Efficacy of levofloxacin loaded non-ionic surfactant vesicles (niosomes) in a Pseudomonas aeruginosa infection model in Sprague Dawley rats

ABSTRACT

Objective: To determine the efficacy of levofloxacin loaded niosomes in treating Sprague Dawley rats infected with Pseudomonas aeruginosa (ATCC 27853). Design and Methodology: Three groups of six (6) animals were infected with a known dose of the pathogen i.e. Pseudomonas aeruginosa via the intraperitoneal (ip) route. At six (6) hours post infection the infected animals were treated with drug free niosomes (control), free levofloxacin (conventional) and levofloxacin trapped in niosomes (ip). Blood was collected via tail snips at days 0,1,3,5,7 and 10 for complete blood counts and viable bacterial counts by colony forming units (CFU/µl). At day 10 the animals were sacrificed and samples from the kidney, liver and spleen were examined for bacterial counts. Results: All animals in the control group succumbed to the infection; one animal from the conventional group died. All niosome treated animals survived. The mean lymphocyte count (X109) was lower for the niosome (7.258±1.773) versus conventional (17.684±10.008) (p<0.03) treated groups at day ten (10). Neutrophil counts (X109) were lower for the niosome (2.563±1.609) versus conventional (6.2±6.548) p<0.02) treated groups. The CFUs in the bloodstream were similar for both treatment groups; the niosome treated group showed greater reduction in liver, kidney and spleen CFUs versus the conventional group (1.33±2.074) vs (5.8± 3.74) (p< 0.043), (1.5±2.35) vs (9.6±8.65) (p< 0.038) and (3.8 4.71) vs (25.6 14.66) (p<0.007) respectively. Conclusions: Further work is recommended on niosomes as a drug delivery system to treat intracellular infections.