ABSTRACT
OBJECTIVE:To prepare and characterize capreomycin sulfate liposomes(CSL).METHODS:Capreomycin sulfate was entrapped into liposomes using active loading that pH gradient methods,ammonium sulfate gradient methods and sodium acetate gradient methods respectively followed by lyophilization technique.The liposome was characterized by entrapment efficiency,particle size,? potential and the stability.RESULTS:The entrapment efficiency of CSL pre-and post-lyophilization prepared by three methods were 65.7% and 65.2 %,20.1% and 18.6%,34.6% and 32.4%,with particle size of 136 and 145 nm,144 and 153 nm,142 and 159 nm,? potential of —20.2 and —19.5 mV,—24.4 and —22.9 mV,—18.7 and —17.8 mV respectively.No obvious changes were found in all the indexes in the stability test.CONCLUSIONS:The pH gradient technique is suitable for preparing CSL in 3 kinds of methods.
ABSTRACT
Objective To prepare a harmine hydrochloride liposome formulation with high encapsulation efficiency. Methods Preformulation investigation was carried out to obtain the drug physicochemical properties such as solubility and lgD in buffers of different pH value. Harmine hydrochloride was encapsulated into liposomes by active loading method. Encapsulation efficiency of liposomes was determined after the free drug was separated from liposome by ultrafiltration. The influence factors on the encapsulation efficiency including drug-lipid weight ratio, incubation temperature, pH value of external water phase were investigated. Results As the pH value increasing, the solubility of harmine hydrochloride was decreased, while the apparent oil-water distribution coefficient was increased. By active loading method, the encapsulation efficiency could be over 80% when the drug to lipid weight ratio was under 1∶5. The pH gradient between intervesicle and intravesicle obviously influenced the encapsulation efficiency, while incubation temperature had little effect on encapsulation efficiency. Conclusion Active loading is suitable for preparing harmine hydrochloride liposome with high encapsulation efficiency.