Research on the detection of encapsulation efficiency in protein-loaded liposomes

Objective To establish the method for the determination of encapsulation efficiency(EE%)in protein-loaded liposomes.Methods The liposomes loading bovine serum albumin(BSA) was prepared as model protein using the modified reverse-phase evaporation method.The mean particle-size was 5.129 μm.The centrifuge-reference method was used for the first time in which empty liposomes were as the reference to eliminate the ingredient′s influence.Additionally,gel filtration,ultracentrifugation,ultrafiltration and dialysis were used to compare the drug EE%.Results The mean recovery was 101.7%,RSD was 2.32%(n=5).The linear range was good in 1.02-1 507.5 mg·L-1.The mean EE% was 69.74%,RSD was 1.34%.But other four methods were lower or higher than the true value.Conclusions The new established method is suitable and accurate,which can be developed for the determination of the drug EE% of the protein-loaded liposomes.