In vivo quantification of gentamicin released from an implant coating

Area of Science:

• Biomaterials Science
• Drug Delivery Systems
• Infectious Disease Research

Background:

• Drug-releasing implants are crucial for localized therapy, particularly in orthopedic surgery.
• Polymeric coatings offer a promising platform for controlled drug release.
• Gentamicin is a widely used antibiotic for preventing and treating bacterial infections.

Purpose of the Study:

• To evaluate the physicochemical properties of poly(D,L-lactide) coatings with incorporated gentamicin.
• To assess the in vitro and in vivo release kinetics of gentamicin from coated implants.
• To determine the local and systemic distribution and biological activity of released gentamicin.

Main Methods:

• Physicochemical analysis: Differential scanning calorimetry, FTIR, GPC, HPLC.
• In vitro and in vivo drug release studies.
• Microbiological assays and histological examination of tissues (bone, kidney).

Main Results:

• Gamma sterilization did not affect coating components or polymer-drug interaction.
• Microbiological analysis confirmed inhibition of bacterial growth on implant surfaces.
• In vivo studies showed detectable gentamicin in endosteum (42 days), kidney (7 days), and bone (4 hours), with no kidney toxicity.
• Microbiologically active concentrations were found locally in the endosteum up to 4 hours.

Conclusions:

• The coating process preserves gentamicin integrity and demonstrates sustained, localized release.
• In vitro burst release correlates with in vivo observations.
• Gentamicin-releasing implants show potential for effective local infection control with minimal systemic toxicity.