纳米晶提高难溶性药物溶出及生物利用度的研究进展

目的综述了纳米晶在提高难溶性药物溶解度、加快药物溶出速度及提高药物口服生物利用度方面的研究进展。方法查阅相关文献31篇,对纳米晶提高难溶性药物溶出及生物利用度的机制、制备方法、物理稳定性及其在提高难溶性药物口服生物利用度方面的应用进行归纳总结。结果纳米晶可通过多种作用机制,有效提高难溶性药物的溶出及口服生物利用度,易于工业化生产。结论纳米晶在提高难溶性药物溶出及生物利用度方面具有广阔的应用前景。     

纳米晶体药物研究进展

纳米晶体技术能够有效提高难溶性药物的溶解度和溶出速度,从而提高其口服生物利用度,降低食物效应,是难溶性药物递送系统最具潜力的研究方向。在调研国内外文献的基础上,本文就纳米晶体药物的特点、组成、制备技术、临床应用及纳米效应的定量表达等方面的研究进展进行综述。     

难溶性药物增溶研究进展

如何增加难溶性药物的溶解度,改善其生物利用度,一直是药剂学研究的重要内容。该文就近年来应用广泛的纳米混悬剂、渗透泵、自微乳化技术、固体分散体、固体脂质纳米粒、液固压缩技术等一些新方法新技术在增加难溶性药物溶解度及改善生物利用度方面的应用进行综述。     

纳米载体提高难溶性药物口服生物利用度的研究进展

纳米载体是药剂学备受关注的研究领域,作为一类新型给药系统,它能显著提高难溶性药物的溶解度、生物利用度和稳定性,且具有明显的缓释作用,因此得到了广泛的应用。目前常用于提高难溶性药物口服生物利用度的纳米载体有纳米脂质体、固体脂质纳米粒、纳米胶束、和纳米结晶等,它们的粒径、表面性质及其释药环境等是影响纳米载体药物口服吸收的主要因素。本文对纳米载体提高难溶性药物口服生物利用度的研究进展作一综述。     

纳米结构脂质载体用于难溶性药物口服传递的研究进展

纳米结构脂质载体可以提高难溶性药物的口服生物利用度,是一种具有前景的难溶性药物口服传递系统。通过查阅文献,对纳米结构脂质载体常见的制备材料、方法,体外表征和释药,及提高难溶性药物口服生物利用度的机制进行综述。     

纳米混悬技术在中药制剂中的应用探究

应用中药制剂中纳米混悬技术有效改善了部分难溶性中药中的有效部位溶解度、有效成分、生物利用度,这一技术的应用推动着我国传统医药向现代化方向发展。本文具体通过分析中药纳米混悬技术在制备中的具体应用方法,总结中药纳米混悬技术中的固化技术。     

纳米技术在口服难溶性药物的研究进展

据报道,有〉70%的化学合成药物存在难溶性问题[1],约40%的新化学实体（NCEs）因其难溶性而无法进入临床试验,使其应用受到很大程度的限制[2]。口服给药不仅方便且患者顺应性高,是新药首选的给药途径之一。但对于生物药剂学分类系统中的第Ⅱ类药物（即穿膜性好,但溶解度低而言,因在胃肠道中溶解度低或溶出速率慢,可能导致口服生物利用度低。因此,解决因药物难溶性引起的口服低吸收问题,可提高这类药物的口服生物利用度。解决药物难溶性主要有两条途径：①提高溶解度,增加药物溶出：提高难溶性药物溶解度或溶出速率的常用方法有成盐、改变药物晶型、使用增溶剂或减小粒径等;②应用纳米给药系统,将药物包入载体内部,使药物以载药传递体形式被肠道吸收。     

难溶性药物的增溶及其缓/控释制剂研究进展

目前由高通量药物筛选而得的活性物质约有40％是水难溶性的，难溶性药物（poorly water—soluble drug）因其在水中溶解度小，药物难以被机体吸收，体内消除速度较快，血药浓度容易出现峰谷现象，口服制剂生物利用度低，且难以实现剂型的多样化。已报道的增溶技术如固体分散技术、环糊精包合技术、胶束增溶、微乳增溶、超微粉碎等已用于增加难溶性药物的溶解度，提高其口服制剂的生物利用度。缓／控释制剂（sustained or controlled release dosage forms）具有减少用药总剂量和用药次数，避免血浓峰谷现象，降低毒副作用，提高病人顺应性等优点，在临床上的应用日益广泛。目前应用增溶技术和缓／控释技术提高难溶性药物的溶解度和生物利用度，研制难溶性药物的缓／控释制剂以成为药剂学研究的热点方向。本文就难溶性药物的增溶及其缓／控释制剂的研究进展做如下综述。     

