Novel fatty acid gentamicin salts as slow-release drug carrier systems for anti-infective protection of vascular biomaterials

Infections of vascular prostheses are still a major risk in surgery. The current work presents an in vitro evaluation of novel slow release antibiotic coatings based on new gentamicin fatty acid salts for polytetrafluoroethylene grafts. These grafts were coated with gentamicin sodium dodecyl sulfate, gentamicin laurate and gentamicin palmitate. Drug release kinetics, anti-infective characteristics, biocompatibility and haemocompatibility of developed coatings were compared to commercially available gelatin sealed PTFE grafts (SEALPTFE™) and knitted silver coated Dacron® grafts (InterGard®). Each gentamicin fatty acid coating showed a continuous drug release in the first eight hours followed by a low continuous release. Grafts coated with gentamicin fatty acids reduced bacterial growth even beyond pathologically relevant high concentrations. Cytotoxicity levels depending on drug formulation bringing up gentamicin palmitate as the most promising biocompatible coating. Thrombelastography studies, ELISA assays and an amidolytic substrate assay confirmed haemocompatibility of developed gentamicin fatty acid coatings comparable to commercially available grafts.