复乳处方设计及其物理稳定性的初步研究

通过对油、乳化剂、稳定剂等辅料的选择,确定了理想的w/o/w复乳处方和制备工艺,测定了复乳的理化性质如显微结构、粒度分布、流变性和荷电性。物理稳定性预测说明:在复乳内外水相中加入大分子物质作稳定剂能有效地提高复乳的稳定性。     

W／O／W型甘草酸单铵盐口服复乳的处方设计及其理化特性研究

采用均匀设计，以乳剂的稳定性参数为考察指标，考察了初乳乳化剂、复乳乳化剂、乳化时间等因素对复乳稳定性的影响；筛选出Ｗ／Ｏ／Ｗ型甘草酸单铵盐口服复乳的优化处方和工艺，并对复乳的主要理化特性和物理稳定性进行了考察。     

W／O／W型甘草酸单胺盐口服复乳的处方设计及其理化特性研究

采用均匀设计，以乳剂的稳定性参数为考察指标，考察了初乳乳化剂、复乳乳化剂、乳化时间等因素对复乳稳定性的影响；筛选出Ｗ／Ｏ／Ｗ型甘草酸单胺盐口服复乳的优化处方和工艺，并对复乳的主要理化特性和物理稳定性进行了考察。     

W/O/W型复乳配方的优选及性质考察

目的优选W/O/W型复乳较佳的配方。方法在前期预实验的基础上筛选出油水相比例、乳化剂Ⅰ的用量、辅助乳化剂的种类与用量、稳定剂的用量、稳定剂Ⅱ的用量、内外渗透压等8个影响复乳配方质量的因素,以复乳产率和离心分离时间为指标,选用L18(2×37)表进行正交试验。同时考察优选配方所制复乳的理化性质和稳定性。结果 8个因素对复乳质量的影响大小依次为:D>G>F>B>E>H>A>C,其中辅助乳化剂和乳化剂Ⅱ的用量是主要的影响因素。结论按照优选的配方可以制备出性状较好的复乳,且所得复乳理化性质和稳定性均良好。     

自乳化复乳给药系统的制备

目的 筛选自乳化复乳处方并考察其制备工艺.方法 以伪三元相图、自复乳的显微结构和粒径为指标,考察内水相质量分数、亲水乳化剂的种类和用量以及高速分散强度对自乳化复乳处方的影响,并研究其稳定性.结果 内水相-油相-Span80-Cremophor EL比例为12.5:75:25:10,高速分散强度为12×103 r·min-1时所得自复乳的显微形态及抗稀释能力较好.结论 制备了由油包水及亲水乳化剂构成的自乳化复乳给药系统.     

提高W/O/W复合型乳剂稳定性的研究进展

目的:了解提高W/O/W复合型乳剂稳定性的各种手段和方法。方法:查阅近几年国内外有关文献资料进行分析综述。结果:乳化剂、油相、制备工艺、内水相、稳定剂均是影响复乳稳定性的因素。结论:国内外学者采取了各种相应的稳定措施,以为复乳的应用开辟一个更广阔的空间。     

胰岛素自复乳化给药系统的制备与质量评价

目的 制备胰岛素自复乳化给药系统并评价其质量.方法 以自复乳的微观结构、体积平均粒径和自乳化速率为评价指标筛选较优处方,并考察其稳定性及体外释放特性.结果 优选的处方组成为内水相-中链甘油三酸酯-亲脂乳化剂-亲水乳化剂(21:24:6:9),平均粒径为6.74±0.55 μm,包裹进入复乳的胰岛素为86.8％±8.2％;于25℃静置30 d后,其显微形态及平均粒径等指标均未见明显变化;8h后胰岛素在体外的累计释放量达约80％,具一定缓释作用.结论 成功制备了胰岛素自复乳化给药系统,可为蛋白多肽类药物的口服给药提供新的方法.     

伪三元相图结合CCD响应面法优化辛夷油微乳处方

目的 优选辛夷油微乳处方.方法 以辛夷油为油相、蒸馏水为水相,借助伪三元相图,选择合适的乳化剂和助乳化剂及其配比范围;以油相质量分数、固定乳化剂与助乳化剂比例(Km值)为考察因素,以乳滴粒径及聚合物分散性指数(PDI)为评价指标,采用中心复合设计响应面法优选上述两因素的最佳比例.结果 优选的辛夷油微乳处方为以辛夷油为油...     

