2.2.2. Electrospinning Process

The polymer blends were electrospun using an electrospinning apparatus (STKIT-40, Linari Engineering, Pisa, Italy), equipped with a high voltage generator (5–40 kV), a glass syringe of 10 mL with a stainless steel needle (0.8 mm), a volumetric pump (Razel R99-E) and a planar collector. The following parameters were used to obtain N loaded scaffolds: DV (voltage) = 22 kV, needle-to-collector distance = 24 cm, flow = 0.379 mL/h, to obtain H loaded scaffolds: DV (voltage) = 24 kV, needle-to-collector distance = 22 cm, flow = 0.379 mL/h, relative humidity: 40%, environmental temperature: 25 ◦C. All the scaffolds were then crosslinked by heating at 150 ◦C for 1 h in a tight container protected from light; the process was also reported as being able to dry sterilize the products [18]. Preliminarily, N stability in the heating process was assessed using a diode array detector (DAD) HPLC (see Section 2.2.5.1). For this purpose, the active ingredient was subjected to the heating treatment in the same conditions as the scaffolds (150 ◦C for 1 h) (in a tight container protected from light). Chromatograms and UV/visible spectra (200–700 nm) at the maximum of the corresponding chromatographic peaks were compared.
