The characterization and biodistribution of cefoxitin-loaded liposomes.

To conquer the clinical restriction of relative short half-life and poor tissue retaining activities, liposomes containing cefoxitin were prepared using three methods in this study. The physicochemical properties including cefoxitin encapsulation percentage, vesicle size, stability, as well as the in vivo biodistribution were studied. The highest entrapment percentage was observed by using reverse phase evaporation method, and the molar ratio of cefoxitin to phospholipids was 1:3, DMPC to cholesterol was 2:1, respectively. From the result of stability, the freeze-drying powder and then stored in the frozen condition of cefoxitin-loaded liposome was an ideal storage state. Accordingly, the formulation by reverse-phase evaporation method was selected to investigate the biodistribution of cefoxitin-loaded liposome and compared to free cefoxitin in rats. It was observed that the cefoxitin levels and the duration retained in the liver, spleen, and pancreas of liposome-injected animals were higher and longer than that of free cefoxitin-injected animals. The drug concentrations of bile after post-injection of liposomal cefoxitin at 0.5, 1 and 2 h were all approximately 2.7 times higher than that of free cefoxitin injection group.