Lipid-albumin Nanoassemblies Loaded With Paclitaxel For Brain Targeting Delivery

Brain glioma is the most common primary central nervous system tumor.It is a life-threatening disease and the 5-year survival rate is only about 35%.Conventional therapy for glioma consists primarily of surgical resection followed by radiotherapy and chemotherapy.However,the therapeutic effect for glioma produced by systemic delivery chemotherapeutic drugs is very limited,because the potential drugs for the treatment of glioma can not reach the brain tissue in sufficient concentrations due to their poor permeability across the blood-brain barrier(BBB).With the rapid development of nanotechnology for biomedical application,nano-drug delivery systems have gained some progress in the treatment of gliomma,but it remains a formidable challenge.The major obstacles to the treatment of glioma include drug transport across the BBB and multidrug resistance of tumor cells.Therefore,we attempted to prepare lipid-albumin nanoassemblies co-loaded with borneol and paclitaxel(BOR/PTX LANs)for the treatment of glioma.The physicochemical properties and the drug release profile were characterized.The cell cytotoxicity,cell uptake,in vivo distribution and anti-glioma effect were also evaluatedIn this study,PTX was selected as a model drug and BSA and egg yolk lecithin(PL 100M)were used to fabricate PTX loaded lipid-albumin nanoassemblies(PTX LANs)and BOR/PTX LANs,which were prepared using desolvation-ultrasonication method.The process and formulation factors were optimized in terms of the particle size,encapsulation efficiency and stability.The physicochemical properties and the drug release profile were investigated.The PTX LANs and BOR/PTX LANs have small particle size and the particle size were 113.2±4.5 nm,107.5±3.2 nm,respectively.The PTX LANs and BOR/PTX LANs have high encapsulation efficiency,the encapsulation efficiency for PTX were 92.5±1.8%and 90.4±1.2%,respectively.The encapsulation efficiency of BOR in BOR/PTX LANs was 85.9±0.8%.The loading capacity of PTX in PTX LANs and BOR/PTX LANs were 2.98±0.12%and 2.83±0.15%,respectively.The loading capacity of BOR in BOR/PTX LANs was 2.68±0.02%.The results of TEM and XPS indicated that LANs had a spherical multilayer structure,the conjugate of BOR/PTX and BSA was in the interior and the surface layers were formed by lipid bilayers.The results of DSC and XRD indicated that the BOR and PTX existed in a molecular or amorphous state.The in vitro release behavior of PTX from LANs was performed in pH 7.4 PBS by dialysis bag method.Both the PTX LANs and BOR/PTX LANs exhibited a sustained release profile compared with PTX solution.The release kinetics fit well to Ritger-Peppas and Weibull models,the PTX released from LANs was maily followed by diffusionThe cytotoxicity and cell uptake of LANs were evaluated in C6 glioma cells.In vitro cytotoxicity tests indicated that the BOR/PTX LANs exhibited the lowest cell viability(IC50=0.96±0.08?g/ml)compared with that of PTX solution(IC50=1.54±0.09 ?g/ml)and PTX LANs(IC50=1.66± 0.12 ?g/ml).The cell uptake of LANs was evaluated with quantitative determination of intracellular drug concentration and qualitative observation by confocal laser scanning microscopy.The results implied that BOR can inhibit the activity of P-gp and increase the PTX accumulation in C6 glioma cells;BOR/PTX LANs significantly improved the cell uptake of PTX in comparision with PTX solution and PTX LANs;The cell uptake was energy-,time-and concentration-dependent,and clathrin-and endosome/lysosome-associated pathways were involved.In addition,both the hemolysis and cytotoxicity studies revealed the safty of the nanocarrier.A sensitive reverse phase HPLC method was developed to determinate the PTX content in plasma and tissue samples after intravenously administration at a dose of 20 mg/kg in mice The result of in vivo distribution showed that the LANs can significantly increase the PTX accumulation in brain tissue.The AUC of BOR/PTX LANs in brain was 2.02-fold compared with PTX solution and 1.52-fold in comparision with PTX LANs.Compared with PTX solution and PTX LANs,the relative uptake efficiency(R)of BOR/PTX LANs was 2.023 and 1.522,respectively,and the drug targeting index(DTI)of that was 4.203 and 1.919,respectively;Compared to PTX solution,the LANs yielded a smaller AUC in the heart,spleen,lung and kidney,indicating that the LANs may decrease the accumulation of PTX and reduce its toxicity in these organs.Moreover,the in vivo real-time imaging analysis also confirmed the remarkable brain targeted ability of BOR loaded LANs.Kunming mice bearing C6 glioma transplanted tumor were used as model to evaluate the tumor targeted ability and in vivo anti-tumor efficacy of BOR/PTX LANs.The in vivo real-time imaging analysis on C6 glioma-bearing mice indicated that the LANs loaded with BOR can significantly increase the DIR in tumor mass compared with the LANs without BOR.The tumor inhibition rate of PTX solution,PTX LANs and BOR/PTX LANs was 49.00%,62.39%,85.71%,respectively.The result indicated that BOR/PTX LANs can greatly improve the anti-glioma effect against PTX solution and PTX LANs.