Innovative pharmaceutical strategies for niclosamide repositioning

The antiparasitic niclosamide has shown promising anticancer activity in preclinical studies against several types of cancer, such as colorectal and prostate.Thus, the objective of this work was to develop innovative formulations for the repositioning of niclosamide as an anticancer agent.In chapter I, a critical review of the literature on the physicochemical properties of the drug was carried out, in addition the results of clinical studies against colorectal and prostate cancer.Besides, a review was carried out on studies that developed formulations containing this drug, as well as hypotheses to improve the biopharmaceutical performance of this molecule.In chapter II, the development of solid amorphous dispersion containing niclosamide was carried out.Drug/polymer solutions were acoustic levitated and characterized by synchrotron X-ray light.This set allowed fast, high quality measurements, as well as the identification of niclosamide recrystallization.Plasdone® and Soluplus® demonstrated better properties to form amorphous dispersions, with the latter showing superior solubility enhancement.The study showed that the developed formulation increased the apparent saturation solubility of niclosamide in water by two times.In chapter III the objective was the development, physicochemical characterization and in vitro anticancer activity of a niclosamide nanoemulsion, having HCT-116 cells as a cellular model.Preliminary results indicated Capmul® MCM C8 as the best liquid lipid for the system, but the first nanoemulsions containing this lipid were not stable to justify its usage.On the other hand, Miglyol® 812 indicated to be a suitable liquid lipid for the system.The niclosamide nanoemulsion (~200 nm) with Miglyol® 812 and poloxamer 188 was stable for 56 days, with a monomodal particle size distribution.Cell viability assay against HCT-116 cells demonstrated that niclosamide cytotoxicity is time and concentration dependent.Results herein obtained encourage further research to understand and optimize niclosamide performance as an anticancer drug substance.