Controlled release from drug microparticles via solventless dry-polymer coating

Area of Science:

• Materials Science
• Pharmaceutical Technology
• Chemical Engineering

Background:

• Conventional solvent-based coating methods struggle with fine microparticles (<100 μm).
• Solvent use, plasticizers, binders, and heat treatments pose limitations and environmental concerns.
• Achieving conformal coatings on small particles without damage is challenging.

Purpose of the Study:

• To develop and validate a novel solvent-less, dry-polymer coating process for controlled release applications.
• To investigate the efficacy of high-intensity vibrations for coating fine microparticles (≤100 μm).
• To model coating thickness and diffusion-based controlled release behavior.

Main Methods:

• Utilized a solvent-less, dry-polymer coating process employing high-intensity vibrations.
• Applied micronized polymers (polyethylene wax, carnauba wax) to active pharmaceutical ingredient (API) microparticles (50-500 μm) via vibratory mixing.
• Mechanically deformed polymer layers into continuous films, exploiting van der Waals forces and particle interactions.
• Developed models to describe coating thickness and controlled release kinetics.

Main Results:

• Successfully coated ascorbic acid and ibuprofen microparticles with polyethylene and carnauba waxes.
• Achieved controlled release of active ingredients on the order of seconds to hours.
• Demonstrated conformal coating on fine particles without breakage, with potential for particles <100 μm.
• Validated diffusion-based mechanisms governing controlled release through modeling.

Conclusions:

• The novel vibration-assisted dry-polymer coating is a viable, solvent-less method for controlled release microparticle formulation.
• This technique effectively coats fine particles (<100 μm), offering an advantage over conventional methods.
• The developed models provide a framework for designing and controlling the coating process for tailored drug release profiles.