Preparation And Evaluation Of Ginsenoside Re Liposomes

Ginsenoside Re is the main typical component of panaxatriol ginsenoside,which has a wide pharmacologic action such as the functions of improving sugar tolerance level,anti-myocardial ischemia and neural protection,etc.However,Re has a poor solubility,retention time in body is short,which cause a low biological availability and limite its clinical application greatly.In recent years,as a new-developed drug carrier,the liposome has been found that there are lots of advantages such as improving drug solubility in water,a good biological compatibility with the biological membrane,extending the action time in the body.In this thesis,thus,Re was made into freeze-dried liposome,and its quality,intestinal absorption features and pharmacokinetics were investigated for extending the internal retention time of Re,improving the biological availability of it,and establishing an experimental foundation to play a greater medicinal value.The HPLC method had been established to measure the Re content and encapsulation efficiency in liposome,and test it with methodology;the liposome and free Re were separated with dialysis method.Re showed a good linear relation in the mass concentration interval of 2-100?g/mL,regression equation is Y=5741.2X-5362.5,r=0.9997.The accuracy,specificity,stability,and sample recovery tests all showed qualified for requirements.It provedthat the phospholipid had not been detected during the stipulated period through the dialysis of blank liposome,and the method of liposome and free Re separation by dialysis method was practicable,the dialysis period was 7 hours.The ethanol injection method,film dispersion-mechanical shock method as well as reverse-phase evaporation method were used in preparing the Re liposome respectively.The encapsulation efficiency is used as the main evaluation index.The results showed that the film dispersion-mechanical shock method was the optimal method for Re liposome preparation.The optimal prescription of Re liposome was screened with orthogonal test method:lecithin and drug mass ratio was 30:1,lecithin and cholesterol mass ratio is 16:1,ice-water bath ultrasound was 15 min,double distilled water was hydrating fluid.In order to improve the stability of Re liposome,Re liposome is made into freeze-dried agent by the freeze-drying method.The optimal preparation process of Re freeze-dried liposome was also done by orthogonal test method:the pre-freezing temperature is-20?,pre-frozen for 24h,sucrose was used as the protective agent,disaccharide-water mass ratio is 1:10,and 0.9%normal saline was rehydrating fluid.Three batches of Re freeze-dried liposome were prepared with the optimal prescription and freeze-dried process.Their quality of the sample appearance,redispersibility,morphology,encapsulation efficiency,drug loading capacity,particle size,Zeta electric potential,external releasing rate and storage stability were evaluated.The appearance of Re freeze-dried liposome was white and tight,its surface was smooth,full,bright and clean,falling off altogether without fragments,its texture was fine and smooth,and its redispersibility was good;its outline was clear,surface was rounding,shape was globular;the average encapsulation efficiency was80.11%;average drug loading capacity was 3.05%;average particle size was?171.32±10.71?mm,PDI was 0.215±0.024,Zeta electric potential was?-31.45±0.92?mV;it had a good slow-release property both in the artificial gastric fluid and artificial intestinal fluid;and then it was sealed at 4?for 6 months,tests showed all indexes no obvious changing,and the storage period can be extended.Absorption properties of Re and Re liposome in different intestinal segments were researched by establishing rat single-pass intestinal perfusion model.The phenol sulfonphthalein was used as the marker,and the Re concentration in perfusion liquid was measured with HPLC method.The absorption rate constant?Ka?and effective permeability quotient(P_eff)were compared under the condition that mass concentration is 20?g/mL,perfusion rate is 0.25mL/min.The Ka values of Re liposome in duodenum,jejunum,ileum and colon were 2.43,1.99,1.40,1.18 times of free drugs respectively;P_eff values were 2.72,2.12,1.42,2.36 times of free drugs respectively.The absorption of free drugs and Re liposome exists in the entire intestinal canal;Re liposome can remarkably improve the Re intestinal absorption,and the main absorption part was in the duodenum and colon.After intragastric administration in the dose of 30mg/kg for the rat,the internal pharmacokinetic parameter of Re suspension and Re liposome were investigated respectively.HPLC Method was established to measure the plasma concentration of rat blood plasma,process the result by Phoenix WinNonlin?Version 6.2,Pharsight Corporation,USA?pharmacokinetics software,and calculate parameters by non-compartment model method.The results showed that in the same dose,the half life elimination?HL?z?of Re liposome group was 6 times of suspension group.The internal retention time?MRTlast?was from 1.35 to 5.07 hours.The internal retention time of liposome group was longer,which improved the Re biological availability to some extent,thereby performed a better therapeutic effect.