药用水基磁流体的一步法制备及其细胞相容性研究

目的制备药用水基磁流体并评价其细胞相容性。方法利用微乳液制备技术,以一步表面活性剂处理法制备药用水基磁流体,并使用透射电镜和光子相关光谱仪研究其形态和粒径分布;分别采用四甲基偶氮唑盐比色试验、乳酸脱氢酶释放试验测定不同浓度药用水基磁流体对正常人肝细胞株(L-02)的体外细胞相容性;运用红外光谱法、热重法、差示热重法、差示扫描量热法对所制备的单层与双层正癸酸包覆的磁流体固态样品进行表征。结果药用水基磁流体粒径在10nm~20nm之间;其放置1y未见发生相分离及明显的数均粒径变化;其对L-02细胞不具有毒性,细胞相容性好。结论药用水基磁流体可用于磁性靶向给药系统。     

RGD靶向超声造影剂对大鼠2期压力性损伤创面的靶向性研究

目的 检测大鼠2期压力性损伤模型中整合素αvβ3的表达情况,制备精氨酸-甘氨酸-天冬氨酸（RGD）靶 向超声造影剂,观察其对大鼠2期压力性损伤模型的靶向性。方法 将36只大鼠随机分为实验组、对照组,每组18 只。实验组采用皮肤桥法建立2期压力性损伤模型,对照组不做处理。成模后HE染色观察2组大鼠皮肤组织病理 变化,免疫组化染色检测整合素αvβ3的表达情况。然后实验组大鼠分别使用自制的RGD靶向超声造影剂和空白造 影剂评估对创面的靶向效果。结果 实验组皮肤HE染色显示损伤达真皮层,对照组未见损伤。实验组新生的毛细 血管内皮细胞和表皮细胞内整合素αvβ3表达呈阳性,对照组呈阴性。实验组大鼠注射RGD靶向超声造影剂后与空 白造影剂相比靶向黏附值明显增高（P＜0.01）。结论 整合素αvβ3在大鼠2期压力性损伤中呈阳性表达,将其作为 靶向位点制备RGD靶向超声造影剂对2期压力性损伤具有良好的靶向性。     

正交试验优选水基磁流体制备工艺

目的:优选水基磁流体制备工艺。方法:采用正交试验,考察NaOH浓度、反应温度、反应时间及分散剂与铁含量重量比4种因素对水基磁流体制备的影响,并通过测定灭菌前、后磁流体的粒径分布来考察其稳定性。结果:以磁流体的粒度和稳定性为考察指标,优选出最佳制备工艺为NaOH浓度2mol/L、反应温度60℃、反应时间30min、分散剂与铁含量重量比5∶1;灭菌前、后粒径和磁性均无显著性差异(P>0.05)。结论:用优选工艺制备的磁流体粒径分布均匀,稳定性好,磁性强。     

RGD肽修饰的异长春花碱-粉防己碱脂质体的制备及体外抑瘤作用研究

目的:制备RGD肽修饰的异长春花碱(VRB)-粉防己碱(TET)脂质体,研究其对脑胶质瘤C6细胞的抑制作用。方法:采用薄膜分散法和硫酸铵梯度法制备RGD肽修饰的VRB-TET脂质体,观察其形态和粒径分布,测定其中VRB的含量;以磺酰罗丹明B法分别测定空白靶向脂质体、VRB普通脂质体和RGD肽修饰的VRB-TET脂质体对C6细胞的抑制作用。结果:所制RGD肽修饰的VRB-TET脂质体呈圆球状或类圆球状,表面光滑,粒径为120 nm左右,其中VRB的平均含量为28.27μg/m L(RSD=0.38%,n=3)。空白靶向脂质体对C6细胞生长无显著影响;RGD肽修饰的VRB-TET脂质体能明显抑制C6细胞生长,其作用后细胞存活率明显低于VRB普通脂质体(P<0.05)。结论:成功制得RGD肽修饰的VRB-TET脂质体,其具有明显的抑制C6细胞生长的作用。     

RGD肽介导的脑胶质瘤靶向治疗和显像的研究进展

RGD肽是含有精氨酸-甘氨酸-门冬氨酸(Arg-Gly-Asp)序列的一类短肽,能和细胞表面的整合素受体特异性结合.整合素受体,尤其是αvβ3高表达于脑胶质瘤等肿瘤细胞表面,而在成熟血管内皮细胞呈低表达.因此,在脑胶质瘤的靶向治疗和显像研究中外源性RGD肽与肿瘤细胞表面的整合素受体的竞争性结合得到广泛研究.本文综述了RGD肽介导的脑胶质瘤靶向治疗及显像的典型方法及近年来的研究进展.     

