Development and evaluation of topical formulations of Levofloxacin and Usnic acid against wound infections

Abstract

One of the major contributing factors in development and progression of antimicrobial resistance is biofilm formation by bacteria. Bacteria form a polymeric matrix enclosing them within the biofilm and making them over 1000 times resistant to antibiotics. The aim of the present work was to utilize natural antibiofilm agent clove oil in conjunction with antibiotics to overcome resistance and enhance their activity for efficient treatment of bacterial biofilm infected burn wounds. Nanosize emulsion (NE)and nanostructured lipid carriers (NLCs) of levofloxacin were developed, optimized and characterized for the treatment of Pseudomonas aeruginosa PAO1 biofilm infected burn wounds in mice. They demonstrated strong in vitro antibacterial and antibiofilm effect against P. aeruginosa biofilms as evidenced by FESEM and confocal microscopy studies. The formulations were also found to be biocompatible and non-irritant. The NE and NLCs were transformed into gels and infected murine burn wounds treated with these gels led to complete eradication of infection and wound healing. Further, NLCs loaded with usnic acid (NLC-UA) were developed, optimized and characterized for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) biofilm infected burn wounds in mice. NLC-UA exhibited strong in vitro antibacterial and antibiofilm effect against MRSA biofilm as evidenced by FESEM and determination of viable cell count (CFU/ml). The formulation was also found to be biocompatible and non-irritant. Usnic acid NLCs were transformed into a gel and infected murine burn wounds treated with it led to complete eradication of infection and wound healing. newline