Judith P. A. Feitosa

Chitosan is abundant, biocompatible, biodegradable, mucoadhesive, and possesses antimicrobial properties, making it suitable for use in medical and pharmaceutical fields. One issue is its insolubility in neutral aqueous media, which can be addressed by derivatization with succinic or phthalic anhydride. The polysaccharide was employed for the synthesis of nanoparticulate systems using different methods: 1) polyelectrolyte complexes with tripolyphosphate (Ch-TPP); 2) conjugated with methotrexate – a drug used in the treatment of rheumatoid arthritis and cancer with many adverse effects (Ch-MTX); 3) hydrogels with oxidized galactomannan (OxG-Ch) or 4) with oxidized cashew gum (OxCG-Ch), both through Schiff base formation. All systems have potential applications in drug delivery or as special dressings. The Ch-TPP system incorporated PEG (to extend circulation time) and the anticancer drug 5-Fluorouracil. The Ch-MTX nanoparticles are stable. Silver nanoparticles were incorporated into the OxG-Ch hydrogel, prepared in situ with the oxidized galactomannan itself. The OxCG-Ch hydrogel was loaded with a curcumin-inclusion complex with 2-hydroxypropyl-β-cyclodextrin. Curcumin possesses pharmacological benefits, including antitumor, anti-inflammatory, antiviral, antioxidant, and antibacterial actions. The complex renders it soluble in an aqueous medium and protects it from degradation. The hydrogels are injectable, adhesive, and self-healing. Cytotoxicity in normal and cancer cells, bactericidal activity, and antioxidant properties were tested. All systems exhibit potential for biological applications.