尼莫地平鼻用冻干脂质体的小鼠药效学及纤毛毒性

采用小鼠模型，验证尼莫地平脂质体鼻黏膜给药的药效学。结果表明，对小鼠抗脑缺氧、抗急性脑缺血及抗急性脑栓塞形成等均有显著的保护作用，其药效与腹腔注射尼莫地平溶液接近，显著优于灌胃给药。另采用蟾蜍上颚纤毛模型，考察了空白脂质体及含药脂质体的纤毛毒性，结果表明尼莫地平脂质体对纤毛运动和形态有一定影响。     

石杉碱甲的大鼠鼻黏膜吸收研究

目的研究治疗早老性痴呆症药物石杉碱甲的鼻黏膜吸收特性。方法采用石杉碱甲进行大鼠鼻腔灌流实验,测定循环液中药物浓度。结果随着石杉碱甲的浓度增加(0.125～0.75mg/mL),其吸收速度呈线性增加(r=0.995)。在pH值5.5～7.5内,随pH值的升高,其吸收速度增加。结论石杉碱甲的鼻黏膜吸收良好,其吸收程度与药液的浓度和pH值有较好的相关性。     

石杉碱甲的大鼠鼻黏膜吸收研究

目的研究治疗早老性痴呆症药物石杉碱甲的鼻黏膜吸收特性。方法采用石杉碱甲进行大鼠鼻腔灌流实验,测定循环液中药物浓度。结果随着石杉碱甲的浓度增加(0.125~0.75mg/mL),其吸收速度呈线性增加(r=0.995)。在pH值5.5~7.5内,随pH值的升高,其吸收速度增加。结论石杉碱甲的鼻黏膜吸收良好,其吸收程度与药液的浓度和pH值有较好的相关性。     

尼莫地平前体脂质体的制备和大鼠药动学的研究

目的：研究增加尼莫地平在脑中分布的方法。方法：采用薄膜载体沉积法制备尼莫地平前体脂质体，考察其性质，并在大鼠体内进行药动学研究。结果：用该法所得前体脂质体包封率可达95％以上，稳定性好；药动学指标优于尼莫地平注射剂。结论：尼莫地平制成前体脂质体可显著提高药物在脑中的分布。     

尼莫地平大鼠在体肠吸收动力学

目的研究尼莫地平在大鼠各肠段的吸收动力学特征。方法采用大鼠在体肠段灌流实验 ,主要从吸收部位、药物浓度、pH值等 3方面对尼莫地平的肠段吸收特性进行研究。结果尼莫地平在大鼠肠道内无特定吸收部位 ,各肠段吸收速率常数按十二指肠、空肠、结肠、回肠顺序依次下降 ,吸收速率常数分别为 0 0 6 87、0 0 6 2 0、0 0 5 97、0 0 4 89h-1。在 4 8～ 14 3μmol·L-1浓度内药物吸收量与浓度呈线性关系 ;在 pH 5 0～ 7 4内药物吸收不受 pH值影响。 结论尼莫地平在大鼠全肠段均有吸收 ,吸收符合一级动力学特征 ,吸收机制为被动扩散 ,适于制备日服 1次缓释给药系统     

尼莫地平鼻用亚微粒凝胶的制备及质量评价

目的:制备鼻用尼莫地平聚氰基丙烯酸正丁酯(PBCA)亚微粒(Nim-PBCA)凝胶,并对其进行质量评价。方法:正交设计优化Nim-PBCA处方,以胶凝温度筛选凝胶中泊洛沙姆407(P407)的用量,并对其体外释放进行研究。结果:选择尼莫地平的质量为10 mg、PBCA体积分数为0.25、Dextran-70浓度为1.0%,优化所得Nim-PBCA包封率为(90.7±8.2)%,载药量为(14.21±2.64)%;P407用量为18%,所得Nim-PBCA凝胶的胶凝温度为33.7℃,体外具明显缓释特性。结论:所研制的PBCA凝胶可供进一步研究成为尼莫地平鼻腔给药的新载体。     

