Figure 4.

Percentage of Roflumilast released by LPHFNPs (red), Man-LPHFNPs (blue), and diffusion profile (black). Roflumilast release profile from LPHFNPs was realized using the dialysis method, under sink conditions. Each sample was dispersed in 1 mL of PBS at pH 7.4, placed in a dialysis tubing (MWCO 12–14 kDa), immersed into PBS (pH 7.4)/ethanol (80/20, v/v), and then incubated at 37 °C under continuous stirring. At fixed time intervals (1, 2, 4, 6, and 24 h), an aliquot of the external medium was withdrawn, replaced with an equal volume of fresh medium, and freeze-dried, and Roflumilast was quantified by HPLC analysis as reported in the experimental part.