Ionically Crosslinked Chitosan Membranes Used as Drug Carriers for Cancer Therapy Application

Abstract

The aim of this paper was to prepare, by the freeze-drying method, ionically crosslinked chitosan membranes with different contents of pentasodium tripolyphosphate (TPP) and loaded with 1,4-naphthoquinone (NQ14) drug, in order to evaluate how the physical crosslinking affects NQ14 release from chitosan membranes for cancer therapy application. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), swelling degree, and through in vitro drug release and cytotoxicity studies. According to the results, the molecular structure, porosity and hydrophilicity of the chitosan membranes were affected by TPP concentration and, consequently, the NQ14 drug release behavior from the membranes was also affected. The release of NQ14 from crosslinked chitosan membranes decreased when the cross-linker TPP quantity increased. Thus, depending on the TPP amount, the crosslinked chitosan membranes would be a potential delivery system to control the release of NQ14 for cancer therapy application. Lastly, the inhibitory potential of chitosan membranes ionically crosslinked with TPP and loaded with NQ14 against the B16F10 melanoma cell line was confirmed through in vitro cytotoxicity studies assessed via MTT assay. The anti-proliferative effect of prepared membranes was directly related to the amount of cross-linker and among all membranes prepared, such that one crosslinked with 0.3% of TPP may become a potential delivery system for releasing NQ14 drug for cancer therapy.

Keywords: 1,4-naphthoquinone; cancer therapy; chitosan; controlled release; ionic crosslinking; pentasodium tripolyphosphate.

Figure 1

Fourier transform infrared (FTIR) spectra of sodium tripolyphosphate (TPP), non-crosslinked and ionically crosslinked chitosan membranes (a) from 4000–500 cm⁻¹ and (b) from 1245–520 cm⁻¹.

Figure 2

FTIR spectra of NQ14, TPP, non-crosslinked and ionically crosslinked chitosan membranes after NQ14 drug loading (a) from 4000–500 cm⁻¹ and (b) from 1245–520 cm⁻¹.

Figure 3

Representation of the $P_3{O}_{10}^{5-}$ and $O{H}^{-}$ ions reaction with $-N{H}_3^{+}$ groups of chitosan by (a) deprotonation and (b) ionic crosslinking.

Figure 4

Wide-angle X-ray diffraction (WAXD) profiles of TPP, non-crosslinked and ionically crosslinked chitosan membranes before NQ14 drug loading (a); NQ14, TPP, and non-crosslinked and ionically crosslinked chitosan membranes after NQ14 drug loading (b).

Figure 5

Proposed hydrogen bonding interactions between chitosan and 1,4-naphthoquinone molecules.

Figure 6

Scanning electron microscope (SEM) photomicrographs of non-crosslinked and ionically crosslinked chitosan membranes before and after NQ14 drug loading, prepared by freezing and lyophilization process: (a,c) microstructure from the top surface, and (b,d) from the cross section view.

Figure 7

Swelling degree of the non-crosslinked and ionically crosslinked chitosan membranes before and after NQ14 loading with the immersing time.

Figure 8

Concentration of NQ14 drug released from non-crosslinked and ionically crosslinked chitosan membranes.

Figure 9

Effect of 1,4-naphthoquinone (NQ14) on the proliferative growth of B16F10 melanoma cell line determined by MTT assay. Membranes loaded with NQ14 (CS/NQ14/05TPP, CS/NQ14/03TPP and CS/NQ14/01TPP), control (membrane without drug-CS/05TPP) and phosphate buffered saline (PBS)/NQ14 control.