Preparation Of Glycyrrhetinic Acid Derivative Modified Liposomes And Evaluation Of Liver Targeting

Objectives To Synthesis of stearyl glycyrrhetinate?18GA?.The preparation of curcumin liposomes?CUR-LIP?,curcumin liposomes modified with glycyrrhetinic acid?GA-CURLIP?and curcumin liposomes modified with stearyl glycyrrhetinate?18GA-CUR-LIP?were prepared in accordance with the pharmaceutical quality inspection standards.To evaluate the liver targeting of three liposomes in vivo.It provides the experimental basis for the clinical research of curcumin targeting liposomes.Methods 1 Preparation and identification of glycyrrhetinic acid derivative: According to the principle of esterification,the liposome modified ligand 18 GA was synthesized from glycyrrhetinic acid and stearyl alcohol.Purified 18 GA by silica gel column.The structure of 18 GA was identified by TLC,FT-IR,¹H NMR and ¹³C NMR.2 Preparation and investigation of three liposomes: The optimal liposome prescription was obtained by single factor experiment and Box-Benhnken response surface experiment.Liposomes were prepared by thin film dispersion-high pressure homogenization under optimal prescription.The particle size of liposomes was determined by using Marvin particle size analyzer and scanning electron microscope.The encapsulation rate and loading efficiency of liposomes were determined by Sephadex method.The concentrations of three groups of drugs were determined,calculation of encapsulation rate,drug loading.3 In vivo distribution of three liposomes: 90 Kunming mice,according to the types of liposomes was divided into three groups,each group of 30 mice.Blood was collected from the inner canthus of mice for 2 min,5 min,10 min,20 min,30 min,60 min,120 min,360 min and 720 min after administration.At the same time,organs?heart,liver,spleen,lung,kidney?of mice were taken for 5 min,30 min,60 min,180 min,360 min and 720 min after administration,each time point parallel cutting take 5 mice.The drug was administered by tail vein,and the dose was calculated as 12 mg/kg according to curcumin.The determination method of biological samples was established and verified by liquid mass chromatography.The pharmacokinetic parameters were calculated using the Minonlin program.Results 1 The synthetize of the target compound 18 GA was completed.The TLC experiments show that the product and standard product have the same Rf values under different developing agents.Infrared spectroscopy showed that it was absorbed at 755 cm^-1 and 2850 cm^-12960 cm^-1.Absorption was found at 1.25 ppm in the NMR hydrogen spectrum and at 26.7 ppm and 63.58 ppm in the NMR carbon spectrum.The product was proved to be the target compound 18 GA.2 The optimal prescriptions for liposomes were phospholipid:cholesterol=100 mg:15 mg,phospholipid:total amount of model drug and ligand?CUR and 18GA?=100 mg:16 mg,18GA:CUR=1:1,and the dosage of hydration solvent was 15 m L.The particle size of liposome was?153.7±26.14?nm,and the encapsulation rate was 72.70%.The drug loading was 4.44 %.3 The targeting efficiency?Te?of the plasma,heart,liver,spleen,lung and kidney in the CUR-LIP group respectively were 0.28,0.16,0.14,0.12,0.17 and 0.13.Te of the heart,liver,spleen,lung and kidney in GA-CUR-LIP group respectively were 0.27,0.16,0.17,0.08,0.13 and 0.16.Te of the plasma heart,liver,spleen,lung and kidney in the 18GA-CUR-LIP group respectively were 0.22,0.18,0.20,0.12,0.12 and 0.16.The peak concentration ratio?Ce?,relative uptake rate?Re?and relative targeting efficiency(R_Te)of GA-CUR-LIP group respectively were 1.06,1.18 and 1.21 compared to the CUR-LIP group.Ce,Re and R_Te of liver tissues in 18GA-CUR-LIP group respectively were 1.19,1.46 and 1.43,compared to the CUR-LIP group.Ce,Re and RTe of liver tissues in 18GA-CUR-LIP group respectively were 1.12,1.23 and 1.18,compared to the GA-CUR-LIP group.Conclusion In this study,18 GA was successfully synthesized,and the optimal formulation of curcumin liposome modified with 18 GA was selected by response surface test.It has been confirmed by animal that both 18 GA and GA-modified liposomes have liver targeting,and 18GA-modified liposomes have stronger liver targeting than GAmodified liposomes in vivo experiment.This experiment can provide reference for the preparation of active targeting liposomes and related studies on in vivo targeting.Figure 17;Table 34;Reference 114.