Antibiotic-Containing Agarose Hydrogel for Wound and Burn Care

Wound infections cause inflammation, tissue damage, and delayed healing that can lead to invasive infection and even death. The efficacy of systemic antibiotics is limited due to poor tissue penetration that is especially a problem in burn and blast wounds where the microcirculation is disrupted. Topical administration of antimicrobials is an attractive approach because it prevents infection and avoids systemic toxicity, while hydrogels are an appealing vehicle for topical drug delivery. They are easy to apply to the wound site by being injectable, the drug release properties can be controlled, and their many characteristics, such as biodegradation, mechanical strength, and chemical and biological response to stimuli can be tailored. Hydrogels also create a moist wound environment that is beneficial for healing. The purpose of this study was to formulate an agarose hydrogel that contains high concentrations of minocycline or gentamicin and study its characteristics. Subsequently, the minocycline agarose hydrogel was tested in a porcine burn model and its effect as a prophylactic treatment was studied. The results demonstrated that 0.5% agarose in water was the optimal concentration in terms of viscosity and pH. Bench testing at room temperature demonstrated that both antibiotics remained stable in the hydrogel for at least 7 days and both antibiotics demonstrated sustained release over the time of the experiment. The porcine burn experiment showed that prophylactic treatment with the agarose minocycline hydrogel decreased the burn depth and reduced the number of bacteria as efficiently as the commonly used silver sulfadiazine cream.