Enrofloxacin Loaded Liposomes Obtained by High Speed Dispersion Method

Abstract

A method for the mass production of liposomes was developed : lipids and nonionic surfactant were dispersed in ethanol at 50°C, when ethanol evaporated, glycerin was added resulting in a homogeneous mixture. Parallelly, enrofloxacin in a mixture of buffer solution and glycerin (1 : 1, v : v) was heated to 50°C. The drug solution was then added to the lipid mixture and homogenized at 3000 rppm for 2-3 min by a homogenizer. This method provided a suspension of multilamellar vesicles (high speed dispersed vesicles, HSDV) with an average diameter that ranged from 280 to 350 nm, their size distribution being bimodal. Such liposomes were characterized in comparison with other traditional liposomes, namely extrusion, reverse phase evaporation, ethanol injection and dehydration-rehydration vesicles. The entrapment efficiency of HSDV (20%) was never less that by others and they showed a high physical stability, since after 23 months both the size and the polydispersity retained the same values they had at the time of the preparation. Encapsulation efficiency also remained almost constant evidencing that the leakage from liposomes was apparently insignificant. Chemical stability of lipid and of the encapsulated drug showed that if liposomes are kept at 4°C and protected from natural light, they do not undergo any degradation.