Summary

Chronic obstructive pulmonary disease (COPD) is a progressive chronic inflammatory disease. In several cases the airway inflammation of COPD patients becomes refractory to corticosteroids and the treatment is impaired. Therefore, there is a need for alternative therapeutic approaches. Resveratrol, a natural compound with anti-inflammatory and antioxidant properties, has the potential to be used as an alternative therapy in the treatment of COPD [1, 2].

The morphology and size distribution of raw and spray dried resveratrol were studied using scanning electron microscopy (SEM) and laser light diffraction, respectively. Aerosol performance and particle size distribution of spray-dried resveratrol were investigated using the Andersen cascade impactor (ACI). Calu-3 sub bronchial epithelial cell line was used to study cell viability (MTT test). Finally, the antioxidant activity of resveratrol was evaluated by measuring DPPH free radicals.

SEM images displayed a spherical morphology for spray dried resveratrol and suitable size for lung deposition (<5 µm). This result was confirmed by laser diffraction analysis, that indicated a median volume diameters (dv_0.5) of 3.86 ± 1.04 µm. Aerosol performance and aerodynamic particle size distribution, were studied using ACI. Results showed suitable aerosol performances for lung delivery (FPF=39.89 ± 1.06%). The viability assay demonstrated that Calu-3 cells could tolerate a wide range of resveratrol concentrations (1.25 nM-80 µM). Furthermore, resveratrol showed good antioxidant activity from 50 μM to 100 μM, with a scavenging activity of more than 50% of DPPH free radicals.

The spray dried resveratrol as inhalation powder has demonstrated to be non-toxic on Calu-3 at the investigated doses and to have antioxidant properties with good aerosols performance. These properties could be used therapeutically for the treatment of COPD and other airway diseases, such as asthma and bronchiectasis. Further investigation on resveratrol transport study across Calu-3 cell and its anti-inflammatory activity in vitro are ongoing.