Encapsulation of PROLI/NO in biodegradable microparticles.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Drug Delivery

Background:

• Nitric oxide (NO) delivery via inhalation requires stable formulations.
• Biodegradable hydrophilic polymers like PLGA and PELA are candidates for microparticle drug delivery.

Purpose of the Study:

• To develop inhalable microparticles for nitric oxide (NO) delivery using biodegradable polymers.
• To evaluate the encapsulation and release characteristics of a hydrophilic NO prodrug (PROLI/NO) within PLGA and PELA microparticles.

Main Methods:

• Microparticles prepared using double emulsion and solvent evaporation techniques.
• Freeze-drying used for microparticle stabilization.
• Nitric oxide release kinetics quantified by C(max), W(50), and R(i).

Main Results:

• Poly-lactic-co-glycolic acid (PLGA) microparticles failed to encapsulate PROLI/NO.
• Polyethylene oxide-co-lactic acid (PELA) microparticles showed 43% entrapment efficiency and a 2.3 µm diameter.
• PELA microparticles exhibited NO release with C(max) = 123 nM/mg, W(50) = 4.11 min, and R(i) = 78.7 nM/mg/min.

Conclusions:

• The hydrophilic polyethylene glycol moiety in PELA facilitates efficient PROLI/NO encapsulation.
• PELA-based microparticles represent a promising strategy for generating stable, inhalable NO formulations.
• PLGA microparticles with gelatin encapsulation resulted in particles too large for inhalation.