermal patch?
Oral dissolving films (ODF) dissolve on or under the tongue within seconds to minutes; transdermal patches stick to the skin and release the API over hours to days. Both are made by solvent-cast film coating, and the MJ Pro coating platform can be built for either — the application is set before the machine is manufactured.
What output can I expect from Huanghai ODF machines?
MJ150-RD about 1,200 films per hour for formulation screening; MJ150-Lab 8,000–10,000 films per hour for pilot-scale work; MJ150 about 30,000 films per hour (Gen I) for commercial production. For packaging, the MJ180 cuts and packs about 11,900 films per hour (Gen I); the EZ320 (about 9,000 films per hour) is for food-grade films only.
What drying technology is used?
The MJ150 production line uses a patented hot-air parallel-flow drying tunnel (Academician Hou Huimin's patent CN201668734U). The MJ150-RD uses oven drying; the MJ150-Lab uses the same hot-air drying process as the MJ150.
Can Huanghai machines coat multi-formula (striped) films?
Yes. Huanghai's patent CN117323228A covers stripe coating that applies two formulations side by side in one pass, useful for fixed-dose combination films.
Explore Complete ODF & TDDS Manufacturing Solutions
Huanghai offers end-to-end ODF film production lines — from R&D (MJ150-RD / MJ150-Lab) to commercial manufacturing (MJ150). Designed for GMP production and to support 21 CFR Part 11 requirements.