Doxycycline containing hydroxyapatite ceramic microspheres as a bone-targeting drug delivery system

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Regenerative Medicine

Background:

• Drug delivery systems enhance therapeutic efficacy.
• Hydroxyapatite (HA) microspheres are investigated for drug loading.
• Doxycycline (DOX) possesses antimicrobial properties relevant to bone infections.

Purpose of the Study:

• Evaluate physical/chemical properties of doxycycline-loaded hydroxyapatite microspheres (HADOX).
• Assess HADOX effects on osteoblast viability and antimicrobial activity.
• Determine DOX's impact on bone socket healing post-tooth extraction in rats.

Main Methods:

• Characterization of microsphere porosity and doxycycline adsorption.
• In vitro drug release kinetics and minimal inhibitory concentration (MIC) assays.
• In vitro osteoblast viability assays and in vivo study of rat tooth extraction sockets.

Main Results:

• HADOX exhibited increased porosity (52.0%) compared to HA (26%).
• Initial drug release of 49.15 μg/ml within 24 hours; MIC inhibited Enterococcus faecalis for 7 days.
• No significant difference in osteoblast viability; HADOX promoted new bone formation and reduced inflammation in vivo.

Conclusions:

• HADOX demonstrates favorable physical and chemical properties for drug delivery.
• HADOX exhibits effective antimicrobial activity and biocompatibility with osteoblasts.
• HADOX is a promising biomaterial for promoting bone repair in infected extraction sites.