纳米混悬剂粒径稳定性及其控制策略

纳米混悬荆具有高溶出速率、高饱和溶解度和黏膜吸附性等特点,可有效提高难溶性药物的生物利用度.本文主要综述纳米混悬剂制备方法及其粒径控制策略,分析难溶性药物制剂开发技术.     

难溶性药物纳米晶体的研究进展

研究表明,在药品开发流水线中水溶性差的药物大约占40%,在药物合成高通量筛选过程中大约占60%,并且这些药物中的大部分同样也难溶于有机溶剂[1-2]。近年来常用提高水难溶性药物溶解度的方法是采用水溶性载体将药物与带电粒子偶联以增加生物利用度,例如环糊精。但是,载药量和包封率低,操作繁琐,是上述方法存在的普遍问题。因此研究人员希望通过不依靠添加剂或载体的方法,提高药物溶解度[3],近年来发展迅速的纳米药物晶体制备技术使这一设想得以实现。     

Coaxial electrospray formulations for improving oral absorption of a poorly water-soluble drug

Development of oral dosage forms containing poorly water-soluble drugs is a major challenge in the pharmaceutical industry. This paper describes the use of coaxial electrospray deposition as a promising formulation technology for oral delivery of poorly water-soluble drugs. The technology produced core-shell particles composed of griseofulvin and poly(methacrylic acid-co-methyl methacrylate) (Eudragit L-100), with a diameter of around 1 μm. The drug phase was in an amorphous state when the griseofulvin core was coated with the Eudragit L-100 shell. The in vitro dissolution and in vivo oral absorption studies revealed that the core-shell formulation significantly improved dissolution and absorption behaviors, presumably because of a reduction in particle size, improvement in dispersity, and amorphization. Results demonstrated that coaxial electrospray deposition possesses great potential as novel formulation technology for enhancing oral absorption of poorly water-soluble drugs.     

Drug nanocrystals in the commercial pharmaceutical development process

Nanosizing is one of the most important drug delivery platform approaches for the commercial development of poorly soluble drug molecules. The research efforts of many industrial and academic groups have resulted in various particle size reduction techniques. From an industrial point of view, the two most advanced top-down processes used at the commercial scale are wet ball milling and high pressure homogenization. Initial issues such as abrasion, long milling times and other downstream-processing challenges have been solved. With the better understanding of the biopharmaceutical aspects of poorly water-soluble drugs, the in vivo success rate for drug nanocrystals has become more apparent. The clinical effectiveness of nanocrystals is proven by the fact that there are currently six FDA approved nanocrystal products on the market. Alternative approaches such as bottom-up processes or combination technologies have also gained considerable interest. Due to the versatility of nanosizing technology at the milligram scale up to production scale, nanosuspensions are currently used at all stages of commercial drug development, Today, all major pharmaceutical companies have realized the potential of drug nanocrystals and included this universal formulation approach into their decision trees.     

Formulation design for poorly water-soluble drugs based on biopharmaceutics classification system: basic approaches and practical applications

The poor oral bioavailability arising from poor aqueous solubility should make drug research and development more difficult. Various approaches have been developed with a focus on enhancement of the solubility, dissolution rate, and oral bioavailability of poorly water-soluble drugs. To complete development works within a limited amount of time, the establishment of a suitable formulation strategy should be a key consideration for the pharmaceutical development of poorly water-soluble drugs. In this article, viable formulation options are reviewed on the basis of the biopharmaceutics classification system of drug substances. The article describes the basic approaches for poorly water-soluble drugs, such as crystal modification, micronization, amorphization, self-emulsification, cyclodextrin complexation, and pH modification. Literature-based examples of the formulation options for poorly water-soluble compounds and their practical application to marketed products are also provided. Classification of drug candidates based on their biopharmaceutical properties can provide an indication of the difficulty of drug development works. A better understanding of the physicochemical and biopharmaceutical properties of drug substances and the limitations of each delivery option should lead to efficient formulation development for poorly water-soluble drugs.     

