In vitro and in vivo activities of ticarcillin-loaded nanoliposomes with different surface charges against Pseudomonas aeruginosa (ATCC 29248)

Background: Pseudomonas aeruginosa exhibits multiple antibiotic resistance mechanisms. Different studies have shown that entrapment of antibiotics into liposomes could increase their anti-Pseudomonas activity. The objectives of this study were to prepare ticarcillin loaded-nanoliposomes with variable surface charges and evaluate their in vitro and in vivo efficacies against Pseudomonas aeruginosa (ATCC 29248). Methods: Ticarcillin-loaded nanoliposomes with positive, negative and neutral surface charges were prepared by extrusion method. Ticarcillin encapsulation efficacies for different formulations were measured by HPLC method. Minimum inhibitory concentration (MIC) of ticarcillin nanoliposomal forms against strain ATCC 29248 were determined by broth dilution method. The killing rate of Pseudomonas aeruginosa was exposed to various concentrations of ticarcillin in free and nanoliposomal forms were analyzed. Ultimately, in vivo therapeutic efficacy of nanoliposomes in burned mice skin infected with strain ATCC 29248 was investigated. Results: The encapsulation efficacies for ticarcillin-loaded cationic nanoliposomes were significantly higher (76% +/- 0.17) than those of neutral (55% +/- 0.14) and anionic (43% +/- 0.14) nanoliposomes. The MIC of free, cationic, neutral and anionic nanoliposomal forms of ticarcillin against ATCC 29248 were to 24, 3, 6 and 48 mg/L, respectively. The killing rates of ticarcillin-loaded cationic nanoliposomes were higher than those of free and other drug formulations. Treatment by ticarcillin-loaded nanoliposomes with positive, neutral and negative surface charges resulted in almost 100, 60 and 20% survival rates, respectively. Conclusion: Our data suggested that cationic ticarcillin-loaded nanoliposomes because of high effectiveness would be a good choice to treatment of Pseudomonas aeruginosa infections.