正交试验法优选PP1脂质体的制备工艺

目的:制备PP1脂质体,筛选最优处方。方法:用薄膜水化法制备PP1脂质体,以高效液相色谱法(HPLC)测定PP1脂质体的包封率,以包封率为主要指标,选取药脂比、胆固醇磷脂比、温度和水化时间为因素,用正交试验筛选最优配方。结果:用薄膜水法制备的PP1脂质体的最优处方的组成为:药脂比为1:10,胆固醇与二棕榈酰磷脂酰胆碱(DPPC)比为1:8,温度为40℃,水化时间为3 min。平均包封率为(63.27±3.32)%。PP1脂质体的平均粒径为(157.73±9.74)nm,Zeta电位为(-4.74±0.44)m V。结论:用薄膜水化法制备出的PP1脂质体包封率高,形态和粒径均匀,重现性好,为研究其在眼部的缓释作用奠定了基础。     

紫杉醇脂质体制备方法优化比较

为了优化紫杉醇脂质体制备工艺,探究逆向蒸发法、高剪切法、薄膜分散法、注入法及复乳法等脂质体制备方法,对逆向蒸发法制备工艺及制剂处方进行单因素考察,由试验结果得出最优处方为药脂比为1∶25,磷脂含量为2.5%,胆固醇与磷脂比为1∶9,并对包封率以及粒径等指标进行初步评价,最终按照优化后的工艺制得的紫杉醇脂质体的包封率较高,粒径大小符合要求,质量稳定。     

CRM197修饰的肿瘤细胞裂解物疫苗抗肝癌作用研究

[目的]探讨CRM197能否增强H22肝癌细胞裂解物疫苗的抗肿瘤活性。[方法]反复冻融H22细胞制备裂解物,与CRM197偶联,制备H22-CRM197疫苗,以小鼠皮下移植瘤模型考察疫苗抗肿瘤活性,并对免疫学机制进行探讨。[结果]与PBS组相比,H22-CRM197免疫显著降低了荷瘤小鼠肿瘤重量(0.53±0.20 g VS 2.04±0.43 g,p0.01);与PBS组比较,H22-CRM197组小鼠免疫血清中检测到高滴度的抗-H22抗体(p0.01);H22-CRM197免疫能够有效地刺激脾淋巴细胞的增殖并诱导产生了明显靶向H22细胞的细胞毒性T淋巴细胞杀伤作用。[结论]CRM197可以显著增强H22肝癌细胞裂解物疫苗的抗肿瘤活性。     

掺入胆固醇和阴离子磷脂对阿霉素免疫脂质体性能的影响

本文研究了胆固醇和阴离子磷脂的掺入对阿霉素—磷脂酰乙醇胺免疫脂质体包裹效力及其在PBS缓俄冲液和在50%血清中的稳定性的影响,并对这种影响可能的机理进行了讨论.阴离子磷脂PG和DPG的掺入使ADM免疫脂质体包裹ADM的效力大大增加,使ADM与PE的克分子比从(0.08—0.8)%增加到75%,其中DPG比PG更有效.掺入胆固醇可以明显提高ADM脂质体在缓冲液和在血清中的稳定性,但使脂质体包裹ADM的效力下降.通过脂质的选择和制备条件的摸索,我们成功地用超声法制备了包裹抗癌药(ADM),表面带有抗人胃癌细胞M85单克隆抗体3HII的小单层脂质体(SUV),其起脂质份是PE:PG:Chol:ADM(4:2:2:1),脂质体内的ADM与PE的克分子比为17—25%.经电镜观察,脂质体直径在60—80nm范围内,大以比较均一.这种脂质体在PBS缓冲液中于室温下保存12天,仍然能够保持其包裹药的70%;在50%的血清中,37℃1小时,能够保持其包裹药的80%.     

