Controlled release of antibiotics from coated orthopedic implants

✍ Scribed by Price, J. S. ;Tencer, A. F. ;Arm, D. M. ;Bohach, G. A.

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 624 KB
• Volume: 30
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/(sici)1097-4636(199603)30:3<281::aid-jbm2>3.0.co;2-m

✦ Synopsis

Chronic osteomyelitis is one of the most serious complications of orthopedic open fracture treatment. The objective of this study was to develop a biodegradable implant coating with impregnated antibiotics as an adjunct to current therapy. We used a polylactic-co-glycolic acid copolymer (PLGA) as the biodegradable carrier and gentamicin as the antibiotic. Our objectives were to establish elution characteristics of the antibiotic from the polymer, and determine i f the coated orthopedic implants would inhibit bacterial growth in vitro. In the elution study, coated implants were incubated in phosphate buffered saline (PBS) at 37°C and sampled daily for gentamicin levels. The in vitro model consisted of test tubes containing Mueller-Hinton culture broth inoculated with 5 x lo6 cfu of Staphylococcus uureus and incubated at 37°C. The implants were switched to a new set of inoculated tubes each day. Tubes were sampled for colony counting to determine bactericidal effects. Implant coatings consisted of 40 mg of gentamicin as a 20% mixture with PLGA. The elution curve showed an average level of 138 kg/mL over 15 days. This local concentration would be more than adequate to kill susceptible organisms. The in vitro study showed a significant reduction in bacterial growth in the test tubes containing coated implants. Control tubes averaged 2.5 x 10' cfu/mL of S. uureus over 24 days. Coated implant tubes averaged 0.9 cfu/mL. This was a reduction of greater than 99.999% (p < 0.0001). This study showed that a thin biodegradable implant coating can be developed with bactericidal activity against the organisms frequently associated with osteomyelitis in cases of open fractures.