冻干工艺及保护剂对羟基喜树碱脂质体质量的影响

用薄膜水化-高压均质法制备羟基喜树碱脂质体,以葡聚糖凝胶色谱法分离脂质体和游离药物,采用HPLC法测定包封率。通过差示扫描量热法测定含不同保护剂的脂质体的最低共熔点和玻璃化转变温度,并比较冻干品外观、冻干前后脂质体包封率和粒径的变化,优选出最佳的冻干工艺、冻干保护剂种类及比例。结果表明,以6%蔗糖为冻干保护剂,经4℃、1 h,-18℃、12 h和-35℃、5 h逐步预冻,然后于-54℃冷冻干燥24 h,制得的冻干品外观良好,脂质体复溶后粒径变化小,包封率达(87.0±2.7)%。     

羟基喜树碱长循环脂质体冻干剂的制备及理化性质

以羟基喜树碱（1）为模型药物，大豆磷脂为载体材料，泊洛沙姆F-68为膜表面修饰材料，所制备的1冻干长循环脂质体冻干剂包封率为82．3％，可在30s内分散为均匀的淡黄色胶体溶液。在pH7．4磷酸盐缓冲液和大鼠血浆中24h内无渗漏。用纯水复溶后测得相转变温度为73℃。稳定性初步试验表明所得脂质体基本稳定。     

尼莫地平前体脂质体的制备及其质量评价

目的制备尼莫地平前体脂质体,并进行质量评价,以期得到高效、低毒和稳定的尼莫地平新剂型。方法采用叔丁醇-水共溶剂冻干法制备尼莫地平前体脂质体,考察了影响药物包封率的因素,并对重建脂质体的药物含量、包封率、粒径、Zeta电位、溶血性及稳定性进行考察。结果磷脂浓度、表面电荷是影响尼莫地平脂质体包封率的主要因素。尼莫地平脂质体包封率大于98%,平均粒径为57 nm,Zeta电位小于-20 mV,无溶血性,稳定性好。结论采用叔丁醇水共溶剂冻干法获得了高包封率、粒径均一、无溶血性、稳定的尼莫地平前体脂质体制剂,可用于静脉注射给药。     

尼莫地平脂质体的制备及体外透皮研究

目的:采用2种方法制备尼莫地平脂质体,并考察其包封率与体外透皮性。方法:用薄膜法和乙醇注入法制备尼莫地平脂质体,考察2种方法所制脂质体的粒径分布及包封率;采用Franz扩散装置对脂质体进行体外透皮试验,并与尼莫地平溶液比较。结果:薄膜法和乙醇注入法制备的脂质体平均粒径分别为(768.7±190.6)、(1 742±270)nm,平均包封率均高达97%以上。与尼莫地平溶液比较,脂质体中药物透皮缓慢,其中以薄膜法制备的脂质体在48h以后其单位面积累积透皮量显著更高。结论:2种制备方法中以薄膜法更优。     

氢溴酸高乌甲素鼻用原位凝胶剂的制备及其处方评价

目的：制备氢溴酸高乌甲素（LH）鼻用原位凝胶剂,并进行处方考察以提高其鼻腔给药的镇痛效果。方法：采用在体蟾蜍上腭纤毛法考察不同LH处方对鼻黏膜纤毛的毒性、大鼠在体鼻腔循环实验考察处方中3种吸收促进剂（β-环糊精、吐温-80和冰片）对LH的鼻黏膜吸收的促进作用以及小鼠扭体法实验考察不同LH处方的镇痛药效,从而确定LH鼻用原位凝胶剂的最佳处方工艺。结果：处方中LH和所选用的辅料对鼻黏膜纤毛均无显著毒性;3种吸收促进剂对LH的鼻黏膜吸收速率常数无显著影响（P〉0．05）;在所有受试处方中,结冷胶和β-环糊精联用处方制剂的镇痛效果最佳,其药效与腹腔注射相同剂量的LH注射液无显著差异（P〉0．05）。结论：结冷胶和β-环糊精联用是制备LH鼻用原位凝胶剂的最佳处方组合。     

