Methods of nanoencapsulation of phytochemicals using organic platforms

Pharmaceuticals help humans to improve their quality of life. For this reason, it is necessary to use them in minimal quantities, achieving the therapeutic effect. The use of organic platforms for nanoencapsulation of bioactive compounds is focused on overcoming the drawbacks of conventional drug delivery approaches. These nanocarriers protect bioactive compounds (reducing the vulnerability to acidic degradation, microorganisms, and UV light) and provide enhanced water solubility, stability, bioavailability, and bioactivity, reducing the toxicity in nontarget organs related to a high dosage. Besides, the nanoparticles can be carefully designed in order to combine both the diagnostics and the therapy, resulting in unique systems called theranostic nanoparticles. To date, different nanoencapsulation methods have been developed in order to achieve a high drug loading efficiency. The selection of the encapsulation method, the physicochemical properties of the polymers, the type of nanoparticle, and the nature of the guest molecule are relevant factors to be considered during nanoencapsulation. Hydrogen bonding, electrostatic binding, hydrophobic and aromatic interactions (in physical entrapment and self-assembly), and covalent bonds (in covalent conjugation) are commonly involved in the entrapment of bioactive compounds by polymer-based nanocarriers. Depending on the chemical structures of the platform and the bioactive compounds that are used, the morphology, particle size, and zeta potential (surface charge) of the final formulation can be similar or significantly different to that observed for a single platform. In this chapter, useful strategies for nanoencapsulation of phytochemicals (e.g., phenolic compounds) and their results are reviewed, and examples using liposomes, micelles, polyelectrolyte complexes, nanogels, and dendrimers are described.