处方因素对亚微乳物理稳定性的影响

目的 初步探讨亚微乳处方中乳化剂及油相因素对其物理稳定性的影响.方法 采用高速剪切分散和高压均质乳化工艺制备亚微乳,单因素试验法考察处方中乳化剂与油相对亚微乳物理稳定性的影响;以平均粒径、D50值、D99值及ζ电位为指标,考察不同处方中亚微乳灭菌前后的物理稳定性,并留样观察其长期稳定性.结果 泊洛沙姆188与中链油相互配伍不能得到性质稳定的亚微乳,且单独以泊洛沙姆188为乳化剂的各处方制剂长期放置后平均粒径明显增大;聚乙二醇硬脂酸酯( HS15)与各油相结合制得的亚微乳均较稳定,长期放置后各项指标基本不变;聚山梨酯80与大豆油-中链油(1∶1)混合油或大豆油配伍制成的亚微乳在灭菌后产生较大粒径的乳滴,而与中链油相配伍可制得粒径较小且均匀分散的体系;蛋磷脂E80单独作为亚微乳乳化剂,乳化效果欠佳.结论 大豆油、中链油及混合油与不同性质的乳化剂相互作用可共同影响亚微乳的粒径,但不同制剂的处方对亚微乳ζ电位无显著影响.     

磷脂对自微乳口服吸收、淋巴转运和体外特征的影响

目的以黄芩素为模型药物制备自微乳(SMEDDS),考察磷脂作为联合乳化剂对SMEDDS乳化、体外释放、体内胃肠吸收以及淋巴转运的影响。方法本研究以油酸乙酯为油相,吐温-80/磷脂为联合乳化剂,Transcutol HP为助乳化剂,构建黄芩素自微乳(BA-PC-SMEDDS),对乳化效率、粒径、Zeta电位、长期储存稳定性、大鼠体内药代动力学和淋巴转运等特征进行考察,并与处方中不含磷脂的传统自微乳(CBA-SMEDDS)进行比较。结果当磷脂作为联合乳化剂时,自微乳的长期储存稳定性提高,药物析出现象得到抑制。BA-PC-SMEDDS口服吸收后的AUC_0～_t为CBA-SMEDDS的1.37倍,淋巴转运程度从56.2%提高到68.6%。结论综上所述,处方中使用磷脂作为联合乳化剂,有利于改善SMEDDS的稳定性,提高难溶性药物的口服吸收,且对淋巴转运有促进作用。     

用三角相图法研究药用微乳的形成条件

目的　用建立的改良三角相图法制备低毒药用微乳。方法　选磷脂和聚氧乙烯辛基苯基醚(OP)为乳化剂,乙醇和正辛醇为助乳化剂,油酸乙酯和橄榄油为油相,以改良三角相图法即固定水相和助乳化剂的比值(W/A)或油相和助乳化剂的比值(O/A),对比经典三角相图法即固定乳化剂和助乳化剂的比值(K_m)制备的微乳所需乳化剂和助乳化剂的量及相体积比的大小。结果　对磷脂为乳化剂形成的微乳系统,改良三角相图法所需乳化剂的量为6%-28%,而经典三角相图法所需乳化剂的量为28%-29.6%。对OP为乳化剂形成的微乳系统,改良三角相图法所需乳化剂为23%-40%;而经典三角相图法所需乳化剂为27.6%-49.8%,以上两种系统,前者均较后者用量小。结论　用改良三角相图代替经典三角相图研究形成药用微乳的理论,对寻找低毒性的微乳有积极的指导意义。     

Unexpected skin barrier influence from nonionic emulsifiers

Skin disorders are often treated with creams containing various active substances. The creams also contain emulsifiers, which are surface-active ingredients used to stabilize the emulsion. Emulsifiers are potential irritants and in the present study the influence of stearic acid, glyceryl stearate, PEG-2, -9, -40, and -100 stearate, steareth-2, -10 and -21 on normal as well as on irritated skin have been evaluated with non-invasive measurements. Test emulsions were created by incorporating 5% emulsifiers in a water/mineral oil mixture (50:50). The emulsions and their vehicle were then applied to normal skin for 48 h and to sodium lauryl sulfate (SLS) damaged skin for 17 h in aluminum chambers. Twenty-four hours after removal of the chambers the test sites were evaluated for degree of irritation. In normal skin, the emulsifiers induced significant differences in TEWL but not in skin blood flow. Five of the emulsifiers increased TEWL. In SLS-damaged skin an aggravation of the irritation was expected. However, no differences regarding skin blood flow was noted from the emulsifiers. Furthermore, three emulsifiers unexpectedly decreased TEWL. These results highlight the possibility of absorption of these emulsifiers into the lipid bilayer, which increase TEWL in normal skin and decrease TEWL in damaged skin.     

