Development of long circulation nano-enabled drug carriers for cancer treatment

Disulfiram (DSF) is an analogue of the dithiocarbamate family used over half a century ago for the treatment of alcoholism and its Food and Drug Administration (FDA) approved. DSF is a potent anti-cancer agent and Cu2+ dependent on mediating growth inhibition and apoptosis against different types of cancer cells. The major biological limitation of DSF against cancer cells is poor solubility and instability in the human body. Repositioning DSF with nano-carriers will improve its half-life, stability and enable long circulation for cancer therapy. Direct nanoprecipitation (D-Nano-Pr) and single emulsion/solvent evaporation (SE) methods were employed to successfully manufactured non-PEGylated and PEGylated nanoparticles (NPs) and including solid lipid nanoparticles (SLNs) of encapsulated DSF. The particle sizes of NPs/SLNs prepared by using the SE method were reduced by probe sonication (PS) or high-pressure homogenization (HPH) techniques. Freshly manufactured DSF NPs/SLNs (including empty NPs/SLNs) were characterized to determine particle sizes, polydispersity index (PDI), zeta potential, thermal degradation using differential scanning calorimetry (DSC), and functional group confirmation of chemical compounds using Fourier transform infrared spectroscopy (FTIR). Percentage encapsulation efficiency, cumulative release, and stability of DSF NPs/SLNs in horse serum media were evaluated by high-performance liquid chromatography (HPLC). This study has also contributed by developing efficient methods used to determine the manufactured NPs/SLNs percentage encapsulation efficiency and stability of DSF in horse serum. The 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) cytotoxicity assays in vitro experiments of NPS/SLNs was performed against MCF 7, MDA-MB-231, and MDA-MB-231PTX10 cancer cell lines, to investigate the inhibition effects of the encapsulated DSF. The MTT cytotoxicity assays of DSF-loaded NPs/SLNs demonstrated increased cytotoxicity and decreased IC50 values indicating therapeutic effect against breast cancer cells. PEGylated DSF NPs demonstrated comparable cytotoxic effects over the free drug. PEGylated DSF PLGA NPs demonstrated the potential to be developed as nanomedicine for cancer therapy. Finally, this study showed manufactured nano-size particles of NPs/SLNs to improve DSF biostability and offer efficient protection to DSF in horse serum. Therefore, there is a high potential to enable DSF long circulation for efficient cancer therapy