甘草次酸结肠靶向微丸的研制

目的:确定甘草次酸结肠靶向微丸的制剂处方,评价其释药特性。方法:采用挤出-滚圆法制备甘草次酸素丸,利用流化床包衣技术对甘草次酸素丸进行包衣,用浆法评价微丸的体外释药性能。结果:采用微晶纤维素和甘草次酸,同时加入黏合剂羧甲基纤维素钠,经过充分搅拌混合,以30%的乙醇作为润湿剂,通过挤出-滚圆制得甘草次酸素丸。以尤特奇S100为膜控材料,加入适量柠檬酸三乙酯与滑石粉配制包衣液,对甘草次酸素丸进行包衣,制得甘草次酸包衣微丸。释放度实验表明甘草次酸素丸在其增重20%时,在0.1 mo L/L的盐酸溶液中不释放,在p H6.8的磷酸缓冲液条件下6 h内其释放率不到20%。而在p H7.4的磷酸缓冲液条件下2 h内释放率达到80%以上。结论:所制的甘草次酸素丸处方合理,制剂工艺简便,通过流化床包衣技术所制的甘草次酸包衣微丸在模拟的胃液中不释放,在小肠液中释放缓慢,在结肠液中释药良好,具有良好的结肠靶向作用。     

掺入胆固醇和阴离子磷脂对阿霉素免疫脂质体性能的影响

本文研究了胆固醇和阴离子磷脂的掺入对阿霉素—磷脂酰乙醇胺免疫脂质体包裹效力及其在PBS缓俄冲液和在50%血清中的稳定性的影响,并对这种影响可能的机理进行了讨论.阴离子磷脂PG和DPG的掺入使ADM免疫脂质体包裹ADM的效力大大增加,使ADM与PE的克分子比从(0.08—0.8)%增加到75%,其中DPG比PG更有效.掺入胆固醇可以明显提高ADM脂质体在缓冲液和在血清中的稳定性,但使脂质体包裹ADM的效力下降.通过脂质的选择和制备条件的摸索,我们成功地用超声法制备了包裹抗癌药(ADM),表面带有抗人胃癌细胞M85单克隆抗体3HII的小单层脂质体(SUV),其起脂质份是PE:PG:Chol:ADM(4:2:2:1),脂质体内的ADM与PE的克分子比为17—25%.经电镜观察,脂质体直径在60—80nm范围内,大以比较均一.这种脂质体在PBS缓冲液中于室温下保存12天,仍然能够保持其包裹药的70%;在50%的血清中,37℃1小时,能够保持其包裹药的80%.     

多肽靶向脂质体的表面配体修饰密度及其体内肿瘤靶向效果的研究

脂质体作为一种药物载体广泛应用于肿瘤药物输送中。配体修饰的靶向脂质体,其靶向配体分子在脂质体表面修饰的构象和密度等参数,对脂质体本身的特性及其体内的靶向效果,有很大的影响。但有关其中的具体相互关系,以及可能的最优条件,国内外文献都尚无定论。据此我们建立了多肽靶向脂质体表面配体修饰的分析方法,并通过影像学手段来研究不同靶向肽含量对脂质体在荷瘤裸鼠中的靶向行为的影响。首先采用孵育插入法将带有多肽的脂质分子插入脂质体表面,用分子筛色谱法分离修饰后的脂质体和未插入的多肽脂质,再用HPLC-ELSD定量各脂质成分,得到多肽靶向脂质体表面的靶向肽密度。而后将修饰有不同密度靶向多肽的荧光脂质体经荷瘤小鼠尾静脉注射,分别在给药前后各时间点对小鼠进行扫描,对扫描得到的图像进行处理并计算AUC、T1/2和MRT等相关药代动力学参数。结果表明,随着脂质体表面多肽密度的增加,即多肽密度大于1.298%的靶向脂质体,其肿瘤部位的荧光AUC、T1/2和MRT都较未修饰的隐形脂质体有所提高,显示其在肿瘤组织中的聚集量增多、停留时间延长,针对肿瘤细胞的特异性作用机制得以彰显。     

新型脂肽类辐射防护剂H6101对小鼠骨髓细胞基因表达谱的影响

目的：脂肽类化合物具有抗辐射活性,通过研究脂肽类辐射防护剂H6101给药后小鼠骨髓细胞基因表达谱的变化,揭示其可能的辐射防护机制。方法：6只ICR雄性小鼠随机分为PBS对照组和H6101给药组,每组3只,给药后1h分离骨髓细胞提取总RNA,经反转录和荧光标记后与小鼠基因表达谱芯片杂交,杂交信号经扫描仪捕获后用Genenomestudio软件进行统计分析。结果：在测定的26766个基因中,给药组与对照组之间的2倍差异表达基因为1738个,其中1041个基因表达上调,697个基因表达下调;TLR信号通路相关基因,炎性细胞因子、造血因子和细胞凋亡相关基因等的转录水平发生明显变化。结论：用基因表达谱芯片筛选出许多不同种类的与H6101辐射防护作用有关的重要基因,这为揭示脂肽分子辐射防护机制提供了研究方向。     

