Colon targeted delivery of niclosamide from β-cyclodextrin inclusion complex incorporated electrospun Eudragit® L100 nanofibers

Electrospun nanofibers incorporated with inclusion complex (IC) of niclosamide (NIC) and hydroxypropyl-beta-cyclodextrin (HPβCD) (NIC-HPβCD-IC) was produced from pH-responsive polymer (Eudragit® L100, EUD), which disintegrates at pH values higher than 6, (EUD-NIC-HPβCD-IC-NF) for targeted delivery of NIC to the colon. Pristine EUD nanofibers (EUD-NF), only NIC loaded (EUD-NIC-NF) and physical mixture of NIC and HPβCD loaded EUD nanofibers (EUD-NIC-HPβCD-NF) were also produced as reference. SEM images revealed the bead-free and uniform morphology of nanofibers. XRD, TGA, and DSC were also performed for both NIC-HPβCD-IC and electrospun nanofibers and it was seen that there are some NIC molecules, which cannot make IC. Dissolution studies were carried out for 240 min at pH 1.2 and pH 7 simulating stomach and colon, respectively. EUD-NIC-NF released almost 53 % of NIC in 120 min, whereas EUD-NIC-HPβCD-NF (15 %) and EUD-NIC-HPβCD-IC-NF (8 %) released at most 15 % of NIC in 120 min. Then, remained NIC in the nanofibers released into the colon for the next 120 min. The slight difference in the release of NIC into stomach from EUD-NIC-HPβCD-NF and EUD-NIC-HPβCD-IC-NF might be due to the uncomplexed NIC molecules in EUD-NIC-HPβCD-IC-NF. More importantly, EUD-NIC-HPβCD-IC-NF was quite effective for preventing the release of NIC in the stomach in contrast to EUD-NIC-NF, which has already released more than half amount of NIC in 120 min. In conclusion, this study might open new areas for developing targeted delivery systems by the combination of nanofibers and CD-ICs for hydrophobic drugs such as NIC.