engleski

Development of liposomes for improved topical treatment of methicillin-resistant Staphyloccocus aureus (MRSA) infections

The objective of this study was development and in vitro evaluation of liposomes for the topical treatment of chronic skin infections. Various types of liposomes differing in lipid composition and surface properties were prepared and examined for physical characteristics, in vitro drug release and antimicrobial activity. Soy phosphatidylcholine (SPC) liposomes and dipalmitoylphosphatidylcholine (DPPC)/dioctadecyldimethylammonium bromide (DODAB) liposomes encapsulating azithromycin were prepared by conventional film hydration method, followed by extrusion (SPC liposomes) or probe sonication (DPPC/DODAB liposomes). Anionic SPC liposomes were additionally coated with 0.3% (w/v) low Mw chitosan. Mean diameters, polydispersity index and zeta potentials of different phospholipid vesicles were determined by photon correlation spectroscopy. In vitro release studies were performed by Franz diffusion-cell method at 32 C using buffer pH 7.5 as receptor medium [1]. Antimicrobial activity of developed liposomal formulations was tested against Staphylococcus aureus ATCC 29213 and 5 different MRSA strains [2]. SPC liposomes were of the smallest mean diameter (160 nm) in comparison to cationic DPPC/DODAB (250 nm) and chitosan-coated liposomes (380 nm), while the encapsulation efficiency was found to be similar for all the formulations (40-47%). All the liposomes exhibited prolonged drug release profiles with an initial burst effect followed by a slower release phase. Moreover, all the liposomes demonstrated significantly enhanced antimicrobial activity than the free drug against tested bacterial strains. Amongst different liposomes tested, DPPC/DODAB liposomes revealed superior anti-MRSA activity allowing up to 8-fold increase in activity compared to chitosan-coated and anionic liposomes. Performed experiments support cationic DPPC/DODAB liposomes as the most promising nanoformulation for the improved topical treatment of chronic skin infections.

Liposomes ; Topical drug delivery ; Skin ; Staphyloccocus aureus

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