Studies Of Polymeric Nanoparticles Simultaneously Loaded With Vincristine Sulfate And Curcumin

Polymer, such as PLA, PLGA, PEG-PLGA, PEG-PLGA-PEG, hasbeen extensivelv used as medical and pharmaceutical materials, because ofits favorable biocompatibility. Nanoscale carrier is small enough tosmoothly through the tumor neovascularity, made the loading drugreleasing sustainedly at inner tumor. Polymeric nanoparticles, however,were imparted of a serial of advantages: stability, sustained release, smallsize, macrocyclic, thus, were regarded as ideal vehicle for anti-tumor drugdelivery.Vincristine Sulfate（VCR） is a conventional chemotherapy agent.Unfortunately, many tumor cells demonstrated drug resistance to VCR.Curcumin, a natural pigent of phenols, has been reported to be able toreverse multidrug resistance of tumor by lots of research. The application,combined VCR and Cur, was forwarded to reverseing the MDR of tumor,enhancing the accumulative concentration, and so effectively suppressingtumorous growth.In this study, mPEG-PLGA nanoparticles simultaneously loaded withvincristine sulfate（VCR） and curcumin （Cur）（VCR/Cur-mPEG-PLGA-NP） were prepared by O/W emulsion-solvent evaporation. The advantage ofnanoscale vehicle, mPEG-PLGA-NP, was given full play to deliver theVCR and Cur loaded into tumor at the same time, and tumor targetingtherapy was realized.Part Ⅰ Preparation andin vitro release characteristics ofVCR/Cur-mPEG-PLGA-NP1. HPLC gradient elution was employed to simultaneously measuringthe content of the dual agents（VCR and Cur） in vitro. At the range from75ng· mL^-1to19200ng· mL^-1, a good linear correlation between the contentof VCR and its peak area, A=4.5829C-0.6006（r=0.9997）, and at therange from15.625ng·mL^-1to8000ng· mL^-1, a good linear correlationexist for Cur, A=81.639C-2.9378（r=0.9993）.2. There indexes, including diameter, entrapmet efficiency and drugloading efficiency, were employed to investigating how six factors, theconcentration of mPEG-PLGA, the initial content of VCR and Cur, theratio of DCM-Ace, the pH of the aqueous phase, the concentration of PVA,the ratio of O/W, influencing the preparation ofVCR/Cur-mPEG-PLGA-NP. Finally, the optimalizing formula was selected:the concentration of mPEG-PLGA is3%（w/v）, the initial content of VCRis0.5mg, Cur is2.0mg, the ratio of DCM-Ace is1:2, the pH of theaqueous phase is7.0, the concentration of PVA is0.5%（w/v）, the ratio ofW/O is1:3（v/v）. 3. According to the optimalizing formula, VCR/Cur-mPEG-PLGA-NPwas prepared. The average diameter is131.5nm, the entrapment efficiencyof VCR is （63.52±2.36）%, and its drug loading efficiency is （1.06±0.04）%.The entrapment efficiency of Cur is （54.60±2.46）%, and its drug loadingefficiency is （3.64±0.16）%. Release study of VCR/Cur-mPEG-PLGA-NPin vitro demonstrated that accumulated release percentage of VCR comesto20%at the initial1h, and about80%at36h. However, the accumulatedrelease percentage of Cur comes to52%, and arround75%at84h. It isconcluded that Cur loaded in the nanoparticles showed bettersustained-release characteristic than VCR.Part Ⅱ Preliminary test of VCR/Cur-mPEG-PLGA-NP on inducingthe multidrug resistant cell line SKOV3/Adr to apoptosis.The cytotoxicity of DMSO, free VCR, free VCR+Cur, NP withoutdrug, VCR-NP and VCR/Cur-NP was investigated using MTT assays. Theresults demonstrated that the cytotoxicity of diluent DMSO and NPwithout drug could be neglected. After treated with the drug ornanoparticles loading drug for48h, the growth of SKOV3/Adr wassignificantly suppressed by VCR+Cur or VCR/Cur-NP, compared to freeVCR or VCR-NP.Part ⅢPreliminary pharmacokinectic study ofVCR/Cur-mPEG-PLGA-NP in rabbits1. HPLC gradient elution was established to simultaneously measuring the content of the dual agents（VCR and Cur） in plasma of rabbits. Theresults demonstrated that at the range from0.020ng· mL^-1to10.24ng· mL^-1, a good linear correlation between the content of VCR and itspeak area, A=87.634C-10.321（r=0.9988）, and at the range from0.005ng· mL^-1to10.24ng· mL^-1, a good linear correlation exist for Cur,A=2858.3C+184.86（r=0.9995）.2. The pharmacokinectcs of the dual agents, after a single dose ofVCR/Cur-mPEG-PLGA-NP injected in rabbits, were studied preliminary.Changs of VCR and Cur content in plasma with the time was investigated.3P97soft was used to processing the data. The results demonstrated thatboth of the dual agents loaded in VCR/Cur-mPEG-PLGA-NP conformedto bi-compartment model after VCR/Cur-mPEG-PLGA-NP injected inrabbits, and the pamameters of nanoparticles loading VCR and Curinjection were carried out.As stated above, VCR, a chemotherapy agent, and Cur, a reversalagent of multidrug resistance, were successfully and simultaneouslyencapsulated in one polymeric nanoparticles, and accurate and reliableHPLC method were established for determinating the dual agents, VCRand Cur, in vivo and in vitror. According to the results of preliminary teston SKOV3/Adr cells, cells growth showed be suppressed to some extentwhen treated with VCR/Cur-mPEG-PLGA-NP. The preliminarypharmacokinectics study enriched the systemic research of VCR/ Cur-mPEG-PLGA-NP. So far, the studies mentioned above were not yetreported, and has definitely academical value.