Malaekeh-Nikouei Bizhan, Jaafari Mahmoud R, Tabassi Sayyed A Sajadi, Samiei Afshin
Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Colloids Surf B Biointerfaces. 2008 Dec 1;67(2):238-44. doi: 10.1016/j.colsurfb.2008.09.001. Epub 2008 Sep 10.
The aim of this study was to prepare and characterize neutral, positively charged, negatively charged and fusogenic liposomes of different sizes that contain cyclosporine A (CyA) and to evaluate their immunosuppressive activity on human T-cells. Neutral liposomes containing CyA were prepared from dipalmitoylphosphatidylcholine (DPPC) and cholesterol using the solvent evaporation method. To prepare positively charged, negatively charged and fusogenic liposomes containing CyA; stearylamine (SA), dicetylphosphate (DCP) and dioleoylphosphatidylethanolamine (DOPE) were added to the neutral liposome formulation, respectively. To reduce the size of liposomes containing CyA, extrusion through polycarbonate filters (1000, 400 and 100 nm) was used. The liposomes were characterized by their size, zeta potential and encapsulation efficiency. The in vitro immunosuppressive effects of an aqueous solution of CyA and different liposomes containing CyA were determined on human T-cells by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay. The mean diameter of the various multilamellar vesicle (MLV) liposomes containing CyA was between 1.76 and 2.49 microm. The encapsulation efficiency for the different MLV and extruded liposomes containing CyA ranged from 73% to 90%. In vitro immunosuppressive evaluation by T-cell culture showed that fusogenic liposomes have the best inhibitory effects on T-cell proliferation compared to the other liposomes. Reducing the size of the liposomes did not affect the in vitro immunosuppressive activity. The average IC(50) for the aqueous solution of CyA and the neutral, positively charged, negatively charged and fusogenic liposomes containing CyA was 4.98 x 10(-2), 7.38, 1.43, 3.84 x 10(-3) and 7.93 x 10(-5) mM, respectively. The results of this study indicate that fusogenic liposomes have the strongest immunosuppressive activity and could be considered as a suitable delivery system for CyA.
本研究的目的是制备并表征含有环孢素A（CyA）的不同大小的中性、带正电荷、带负电荷和促融合脂质体，并评估它们对人T细胞的免疫抑制活性。使用溶剂蒸发法由二棕榈酰磷脂酰胆碱（DPPC）和胆固醇制备含CyA的中性脂质体。为了制备含CyA的带正电荷、带负电荷和促融合脂质体，分别将硬脂胺（SA）、二鲸蜡基磷酸酯（DCP）和二油酰磷脂酰乙醇胺（DOPE）添加到中性脂质体制剂中。为了减小含CyA脂质体的大小，采用通过聚碳酸酯滤膜（1000、400和100nm）挤压的方法。通过脂质体的大小、zeta电位和包封率对其进行表征。采用MTT[3-（4,5-二甲基噻唑-2-基）-2,5-二苯基溴化四氮唑]法测定CyA水溶液和不同含CyA脂质体对人T细胞的体外免疫抑制作用。各种含CyA的多层囊泡（MLV）脂质体的平均直径在1.76至2.49微米之间。不同含CyA的MLV和挤压脂质体的包封率在73%至90%之间。通过T细胞培养进行的体外免疫抑制评估表明，与其他脂质体相比，促融合脂质体对T细胞增殖具有最佳抑制作用。减小脂质体大小不影响体外免疫抑制活性。CyA水溶液以及含CyA的中性、带正电荷、带负电荷和促融合脂质体的平均半数抑制浓度（IC50）分别为4.98×10−2、7.38、1.43、3.84×10−3和7.93×10−5mM。本研究结果表明，促融合脂质体具有最强的免疫抑制活性，可被视为CyA的合适递送系统。