RGD多肽结合型长循环脂质体的肿瘤靶向性研究

目的 :研究RGD(精氨酸、甘氨酸、天门冬氨酸 )多肽结合型长循环脂质体的肿瘤靶向性。方法 :将长循环脂质体 ,通过共价键反应与RGD基元多肽进行结合 ,然后研究其在荷瘤小白鼠体内的肿瘤靶向性。结果 :RGD结合型长循环脂质体在Colon26荷瘤小白鼠体内具有较好的肿瘤靶向性。结论 :含RGD基元多肽结合型长循环脂质体可能成为一种新型的受体介导靶向制剂     

RGD修饰载紫杉醇脂质体用于抗脑胶质瘤的体外研究

目的制备RGD修饰载紫杉醇脂质体并考察其体外抗脑胶质瘤治疗效果。方法采用薄膜分散法制备RGD修饰载紫杉醇脂质体（RGD—LP-PTX）,考察其理化性质。用鼠源性脑胶质瘤c6细胞考察肿瘤细胞对脂质体的摄取效率。MTT实验考察脂质体对肿瘤细胞的增殖抑制率。结果制备得到的RGD—LP粒径在120nm左右,PD,〈0.3。C6细胞对RGD．LP的摄取能力显著〉LP;RGD-LP-PTX对C6细胞的生长的抑制作用显著强于LP。结论经过RGD修饰后,脂质体具有良好的脑胶质瘤细胞靶向性,且能够显著增强栽药脂质体对脑胶质瘤细胞的增殖抑制作用。     

RGD结合型阿克拉霉素A脂质体的抑瘤作用

目的：观察RGD多肽结合型阿克拉霉素A长循环脂质体（RGD—ACM—A—liposome）对动物实验肿瘤的抑制作用。方法：以逆相蒸发法制备ACM—A长循环脂质体,并通过反应与RGD基元多肽进行共价键结合．然后静脉注射于荷瘤小鼠体内,之后处死动物,解剖肿瘤,计算并比较抑瘤率及生命延长率。结果：RGD多肽结合型阿克拉霉素A长循环脂质体对小鼠S180和EAC腹水癌具有较好的抑制作用。结论：RGD多肽结合型阿克拉霉素A长循环脂质体可能通过导致血管凋亡以及局部释放抗癌药杀灭癌细胞,对新生肿瘤具有抑制与治疗作用。     

含RGD修饰的丹参酮ⅡA多级靶向纳米粒的质量评价

目的探讨丹参酮ⅡA多级靶向纳米粒的制备及其质量评价。方法采用乳化溶剂蒸发法制备丹参酮ⅡA多级纳米粒;测定丹参酮ⅡA多级靶向纳米粒的粒径分布及纳米微粒表面结构;并检测丹参酮ⅡA多级靶向纳米粒的载药量、包封率及体外药物释放规律。结果课题组制备的丹参酮ⅡA多级靶向纳米粒,大小均匀,载药纳米粒的平均粒径为190nm,Zeta电位为4.3mV,包封率(94.12±5.20)%,载药量(2.05±0.12)%。与游离的丹参酮ⅡA单体相比,丹参酮ⅡA多级靶向纳米粒释放速度明显减慢,在120h累积释放量为72.59%。结论采用乳化溶剂蒸发法成功制备了含RGD修饰的丹参酮ⅡA多级靶向纳米粒。与丹参酮ⅡA单体相比,制备成纳米制剂后,多级靶向载药纳米粒能随着时间的延长将药物逐步释放出来,具有良好的缓释特征。     

