Encapsulation of biologically active agents in emulsions stabilized by natural polymers

Resumen

The use of nanocarriers for the encapsulation of different molecules has been explored over the recent years for multiple applications. They have been used for the vehiculization of hydrophobic molecules in aqueous media (or hydrophilic ones in oily media), protection of sensitive molecules or immobilization of different molecules in supports. Among the different nanocarriers that have been developed, polymeric nanocapsules have attracted the interest of many researchers thanks to their great advantages. In this thesis, polysaccharide coated nanoemulsions have been developed as potential nanocarriers for the encapsulation of different molecules. Thanks to their versatility, these nanocarriers allow the encapsulation of hydrophobic in the oily core, while hydrophilic ones can be entrapped in the polymer coating. Besides, the components of the nanocapsules can be modified upon the needs of the final application. All the developed nanocapsules were coated with the adequate polymer depending on the final application and the characteristics that needed to be achieved. Both chitosan, alginate and xanthan were used successfully. The developed nanocapsules have proven to be very effective for the encapsulation of antibiotics such as bedaquiline and daptomycin used the treatment of Mycobacterium tuberculosis and Methicillin-resistant Staphylococcus aureus (MRSA) infections, respectively. An exploratory research has been also carried out to encapsulate the drug disulfiram for its repurposing for the treatment of pancreatic cancer and MRSA infections. The developed nanocapsules have shown great capability as immobilizing agents of the enzyme chloroperoxidase and the encapsulation of magnetic nanoparticles (NP). They have also been able to encapsulate holmium vanadate NP for their use as contrast agents. Physicochemical characterization as well as efficacy test for the different purposes were performed in all the cases. For all the tested applications, the developed nanocapsules showed great versatility for their use as nanocarriers of many different drugs, enzymes and nanoparticles as well as being able to modify the surface with different polymers to meet the application requirements.