??Nanomedicine for Drug Delivery: Design of nano-formulations to improve transport anti-cancer drugs

Nanoparticles are nano-sized drug carriers used to improve the transport, biodistribution, and pharmacokinetics of encapsulated drugs. In cancer treatment, nanoparticles have been widely applied by virtue of their ability to reduce the side effects of systemic chemotherapy caused by the undesired off target accumulation and to enhance treatment selectivity. Indeed, nanoparticles are known to selectively interact with certain tumours by exploiting the Enhanced permeability and retention (EPR) effect, or to actively negotiate with cancer cells through recognition between target-specific receptors and ligands on nanoparticles’ surface. Moreover, since nanoparticles host drugs inside a core, which can be made of different materials, they preserve drug integrity during its transport, reducing degradation and clearance, thereby maximizing the available dose. Despite these advantages, the clinical translation of nanoparticles is difficult since many formulations failed to provide a therapeutic advantage in patients. The main reason for this, is the lack of proper design parameters, which should consider the specificity of the tumour to be targeted, the physical and chemical properties of the drug to be encapsulated as well as those of the material composing the carrier, and the presence of biological barriers. This thesis aims to develop protocols to produce polymer nanoparticles for the encapsulation of Colchicine derivatives, using both hydrophobic and hydrophilic derivatives. In details, we used ad hoc designed polyesterurethanes to obtain nanoformulations through two methods: 1) Nanoprecipitation/Self-assembly method to produce core-shell nanoparticles with the ability to encapsulate hydrophobic drugs. To achieve this, we used a proprietary poly(caprolactone) (PCL)-based polyurethane for the polymeric core, and a mixture of lipids (DSPE-PEG and EGG-PG) for the lipidic shell, Nanoprecipitation is a simple method that allows the immediate formation of nanoparticles without applying intense mechanical efforts, using non-toxic, water-miscible solvents. 2) Ionotropic gelation method to produce nanoparticle designed with a PCL-poly(ethylene glycol) (PEG) -based polyurethane with the ability to encapsulate hydrophilic drugs. The Ionotropic gelation is a simple synthesis method based on the capability of polyelectrolytes to crosslink in the presence of counter ions that allow the formation of nanoparticles without applying high temperatures and avoiding the use of toxic solvent, therefore with the ability to preserve the activity of the biomolecule entrapped within the nanoparticle. All formulations were optimized and characterized in terms of size, PDI, and surface charge. The most promising formulations were also characterized in terms of biological response against a glioblastoma cancer cell line (U87MG). The work showed that nanoparticles could be obtained with both methods, having narrow size distribution. We also showed that the nanoprecipitation method favoured the encapsulation of the hydrophobic drug CCI-001, an anti-mitotic novel compound, developed to destabilize the microtubule polymerization and to improve the selectivity to β-III tubulin, the overexpression of which is associated with cancer activity. The un-encapsulated drug demonstrated strong cytotoxic activity against the U87MG cell line at nanomolar concentration, confirming the potentiality of the compound.