Dual effect biodegradable ciprofloxacin loaded implantable matrices for osteomyelitis: controlled release and osteointegration

Ciprofloxacin biodegradable implantable matrices (CPX-IMs) of tailored porous surfaces were fabricated by hot melt injection molding of poly-l-lactic acid (PLLA) followed by coating with PLLA/sodium chloride. CPX-IDs were designed to have a non-porous coat (NPC) or a porous coat of small pore size (SPC; 150-250 mu m) or a large pore size (LPC; 250-350 mu m). CPX-IMs surface pore size was confirmed by scanning electron microscope. The hardness of NPC, LPC, and SPC CPX-IMs were 58 +/- 2.8, 53 +/- 1.9, and 50 +/- 2.1 N, respectively. The measured porosity values were 41.2 +/- 1.53, 65.2 +/- 1.1, and 60.7 +/- 1.2%, respectively. Differential scanning calorimetry was employed to study the compatibility of ingredients, the effect of injection molding on polymer properties, and implants degradation. Coating of CPX-IMs prolonged drug release to reach a value of 90% release in 40 days. Antibacterial activity tests showed sufficiency of CPX to inhibit pathogens known to cause osteomyelitis. The in vivo study showed tissue compatibilities of the inserted matrices in tested rats with no sign of infection throughout the experiment period. SPC and LPC CPX-IMs demonstrated a better osteointegration, cell adhesion, and infiltration of different types of bone cells within implants structure compared to the non-porous matrix. Furthermore, LPC CPX-IMs showed a superior bone cell attachment and osteointegration relative to SPC CPX-IMs. Findings of this study confirmed the impact of porosity and pore sizes on cell proliferation and fracture healing concurrently with the sustained local antibiotic therapy for treatment or prevention of osteomyelitis.