阿糖胞苷多囊脂质体的制备及体外释放度考察

目的制备阿糖胞苷多囊脂质体,并考察其体外释放特性。方法采用复乳法制备阿糖胞苷多囊脂质体;RP-HPLC法测定含量、包封率和体外释放特性;以包封率为指标,单因素及正交试验筛选、优化工艺和处方;光学显微镜下观察多囊脂质体形态;以激光粒度测定仪测定粒径。结果一次乳化时间为8 min、氮气流速为0.3 m3.h-1时包封率最高;优化处方中二油酰磷脂酰胆碱(DOPC)、二棕榈酰磷脂酰甘油(DPPG)、胆固醇(CH)、三油酸甘油酯(TO)的质量浓度分别为10、2、7.5、4 g.L-1,赖氨酸浓度为40 mmol.L-1,有机溶剂选择氯仿-乙醚(体积比1∶1)。阿糖胞苷多囊脂质体在400倍显微镜下形态光滑、圆整,内部呈蜂窝状,无磷酯碎片;平均粒径19.49μm,跨距0.91;包封率达70%以上;以人空白血浆为释放介质,两周释放药物约60%。结论制备的阿糖胞苷多囊脂质体外观良好,包封率较高,体外释放试验表明药物缓慢释放,无突释现象。     

N-三甲基壳聚糖包覆牛血清白蛋白脂质体的制备及质量影响因素研究

目的:制备N-三甲基壳聚糖(TMC)包覆的牛血清白蛋白(BSA)脂质体,并考察其质量影响因素。方法:采用逆相蒸发法制备BSA脂质体,壳聚糖与碘甲烷进行季胺化反应合成TMC,用于脂质体包衣,制备TMC包覆的BSA脂质体。采用高速离心考马斯亮蓝G-250法测定包封率,考察脂类大豆卵磷脂(PC):胆固醇(CH):磷脂酰丝氨酸(PS)组成比、TMC与脂相质量比、离子强度对脂质体包封率和粒径的影响。结果:所考察因素对粒径和包封率均有影响,以脂类组成PC:CH:PS(8:9:1)、TMC与脂相质量比0.25:1、离子强度小于20 mmol·L~(-1)为宜,所制脂质体包封率为(46.82±2.07)%。结论:TMC可包覆BSA制备脂质体,所得制剂粒径均匀,稳定性好。     

pH梯度结合逆向蒸发法制备槐定碱纳米脂质体及体外释放度研究

目的:采用pH梯度结合逆向蒸发法制备槐定碱纳米脂质体,对影响包封率和粒径的因素进行考察,并对其体外释放进行评价。方法:以正交设计及单因素实验考察影响脂质体包封率及粒径的主要因素,同时对优化后的脂质体进行了质量评价及体外释放度研究。结果:磷脂的浓度为5 mg.mL-1,药脂比为1∶15,胆脂比为1∶4,内水相的pH值为2.0,均质压力为100 bar时,制备的脂质体包封率可达(90.30±0.63)%,脂质体外观圆整均匀,平均粒径为(117±6)nm。结论:pH梯度结合逆向蒸发法制备的槐定碱纳米脂质体包封率高,粒径均匀,稳定性好,具有一定的缓释作用。     

贝伐单抗多囊脂质体的处方优化及体外释放特性研究

目的:制备具有缓释作用的贝伐单抗(BEV)多囊脂质体(BEV-MVLs),并对其体外释放特性进行研究。方法:采用复乳法制备BEV-MVLs,以有机相中三油酸甘油酯(TO)的浓度、1,2-二油酰基磷脂酰胆碱(DOPC)-胆固醇(CH)的比值(mol/mol)、外水相中L-赖氨酸的浓度为因素,以包封率为指标,采用Box-Behnken设计-响应面法对处方进行优化。采用倒置荧光显微镜和扫描电镜观察BEV-MVLs的形态,激光粒度仪测定其粒径,高效液相色谱法测定BEV含量并计算其包封率和体外累积释放度。结果:最优处方为有机相中TO 2.72 mmol/L、DOPC-CH比值0.67(mol/mol)、外水相中L-赖氨酸40 mmol/L。所制BEV-MVLs的包封率为(80.65±4.42)%(n=3),与预测值的相对误差为2.54%;脂质体外观呈球形,大小较均匀,为典型的非同心囊泡结构,平均粒径为16.80μm;30 d的体外累积释放度约为92%。结论:成功制得具有缓释作用的BEV-MVLs,其包封率达到预期效果。     

