Systematic aging of degradable nanosuspension ameliorates vibrating-mesh nebulizer performance

The process of vibrating-mesh nebulization is affected by sample physicochemical properties. Exemplary, electrolyte supplementation of diverse formulations facilitated the delivery of adequate aerosols for deep lung deposition.

This study addressed the impact of storage conditions of poly(lactide-co-glycolide) nanosuspension on aerosol properties when nebulized by the eFlow®rapid.

First, purified nanosuspensions were supplemented with electrolytes (i.e. sodium chloride, lactic and glycolic acid). Second, the degradable nanoparticles (NP) were incubated at different temperatures (i.e. 4, 22 and 36 °C) for up to two weeks. The effect of formulation supplementation and storage on aerosol characteristics was studied by laser diffraction and correlated with the sample conductivity.

Nebulization of purified nanosuspensions resulted in droplet diameters of >7.0 µm. However, electrolyte supplementation and storage, which led to an increase in sample conductivity (>10-20 µS/cm), were capable of providing smaller droplet diameters during vibrating-mesh nebulization (≤5.0 µm). No relevant change of NP properties (i.e. size, morphology, remaining mass and molecular weight of the employed polymer) was observed when incubated at 22 °C for two weeks.

Sample aging is an alternative to electrolyte supplementation in order to ameliorate the aerosol characteristics of degradable NP formulations when nebulized by vibrating-mesh technology.