Preparation And Quality Research Of PEG-modified Gemcitabine Hydrochloride Liposomes

In order to obtain excellent and high stability formulation of gemcitabine hydrochloride liposomes,PEGylated gemcitabine hydrochloride liposomes were prepared by modified membrane method and freeze-thawing method with PEG-modified distearoylphosphatidylethanolamine(PEG2000-DSPE),hydrogenated soybean phospholipid(HSPE)and cholesterol(Chol).We established HPLC method for the determination of gemcitabine hydrochloride and then verified this method.The method was specific,good reproducibility(RSD <2%),and high accuracy.Gemcitabine hydrochloride had a good linearity in the range of 1~40 ?g/mL.we took use of dextran gel column to separate liposomes from free drug and determinate the entrapment efficiency of gemcitabine hydrochloride liposomes.And then,different methods were compared,such as the methods of thin film dispersion,reverse phase evaporation,ethanol injection,modified film method,freeze-thawing method,ammonium sulfate gradient method and the way of PEG2000-DSPE incorporation.Finally,we used modified membrane method and freeze-thawing method to prepare PEGylated gemcitabine hydrochloride liposomes.According to the results of monofactorial tests and response surface methodology on the entrapment efficiency,we optimized the preparation technology and formulation of PEGylated gemcitabine liposomes.Under optimized conditions,The average encapsulation efficiency of PEGylated gemcitabine liposomes was 71.8%,the average particle size was 202.1 ± 5.6 nm,PDI was 0.209 ± 0.04,and the Zeta potential was-17.9 ± 0.73 mV.Observed by transmission electron microscopy,PEGylated liposomes were spherical,and uniform.The stability test results showed that,within a certain range,PEGylated liposomes had certain anti-dilution and antioxidant properties and PEGylated liposomes could be stable storage for 30 days at 4 ? and unstable in acidity,basicity and high temperature.For the purpose of long-term preservation,we prepared lyophilized liposomes of gemcitabine hydrochloride.The results showed that the drug retention rate of PEGylated liposomes after lyophilization was above 90%,and the average particle size was 227.4 ± 6.4nm,PDI was 0.223 ± 0.05,the Zeta potential was-17.4 ± 0.86 mV.The stability test results showed that PEGylated lyophilized liposomes could be stable storage for 3 months at 4 ?.In vitro release results showed that the release rate of drugs in PEGylated liposomes was lower than that of free drugs and common liposomes which demonstrated that PEGylated liposomes had sustained release effect.In conclusion,PEGylated gemcitabine liposomes and their lyophilized preparations were prepared,and then their preparation techniques and formulationproperties were studied.It provides favourable foundation for further investigations of liposomes of gemcitabine hydrochloride and other water soluble anti-cancer of low molecular weight.