Biodegradable polymeric capsules obtained via room temperature spray drying: preparation and characterization

Area of Science:

• Polymer Science
• Materials Science
• Nanotechnology

Background:

• Biodegradable polymers are crucial for sustainable materials.
• Controlling particle morphology is key for drug delivery and other applications.
• Spray drying is a common method for particle formation.

Purpose of the Study:

• To investigate the relationship between biodegradable polymer solution chemistry/viscosity and micro/nanosphere morphology.
• To understand the effect of encapsulated aqueous material on particle formation.
• To correlate polymer thermal properties with resulting particle characteristics.

Main Methods:

• Preparation of 2 wt% solutions of polyhydroxybutyrate (PHB), polylactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA), and Eastar Bio GP (GP) in dichloromethane.
• Spray drying of polymer solutions at room conditions, with and without an encapsulated aqueous material.
• Comprehensive thermal characterization (T(g), T(m), T(d)) of the polymers.

Main Results:

• Decreased solution viscosity leads to smoother microsphere formation.
• Very low viscosity promotes the development of well-defined nanospheres.
• Presence of an aqueous core causes micro/nanocapsules to coalesce into larger aggregates due to water's plasticizing effect.

Conclusions:

• Solution viscosity is a critical parameter controlling micro- and nanosphere morphology.
• The presence of water significantly influences particle aggregation.
• Understanding these relationships is vital for designing biodegradable polymer-based micro/nanoparticles.