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Optimised process and formulation conditions for extended release dry polymer powder-coated pellets.
Ildikó Terebesi1, Roland Bodmeier
1College of Pharmacy, Freie Universität Berlin, Berlin, Germany.
Summary
Dry polymer powder coating effectively creates extended release ethylcellulose coatings for drugs. This method improves film formation and permeability without water, offering an alternative to traditional coating techniques.
Area of Science:
- Pharmaceutical Technology
- Materials Science
- Drug Delivery Systems
Background:
- Traditional extended-release coatings often rely on organic solvents or aqueous dispersions, posing environmental and processing challenges.
- Ethylcellulose, a widely used polymer for controlled drug release, typically requires water for effective film formation in coating processes.
- Developing water-free coating methods is crucial for improving efficiency and sustainability in pharmaceutical manufacturing.
Purpose of the Study:
- To enhance film formation and permeability of extended-release ethylcellulose coatings using dry polymer powder coating.
- To investigate the feasibility of dry powder coating for drugs with varying solubility profiles.
- To explore alternative methods for preparing plasticized ethylcellulose powders for improved coating performance.
Main Methods:
- Utilized ethylcellulose (7 and 10 cp) and Eudragit® RS for dry powder coating of pellets in a fluidised bed ball coater.
- Prepared pre-plasticized ethylcellulose powders via spray-drying or hot melt extrusion/cryogenic grinding.
- Characterized film formation, polymer properties, and drug release using DSC, DMA, SEM, and dissolution testing with model drugs (chlorpheniramine maleate, theophylline).
Main Results:
- Achieved successful film formation and extended drug release with ethylcellulose via dry powder coating, eliminating the need for water.
- Demonstrated that plasticized ethylcellulose exhibits improved mechanical properties and reduced glass transition temperature (Tg), facilitating particle coalescence and dense film formation.
- Showed that lower viscosity ethylcellulose (7 cp) yielded better film formation and required less stringent curing conditions; permeability was tunable using ethylcellulose/HPMC blends.
Conclusions:
- Dry polymer powder coating is a viable, water-free technique for producing extended-release ethylcellulose coatings for drugs of diverse solubilities.
- Pre-plasticized ethylcellulose powders offer an efficient alternative for dry powder coating applications.
- This method presents a promising alternative to conventional solvent-based or aqueous dispersion coating techniques.
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