长效利拉鲁肽多囊脂质体的制备及质量评价

目的制备长效利拉鲁肽多囊脂质体(liraglutide-load multivesicular liposomes,Lrg-MVLs),并对其理化性质和体外释放进行了考察。方法采用复乳法制备Lrg-MVLs,以成形性、粒径为评价指标,采用单因素试验优化Lrg-MVLs制备条件。测定了优化处方制备的Lrg-MVLs包封率和粒径,并考察了其体外释放度。结果优化处方制备的Lrg-MVLs平均粒径为8.23μm,包封率为(88.69±0.65)%。体外释放结果显示,Lrg-MVLs体外持续释放达168 h,2 h释放(1.18±0.77)%,无突释现象,体外释放符合Ritger-Peppas模型。结论 Lrg-MVLs呈典型的非同心圆结构,粒径均匀、包封率高,可用于包载Lrg(liraglutide)达到缓慢释放的目的。     

酪丝亮肽多囊脂质体的制备和体外释放研究

目的:制备酪丝亮肽多囊脂质体,并考察其体外释药性能。方法:采用复乳法制备酪丝亮肽多囊脂质体,RP-HPLC法测定酪丝亮肽含量,以稳定性、包封率和体外释放为指标,正交试验设计法对酪丝亮肽多囊脂质体处方工艺进行优化。结果:酪丝亮肽多囊脂质体粒径均一,有80%的粒径分布在20~30μm,包封率达92.43%。酪丝亮肽多囊脂质体体外释放符合Korsmeyer-Peppas模型,37℃条件下在PBS介质中释药t1/2达111.5 h。结论:酪丝亮肽多囊脂质体稳定性好,包封率高,具有良好的缓释效果。     

胸腺五肽多囊脂质体的制备及体外释放的考察

目的 制备胸腺五肽多囊脂质体,并考察其包封率和体外释放情况.方法 采用复乳法制备胸腺五肽多囊脂质体,并用单因素、正交实验对处方进行优化.结果 制备的胸腺五肽多囊脂质体的外观圆整均匀,形态良好,包封率为80.15%±3%.体外释放的零级动力学方程为:Y=0.536X+20.431(r2=0.9814),132 h的累积释放率为92.01%.结论 复乳法制备的胸腺五肽多囊脂质体的工艺可行,包封率较高,有明显的缓释特征.     

辣椒碱多囊脂质体的制备及在大鼠体内的药动学研究

目的 制备辣椒碱多囊脂质体,并考察其包封率和在大鼠体内的药动学.方法采用复乳法制备辣椒碱多囊脂质体、单因素筛选处方,并考察大鼠sc辣椒碱多囊脂质体后的体内药动学.结果制备的辣椒碱多囊脂质体的外观圆整,大小均匀,包封率为71.9%±3.8%,平均粒径为8.1 μm.大鼠sc辣椒碱多囊脂质体后,与辣椒碱溶液相比,Cmax分...     

离子载体A23187介导pH梯度法制备重酒石酸长春瑞滨长循环脂质体

目的:采用A23187制备重酒石酸长春瑞滨长循环脂质体,优化了处方工艺,并考察了含量、包封率、药脂比和体外释放等检测指标。方法:采用A23187介导的pH梯度法制备了重酒石酸长春瑞滨脂质体;用HPLC法检测了脂质体中重酒石酸长春瑞滨的含量和脂质(HSPC)的含量,考察了药脂比;采用阳离子交换树脂分离脂质体和游离药物,HPLC法检测包封率;以4 mmol.L-1NH4Cl-PBS(pH 7.4)为体外释放介质考察了脂质体的体外释放行为。结果:重酒石酸长春瑞滨脂质体包封率为96.1%,药脂比为1∶5(w/w);高药脂比有利于延长药物体外释放的时间。结论:采用A23187介导的pH梯度法制备重酒石酸长春瑞滨脂质体工艺可行、载药量大、包封率高;所建立体外释放的检测方法快速、准确。     

鬼臼毒素MPEG修饰脂质体的制备及体外释放的研究

目的:制备鬼臼毒素(PPT)MPEG修饰脂质体(PPT-MPL),以及考察PPT-MPL体外释放行为。方法:合成甲氧基聚乙二醇磷脂酰乙醇胺(MPEG-PE),并用薄膜分散法制备脂质体;以包封率为指标,运用正交试验法设计优化脂质体处方和工艺,采用改进的超滤法测定脂质体的包封率,以及透析法研究体外释放行为。结果:优化后的PPT-MPL平均粒径为(106.20±4.10)nm,包封率为(83.30±2.50)%;加入血浆后PPT-MPL体外释放速率比普通脂质体慢(P<0.05)。结论:该法制备PPT-MPEG修饰脂质体,具有粒径小、包封率高以及明显的缓释效果。     

