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 C-60 fullerene (C-60), 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 C-60 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. C-60 enhances the beads shape stability. HPLC studies suggest the (up to 18 days) prolonged release of hydrophobic Anaesthesinum from C-60-containing composites. Changing the C-60 content allows adjusting the drug release time. The presence of CS and C-60 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 C-60 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 C-60-containing composites.