栀子环烯醚萜苷鼻腔给药的吸收特性

目的研究栀子环烯醚萜苷类成分鼻腔给药的吸收特性,为其鼻腔给药制剂设计提供依据。方法采用Franz扩散池,选用新鲜猪鼻黏膜为渗透屏障,以栀子苷为测定指标,HPLC测定含量,进行渗透试验;采用大鼠鼻腔循环灌流实验,以PBS溶液(pH7.4)作为鼻腔循环液,HPLC测定栀子苷,进行在体鼻黏膜吸收试验。结果栀子苷表观渗透系数Papp为(2.01±0.23)×10 5cm 2.s 1;药物稳态流量Jss为(1.61±0.18)×10 4μg.cm 2.s 1,透黏膜扩散属于以膜两侧浓度差为动力的被动扩散。栀子苷大鼠在体鼻黏膜吸收动力学方程lnC=1.165 7 0.001 6t,r=0.991 4,k=(1.6±0.021)×10 3min 1。结论栀子环烯醚萜苷可经鼻吸收,可制成经鼻给药的新制剂用于脑部疾病的防治。     

Liposomes as delivery systems for nasal vaccination: strategies and outcomes

Importance of the field: Among the particulate systems that have been envisaged in vaccine delivery, liposomes are very attractive. These phospholipid vesicles can indeed deliver a wide range of molecules. They have been shown to enhance considerably the immunogenicity of weak protein antigens or synthetic peptides. Also, they offer a wide range of pharmaceutical options for the design of vaccines. In the past decade, the nasal mucosa has emerged as an effective route for vaccine delivery, together with the opportunity to develop non-invasive approaches in vaccination.

Areas covered in this review: This review focuses on the recent strategies and outcomes that have been developed around the use of liposomes in nasal vaccination.

What the reader will gain: The various formulation parameters, including lipid composition, size, charge and mucoadhesiveness, that have been investigated in the design of liposomal vaccine candidates dedicated to nasal vaccination are outlined. Also, an overview of the immunological and protective responses obtained with the developed formulations is presented.

Take home message: This review illustrates the high potential of liposomes as nasal vaccine delivery systems.     

Preparation and In Vitro Characterization of Mucoadhesive Hydroxypropyl Guar Microspheres Containing Amlodipine Besylate for Nasal Administration

Amlodipine besylate microspheres for intranasal administration were prepared with an aim to avoid first-pass metabolism, to achieve controlled blood level profiles and to improve therapeutic efficacy. Hydroxypropyl Guar, a biodegradable polymer, was used in the preparation of microspheres by employing water in oil emulsification solvent evaporation technique. The formulation variables were drug concentration, emulsifier concentration, temperature, agitation speed and polymer concentration. All the formulations were evaluated for particle size, particle shape and surface morphology by scanning electron microscopy, percentage yield, drug entrapment efficiency, in vitro mucoadhesion test, degree of swelling and in vitro drug diffusion through sheep nasal mucosa. The microspheres obtained were free flowing, spherical and the particles ranged in size from 13.4±2.38 μm to 43.4±1.92 μm very much suitable for nasal delivery. Increasing polymer concentration resulted in increased drug entrapment efficiency and increased particle size. Amlodipine besylate was entrapped into the microspheres with an efficiency of 67.2±1.18 % to 81.8±0.64 %. The prepared microspheres showed good mucoadhesion properties, swellability and sustained the release of the drug over a period of 8 h. The data obtained were analysed by fitment into various kinetic models; it was observed that the drug release was matrix diffusion controlled and the release mechanism was found to be non-Fickian. Stability studies were carried out on selected formulations at 5±3°, 25±2°/60±5% RH and 40±2°/75±5% RH for 90 days. The drug content was observed to be within permissible limits and there were no significant deviations in the in vitro mucoadhesion and in vitro drug diffusion characteristics.     