肿瘤热疗用磁流体的制备和表征

目的制备和表征肿瘤热疗用磁流体。方法在聚乙二醇6000（PEG-6000）的存在下用化学共沉淀法制备肿瘤热疗用四氧化三铁（Fe3O4）磁流体,用邻二氮菲显色法测定磁流体中铁的含量,通过电子显微镜、X衍射、红外和振动样品磁强计对制备的磁流体进行表征。测定了磁流体在交变磁场作用下的热效应,并将该磁流体用于VX2兔肿瘤的热疗。结果红外图谱和X衍射图谱证明所制备的磁流体样品为Fe3O4;电镜照片显示磁性粒子近乎圆形且分散良好;经X衍射数据计算得磁性粒子的粒径为13.3±3.8nm;样品的饱和磁化强度和剩余磁化强度分别为23.39A/m（1.556emu/g）和0.56A/m（0.02604emu/g）,矫顽力为12Oe;磁流体的特征吸收率为69±10W/g[Fe]。将该磁流体直接注射于VX2兔肝肿瘤部位后,置于交变磁场中进行热疗,测得肿瘤部位温度可达到41-46℃。结论在PEG-6000存在下所制备的Fe3O4磁流体有望用于肿瘤热疗。     

Preparation of novel double liposomes using the glass-filter method

The glass-filter method, a newly developed preparative method for liposomes, was applied for preparation of novel double liposomes. Double liposomes were prepared by filtering a suspension of liposomes prepared using a G4 filter (pore size: 10-16 microm) into a G3 filter (pore size: 40-100 microm) coated with a similar lipid layer. The morphological structure of the double liposomes was confirmed using scanning electron microscopy by the freeze-fracture method to be multivesicular vesicles consisting of small liposomes enveloped in larger liposomes. The diameter of liposomes prepared using the G4 filter was 0.8-2 microm and that of liposomes prepared using the G3 filter or double liposomes was 5-10 microm. These results suggested that the particle size of liposomes is dependent on the pore size of the glass-filter. The encapsulation efficiencies of double liposomes for brilliant blue FCF (BB) and erythrosine (ER) were higher than those of liposomes prepared by the standard Bangham method. Double liposomes showed suppressed release of BB or ER compared with normal liposomes. In particular, no release of BB was observed from the double liposomes prepared with stearylamine. These findings implied that the outer lipid layer protects the inner liposomes. The glass-filter method is the only method that we can get the double liposomes in a short period, and double liposomes prepared by this novel method had adequate size and good stability in vitro.     

Improved oral bioavailability of alendronate via the mucoadhesive liposomal delivery system

This study aimed to design the chitosan coated liposomes of alendronate and optimize their in vitro/in vivo characteristics to improve the bioavailability as well as potentially to reduce the mucosal irritation of alendronate. Liposomes of alendronate were prepared with DSPC/DSPG by using thin layer film hydration method and then the surface of anionic liposomes was coated by chitosan. In vitro characteristics of liposomes (e.g., stability in various biological media, mucoadhesiveness and cellular uptake profiles) were evaluated along with the pharmacokinetic studies in rats. Lipid vesicles of 200 nm size were obtained with narrow size distribution (PI<0.1) and subsequently coated with chitosan. Chitosan coated liposomes were stable for 24 h without either size change or drug leakage in various biological fluids including simulated gastric fluids and intestinal fluids. Furthermore, it exhibited strong mucoadhesive properties. Compared to the untreated drug (non-liposome), the chitosan coated liposomes indicated significantly (p<0.05) increased cellular uptake of alendronate in Caco-2 cells and also 2.6-fold enhancement in oral bioavailability of alendronate in rats. Taken all together, the mucoadhesive liposomes for the oral delivery of alendronate was prepared by using DSPC and DSPG with narrow size distribution and appeared to be effective to enhance the bioavailability of alendronate in rats.     

