Multi-Formula Stripe Coating Process Window: Viscosity, Leveling, and Drying Control for Single-Coat Film Formation
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Introduction
For compounded ODFs (Orally Dissolvable Films), multi-formula stripe coating allows for significant efficiency gains and flexibility in dosage combinations. However, it requires precise control over viscosity matching, interface leveling, and drying logic to avoid defects.
Challenges in the Process
- Compound and gradient dosage: Significant viscosity and solid content differences between formulations can amplify interface fluctuations.
- Cross-contamination and boundary clarity: Need to control the interaction between adjacent formulations and the stripe edge.
- Drying and shrinkage: Different volatilization rates cause uneven thickness and content distribution.
Key Process Window Controls
- Viscosity & rheology: Match the coating range for each formulation within the target stripe thickness and edge clarity constraints.
- Leveling & interface: Control the leveling time before coating to avoid stripe diffusion or breakage.
- Drying logic: Use stable hot-air gradients and reasonable airflow paths to balance solvent removal and film surface uniformity.
HUANGHAI’s Solution
- Multi-formula stripe coating technology (patented solution): Industrialized logic to achieve dual-formulation single-coat film formation.
- From R&D to scale-up: Lock in the formulation window and stripe morphology on MJ150-L before transitioning to MJ150 for production.
- Integration with downstream packaging: Reverse-calibrate stripe spacing and shrinkage rates based on cutting dimensions and individual pouch specifications.
Conclusion
The key to stripe coating is “window alignment.” By closing the loop between formulation rheology, stripe morphology, and drying logic on the same method card, consistency between batches can be maintained during scale-up.