鼻腔给药的生物利用度研究进展

目前，鼻腔给药生物利用度的研究主要集中在吸收促进剂、药物性质、剂型和载体等因素的影响。虽然药物通过鼻腔吸收受诸多因素的影响，但由于鼻腔特殊的解剖生理结构，药物吸收迅速；且与其他给药途径相比，尤其对于多肽和蛋白类药物而言，鼻腔给药这种非侵入性给药方法更简单、安全并且节省费用，因此，有望成为未来全身给药的重要途径之一。本文综述了近年来药物经鼻腔给药的生物利用度的研究进展。     

多肽类药物鼻腔给药研究进展

随着生物制药技术的发展,越来越多的多肽类药物在医药领域得到应用。但由于这类药物稳定性不佳、口服易被酶解等问题,临床多采用注射途径给药。鼻腔给药不仅能够克服口服给药的首过效应、注射给药的顺应性差等问题,而且具有脑靶向、低剂量高活性的优点。本文主要就多肽类药物的鼻腔给药进行综述,系统地介绍了鼻腔的组织构造,药物本身性质、制剂的特性和鼻腔内环境对药物鼻腔吸收的影响,以及通过添加吸收促进剂、酶抑制剂和设计成不同药物载体等方法改善药物鼻腔吸收,并叙述了鼻腔给药的研究热点-鼻脑传递,为后续相关制剂研发提供参考。     

药物的鼻腔黏膜吸收

鼻腔给药具有诸多优点，如能够避免肝脏的首过效应和胃肠道的降解，提高化学药物和肽类药物的生物利用度；增加药物向脑内递释，提高脑部疾病的治疗效果；具有特有的免疫性质等。介绍药物鼻腔黏膜吸收的特点和影响因素，综述鼻腔给药制剂的研究方法和研制情况，旨为该领域研究提供参考。     

鼻腔作为全身给药途径的研究

目的：以安乃近、对乙酰氨基酚、双氯灭痛、吲哚美辛、吡罗昔康和普罗帕酮为模型药，进行药物的鼻腔吸收研究，完善和发展鼻腔吸收的系统研究方法。方法：采用Ｖ－Ｃ扩散池进行离体透膜试验；采用大鼠鼻腔循环装置进行在体内吸收试验；鼻腔全身吸收实验在志愿者体内进行，同时还采用示踪元素标记化合物法进行了药物的鼻腔吸收研究。此外，对药物的鼻粘膜纤毛毒性也进行了研究。结果：安乃近、对乙酰氨基酚鼻腔吸收良好，有望开发为鼻腔给药制剂；普罗帕酮鼻纤毛毒性较大，不适合鼻腔给药；另三种药物初步结果表明鼻腔吸收良好，值得进一步研究。结论：本文提出并采用的一系列研究方法适合作药物鼻腔吸收研究     

鼻腔给药的研究进展

鼻腔给药是一种极具潜力的药物转运系统。本文对影响鼻腔给药药物吸收的因素进行了介绍,并对鼻腔药物转运系统中所使用的药物吸收促进剂、生物粘附材料、研究方法等进行了综述。     

鼻腔给药系统药用辅料研究进展

介绍与分析国内外用于鼻腔给药系统(NDDS)的生物黏附剂、吸收促进剂及酶抑制药的种类、应用特点以及对鼻腔吸收的影响，综述用于鼻腔给药的药用辅料的研究进展，这些辅料对NDDS的成型、药物的吸收与疗效有重要影响。     

扑热息痛滴鼻剂与口服片剂在兔体内的药动学参数比较与评析

全身性用药通常以口服、注射、直肠、透皮等途径给药。由于影响药物口服吸收的因素诸多，而注射、直肠给药对药物本身及附加剂、基质的要求甚高，所以近年来鼻腔给药引起了医药研究人员的极大兴趣。人鼻腔表面积约为150cm2[1]，长度7.5cm，鼻腔粘膜血管丰富，动脉、静脉和淋巴毛细血管交织成网状。此外，鼻腔粘膜对药物代谢极微弱，鼻腔呼吸区细胞上具有与纤毛密切相关的微小绒毛，进一步增加了对药物吸收的有效表面积，药物可迅速自鼻粘膜吸收，提高了生物利用度。本文对扑热息痛滴鼻剂与口服片剂在兔体内的药动学参数予以比较和评析。l材…     