液固压缩技术在药剂学中的应用

液固压缩技术是利用液体赋形剂溶解难溶性药物,然后用涂层材料吸收后得到固体粉末的一种技术。该技术可有效增加生物药剂学分类系统(BCS)Ⅱ类水难溶性药物溶出速率,通过液固压缩技术制得的粉末具有良好的流动性和可压性,工艺简单、成熟。重点介绍液固压缩技术的理论基础、作用机制和制备方法,并对液固压缩技术在难溶药物固体制剂和缓控释制剂中的应用进行归纳总结。     

Oral formulation strategies to improve solubility of poorly water-soluble drugs

INTRODUCTION: In the past two decades, there has been a spiraling increase in the complexity and specificity of drug-receptor targets. It is possible to design drugs for these diverse targets with advances in combinatorial chemistry and high throughput screening. Unfortunately, but not entirely unexpectedly, these advances have been accompanied by an increase in the structural complexity and a decrease in the solubility of the active pharmaceutical ingredient. Therefore, the importance of formulation strategies to improve the solubility of poorly water-soluble drugs is inevitable, thus making it crucial to understand and explore the recent trends. AREAS COVERED: Drug delivery systems (DDS), such as solid dispersions, soluble complexes, self-emulsifying drug delivery systems (SEDDS), nanocrystals and mesoporous inorganic carriers, are discussed briefly in this review, along with examples of marketed products. This article provides the reader with a concise overview of currently relevant formulation strategies and proposes anticipated future trends. EXPERT OPINION: Today, the pharmaceutical industry has at its disposal a series of reliable and scalable formulation strategies for poorly soluble drugs. However, due to a lack of understanding of the basic physical chemistry behind these strategies, formulation development is still driven by trial and error.     

Glibenclamide Nanocrystals for Bioavailability Enhancement: Formulation Design,Process Optimization,and Pharmacodynamic Evaluation

The aim of this study is to improve the bioavailability of a poorly water-soluble drug glibenclamide (GLB), by preparing drug nanocrystals using wet milling by zirconia beads. To improve the dissolution characteristics, various formulation and process variables were identified and optimized by employing a 3² factorial design at two stages. Based on preliminary studies, the formulation variables selected were polymer-to-drug ratio and surfactant-to-drug ratio and the process variables selected were milling speed and milling time. The particle size, zeta potential, saturation solubility, and percentage drug released at 10 min were selected as dependent variables at both stages. F _ratio suggested that the predetermined response parameters were significantly dependent on the independent variables. An optimum desirability of 0.9925 was achieved using response profiler by Statistica® 8.0. The optimized formulation prepared as per levels obtained through desirability showed a close agreement between the predicted and expected values. X-ray diffraction studies concluded that the crystallinity of prepared nanocrystals was intact and the increased dissolution could be ascribed to conversion of unmilled drug to nanocrystals. In vivo studies carried out on male Wistar rats suggested a higher AUEC_(0–8h) for GLB nanocrystals as compared to pure GLB which could be ascribed to significant improvement of release from GLB nanocrystals as compared to pure GLB. It could be concluded that prepared GLB nanocrystals showed better bioavailability as compared to pure GLB and could offer improved drug therapy.     

Application of Drug Nanocrystal Technologies on Oral Drug Delivery of Poorly Soluble Drugs

The limited solubility and dissolution rate exhibited by poorly soluble drugs is major challenges in the pharmaceutical process. Following oral administration, the poorly soluble drugs generally show a low and erratic bioavailability which may lead to therapeutic failure. Pure drug nanocrystals, generated by “bottom up” or “top down” technologies, facilitate a significant improvement on dissolution behavior of poorly soluble drugs due to their enormous surface area, which in turn lead to substantial improvement in oral absorption. This is the most distinguished achievement of drug nanocrystals among their performances in various administration routes, reflected by the fact that most of the marketed products based on the nanocrystals technology are for oral application. After detailed investigations on various technologies associated with production of drug nanocrystals and their in vitro physicochemical properties, during the last decade more attentions have been paid into their in vivo behaviors. This review mainly describes the in vivo performances of oral drug nanocrystals exhibited in animals related to the pharmacokinetic, efficacy and safety characteristics. The technologies and evaluation associated with the solidification process of the drug nanocrystals suspensions were also discussed in detail.     