香菇C91-3菌LP1蛋白在小鼠体内的 抗肿瘤免疫作用

目的通过观察注射C91-3菌LP1蛋白对H22荷瘤小鼠的影响,探讨LP1蛋白在小鼠体内的抗肿瘤免疫作用。方法使用鼠肝癌H22细胞接种于BALB/C小鼠右腋下,建立小鼠H22实体瘤模型。取上述建立成功的H22实体瘤模型小鼠64只,体重20~25g;分为A、B两组,每组32只。A组再分为LP1实验Ⅰ组(300μg/只)、LP1实验Ⅱ组(100μg/只)、PBS对照组和顺铂对照组(4 mg/kg),每组8只,各组隔日给药1次,共给药5次。A组用于检测LP1蛋白作用后在小鼠体内对H22肿瘤的抑瘤作用、血清中IL-2含量以及脾中NK细胞活性等生理指标。B组按同样的方法分组,隔日给药1次,直至荷瘤小鼠死亡,记录各组小鼠的生存期,计算生命延长率。结果 LP1蛋白可以延长H22荷瘤小鼠的生存期,LP1实验组生存期达16.6d,较PBS对照组13.2d有明显提高。LP1蛋白在体内对H22实体瘤具有一定的抑制作用,对H22实体瘤进行病理切片、HE染色观察后发现,LP1实验组中H22肿瘤组织较PBS对照组肿瘤组织内出现炎性细胞浸润,局部可见坏死现象。使用ELISA法和LDH法分别检测H22荷瘤小鼠血清中IL-2含量以及NK细胞活性,发现LP1实验组IL-2水平和NK细胞活性较PBS对照组和顺铂对照组显著提高。结论 LP1蛋白可延长H22荷瘤小鼠的生存期限,提高小鼠的生存质量,具有一定的肿瘤抑制作用。其抑制作用主要是由增强H22荷瘤小鼠自身免疫力,提高NK细胞活性,发挥机体自身肿瘤免疫功能造成的。     

葛根素对U14宫颈癌小鼠血液流变学、脾淋巴细胞增殖及细胞毒性影响

摘要 目的：研究葛根素治疗对U14宫颈癌小鼠血液流变学、脾淋巴细胞增殖活性及对宫颈癌细胞毒性的影响。方法：45只雌性昆明小鼠随机分为对照组、模型组和葛根素组。模型组和葛根素组小鼠通过腋下注射U14小鼠宫颈癌细胞建立U14宫颈癌移植瘤小鼠,并且葛根素小鼠通过葛根素灌胃进行治疗,对照组和模型组小鼠给予等量生理盐水。比较各组小鼠血流变学、脾淋巴细胞增殖活性及对宫颈癌细胞毒性。结果：经葛根素治疗的葛根素组宫颈癌小鼠肿瘤重量显著低于模型组小鼠（P<0.05）,葛根素治疗宫颈癌小鼠的抑瘤率是（42.91±12.91）%。宫颈癌小鼠低切/高切全血粘度、血浆粘度值以及血细胞比容均显著升高（P<0.05）,而葛根素治疗可显著降低宫颈癌小鼠低切/高切全血粘度、血浆粘度值以及血细胞比容（P<0.05）。宫颈癌小鼠脾脏重量、脾脏指数和脾淋巴细胞体外增殖能力均显著下降（P<0.05）,而葛根素治疗可显著提高宫颈癌小鼠脾脏重量、脾脏指数和脾淋巴细胞体外增殖能力（P<0.05）。此外,经葛根素治疗的宫颈癌小鼠脾淋巴细胞对U14宫颈癌细胞细胞毒性显著高于模型组宫颈癌小鼠（P<0.05）。结论：葛根素治疗可降低U14宫颈癌小鼠血液粘度、改善血流变性质,并且可以提高脾淋巴细胞的增殖活性和对宫颈癌细胞的杀伤力。     