Hepatitis B surface protein docked vesicular carrier for site specific delivery to liver

The intrinsic liver tropism of liposomes can be augmented by the addition of targeting features such as the incorporation of hepatotropic elements of the hepatitis viruses. Hepatitis B virus is known to infect hepatocytes after viremia by asialoglycoprotein receptor mediated uptake. However, the specificity of hepatitis B virus surface protein (HBsAg) towards hepatocytes has confronting reports. In the present study, we evaluated the functional ability of HBsAg to be employed as a ligand for targeting hepatocytes. We prepared (14)C labeled small unilamellar vesicles (SUVs) composed of egg PC/Cholesterol/N-glutarylphosphatidylethanolamine (NGPE) in a 60:30:10 molar ratio. HBsAg was covalently linked to SUVs using a water-soluble carbodiimide (EDC) mediated conjugation with NGPE. In vitro cell binding and uptake studies revealed that bioprotein docked carrier system was efficiently taken up by HepG2 cells by the receptor mediated endocytosis. The biodistribution behaviour of plain and HBsAg coated liposomes was also examined followed by intravenous injection. The study revealed that almost 75% of the radioactivity was recovered in the liver after 4 h of injection that was nearly three-fold greater in magnitude than the plain liposomes. Further, fractionation of liver into liver parenchymal cells (PC) and non-parenchymal cells confirmed the preferential localization of the HBsAg coated liposomal carrier in the parenchymal cells.     

前列腺癌新型靶向纳米超声造影剂的合成及初步评价

目的：研究制备一种前列腺癌新型靶向性纳米超声造影剂。方法：采用PEG及抗前列腺癌特异性膜抗原（PSMA）适体A10-3.2修饰多壁碳纳米管（MWCNTs）合成新型靶向纳米超声造影剂,对其进行合成验证、体外特征评价、生物相容性研究及体外显影评价。结果：Zeta电位、透射电镜扫描图（TEM）、红外分析图（FT-IR）均表明此靶向纳米造影剂合成成功。体外细胞学研究表明,该造影剂细胞毒性小、生物相容性好。体外显影结果表明,该造影剂具有良好的显影效果。结论：该新型造影剂制备成功,具备靶向显影的潜能。     

Formulation of acyclovir-loaded solid lipid nanoparticles: 2. Brain targeting and pharmacokinetic study

Acyclovir (ACV) is widely used in the treatment of herpes encephalitis. The present study was conducted to prepare chitosan-tween 80 coated solid lipid nanoparticles (SLNs) as a delivery system for brain targeting of ACV in rabbits. The SLNs were prepared and coated in one step by microemulsion method using a coating solution containing chitosan (0.1% w/v) and tween 80 (2% w/v) for loading sustained release ACV. In vitro characterization was performed for coated ACV-SLNs. Concerning in vivo experiments; a single intravenous bolus dose of coated ACV-SLNs was given versus free ACV solution to rabbits (62?mg/kg). Plasma pharmacokinetic parameters were calculated from the ACV concentration-time profiles in plasma using the two compartmental analysis. The values of AUC_0?∞ and MRT of coated ACV-SLNs were higher than free drug by about twofold, 233.36?±?41.56?μg.h/mL and 1.81?±?0.36?h, respectively. The noncompartmental analysis was conducted to estimate the brain pharmacokinetic parameters. The AUC_0?∞ brain/AUC_0?∞ plasma ratio for coated ACV-SLNs and free ACV was 0.22 and 0.12, respectively. These results indicated the effectiveness of using coated ACV-SLNs for brain targeting.     

Novel method of doxorubicin-SPION reversible association for magnetic drug targeting

