Related Experiment Videos
Ofloxacin-loaded liposomes: in vitro activity and drug accumulation in bacteria
P M Furneri1, M Fresta, G Puglisi
1Department of Microbiological Sciences, University of Catania, Italy. furneri@mbox.unict.it
Abstract:
Different ofloxacin-loaded unilamellar vesicles were prepared by the extrusion technique, and their antimicrobial activities were determined in comparison to those of the free drug by means of MIC determinations with both American Type Culture Collection standards and wild-type bacterial strains (six strains of Enterococcus faecalis, seven strains of Escherichia coli, six strains of Staphylococcus aureus, and six strains of Pseudomonas aeruginosa). The accumulation of ofloxacin and liposome-ofloxacin was measured by determining the amount of the drug inside the bacteria as a function of time. Encapsulated fluoroquinolone yielded MICs which were at least twofold lower than those obtained with the free drug. In particular, liposomes made up of dimyristoylphosphatidylcholine-cholesterol-dipalmitoylphosphatidylser ine and dimyristoylphosphatidylcholine-cholesterol-dihexadecylphosphate (4:3:4 molar ratio) provided the best improvement in antimicrobial activity against the various bacterial strains investigated. The liposome formulation produced higher intracellular fluoroquinolone concentrations than those achieved simultaneously with the free drug in both E. coli and P. aeruginosa.
Insights
Ofloxacin-loaded liposomes show enhanced antimicrobial activity against various bacteria, requiring lower doses for effectiveness. These liposomes also increase intracellular drug concentration, improving efficacy.
Area of Science:
- Pharmaceutical Sciences
- Microbiology
- Drug Delivery
Background:
- Ofloxacin is a fluoroquinolone antibiotic used to treat bacterial infections.
- Liposomes are lipid-based nanoparticles used for drug delivery.
- Improving the efficacy and delivery of antibiotics is crucial for combating bacterial resistance.
Purpose of the Study:
- To prepare and characterize ofloxacin-loaded unilamellar vesicles.
- To evaluate the antimicrobial activity of these liposomal formulations compared to free ofloxacin.
- To assess the intracellular accumulation of ofloxacin delivered via liposomes.
Main Methods:
- Unilamellar vesicles loaded with ofloxacin were prepared using the extrusion technique.
- Antimicrobial activity was determined by Minimum Inhibitory Concentration (MIC) assays against standard and wild-type bacterial strains (Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa).
- Intracellular drug accumulation was quantified over time.
Main Results:
- Liposomal ofloxacin demonstrated at least a twofold lower MIC compared to free ofloxacin across tested bacterial strains.
- Specific liposome formulations (dimyristoylphosphatidylcholine-cholesterol-dipalmitoylphosphatidylserine and dimyristoylphosphatidylcholine-cholesterol-dihexadecylphosphate at 4:3:4 molar ratio) showed the greatest antimicrobial improvement.
- Liposomal delivery resulted in higher intracellular ofloxacin concentrations in E. coli and P. aeruginosa compared to free ofloxacin.
Conclusions:
- Liposomal encapsulation enhances the antimicrobial efficacy of ofloxacin.
- Optimized liposome formulations can significantly improve antibiotic activity and intracellular delivery.
- This approach holds promise for developing more effective treatments against bacterial infections.