title: Effect of freezing on the release rate of gentamicin palmitate and gentamicin sulfate from bone tissue.
abstract: In this study we evaluated gentamicin palmitate salt and gentamicin sulfate salt mixed with bone chips after storage at -80°C. Different concentration rates of gentamicin sulfate and gentamicin palmitate were mixed with human bone chips and stored for 1-6 months at -80°C. Nonstored samples were used as control. The release of the antibiotics from the bone was carried out in phosphate-buffered saline. Antibiotic concentrations in the elutions were determined with microbiological agar diffusion assay using Bacillus subtilis. Susceptibility tests were carried out using Staphylococci strains. The rate of gentamicin base (GB) released from bone was similar for all gentamicin salts and all storage conditions. The elutions released were efficient on reducing S. aureus and S. epidermidis CFU during all storage time. In resume, the capacity of bone grafts to act as gentamicin carriers has been confirmed in this study. GS + GP showed equivalent efficacy against S. aureus and S. epidermidis compared with GS pure. The lower delivery rate of GS + GP, related to its affinity with fat tissue can be an advantage for longer release times, increasing the local protection against infections. Storage at -80°C does not interfere on the gentamicin salts activity used.
authors.affiliation: Experimental Orthopaedics, Medical University Innsbruck, Innsbruck, Austria.
authors.forename: Débora C
authors.initials: DC
authors.lastname: Coraça-Huber
authors.forename: Alexander
authors.initials: A
authors.lastname: Wurm
authors.forename: Manfred
authors.initials: M
authors.lastname: Fille
authors.forename: Johann
authors.initials: J
authors.lastname: Hausdorfer
authors.forename: Michael
authors.initials: M
authors.lastname: Nogler
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Kühn
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology; D016025:Bone Transplantation; D001842:Bone and Bones / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000008:administration & dosage; D005615:Freezing; D005839:Gentamicins / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D008826:Microbial Sensitivity Tests; D010168:Palmitates / Q000008:administration & dosage / Q000378:metabolism; D013203:Staphylococcal Infections / Q000517:prevention & control; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D020099:Coated Materials, Biocompatible; D005839:Gentamicins; D010168:Palmitates
keywords: anti-infective; bacillus subtilis; bone allografts; gentamicin palmitate; staphylococci; storage