Local Antibiotic Delivery Ceramic Bone Substitutes for the Treatment of Infected Bone Cavities and Bone Regeneration: A Systematic Review on What We Have Learned from Animal Models

AIMS

the focus of this study is to evaluate if the combination of an antibiotic with a ceramic biomaterial is effective in treating osteomyelitis in an infected animal model and to define which model and protocol are best suited for in vivo experiments of local bone infection treatment.

METHODS

a systematic review was carried out based on PRISMA statement guidelines. A PubMed search was conducted to find original papers on animal models of bone infections using local antibiotic delivery systems with the characteristics of bone substitutes. Articles without a control group, differing from the experimental group only by the addition of antibiotics to the bone substitute, were excluded.

RESULTS

a total of 1185 records were retrieved, and after a three-step selection, 34 papers were included. Six manuscripts studied the effect of antibiotic-loaded biomaterials on bone infection prevention. Five articles studied infection in the presence of foreign bodies. In all but one, the combination of an antibiotic with bioceramic bone substitutes tended to prevent or cure bone infection while promoting biomaterial osteointegration.

CONCLUSIONS

this systematic review shows that the combination of antibiotics with bioceramic bone substitutes may be appropriate to treat bone infection when applied locally. The variability of the animal models, time to develop an infection, antibiotic used, way of carrying and releasing antibiotics, type of ceramic material, and endpoints limits the conclusions on the ideal therapy, enhancing the need for consistent models and guidelines to develop an adequate combination of material and antimicrobial agent leading to an effective human application.

Conformationally restricted, dipeptide-based, self-assembled nanoparticles for efficient vancomycin delivery

Aim: Emergence of vancomycin (Van) resistance, and usage of its higher dose and short half-life are posing a serious concern. Slow and sustained release of Van using a nanodelivery system may overcome these problems. Materials & methods: Arginine-α,β-dehydrophenylalanine (RΔF) was synthesized using solution-phase synthesis which self-assembled into nanospheres. Van was entrapped in the nanoparticles (NPs). In vitro and in vivo efficacy of Van-RΔF was determined using broth microdilution and the mouse thigh infection model, respectively. Results & conclusion: Van-RΔF NPs efficiently inhibited bacterial growth (Staphylococcus aureus), while Van alone showed limited growth inhibition in in vitro. Intravenous administration of Van-RΔF in mice with bacterial thigh infection showed enhanced efficacy (double) compared with Van alone, which indicates its high potential for further development.