Solubility enhancers for oral drug delivery

With recent progress in high throughput screening of potential therapeutic agents, the number of poorly water-soluble drug candidates has risen sharply and formulating for poorly water-soluble compounds for oral delivery now presents one of the most frequent and greatest challenges to scientists in the pharmaceutical industry. Many new drugs and potential therapeutic compounds under investigation possess high lipophilicity, poor water solubility, and low oral bioavailability. Furthermore, development of improved oral dosage forms for currently marketed drugs can also enhance their therapeutic value. Oral delivery systems designed for poorly water-soluble drugs include micelles with surfactants, microemulsions, self-emulsifying/microemulsifying drug delivery systems (SEDDS/SMEDDS), solid dispersions, microspheres and cyclodextrin inclusion complexes. These delivery systems have been shown to enhance oral bioavailability and therapeutic effects of poorly water-soluble drugs mainly by improving the poor solubility. As a consequence of extensive research, various oral delivery systems for poorly water-soluble agents are being developed in clinical phases worldwide. New formulation technologies and multidisciplinary expertise may lead to development of advanced and effective oral drug delivery systems applicable to a wide range of poorly water-soluble drugs in the near future.     

Development and Characterization of a Scalable Controlled Precipitation Process to Enhance the Dissolution of Poorly Water-Soluble Drugs

PURPOSE: Poorly water-soluble compounds are being found with increasing frequency among pharmacologically active new chemical entities, which is a major concern to the pharmaceutical industry. Some particle engineering technologies have been shown to enhance the dissolution of many promising new compounds that perform poorly in formulation and clinical studies (Rogers et. al., Drug Dev Ind Pharm 27:1003-1015). One novel technology, controlled precipitation, shows significant potential for enhancing the dissolution of poorly soluble compounds. In this study, controlled precipitation is introduced; and process variables, such as mixing zone temperature, are investigated. Finally, scale-up of controlled precipitation from milligram or gram to kilogram quantities is demonstrated. METHODS: Dissolution enhancement capabilities were established using two poorly water-soluble model drugs, danazol and naproxen. Stabilized drug particles from controlled precipitation were compared to milled, physical blend, and bulk drug controls using particle size analysis (Coulter), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), dissolution testing (USP Apparatus 2), and residual solvent analysis. RESULTS: Stabilized nano- and microparticles were produced from controlled precipitation. XRD and SEM analyses confirmed that the drug particles were crystalline. Furthermore, the stabilized particles from controlled precipitation exhibited significantly enhanced dissolution properties. Residual solvent levels were below FDA limits. CONCLUSIONS: Controlled precipitation is a viable and scalable technology that can be used to enhance the dissolution of poorly water-soluble pharmaceutical compounds.     

Oral formulation strategies to improve solubility of poorly water-soluble drugs

Introduction: In the past two decades, there has been a spiraling increase in the complexity and specificity of drug–receptor targets. It is possible to design drugs for these diverse targets with advances in combinatorial chemistry and high throughput screening. Unfortunately, but not entirely unexpectedly, these advances have been accompanied by an increase in the structural complexity and a decrease in the solubility of the active pharmaceutical ingredient. Therefore, the importance of formulation strategies to improve the solubility of poorly water-soluble drugs is inevitable, thus making it crucial to understand and explore the recent trends.

Areas covered: Drug delivery systems (DDS), such as solid dispersions, soluble complexes, self-emulsifying drug delivery systems (SEDDS), nanocrystals and mesoporous inorganic carriers, are discussed briefly in this review, along with examples of marketed products. This article provides the reader with a concise overview of currently relevant formulation strategies and proposes anticipated future trends.

Expert opinion: Today, the pharmaceutical industry has at its disposal a series of reliable and scalable formulation strategies for poorly soluble drugs. However, due to a lack of understanding of the basic physical chemistry behind these strategies, formulation development is still driven by trial and error.