Gentamicin Sponge for Anti-infection, a Controversial Old Topic and Preliminary Exploration of the Solution, in Vitro and in Vivo Experiments

Abstract Purpose: Our study was to construct drug-loading and drug-release quantitative equation of gentamicin sponge, in addition, obtain the wound infection prevented and treated scheme of gentamicin sponge. Methods: Sterile sponge was cut into 1×1×0.5cm size and immersed into 40mg/ml, 16mg/ml, 8mg/ml, 4mg/ml, 1.6mg/ml, 0.8mg/ml or 0mg/ml gentamicin solution for 12h, 24h, 48h, 96h or 120h to evaluate gentamicin-loading of sponge. Sponge was immersed in gentamicin solution of different concentrations for 48h and then air-dried. Air-dried sponge was immersed into 10ml 0.9% physiological saline to evaluated gentamicin-release. Staphylococcus aureus (MSSA) and Pseudomonas aeruginosa (P. aeruginosa) were used to explore infection prevented scheme of gentamicin sponge. Besides, femur fractured with wound infection rat model was used to discuss the infection treated scheme. Results: The equation of gentamicin-loading of sponge was: z=(0.03718±0.01672)x+(-4.578e-4±0.06253)y+(-2.50935e-4±1.47521e-4)x2+(0.00303±0.00149)y2+(0.00408±3.52827e-4)xy (R2 was 0.97) and drug-release equation was z=(4.37205±1.18048)x+(-7.05921±3.09628)y+(-0.04596±0.01287)x2+(0.3309±0.07912)y2+(0.31559±0.02754)xy (R2 was 0.95). The antibacterial zone sizes of sponges immersed in 40mg/ml, 16mg/ml, 8mg/ml, 4mg/ml, 1.6mg/ml, 0.8mg/ml gentamicin solution were larger than 0mg/ml air-dried sponge, and the difference had statistically significant (p<0.01). Rats of groups of 40mg/ml air-dried sponge, 16mg/ml air-dried sponge, 8mg/ml air-dried sponge had no wound suppuration in both MSSA and P. aeruginosa infection rat model. Conclusions: The quantified equation of gentamicin-loading and release of sponge was with high accuracy. 1.6 mg/ml air-dried sponge and 0.8mg/ml air-dried sponge were enough to prevent wound infection. Besides, if wound were confirmed to be sensitive bacteria infected, we recommended to use 40mg/ml air-dried sponge, 16mg/ml air-dried sponge or 8mg/ml air-dried sponge to treat.