Antibiotic Loaded Nano Rod Bone Cement for the Treatment of Osteomyelitis.

Abstract

Polymethyl Methacrylate (PMMA) bone cement is the clinical gold standard biomaterial for local antibiotic therapy in osteomyelitis. However, it releases 50% of the antibiotic within the first three days. It generates excessive heat during polymerization and is non-biodegradable. It must be removed by another operation. The best-known alternative for PMMA is hydroxyapatite. The present patented work is focused on synthesizing the biodegradable hydroxyapatite in nano form for slow and sustained release of antibiotics and studying the release kinetics of antibiotics. Nano-hydroxyapatite was synthesized by co-precipitation method and characterized by particle size analyser, transmission electron microscopy, fourier transform infrared spectroscopy and energy dispersive X-Ray analysis. Antibiotic loaded nano-hydroxyapatite was prepared as 7 mm beads. The efficiency of drug-loaded nano-hydroxyapatite beads against osteomyelitic isolates was evaluated by well diffusion assay. Zero-order, first order, second order, Higuchi model, Korsmeyer-Peppas and Gompertz models were fit into the release kinetics of antibiotics from hydroxyapatite. Average size of nano-hydroxyapatite was 5 nm. The bactericidal activity exhibited by antibiotic- loaded micro-sized hydroxyapatite was therapeutic until 10 days only, whereas antibiotic-loaded nano-hydroxyapatite was therapeutic until 8 weeks. This confirms the burst release of antibiotics from micro-sized hydroxyapatite beads. In contrast, the release was slow and sustained up to 8 weeks from nano-hydroxyapatite. Korsmeyer-Peppas model fits into the release kinetics of antibiotics from nanohydroxyapatite. Nano-hydroxyapatite with a Ca/P ratio of 1.78 is suitable for the slow and sustained delivery of antibiotics for 8 weeks.