Macromolecular composition and drug-loading effect on the delivery of paclitaxel and folic acid from acrylic matrices

Drug delivery systems based on synthetic polymers are widely employed in the treatment of several pathologies. In particular, the use of implantable devices able to release one or more active principles in a topic site with a controlled delivery kinetic represents an important improvement in this field. However, the release kinetic, that could be affected by different parameters, like polymer composition or chemical nature and initial drug loading, represents one of the problems related to the implantation of delivery systems. In this study, acrylic membranes with different macromolecular composition were prepared and studied analyzing delivery kinetic properties. Drug delivery systems were prepared using as matrix the copolymer poly(methylmethacrylate-co-butylmethacrylate) in three different compositions and folic acid (less hydrophobic) or Paclitaxel (more hydrophobic) as drugs, to evaluate the effect of macromolecular composition and hydrophilicity degree on the release properties. In addition, the effect of the initial drug loading was considered, loading drug delivery systems with four different initial drug percentages. Results showed a direct dependence of kinetics from macromolecular composition, hydrophilicity degree of solutes, and initial drug loading, allowing one to conclude that it is possible to design and to develop drug delivery systems starting from poly(methylmethacrylate-co-butylmethacrylate) matrices with specific properties by varying these three parameters.     

Macromolecular Carrier Systems for Targeted Drug Delivery: Pharmacokinetic Considerations on Biodistribution

This review article describes the current status and future perspectives of site-specific drug delivery by means of macromolecular carrier systems. Basic aspects and recent advances of targeted delivery of 1) conventional drugs, 2) protein drugs, and 3) gene medicines including antisense oligonucleotides and plasmid DNA, are reviewed from a pharmacokintic perspective. Successful in vivo application of macromolecular carrier systems requires pharmacokinetic considerations at whole body, organ, cellular and subcellular levels. The integration of simultaneous research progress in the multidisciplinary fields such as biochemistry, cell and molecular biology, pharmacology, and pharmacokinetics will accelerate the emergence of marketed drugs with macromolecular carrier systems.     

Properties of Film-Formers and Their Use in Aqueous Systems

For the manufacture of film tablets a variety of polymers with different properties are used in organic and aqueous systems. In the present review, the most important film-forming agents and application systems are discussed with regard to their chemical qualities and physical formulation properties. Furthermore, general phenomena and differences among these agents are illuminated by means of models from macromolecular chemistry.     

Interpenetrating Polymer Networks polysaccharide hydrogels for drug delivery and tissue engineering

The ever increasing improvements of pharmaceutical formulations have been often obtained by means of the use of hydrogels. In particular, environmentally sensitive hydrogels have been investigated as “smart” delivery systems capable to release, at the appropriate time and site of action, entrapped drugs in response to specific physiological triggers. At the same time the progress in the tissue engineering research area was possible because of significant innovations in the field of hydrogels. In recent years multicomponent hydrogels, such as semi-Interpenetrating Polymer Networks (semi-IPNs) and Interpenetrating Polymer Networks (IPNs) have emerged as innovative biomaterials for drug delivery and as scaffolds for tissue engineering. These interpenetrated hydrogel networks, which can be obtained by either chemical or physical crosslinking, in most cases show physico-chemical properties that can remarkably differ from those of the macromolecular constituents. Among the synthetic and natural polymers that have been used for the preparation of semi-IPNs and IPNs, polysaccharides represent a class of macromolecules of particular interest because they are usually abundant, available from renewable sources and have a large variety of composition and properties that may allow appropriately tailored chemical modifications. Sometimes both macromolecular systems are based on polysaccharides but often also synthetic polymers are present together with polysaccharide chains.     

