Study On The Nano-formulations Of 6-gingerol,the Main Active Constitute Of Ginger

Ginger（Zingiber officinale Roscoe,Zingiberaceae）is a traditional food-derived medicinal plant with a long history,and is extensively used not only as a food spice but also as a kind of medicine in various countries such as China,India,Mexico,and other areas from early on.Traditional Chinese Medicine uses ginger to treat many diseases including wind cold,cough,rheumatism,indigestion,vomiting and so on.Studies from home and aboard have shown that Ginger possesses various pharmacological activities such as antioxidant,antitumor,anti-inflammatory,antibacterial,improve the cardiovascular system and so on.Among the various ingredients in ginger,6-Gingerol is one of the major pungent and the most abundant components which has been found to exhibit multiple pharmacological effects namely anti-inflammation,antioxidant,antibacterial,antitumor,liver and kidney protection,hypoglycemic as well as hypolipidemic activities,etc.However,the oral bioavailability of 6-Gingerol was very low due to its poor water solubility,and this has limited its further clinical application.Therefore,based on this problem,novel nano-drug delivery system was used to load 6-Gingerol to improve its water solubility and oral bioavailability in the present work.Chapter Ⅰ ReviewThis chapter reviewed the literature mainly concerned with the present work from three aspects.The first aspect was the literature review about the various pharmacological activities and the main active components of Ginger.Then the research status of 6-gingerol,the main active ingredient in ginger,was reviewed,including its separation and purification method,its main pharmacological activities,as well as the current research on 6-gingerol preparations.The third aspect summarized some of the advantages of nano-formulations as a novel drug delivery system,as well as the current studies of major forms of nano-formulations.Chapter Ⅱ Extraction and purification of 6-Gingerol from Ginger,and pre-formulation studiesIn this chapter,6-Gingerol was extracted and purified by solvent extraction and silica gel column chromatography method.The obtained 6-Gingerol was identified through high performance liquid chromatography and nuclear magnetic resonance,and the yield of 6-Gingerol was 54.5 mg/g.HPLC methods for the analysis of in vitro and in vivo 6-Gingerol samples were established respectively and both validated.The validation results showed that the in vitro and in vivo analytical methods were both meet the requirement of methodology.The established in vitro analytical method for 6-Gingerol was specific,the linear range of standard curve was 1-200μg/mL,the limit of quantitation and detection were 0.5μg/mL and 0.1μg/mL,respectively.And the intra-and inter-day precision of the method were both consistent with the requirements.The established in vivo 6-Gingerol sample analysis method had good specificity and good linearity in different biosamples,the intra-and inter-day precision were less than 4%,and the recovery rate of sample treat method was satisfied.The equilibrium solubility of 6-gingerol in different pH media was also determined.The results showed that the equilibrium solubility of 6-gingerol in water,pH 1.2 HCL and pH 7.4 PBS were 252.31μg/mL,226.24μg/mL,and 258.87μg/mL,respectively,indicating that the water solubility of 6-Gingerol was poor.Chapter Ⅲ Preparation,in vitro and in vivo studies of 6-Gingerol-loaded nanostructured lipid carriersIn this chapter,6-Gingerol-loaded nanostructured lipid carriers were developed through high pressure homogenization method.The formulation consisted of a solid lipid（glyceryl monostearate）,another liquid lipid（decanoyl/octanoyl-glycerides）and mixed surfactants（Tween80 and Poloxamer 188）,and was optimized by orthogonal design method,and the optimal 6-Gingerol-loaded nanostructured lipid carriers formulation was evaluated both in vitro and in vivo.The 6-Gingerol-loaded nanostructured lipid carriers prepared with optimal formulation exhibited a homogenous spherical shape with mean particle size and zeta potential of 63.59±5.54 nm and-12.18±1.06 mV,respectively.Encapsulation efficiency and drug loading of 6-Gingerol were76.71±1.11%and 1.17±0.35%,respectively.In vitro release profile of 6-Gingerol from nanostructured lipid carriers was sustained,which suggested that the formulation could prolong the drug action time in vivo effectively.After oral administration of the 6-Gingerol-loaded nanostructured lipid carriers,drug concentrations in serum,MRT,and AUC_0-t were significantly higher as compared with the free 6-Gingerol suspension.The developed nanostructured lipid carriers have sustained release profile,and could enhance the oral bioavailability of 6-Gingerol remarkably.Chapter Ⅳ Preparation,in vitro and in vivo studies of 6-Gingerol-loaded polymeric micellesIn this chapter,a polymeric micelles drug delivery system of 6-Gingerol consisting of Poly（ethylene glycol）-poly（ε-caprolactone）（PEG-PCL）and D-α-Tocopheryl polyethylene glycol 1000succinate（TPGS）was prepared via solvent injection method.The developed 6-Gingerol-loaded TPGS/PEG-PCL micelles were characterized based on particle size,polydispersity index,zeta potential,encapsulation efficiency,drug loading and in vitro release.The pharmacokinetics and tissue distribution studies were also evaluated.The nanoformulation produced a particle size of73.24±2.84 nm with acceptable PDI（0.129±0.03）,zeta potential（-2.74±0.92 mV）,drug loading（4.58±0.05%）and encapsulation efficiency（79.31±0.39%）.The in vitro release profile showed that the 6-Gingerol-loaded TPGS/PEG-PCL micelles enhanced the solubility of 6-Gingerol,while the pharmaceutical analysis in rats indicated that the micelles significantly improved the oral bioavailability of 6-Gingerol,the C_max,MRT and AUC of 6-Gingerol-loaded TPGS/PEG-PCL micelles were about 553.4%,118.9%,and 359.0%of free 6-Gingerol suspension,respectively.Results of tissue distribution showed that the tissue drug concentration of 6-Gingerol-loaded TPGS/PEG-PCL micelles were higher as compared with free 6-Gingerol in all three time points researched.The 6-Gingerol-loaded TPGS/PEG-PCL micelles exhibited enhanced drug distribution in mice’s tissues,especially showed brain targetability.