2.4. Loading of Ciprofloxacin on HNTs, Ht and HNTs-Ht

To a dispersion of HNTs, Ht or HNTs-Ht (see infra) in methanol (5 mL), a ciprofloxacin solution (1 mL, 1 × 10⁻² M in HCl 0.1 N) was added. The suspension was sonicated for 5 min, at an ultrasound power of 200 W and at 25 °C and was left under stirring for 18 h at room temperature. After this time, the solvent was filtered off, under vacuum, and the powder was washed several times with methanol and then dried.