Self-Microemulsifying Drug Delivery System Of [6]-shogaol:and Its Anti-hyperuricemic Study

[6]-shogaol?[6]-S?is a pungent compound extracted from dried rhizomes of ginger,which possesses a wide range of pharmacological effcet,for instance,anti-cancer,anti-oxidation,anti-inflammation and so on.However,poor water solubility,irritating and pungent taste as well as low bioavailability greatly limit the medical application and clinical effect of[6]-S.To solve the aforementioned problem,self-microemulsifying drug delivery system?SMEDDS?was selected as the carrier of[6]-S to increase the solubility,promote oral bioavailability as well as increase the anti-hyperuricemic?HUA?effect.This paper was mainly described in the following five chapters.Chapter one:ReviewsIn this chapter,the physicochemical properties,pharmacological effects and formulation studies of[6]-S were reviewed.Notably,the nature,composition and research prospects of SMEDDS were introduced,while the research progress of hyperuricemia was also elucidated.These provided a solid theoretical basis for the study of this thesis.Chapter two:purification process,in vitro detection method and basic properties of[6]-Shogaol[6]-S with purity more than 97.15%was extracted by ethyl acetate and purified via two-stage purification process which contained silica gel and C₁₈ columns.The molecular weight was 276 identified with ESI-MS.Additionally,studies involving ¹H-NMR?and ¹³C-NMR were performed to confirm the monomer to be[6]-S.A method for the determination of[6]-S in vitro by high performance liquid chromatography?HPLC?was established,and the methodological validation of the analytical method was performed.The equilibrium solubility of[6]-S in pH 1.2 HCl solution,pH 6.8,pH 7.4 phosphate buffer solution?PBS?and double distilled water?DDW?were measured respectively.Notably,the solubility of[6]-S reached the highest rate in pH 7.4 PBS?32.26±3.11?g/mL?,indicating that[6]-S is a water insoluble drug.The oil-water partition coefficient of[6]-S determined through shake-flask method was 2.95±0.24,affirming that[6]-S was Lipophilic compound.Chapter three:Preparation and in vitro evaluation of[6]-Shogaol-SMEDDSIn this part,the solubility of[6]-S in various component was assessed,and the compatibility of oil phases,emulsifiers and co-emulsifiers was investigated.The oil phase,emulsifier and co-emulsifier were selected as ethyl oleate,Tween 80 and PEG400 according to the results of pseudo ternary phase diagram.With the help of central composite design-response surface methodology?CCD-RSM?and the percentage transmittance of[6]-S self-microemulsion dispersion system as the index,the best formulation of[6]-S self-microemulsion was accordingly synthesized using[6]-S?8.92%?,ethyl oleate?18.62%?,tween 80?46.32%?and PEG 400?26.77%?.The optimum preparation condition was determined as follows:stirring speed?300 rpm?and stirring temperature?37°C?.The in vitro quality of[6]-S-SMEDDS prepared via the optimum formulation process was evaluated based on the type of microemulsion using dyeing method.Besides,the particle size,Zeta potential and polydispersity coefficient?PDI?were characterized by laser particle size analyzer.Additionally,the entrapment efficiency?EE%?was determined by ultrafiltration centrifugation and the in vitro release of[6]-S–SMEDDS in four media?pH 1.2,pH 6.8,and pH 7.4?and double distilled water was investigated through dialysis bag method.The results showed that[6]-S-SMEDDS was O/W system,and dispersed rapidly and uniformly in double distilled water,forming uniform round or quasi-circular nanodroplets with an average particle size of 20±0.26nm,Zeta potential of-19.68±0.37 mV and PDI of 0.18±0.022.The average EE%was82.08%±1.12,with acceptably good stability.In vitro release experiments showed that the cumulative release rate of[6]-S-SMEDDS were significantly higher than that of free[6]-S.Chapter four:Pharmacokinetic study of[6]-Shogaol-SMEDDS in rats and its tissue distribution characteristic study in miceAn HPLC assay method with high specificity,precision and recovery rate was established,which was used to determine the pharmacokinetics and tissue distribution of[6]-S and[6]-S-SMEDDS.Ten male SD rats were randomly and equally divided into[6]-S and SMEDDS groups for the pharmacokinetic study with the dosage of oral administration being 100 mg/kg.Pharmacokinetic study showed that t_max,t_1/2/2 and MRT of[6]-S were 45 min,50.16 min and 72.38 min,while t_max,t_1/2/2 and MRT of[6]-S-SMEDDS were 60 min,202.33 min and 291.96 min.The results showed that[6]-S-SMEDDS had sustained release effect.The C_max of the free drug was 0.89±0.16?g/mL,while that of[6]-S-SMEDDS increased to 3.70±0.19?g/mL.The AUC_{0-720 min} of[6]-S and[6]-S-SMEDDS was 148.14±14.75 min*ug/L and 846.14±59.37 min*ug/L,respectively.The relative bioavailability?F%?of[6]-S-SMEDDS was 571.18%compared with the[6]-S,indicating that[6]-S-SMEDDS could improve the oral bioavailability of[6]-S,indicating that the oral absorption of the drug could be significantly improved after it was incorporated into SMEDDS.Fifty KM mice were randomly divided into free drug and[6]-S-SMEDDS groups to study the tissue distribution with the single oral administration dose of 25 mg/kg.The results showed that the concentration of the drug in the[6]-S-SMEDDS group was were relatively higher than that of the free drug group at 0.25,0.5,1,2,and 4 h with increased passive targeting tendency of[6]-S to liver and spleen.After 2 h of oral administration,the concentration of the drug in the tissue was greatly reduced,but the concentration of[6]-S in the SMEDDS group was still higher than that of the free drug.Chapter five:Study on anti-hyperuricemia activity of[6]-ShogaolIn this chapter,an in vivo assay of uric acid with high specificity,precision and recovery was established to evaluate the effects of[6]-S and[6]-S-SMEDDS on hyperuricemic rats induced via treatment with potassium oxalate and hypoxanthine.The pharmacodynamic results showed that both of[6]-S and[6]-S-SMEDDS could significantly reduce the serum uric acid and xanthine oxidase?XOD?values compared with the model rats,as well as the levels of interleukin 1??IL-1??,interleukin-6?IL-6?,tumor necrosis factor-??TNF-??,cyclooxygenase-2?COX-2?in hyperuricemic rats.Pathological sections showed that different doses of[6]-S and[6]-S-SMEDDS could repair the renal injury caused by hyperuricemia in a dose-dependent manner through reduction of the vacuolation of cytoplasm.Therefore,[6]-S could be used as a potential therapeutic agent for gout and its complications,while its SMEDDS system could substantially improve its efficacy.