Confocal Laser Scanning Microscopic Visualization of the Transport of Dextrans After Nasal Administration to Rats: Effects of Absorption Enhancers

Purpose. To visualize the transport pathway(s) of high molecular weight model compounds across rat nasal epithelium in vivousing confocal laser scanning microscopy. Furthermore, the influence of nasal absorption enhancers (randomly methylated -cyclodextrin and sodium taurodihydrofusidate) on this transport was studied. Methods. Fluorescein isothiocyanate (FITC)-labelled dextrans with a molecular weight of 3,000 or 10,000 Da were administered intranasally to rats. Fifteen minutes after administration the tissue was fixed with Bouin. The nasal septum was surgically removed and stained with Evans Blue protein stain or DiIC18(5) lipid stain prior to visualization with the confocal laser scanning microscope. Results. Transport of FITC-dextran 3,000 across nasal epithelium occurred via the paracellular pathway. Endocytosis of FITC-dextran 3,000 was also shown. In the presence of randomly methylated -cyclodextrin 2% (w/v) similar transport pathways for FITC-dextran 3,000 were observed. With sodium taurodihydrofusidate 1% (w/v) the transport route was also paracellular with endocytosis, but cells were swollen and mucus was extruded into the nasal cavity. For FITC-dextran 10,000 hardly any transport was observed without enhancer, or after co-administration with randomly methylated -cyclodextrin 2% (w/v). Co-administration with sodium taurodihydrofusidate 1% (w/v) resulted in paracellular transport of FITC-dextran 10,000, but morphological changes, i.e. swelling of cells and mucus extrusion, were observed. Conclusions. Confocal laser scanning microscopy is a suitable approach to visualize the transport pathways of high molecular weight hydrophilic compounds across nasal epithelium, and to study the effects of absorption enhancers on drug transport and cell morphology.     

经鼻给药的机遇与挑战

作为一种非侵入给药方式,鼻腔给药具有快速起效、使用方便、依从性高、无首过效应、不良反应较小、黏膜免疫等诸多优点,且提供了鼻脑递送途径,鼻用制剂日益成为研发热点,以着力解决未被满足的临床需求。但是,因鼻腔结构和生理学上的特殊性,鼻用制剂的开发和评价还存在诸多挑战。     

尼莫地平贴剂体外渗透性及皮肤刺激性考察

尼莫地平经皮吸收贴剂选用丙烯酸酯为骨架材料 ,由背衬层、压敏胶层、覆盖层组成 .通过人体皮肤刺激性实验和体外经皮渗透实验对几组以不同浓度的油酸和月桂氮酮 (azone ,AZ)为渗透促进剂的处方进行了筛选 .结果表明含 5 %azone的尼莫地平贴剂对皮肤有轻度刺激性 ,其它处方对皮肤无刺激性 ;尼莫地平贴剂的体外经皮渗透符合零级动力学过程 ,含 10 %油酸的处方渗透性最好 .     

Enteral Absorption of Insulin in Rats from Mucoadhesive Chitosan-Coated Liposomes

Purpose. The mucoadhesiveness of polymer-coated liposomes was evaluated to develop a novel drug carrier system for oral administration of poorly absorbed drugs such as peptide drugs. Methods. Multilamellar liposomes consisting of dipalmitoylphosphatidylcholine (DPPC) and dicetyl phosphate (DCP) (DPPC:DCP = 8:2 in molar ratio) were coated with chitosan (CS), polyvinyl alcohol having a long alkyl chain (PVA-R) and poly (acrylic acid) bearing a cholesteryl group. The adhesiveness of the resultant polymer-coated liposomes to the rat intestine was measured in vitro by a particle counting method with a Coulter counter. The CS-coated liposomes containing insulin were administered to normal rats and the blood glucose level was monitored. Results. The existence of polymer layers on the surface of liposomes was confirmed by measuring the zeta potential of liposomes. The CS-coated liposomes showed the highest mucoadhesiveness and the degree of adhesion was dependent on the amount of CS on the surface of the liposomes. The blood glucose level of rats was found to be significantly decreased after administration of the CS-coated liposomes containing insulin. The lowered glucose level was maintained for more than 12h after administration of the liposomal insulin, which suggested mucoadhesion of the CS-coated liposomes in the intestinal tract of the rats.