A supercritical assisted process for the production of amoxicillin-loaded liposomes for antimicrobial applications

Abstract

Most common limitations of drug carriers, such as liposomes, are low Encapsulation Efficiency (EE) and possible degradation of the encapsulated drugs. Several techniques were developed to overcome these problems; among these, Supercritical assisted Liposome formation (SuperLip) is a CO2-mediated technique to produce liposomes at nanometric level.SuperLip was employed to produce amoxicillin-loaded liposomes. Vesicles have been loaded with 1, 5, 10 and 20 % (w/w) amoxicillin to lipid ratio; then, 1 % (w/w) cholesterol/lipid was added to liposomes lamellae. Liposomes showed mean diameters of about 200 nm and EE up to 84 %.Antimicrobial effect of amoxicillin-loaded liposomes on Escherichia coli was studied. E. coli growth was monitored inoculating bacteria in Luria-Bertani medium with different liposome concentrations (25, 50 and 100 ppm) and different antibiotic/lipid ratio (5, 10 and 20 %, w/w). An increase in the amoxicillin/lipid ratio enhanced growth inhibition of E. coli, especially at 100 ppm of dosage.