The Nano-Drug Delivery System Of Bisdemethoxycurcumin And Its Pharmacological Effects Study

Bisdemethoxycurcumin(BDMC)is a natural product extracted from the rhizomes of turmeric Curcuma longa L,which also is regarded as a kind of functional food.Existing report has suggested that BDMC possessed various pharmacological effects,for instance,anti-tumor,anti-inflammatory,liver protection and so on.It has the advantages of broad anti-tumor spectrum and high biological safety.Thus,BDMC has been attractive and has gained increased attention in these years.Despite its known pharmacological benefits,BDMC has less been used as efficient natural drugs in the market for treating the diseases.The main reason is that it possesses poor solubility and bioavailability,culminating pure BDMC in poor or diminished efficacy.Otherwise,the current research is mostly focused on the study of pharmacological effects and its mechanism,while there are few studies on its drug delivery system.In this regard,a newly drug delivery system encapsulating BDMC efficiently and improving bioavailability was highly desired.Additionally,according to the previously report,the curcuminoids has the pharmacological effects of anti-hyperuricemia by lowering the uric level,working on xanthine oxidase(XOD)as well as urate transporter 1(URAT1)and functioning as the dual inhibitors.And hyperuricemia develops into gout often accompanied by joints pain,fever and other phenomena.Therefore,based on the above reasons,this study fabricated the BDMC-SMEDDS and the m PEG/PDLLA-TPGS polymer micelles,aiming at complementing the BDMC research.Then,the pharmacology effects of reducing uric acid levels and resisting heat pain in rats was investigated and verfied,hoping to provide a solution for the development of BDMC and other poor water insoluble natural products in pharmaceutical field.Chapter I: ReviewThis chapter first provides an overview of BDMC,including the physical and chemical properties,the pharmacological activitives,and preparations of BDMC.Then,it describes the SMEDDS and polymer micelles nano-drug delivery system to be prepared in this study,including its drug loading principle,composition,preparation method,applicable drugs for loading,etc.Finally,the research progress,pathogenesis and existing drug treatment strategies of hyperuricemia are summarized.Overall,the review of BDMC,nano drug delivery system and hyperuricemia in this part lays a theoretical foundation for futher study.Chapter Ⅱ: HPLC Analysis Method Establishment and Preformulation StudiesIn this chapter,firstly,the in vitro sample detection method of BDMC is established on Agilent 1260 and Shimadzu LC-20 A high performance liquid chromatograph,and the methodology is verified.Secondly,according to the established quantitative detection method,the preliminary solubility of BDMC in p H 1.2 HCl solution,p H 6.8 PBS and p H 7.0 deionized water within 72 h is investigated.The results show that,after verification,the BDMC quantitative detection method established in this study on Agilent 1260 HPLC and Shimadzu LC-20 A HPLC meets the methodological requirements and is valid.In addition,the solubility of BDMC in the above three kinds of media are 0.79 ± 0.007 μg/m L,0.84 ± 0.007 μg/m L and 0.59 ±0.006 μg/m L,respectively.According to the solubility data,BDMC can be judged to be a kind of poorly water-soluble natural product.It provides a theoretical basis for the selection and preparation of the nano-drug delivery system.Chapter Ⅲ: Preparation and Characterization of BDMC-SMEDDSIn this chapter,by measuring the solubility of BDMC in potential excipients,investigating the compatibility of candidate emulsifiers and co-emulsifiers,constructing a pseudo ternary phase diagram,and using RSM-CCD to optimize the prescription,it is determined that the BDMC-SMEDDS is composed of BDMC(5%),emulsifier(Cremophor EL 35,64.52%),co-emulsifier(PEG-400,14.72%)and ethyl oleate(oil phase,20.76%).By accurately weighing the aforementioned