pH-Sensitive Liposomes

Abstract

pH sensitive liposomes are lipid compositions that can be destabilized when the external pH is changed; usually from a neutral or slightly alkaline pH to an acidic pH. They are designed to circumvent delivery of liposome contents to the lysosomes of cells following internalization of the vesicle via the endocytic pathway. In the majority of compositions, a lipid containing a pH titratable group is mixed with phosphatidylethanolamine containing unsaturated acyl chains in a molar ratio (pH sensitive component/PE) of 1/4 or greater. There are five major groups of phosphatidylethanolamine containing pH-senstive lipid compositions. These can be classified by their acid-titratable component: phospholipids, acylated amino acids, fatty acids, cholesterol derivatives and miscellaneous double chain amphiphiles. The biophysical mechanism of action involves a transition of the lipids from the lamellar phase to the hexagonal phase. In cell culture, pH sensitive vesicles can increase the delivery of fluorescent markers, proteins, cytotoxic compounds, RNA and DNA into the cytoplasm. The mechanism of delivery is suggested to involve the destabilization of the liposome in the endosome as the pH is reduced from 7.4 to 5.0 and subsequent destabilization of, or fusion with, the endosomal membrane; some of the liposome contents are introduced into the cytoplasm. In most cases, the extent of liposome contents delivery into the cytoplasm is less than 1% of the amount that becomes cell associated. However further studies, with more reliable assays to differentiate cytoplasmic from lysosomal delivery, are required to place an exact value on this efficiency. The efficiency of pH sensitive liposomes in vivo is limited by stability of certain of the liposome compositions in serum and targeting to the appropriate cell. Cholesterol hemisuccinate is a particularly attractive component for in vivo use since it stabilizes the liposome when in serum at pH 7.4. The use of pH sensitive liposomes in drug delivery should continue to expand due to the increasing number of macromolecular therapeutic agents with intracellular targets.     

A method to determine the incorporation capacity of camptothecin in liposomes

The purpose of this study was to establish a new experimental approach to determine the maximum amount of campothecin (CPT) that can be incorporated in liposomes, and to use this method to compare the CPT-incorporation capacity of various liposome formulations. Small, CPT-saturated liposomes were prepared by dispersing freeze-dried blends of lipids and drug in phosphate buffer, and subsequent probe-sonication. Excess precipitated CPT could be separated from the liposomes by ultra-centrifugation. The small and homogeneous liposome size obtained gave a good and reproducible recovery of liposomes in the supernatant (>80%), whereas the acidic pH (pH 6.0) kept CPT in its hydrophobic lactone form, which is poorly soluble in the buffer. The maximum CPT-incorporation capacity of 12 different liposome formulations was investigated, using the described method, and was found to vary widely. With liposomes made of neutral and anionic phospholipids, the solubili ty of CPT in the buffer was improved by approximately a factor of 10 (from ∼2.7 to 15–50 μg/mL) as compared with buffer. With cationic liposomes containing 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), a maximum CPT-solubilization of ∼100-fold, the buffer solubility was reached, probably owing to an electrostatic interaction between the cationic lipids and the carboxylate-CPT isomer. Increasing DOTAP fractions within egg-phosphatidylcholine (EPC)/DOTAP liposomes reached a CPT-incorporation plateau at ∼20 mol% DOTAP. The presented approach appears suitable to study the incorporation capacity of any drug component within small vesicles as long as the liposome incorporation is high relative to the intrisic water solubility of the drug.     

Structure Relationship of Cationic Lipids on Gene Transfection Mediated by Cationic Liposomes

The aim of this study was to investigate the transfection efficiency of cationic liposomes formulated with phosphatidylcholine (PC) and novel synthesized diethanolamine-based cationic lipids at a molar ratio of 5:1 in comparison with Lipofectamine™ 2000. Factors affecting transfection efficiency and cell viability, including the chemical structure of the cationic lipids, such as different amine head group (diamine and polyamine; and non-spermine and spermine) and acyl chain lengths (C14, C16, and C18) and the weight ratio of liposomes to DNA were evaluated on a human cervical carcinoma cell line (HeLa cells) using the pDNA encoding green fluorescent protein (pEGFP-C2). Characterizations of these lipoplexes in terms of size and charge measurement and agarose gel electrophoresis were performed. The results from this study revealed that almost no transfection was observed in the liposome formulations composed of cationic lipids with a non-spermine head group. In addition, the transfection efficiency of these cationic liposomes was in the following order: spermine-C14 > spermine-C16 > spermine-C18. The highest transfection efficiency was observed in the formulation of spermine-C14 liposomes at a weight ratio of 25; furthermore, this formulation was safe for use in vitro. In conclusion, cationic liposomes containing spermine head groups demonstrated promising potential as gene carriers.Key words: cationic lipids, cationic liposomes, gene transfection     

The role of liposome charge on immune response generated in BALB/c mice immunized with recombinant major surface glycoprotein of Leishmania (rgp63)

