Biodegradable nanoparticle flocculates for dry powder aerosol formulation

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Biotechnology

Background:

• Uncontrolled nanoparticle agglomeration hinders dry powder inhalation therapy formulation.
• Current spray-drying and freeze-drying methods for nanosuspensions may require excessive excipients and offer limited control over aerosol properties.

Purpose of the Study:

• To develop an alternative method for producing dry nanoparticle powders with controlled aerodynamic properties for inhalation.
• To investigate nanoparticle flocculation followed by freeze-drying as a viable formulation strategy.

Main Methods:

• Biodegradable poly(DL-lactic-co-glycolic acid) nanoparticles were self-assembled into flocs using electrostatic interactions between oppositely charged polyelectrolyte coatings.
• Nanoparticle floc size was controlled by adjusting the mixing ratio of charged nanoparticles.
• Flocculated nanoparticles were freeze-dried to obtain dry powders.

Main Results:

• The flocculation method allowed for controlled agglomeration of nanoparticles.
• The resulting dry powders exhibited low density (approx. 0.1 g/cm3) and a weblike morphology.
• The dry powders demonstrated desirable aerodynamic properties suitable for dry powder aerosols.

Conclusions:

• Nanoparticle flocculation followed by freeze-drying is a promising alternative for formulating dry powders for inhalation therapy.
• This method provides better control over agglomerate size and aerosolizability compared to traditional drying techniques.
• The developed formulation strategy yields powders with advantageous properties for pulmonary drug delivery.