Preparation of optimized Naproxen nano liposomes using response surface methodology

The aim of this study was to prepare and optimize a liposomal delivery system for Naproxen (NPX), a practically water insoluble drug. NPX liposomes, which were consisted of cholesterol (CH) and phosphatidylcholine (PC) in different molar ratios, were prepared by modified ethanol injection method and optimized employing response surface methodology (RSM). Proportion of PC:CH and total lipid:drug ratio were selected as the independent variables while the particle size (PS), encapsulation efficiency percent (EE%) and drug release of the liposomes over 24 h (D_24h) were considered as dependent variables. The effects of PC:CH and total lipid:drug ratios were studied and optimized to obtain the liposomal vesicles with desired quality. Graphical response surface and contour plots were also employed to understand the interaction of different variables. The optimum points for the variables were obtained from the optimization plot. The mean PS, EE% and D_24h of NPX liposomes were about 178.11 nm, 53.14 and 46.62 % respectively. The results indicated that PC:CH and total lipids:drug ratios were the major contributing variables for EE% and D_24h. However, only PC:CH ratio was the main contributing variable for PS. The optimum formulation of NPX liposomes, in which PC:CH ratio and lipids:drug ratio were 3.81 and 2.98 respectively, had high EE% (58 %) and D_24h (>50 %) as well as appropriate PS (<162.4 nm). Ethanol injection method besides RSM, are simple, rapid and beneficial approaches for liposome preparation and optimization.     

Physico-chemical characteristics of methotrexate-entrapped oleic acid-containing deformable liposomes for in vitro transepidermal delivery targeting psoriasis treatment

This study aimed to investigate the physico-chemical characteristics and in vitro permeability of methotrexate (MTX)-entrapped deformable liposomes prepared from phosphatidylcholine (PC) and oleic acid (OA), comparing with those of MTX-entrapped conventional liposomes prepared from PC and cholesterol (CH). Two formulations of MTX-entrapped PC2:CH1 and PC9:CH1 liposomes and one formulation of MTX-entrapped PC2.5:OA1 liposomes were prepared. The size, size distribution, zeta potential, thermal properties, entrapment efficiency, stability, and in vitro permeability across a porcine skin of the MTX-entrapped liposomes were evaluated. All liposome formulations showed a narrow size distribution with the size range of 80-140 nm which is appropriate for the skin permeability. The percentage of MTX loading, entrapment efficiency and the stability of MTX-entrapped PC2:CH1 and PC9:CH1 liposomes were slightly higher than those of MTX-entrapped PC2.5:OA1 liposomes. However, the MTX-entrapped PC2.5:OA1 liposomes enhanced the skin permeability characterized by the higher concentration and flux of MTX diffused across or accumulated in the epidermis and dermis layers of porcine skin. The enhanced permeability of MTX-entrapped PC2.5:OA1 liposomes was explained by 2 mechanisms: (1) the deformable and elasticity characteristics of OA-containing liposomes and (2) a property as a skin penetration enhancer of OA. This suggested that the PC2.5:OA1 deformable liposome was one of promising candidates to enhance the permeability of MTX for the treatment of psoriasis.     

Recombinant human tumor necrosis factor-α covalently conjugated to long-circulating liposomes

Recombinant tumor necrosis factor-α (rHuTNF) was covalently conjugated to a phospholipid, N-glutaryl phosphatidylethanolamine (NGPE). The resultant rHuTNF-NGPE conjugates were incorporated into liposomes composed of phosphatidylcholine (PC) and cholesterol (Chol) with or without polyethyleneglycol conjugated to phosphatidylethanolamine (PEG3000-PE). Efficient incorporation (35–50%) of rHuTNF-NGPE conjugates into liposomes was obtained for both PC/Chol and PC/Chol/PEG3000-PE liposomes. An in vitro cytotoxicity assay showed that rHuTNF-NGPE conjugates incorporated into liposomes exhibit a reduced biological activity as compared to the free rHuTNF. Biodistribution studies using ¹²⁵I-labeled rHuTNF showed a significant increase in the circulation time of rHuTNF by incorporation into PC/Chol/PEG3000-PE liposomes, but not conventional PC/Chol liposomes. However, studies using a radioactive lipid as a liposome marker showed that incorporation of rHuTNF-NGPE conjugates resulted in increased clearance from the blood and accumulation in the spleen and liver of both liposomal formulations. The liposome clearance from the blood depends on the protein/lipid ratio of liposomes. The higher the protein/lipid ratio, the higher the liposome clearance from the blood and accumulation in the spleen and liver, suggesting that accumulation of rHuTNF-bound liposomes in the spleen and liver involves interactions with TNF-receptors in these organs.     