Liposomes as a lipid-based system have been shown to be an effective adjuvant formulation. In this study, the role of liposome charge in induction of a Th1 type of immune response and protection against leishmaniasis in BALB/c mice was studied. Liposomes containing rgp63 were prepared by Dehydration-Rehydration Vesicle (DRV) method. Neutral liposomes consisted of dipalmitoylphosphatidylcholine and cholesterol. Positively and negatively charged liposomes were prepared by adding dimethyldioctadecylammonium bromide (DDAB) or dicetyl phosphate (DCP) to the neutral liposome formulation, respectively. Female BALB/c mice were immunized subcutaneously with negatively, positively charged or neutral liposomes encapsulated with rgp63, rgp63 in soluble form or PBS, three times in 3 week intervals. The extent of protection and type of immune response generated were studied in different groups of mice. The group of mice immunized with rgp63 encapsulated in neutral liposomes showed a significantly (P < 0.01) smaller footpad swelling upon challenge with Leishmania major compared with positively or negatively charged liposomes. The mice immunized with neutral liposomes also showed a significantly (P < 0.01) the lowest splenic parasite burden, the highest IgG2a/IgG1 ratio and IFN-γ production and the lowest IL-4 level compared to the other groups. The results indicated that a Th1 type of immune response was induced in mice immunized with neutral liposomes more efficiently than positively charged liposomes and conversely negatively charged liposomes induced a Th2 type of immune response.     

Liposomes alter thermal phase behavior and composition of red blood cell membranes

Unilamellar liposomes composed of natural phospholipids provide a new promising class of protective agents for hypothermic storage, cryopreservation, or freeze-drying of red blood cells (RBCs). In this study, FTIR spectroscopy, MALDI-TOF MS, and colorimetric assays were used to investigate the effects of liposomes composed of a homologous series of linear saturated phosphatidylcholine phospholipids (18:0; 16:0; 14:0; 12:0) on RBC membranes. RBCs were incubated with liposomes at 37°C and both the liposomal and the RBC fraction were analyzed after incubation. FTIR studies showed that liposomes composed of short acyl chain length lipids cause an increase in RBC membrane conformational disorder at suprazero temperatures, whereas long acyl chain length lipids were found to have little effects. The increased lipid conformational disorder in the RBC membranes coincided with a decrease in the cholesterol-to-phospholipid ratio. The opposite effects were found in the liposomes after incubation with RBCs. MALDI-TOF MS analysis showed the presence of short acyl chain length lipids (14:0 and 12:0) in RBC membranes after incubation, which was not observed after incubation with liposomes containing long acyl chain length lipids (18:0 and 16:0). Liposomes alter RBC membrane properties by cholesterol depletion and lipid addition.     

Serum-induced leakage of liposome contents

Efflux of contents from small unilamellar vesicles of various compositions, containing a highly quenched fluorescent compound (calcein, 175 mM) was determined as a function of temperature in the presence and absence of human serum. Efflux of calcein from the liposomes was monitored as an increase in fluorescence as calcein became dequenched upon release from the liposomes. The presence of serum significantly increased liposome leakage in all cases. Incorporation of increasing molar ratios of cholesterol into liposomes reduced leakage of calcein from liposomes incubated with buffer and with serum. Leakage was significantly faster from liposomes with an osmotic gradient across the membrane (higher inside) than from equiosmolar liposomes. The leakage of [¹⁴C]sucrose from egg lecithin liposomes at 37°C was also dramatically increased in the presence of serum.     

Lipid Dependent Cardio- Haemodynamic Tolerability of Liposomes in Rats

Abstract

Rationale and Objectives:

The use of contrast-carrying liposomes in diagnostic applications (1) or of haemoglobin liposomes in blood replacement therapy (2) requires infusion of large lipid doses. Saturated lipids like HSPC are often used in these formulations to render the liposomes more stable (3). Previous studies have indicated that intravenous injection of such liposome preparations can result in significant haemodynamic changes in rats (14). The purpose of this study was to systematically evaluate cardio- and haemodynamic effects of liposomes prepared from saturated and unsaturated phosphatidylcholine alone or in combination with other lipid components.

Methods;

Liposomes made from SPC, HSPC, DSPC, DSPC/CH, DSPC/DSPG, DSPC/CH/DSPG were infused in anaesthetized rats (total lipid dose: 300 mg lipid/kg BW) and cardio-heamodynamic parameters were measured.

