This work describes the development of novel pH-sensitive nanoparticles (NPs) for the delivery of melatonin (MLT) in breast cancer therapy. The MLT was encapsulated in composite NPs consisting of chitosan (CTS) and hydroxypropyl methylcellulose (HPMC) crosslinked in the presence of tripolyphosphate (TPP). The structure of the composite NPs was characterized using fourier transform infrared (FT-IR), wide angle X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The release behavior of MLT from the composite NPs were investigated in acidic and neutral medium in vitro. Cytotoxicity of MLT encapsulated in the NPs toward MDA-MB-231 breast cancer cells was measured using thiazolyl blue tetrazolium bromide assay (MTT) and compared with that of the free MLT. Results demonstrate that MLT encapsulated in CTS/HPMC NPs had higher toxicity toward the MDA-MB-231 cancer cells compared to the free MLT, thus making the NPs potentially useful in breast cancer therapy.