西罗莫司脂质体的制备及处方因素考察

目的 制备西罗莫司脂质体并对处方进行筛选,以期得到高包封率的脂质体制剂.方法 选用乙醇注入法制备西罗莫司脂质体,微柱离心-HPLC法测定包封率,以包封率为评价指标,考察磷脂浓度、磷脂胆固醇质量比、药脂比、水相介质pH等因素对脂质体的影响,在此基础上运用正交设计对处方进行优化.结果 正交试验结果表明磷脂浓度为4%,磷脂与胆固醇质量比例为8:1,药物磷脂质量比为1:20,水相pH为7.4为最佳处方,制得的脂质体包封率为(82.11±2.13)%.结论 优选出最佳处方,制得的西罗莫司脂质体包封率高,重现性好.     

如何优化番木鳖碱脂质体制备工艺

目的优化制备番木鳖碱脂质体的处方。方法采用乙醇注入式硫酸铵梯度法制备番木鳖碱脂质体;并以番木鳖碱脂质体的包封率为主要评价指标,采用正交设计法优化番木鳖碱脂质体的配方。结果获得了番木鳖碱脂质体的工艺处方：卵磷脂与胆固醇的重量比为6：1．番木鳖碱和卵磷脂的重量比为1：30,当硫酸铵浓度达到0．15mol·L^-1,卵磷脂的重量与硫酸铵溶液的体积比为12：1。按该处方工艺制备3批番木鳖碱脂质体。包封率平均值为92．17％。结论按照优化处方,采用乙醇注入式硫酸铵梯度法可制得包封率稳定,粒径较小且分布较窄的番木鳖碱脂质体。     

茶多酚脂质体的制备研究

目的优化制备茶多酚-维生素E脂质体的配方。方法采用逆相蒸发法制备。以包封率作为考察指标,经正交优化选择,确定制备脂质体的最佳配方。结果最佳配方为:卵磷脂/胆固醇(摩尔比)为2∶1;茶多酚浓度为10 mg/mL;维生素E/卵磷脂(质量比)为1∶8;有机相/水相(体积比)为3∶1,此时包封率可达(50.81±1.92)%。显微镜下观察到了脂质体结构。平均粒径为327 nm。结论此法操作简便可靠,所需设备简单,重现性较好,可适用于包埋水溶性药物。     

Novel long-circulating liposomes containing peptide library-lipid conjugates: synthesis and in vivo behavior

Rapid uptake of intravenously injected liposomes by the mononuclear phagocyte system has limited their use as drug delivery vehicles. Recently, various long-circulating liposomes have been prepared by incorporating glycolipids or other amphiphilic molecules into the lipid bilayer of conventional liposomes. The purpose of the present study was to design a new class of biodegradable membrane modifiers that would increase the half-life of liposomes in vivo. Using solid-phase peptide synthesis, synthesized were 30-residue random libraries consisting of a random sequence of glycine, beta-alanine and gamma-aminobutyric acid. The libraries were coupled to stearic acid (SA) or phosphatidylethanolamine (PE). The resulting amphiphilic conjugates were mixed with egg phosphatidylcholine (PC) and cholesterol (Chol) in a 6:47:47 ratio, and unilamellar liposomes were prepared. For comparison, plain PC/Chol (50:50) liposomes, as well as liposomes containing polyethylene glycol (PEG)-SA/PC/Chol (6:47:47) and PEG-PE/PC/Chol (6:47:47) were also prepared. Calcein was entrapped in the liposomes, which were given intravenously to rats at a dose of 9.2 mumol lipid/kg, and the amount of intact liposomes present in serum was followed with time. While the conventional liposomes had a short elimination half-life (28 min), the liposomes modified with library-PE had a much longer half-life (170 min), while library-SA provided no improvement of the liposome pharmacokinetics. PEG-PE greatly improved the half-life of the liposomes (400 min) while PEG-SA only provided a marginal improvement. All liposome preparations were cleared in a biphasic fashion. In conclusion, a novel biodegradable lipopeptide conjugate was designed that endows liposomes with a prolonged circulation time in vivo. The pharmacokinetic profile of these modified liposomes was drastically improved over that of conventional liposomes. Since the library is prepared by solid-phase synthesis, length and/or composition could easily be modified in order to modulate the clearance profile of the liposomes. Tailoring of the pharmacokinetic profile of the liposomes depending on their intended application may allow for a greater flexibility of use than PEG-PE.     