Results:

DSPC-liposomes significantly reduced blood pressure (BP) and total peripheral resistance (TPR) by -53.7 % and -45.7 % of prevalue, respectively. Similar results were obtained for HSPC-liposomes. Marked ECG-changes were recorded for both formulations. SPC-liposomes caused a transient and moderate reduction of BP and TPR (-17.0 % and -22.3 %, respectively). Short-lasting ECG changes were also observed. The addition of cholesterol or DSPG to DSPC liposomes reduced cardiac and haemodynamic side effects in rats.

Conclusion;

The lipid composition of liposomes is of major importance for the incidence of cardiovascular side effects in rats. Liposomes composed of pure saturated phosphatidylcholine cause significant changes which can be diminished by the addition of other lipid components like cholesterol.     

Physicochemical and Safety Evaluation of 5-Aminolevulinic Acid in Novel Liposomes as Carrier for Skin Delivery

In this study we successfully entrapped 5-aminolevulinic acid (ALA) in liposome, although it exists as a zwitter ion. A molar ratio of 2:1:2.5 phosphatidyle-thanolamine (PE)/cholesterol/sodium stearate represented the best condition to achieve high entrapment efficiency (29.37 ± 1.21%), and the average vehicle size was 133.6 ± 2.8 nm. After 32 days of storage, the vehicle sizes of formulations with PE series were still approximately less than 200 nm. The safety of liposomes was tested and ensured both with regard to cellular cytotoxicity and erythrocyte hemolysis. Safety studies showed that liposome formulations did not affect cell viability except when both potassium stearate and sodium oleate were added. Moreover, PE and PE/cholesterol did not damage human erythrocytes in this study. The range of the hemolytic effect caused by liposomes was 5 to 37% and the effect was dependent on the amount of sodium stearate added to the formulation. According to the release rates and skin penetration of ALA liposomes in vitro, PE/cholesterol/sodium stearate liposomes might increase skin penetration, and it was shown that penetration across the stratum–corneum (sc) layer was the rate-limiting process. Images from confocal laser scanning microscopy (CLSM) confirmed the great potency of liposomes for delivering ALA into skin.     

Comments

Abstract

Animal Models

Upon reading the forum papers we note that “stealth” properties of liposomes apparently still have not been examined extensively in any animal model other than relatively young rodents (mainly mice). The “stealth” concept would be enhanced by studies in species other than mice. If opsonic properties of blood proteins, particularly the presence of naturally-occurring antibodies to phospholipids and cholesterol and resultant complement activation, have any relevance to the removal of liposomes from mouse blood, then it is possible that different liposomes will exhibit “stealth” properties under other circumstances (such as in older mice that often have high titers of antibodies to lipids) or in other animal species. In view of the presumed interest in the commercial exploitation of “stealth” technology it would seem useful to have validating experiments performed in other species, such as dogs, pigs, sheep, and especially in primates.     

Encapsulation of enrofloxacin in liposomes I: preparation and in vitro characterization of LUV

Liposomes are effectively used in the treatment of microbial infections. Higher cellular uptake has been reported when antibiotics are encapsulated in liposomes. In this study, enrofloxacin (ENF) was encapsulated in large unilamellar vesicles (LUVs) and the effects of formulation variables on the liposome characteristics were investigated. Liposomes were prepared using dry lipid film method. A number of variables such as molar ratios of phospholipid (DPPC; DL-alpha-phosphatidylcholine dipalmitoyl), cholesterol, ENF and amount of alpha-tocopherol and the volumes of internal (chloroform) and external phases [phosphate buffered saline PBS (pH 7.4)] were studied. In vitro characterization of the liposomes including the encapsulation capacity, size and drug release properties were carried out. Using of this method, spherical LUV liposomes with high drug content could be produced. Particle size of liposomes changed between 3.12 and 4.95 microm. The molar ratios of DPPC, cholesterol and ENF affected the size of the liposome (p < 0.05). The drug encapsulation capacities were high and changed between 37.1% and 79.5%. The highest ENF encapsulation was obtained with the highest cholesterol content. An increase in the drug encapsulation capacity of the liposome was found with increasing molar ratios of DPPC, cholesterol and ENF (p < 0.05). Furthermore, the release of ENF from the liposomes decreased as the molar ratios of DPPC, cholesterol and ENF increased (p < 0.05). In conclusion, a convenient colloidal carrier for the controlled release of ENF can be prepared by changing the formulation parameters of LUVs.