C₆₀ fullerene loaded hydroxyapatite-chitosan beads as a promising system for prolonged drug release

Bioactive composite material in the form of beads, based on natural polysaccharide Chitosan (CS), hydroxyapatite (HA), and C₆₀ fullerene (C₆₀), was synthesized under influence of microwave irradiation (MW). The bead is a 3D matrix consisting of CS macromolecules cross-linked with sodium tripolyphosphate with HA and C₆₀ particles immobilized in its structure. XRD and FTIR data confirmed the formation of calcium deficient carbonate substituted HA with needle-shaped nanocrystallites of about 80 nm. MW does not influence CS structure. C₆₀ enhances the beads shape stability. HPLC studies suggest the (up to 18 days) prolonged release of hydrophobic Anaesthesinum from C₆₀-containing composites. Changing the C₆₀ content allows adjusting the drug release time. The presence of CS and C₆₀ provides the Anaestesinum release profile, according to the calculated correlation coefficient (r = 0.99), close to the zero order kinetic release profile. The inhibition zone test (ZOI) shows the antimicrobial activity of the composites containing 0.004 mg/ml C₆₀ against S. aureus ATCC 25923 and E. coli ATCC 25922 (ZOI 16 ± 1 and 10 ± 2 mm, respectively). Cell viability test indicates no toxicity of 0.3 and 0.15 mg/ml C₆₀-containing composites.