Physicochemical properties and antioxidant activity of gamma-oryzanol-loaded liposome formulations for topical use

The objective of this study is to prepare the γ-oryzanol-loaded liposomes and investigate their physicochemical properties and antioxidant activity intended for cosmetic applications. Liposomes, Composing phosphatidylCholine (PC) and Cholesterol (Chol), CHAPS or sodium taurocholate (NaTC) were prepared by sonication method. γ-oryzanol-loaded liposomes were prepared by using 3, 5 and 10% γ-oryzanol as an initial concentration. The formulation factors in a particular type and composition of lipid and initial drug loading on the physicochemical properties (i.e., particle size, zeta potential, entrapment efficiency, drug release) and antioxidant activity were studied. The particle sizes of bare liposomes were in nanometer range. The γ-oryzanol-loaded liposomes in formulations of PC/CHAPS and PC/NaTC liposomes were smaller than PC/Chol liposomes. The incorporation efficiency of 10% γ-oryzanol-loaded PC/Chol liposomes was less than γ-oryzanol-loaded PC/CHAPS liposomes and PC/NaTC liposomes allowing higher in vitro release rate due to higher free γ-oryzanol in buffer solution. The antioxidant activity of γ-oryzanol-loaded liposomes was not different from pure γ-oryzanol. Both γ-oryzanol-loaded PC/CHAPS liposomes and PC/NaTC liposomes were showed to enhance the antioxidant activity in NHF cells. γ-oryzanol-loaded PC/Chol liposomes demonstrated the lowest cytotoxicity in NHF cells. It was conceivably concluded that liposomes prepared in this study are suitable for γ-oryzanol incorporation without loss of antioxidant activity.     

脂质体处方和制备方法对阿昔洛韦棕榈酸酯脂质体稳定性的影响

目的研究不同处方组成和制备方法对阿昔洛韦棕榈酸酯脂质体在4℃和25℃分别贮存90 d和180 d后的稳定性的影响。方法用卵磷脂(PC)/胆固醇(CH)/磷脂酰丝氨酸(PS),卵磷脂(PC)/胆固醇(CH)/硬脂酰胺(SA),卵磷脂(PC)/胆固醇(CH)/胆固醇硫酸酯(CS),神经酰胺(CM)/胆固醇(CH)/棕榈酸(PA)/胆固醇硫酸酯(CS),以薄膜分散法、逆向蒸发法和去水化/水化法,分别制备多室脂质体(MLV)、大单室脂质体(LUV)、去水化/水化脂质体(DRV),以平均粒径、渗漏率、pH值和Zeta电位4个指标考察不同贮存条件下脂质体的稳定性。结果脂质体稳定性顺序依次为,对不同脂质体处方:PC/CH/CS>CM/CH/PA/CS>PC/CH/PS>PC/CH/SA;对不同制备方法:LUV优于MLV和DRV;4℃时脂质体的稳定性优于25℃时的脂质体。结论脂质体的稳定性与制剂处方和制备方法密切相关。     

Microencapsulated liposomes in controlled drug delivery: strategies to modulate drug release and eliminate the burst effect

The release of fluorescein isothiocyanate labeled bovine serum albumin (FITC-BSA) from alginate-microencapsulated liposomes was studied to evaluate the properties of this system for controlled drug delivery. Liposomes composed of phosphatidylcholine (PC) and cholesterol (Chol) (molar ratio 7:3) and of PC, phosphatidylglycerol (PG), and cholesterol (6:1:3) were encapsulated in alginate (Alg) crosslinked with Ca(2+) (Ca-Alg), Al(3+) (Al-Alg), and Ba(2+) (Ba-Alg). Capsules were coated with poly(l-ornithine) followed by a final alginate coat. A rapid initial burst of protein release was observed from liposomes encapsulated in Ca-Alg and Al-Alg. No burst was observed when liposomes were encapsulated in Ba-Alg, indicating that the crosslinking ions could significantly affect the release of entrapped protein. Also, the release from encapsulated liposomes varied significantly with liposome composition, especially with Ca-Alg as observed with encapsulation of PC, dioleoylphosphatidylcholine (DOPC), and DOPC/Chol liposomes. Cholesterol increased the leakiness of the liposomes after encapsulation. In all cases, the release from microencapsulated liposomes was much faster than that from free liposomes suggesting an interaction between the liposomes and the alginate. Differential scanning calorimetry supports the hypothesis that alginate was inserted into the lipid bilayer resulting in a rapid release of protein from microencapsulated liposomes. Moreover, it was observed that the degree of interaction between liposomes and alginate varied with liposome composition.