Cancer-targeted polymeric drugs

A major challenge in cancer chemotherapy is the selective delivery of small molecule anti cancer agents to tumor cells. Water-soluble polymer-drug conjugates exhibit good water solubility, increased half-life, and potent anti tumor effects. By localizing the drug at the desired site of action, macromolecular therapeutics have improved efficacy and enhanced safety at lower doses. Since small molecule drugs and macromolecular drugs enter cells by different pathways, multi-drug resistance (MDR) can be minimized. Anti-cancer polymer-drug conjugates can be divided into two targeting modalities: passive and active. Tumor tissues have anatomic characteristics that differ from normal tissues. Macromolecules penetrate and accumulate preferentially in tumors relative to normal tissues, leading to extended pharmacological effects. This "enhanced permeability and retention" (EPR) effect is the principal reason for current successes with macromolecular anti-cancer drugs. Both natural and synthetic polymers have been used as drug carriers, and several bioconjugates have been clinically approved or are in human clinical trials. While clinically useful anti-tumor activity has been achieved using passive macromolecular drug delivery systems, further selectivity is possible by active targeting. Attachment of targeting moieties to the polymer backbone can further exploit differences between cancer and normal cells through selective receptor-mediated endocytosis. This strategy would augment the EPR effect, thereby further improving the therapeutic index of the macromolecular drug. This review discusses the development and therapeutic potential of prototype macromolecular drugs for use in cancer chemotherapy. Specific examples are selected to illustrate the basic design principles for soluble polymeric drug delivery systems.     

Die Gelstruktur von Öl-in-Wasser Emulsionssalben

The Gel Structure of Oil-in-Water Emulsions The gradual development of gel structures, using several oil-in-water emulsion systems with complex emulsifiers, is shown by electron optical pictures.     

Nanoparticles of biodegradable polymers for clinical administration of paclitaxel

Paclitaxel is one of the best antineoplastic drugs found from nature in the past decades, which has been found effective against a wide spectrum of cancers including ovarian cancer, breast cancer, small and non small cell lung cancer, colon cancer, head and neck cancer, multiple myeloma, melanoma, and Kaposi's sarcoma. Like many other anticancer drugs, it has difficulties in clinical administration due to its poor solubility in water and most pharmaceutical reagents. In its current clinical application, an adjuvant called Cremophor EL has to be employed, which has been found to be responsible for many serious side effects. Nanoparticles of biodegradable polymers can provide an ideal solution to such an adjuvant problem and realize a controlled and targeted delivery of the drug with better efficacy and less side effects. With further development, such as particle size optimization and surface coating, nanoparticle formulation of paclitaxel can promote a new concept of chemotherapy to realize its full efficacy and to improve quality of life of the patients, which includes personalized chemotherapy, local chemotherapy, sustained chemotherapy, oral chemotherapy, chemotherapy across the blood-brain barrier, chemotherapy across the microcirculation barrier, etc. The present research proposes a novel formulation for fabrication of nanoparticles of poly(lactic-co-glycolic acid) (PLGA) by a modified solvent extraction/evaporation technique, in which natural emulsifiers, such as phospholipids, cholesterol and vitamin E TPGS are creatively applied to achieve high drug encapsulation efficiency, desired drug released kinetics, high cell uptake and high cytotoxicity. The nanoparticles composed of various recipes and manufactured under various conditions were characterized by laser light scattering (LLS) for size and size distribution, scanning electron microscopy (SEM) and atomic force microscopy (AFM) for morphological properties, X-ray photoelectron spectroscopy (XPS) and Fourier Transformation Infrared Spectroscopy (FTIR) for surface chemistry, zeta-potential for surface charge, and differential scanning calorimetry (DSC) for the thermogram properties. The drug encapsulation efficiency and the drug release kinetics under in vitro conditions were measured by high performance liquid chromatography (HPLC). It was found that these natural emulsifiers have great advantages for nanoparticle formulation of paclitaxel over the traditional macromolecular emulsifiers, such as polyvinyl alcohol (PVA). Nanoparticles of desired small size and narrow size distribution can be obtained. The drug encapsulation efficiency can be achieved as high as 100 %. The released kinetics can be made under control. The HT-29 cancer cell line experiment showed that after 24 hours of incubation, the cell mortality caused by the drug administered by such nanoparticle formulation could be more than 13 times higher than that caused by the free drug under similar conditions.     

Interfacial inhibition of macromolecular interactions: nature's paradigm for drug discovery

One of nature's strategies for interfering with molecular interactions is to trap macromolecules in transition states with their partners in dead-end complexes that are unable to complete their biological function. This type of inhibition, which we refer to as "interfacial inhibition", is illustrated by two natural inhibitors, brefeldin A (BFA) and camptothecin (CPT), whose modes of action have been elucidated fully in structural studies. Interfacial inhibition occurs at the protein-protein interface in the case of BFA and at the protein-DNA interface in the case of CPT. In both systems, the drugs take advantage of transient structural and energetic conditions created by the macromolecular complex, which give rise to "hot-spots" for drug binding. In addition to these examples, several natural compounds such as forskolin, tubulin inhibitors and immunophilins target protein interfaces. We propose that interfacial inhibition is a paradigm for the discovery of drugs that interfere with macromolecular complexes.