materials and stirring,the BDMC-SMEDDS is obtained.The mean dropletsize size and PDI of the prepared BDMC-SMEDDS is 21.25 ± 3.23 nm and 0.29 ± 0.16,while Zeta potential is-8.28 ± 0.18 m V.The encapsulation efficiency and drug loading rate are 98.31 ± 0.32%and 4.91%,respectively.The appearance after self-emulsification was clear and transparent and the shape of droplet is almost spherical.Otherwise,the results of droplet size determination of BDMC-SMEDDS after dilution in p H 6.8 and p H 7.0environment shows that there is no significant change(p > 0.05)was observed within8 hours.The appearance is clear,uniform and transparent within 3 months during the storage time at room temperature and no significant changes were observed in particle size distribution,PDI,Zeta potential,and drug leakage rate(p > 0.05).In the release study,the cumulative drug release rate of BDMC-SMEDDS in 84 h reaches 60% both in the two kinds of release media of p H 1.2 HCl solution and p H 6.8 PBS,which is much higher than 20% of free BDMC.The above results indicated that the in vitro evaluation results of the prepared BDMC-SMEDDS meet the expected expectations,and it is expected to become a satisfied BDMC nano-drug delivery system.Chapter Ⅳ: Preparation and Characterization of BDMC polymeric micelleIn this chapter,through single-factor experiments and using the particle size,PDI and encapsulation rate as indices,the formulation of BDMC-PT micelle was designed and screened out.And the composion of BDMC-PT micelle was m PEG/PDLLA,TPGS and BDMC at a ratio of 10:10:1.The particle size,PDI and zeta potential of BDMCPT micelles prepared by thin film dispersion method is 24.46 ± 0.32 nm,0.20 ± 0.02 and zeta potential is-38.30 ± 0.65 m V,respectively.Encapsulation efficiency and drug loading are 94.68 ± 0.47% and 4.73%,respectively.Under the storage condition of 4℃within 30 days,the particle size,zeta potential and drug leakage of BDMC-PT micelles did not change significantly(p > 0.05).The critical micelle concerntration(CMC)value was measured as 8.13 μg/m L by using the pyrene fluorescence probe spectroscopy.In the release investigatation,the cumulative drug release rate of BDMC-PT micelles within 36 hours reached 60% both in p H 1.2 HCl solution and p H 7.0 double-distilled water,which was much higher than the BDMC suspension(20%).In summary,the BDMC-PT micelles prepared in this experiment have suitable particle size,high encapsulation efficiency and drug loading rate,low CMC value,and satisfactory drug release properties.Chapter Ⅴ: Studies on Pharmacokinetics Parameters and Antihypericemia of BDMC-SMEDDSIn this chapter,through reversed phase column based HPLC(RP-HPLC),the amounts of BDMC from in vivo samples were quantified with emodin as the internal standard and the standard curves was obtained,which lays the foundation for the quantitative analysis of in vivo samples.Through orally adminstrating to standard weight SD rats with raw materials and drug-loaded preparations,the relative bioavailability of BDMC-SMEDDS and BDMC-PT micelles is obtained and calculated to be 372.88% and 298.36% of BDMC APIs.It shows that both BDMC-SMEDDS and BDMC-PT micelles have successfully improved the oral bioavailability of BDMC,while the effect of BDMC-SMEDDS is relatively better than that of BDMC-PT micelles.Through establishing the rat hyperuricemia model,the uric acid-lowering effect of BDMC and BDMC-SMEDDS was studied.The results showed that within 10 hours,BDMC and BDMC-SMEDDS can successfully reduce serum uric acid levels,indicating that BDMC has the potential pharmacology effect of reducing uric acid.In addition,by comparing the changes in the pain threshold of SD rats before and after orally adminstrating of BDMC and BDMC-SMEDDS,the effect of BDMC-SMEDDS on the resistance of heat pain was evaluated.The results show that BDMC can prelong the pain threshold at a relatively high-dose(200 mg/kg),while BDMC-SMEDDS can exert this effect at a smaller dose(50 mg/kg).