A new method of reversible association of doxorubicin (DOX) to superparamagnetic iron oxide nanoparticles (SPION) is developed for magnetically targeted chemotherapy. The efficacy of this approach is evaluated in terms of drug loading, delivery kinetics and cytotoxicity in vitro. Aqueous suspensions of SPION (ferrofluids) were prepared by coprecipitation of ferric and ferrous chlorides in alkaline medium followed by surface oxidation by ferric nitrate and surface treatment with citrate ions. The ferrofluids were loaded with DOX using a pre-formed DOX-Fe(2+) complex. The resulting drug loading was as high as 14% (w/w). This value exceeds the maximal loading known from literature up today. The release of DOX from the nanoparticles is strongly pH-dependent: at pH 7.4 the amount of drug released attains a plateau of approximately 85% after 1h, whereas at pH 4.0 the release is almost immediate. At both pH, the released drug is iron-free. The in vitro cytotoxicity of the DOX-loaded SPION on the MCF-7 breast cancer cell line is similar to that of DOX in solution or even higher, at low-drug concentrations. The present study demonstrates the potential of the novel method of pH-sensitive DOX-SPION association to design novel magnetic nanovectors for chemotherapy.     

挤出-滚圆和流化床包衣法制备硫普罗宁肠溶微丸的研究

目的应用挤出 滚圆法及流化床包衣制备硫普罗宁肠溶微丸，并对其性质进行考察。方法采用国产挤出 滚圆造粒机制备硫普罗宁微丸，采用L9(34)正交设计实验优化工艺条件；用微型流化床包衣设备，将微丸包肠溶衣，考察微丸的粉体学性质及不同包衣增重微丸的体外释放实验。结果制得的硫普罗宁微丸圆整度好，大小均匀。15%包衣增重的微丸体外释放比较理想。结论应用国产挤出 滚圆造粒机制备硫普罗宁微丸，工艺简便，制得的微丸质量好，采用适当的包衣工艺，可制得硫普罗宁肠溶微丸。     

Tricalcium phosphate delayed release formulation for oral delivery of insulin: a proof-of-concept study

Several attempts have been made for delivering insulin orally utilizing several polymers with varying degrees of effectiveness. A major obstacle associated with polymeric delivery system for protein or polypeptide drugs is the poor retention of the structure and its biological activity of encapsulated proteins particularly for the unstable insulin. Calcium phosphate ceramic is considered highly compatible to protein or peptide drugs, particularly insulin. Therefore, an attempt has been made to load insulin in tricalcium phosphate (TCP) microspheres and coat with pH sensitive polymer of methacrylate derivative, and to study the stability and conformational variations of loaded insulin, and finally the biological activity of the formulation in diabetic rats. TCP microspheres were prepared by a standard procedure. Human insulin was loaded in to these porous microspheres by diffusion filling and coated with Eudragit S100. This was subjected to in vitro release studies in simulated fluids and the stability and conformational variations of the released insulin were studied using photon correlation spectroscopy and circular dichroism (CD). Biological activity of the formulation was studied on induced diabetic rats. Insulin released in the intestinal fluid (SIF) maintained the native conformation without showing any aggregation. A dose dependent reduction of blood glucose level (BGL) was achieved in streptozotocin induced diabetic Wistar rats, demonstrating its biological activity. It has been established from this preliminary study that insulin loaded in to TCP microspheres is highly compatible with no degradation or loss of biological activity of loaded insulin. The TCP microsphere based delayed release formulation of insulin has effected a decrease in elevated glucose level in induced diabetic rats, establishing its feasibility towards the development of a noninvasive delivery device.     

Mannosylated liposomes for bio-film targeting

Vesicular systems in general are investigated to achieve bacterial bio-film targeting as their architecture mimics bio-membranes in terms of structure and bio-behavior. This paper elaborates upon the role of the inherent characteristics of the carrier system and further envisages the role of anchored ligands in navigating the contents in the vicinity of bio-films. Vesicles in the present study were coated with hydrophobic derivatives of mannan (cholesteryl mannan and sialo-mannan). The prepared vesicles were characterized for size, shape, percentage entrapment and ligand binding specificity and results were compared with the uncoated versions. Using a set of in vitro and in vivo models, the bio-film targeting potential of plain and mannosylated liposomal formulations were compared. Results suggested that mannosylated vesicles could be effectively targeted to the model bacterial bio-films, compared with plain vesicles. Moreover, the sialo-mannan coated liposomes recorded superior targetability as reflected in the significantly higher percentage growth inhibition when compared with cholesteryl mannan coated liposomes. The engineered systems thus have the potential use for the delivery of anti-microbial agents to the bio-films.