用于全身治疗的鼻腔给药系统

从药剂学角度对鼻的解剖生理及给药特点、影响药物在鼻腔中吸收的因素，特别就吸收促进剂和剂型因素与多肽和蛋白质类药物鼻腔给药的关系进行了综述。     

鼻用原位凝胶给药系统中药物吸收的影响因素与改进措施

药物的吸收主要是由药物的理化性质、剂型以及给药途径所决定的。原位凝胶是指在生理条件刺激下能发生分散状态或构象的可逆变化、完成溶液与凝胶间相互转变的新剂型。原位凝胶经鼻腔给药,既避免了药物的胃肠首过效应,又因其能延长药物在给药部位滞留时间,从而避免药物被鼻纤毛快速清除。本文通过系统查阅近年国内外鼻用原位凝胶给药系统的相关文献,就鼻腔的生理特点、药物理化性质与原位凝胶的制剂处方等影响其药物吸收的主要因素及改进措施,进行分析、整理和归纳,旨在为鼻用原位凝胶给药系统的设计与质量控制提供参考。     

脂质体在鼻腔给药中的应用

通过介绍脂质体的特点，指出脂质体在鼻腔给药的优点。探讨脂质体在鼻腔黏膜的作用机制。利用脂质体增加药物鼻腔黏膜的透过吸收的原理，可以对疾病进行有效的治疗。介绍脂质体作为鼻腔药物载体的研究现状，展望脂质体纳米化是脂质体鼻腔给药药物的发展趋势。     

Cyclodextrins in nasal drug delivery

Nasal drug delivery is an attractive approach for the systemic delivery of high potency drugs with a low oral bioavailability due to extensive gastrointestinal breakdown and high hepatic first-pass effect. For lipophilic drugs nasal delivery is possible if they can be dissolved in the dosage form. Peptide and protein drugs often have a low nasal bioavailability because of their large size and hydrophilicity, resulting in poor transport properties across the nasal mucosa. Cyclodextrins are used to improve the nasal absorption of these drugs by increasing their aqueous solubility and/or by enhancing their nasal absorption. With several cyclodextrins very efficient nasal drug absorption has been reported, but also large interspecies differences have been found. Studies concerning the safety of cyclodextrins in nasal drug formulations demonstrate the non-toxicity of the cyclodextrins and also clinical data show no adverse effects. Therefore, some cyclodextrins can be expected to become effective and safe excipients in nasal drug delivery.     

Nasal clearance in health and disease.

This paper reviews the anatomical and physiological factors of importance for nasal drug delivery and discusses in particular the influence of the nasal mucociliary clearance mechanism on the nasal absorption of drugs. The effect of nasal pathological conditions on the mucociliary clearance mechanism and the possible effect of such disease states on nasal drug transport are also discussed. Strategies for the exploitation of bioadhesive drug delivery systems and especially nasal absorption enhancers for the improvement of nasal drug delivery are evaluated to include considerations of the mechanism of action and correlation between the degree of bioadhesion and absorption enhancement and transport of drugs across the nasal membrane. A range of studies involving bioadhesive/absorption enhancer systems are detailed. A selected bioadhesive material, chitosan, which has been shown to have excellent absorption enhancer properties for a variety of drugs is discussed in some detail.     

Absorption enhancers for nasal drug delivery

This paper describes the basic concepts for the transmucosal delivery of drugs, and in particular the use of the nasal route for delivery of challenging drugs such as polar low-molecular-weight drugs and peptides and proteins. Strategies for the exploitation of absorption enhancers for the improvement of nasal delivery are discussed, including consideration of mechanisms of action and the correlation between toxic effect and absorption enhancement. Selected enhancer systems, such as cyclodextrins, phospholipids, bioadhesive powder systems and chitosan, are discussed in detail. Examples of the use of these enhancers in preclinical and clinical studies are given. Methods for assessing irritancy and damage to the nasal membrane from the use of absorption enhancers are also described. Finally, the mucosal use of absorption enhancers (chitosan) for the improved nasal delivery of vaccines is reported with reference to recent phase I/II clinical studies.     

Nasal route and drug delivery systems

Nasal drug administration has been used as an alternative route for the systemic availability of drugs restricted to intravenous administration. This is due to the large surface area, porous endothelial membrane, high total blood flow, the avoidance of first-pass metabolism, and ready accessibility. The nasal administration of drugs, including numerous compound, peptide and protein drugs, for systemic medication has been widely investigated in recent years. Drugs are cleared rapidly from the nasal cavity after intranasal administration, resulting in rapid systemic drug absorption. Several approaches are here discussed for increasing the residence time of drug formulations in the nasal cavity, resulting in improved nasal drug absorption. The article highlights the importance and advantages of the drug delivery systems applied via the nasal route, which have bioadhesive properties. Bioadhesive, or more appropriately, mucoadhesive systems have been prepared for both oral and peroral administration in the past. The nasal mucosa presents an ideal site for bioadhesive drug delivery systems. In this review we discuss the effects of microspheres and other bioadhesive drug delivery systems on nasal drug absorption. Drug delivery systems, such as microspheres, liposomes and gels have been demonstrated to have good bioadhesive characteristics and that swell easily when in contact with the nasal mucosa. These drug delivery systems have the ability to control the rate of drug clearance from the nasal cavity as well as protect the drug from enzymatic degradation in nasal secretions. The mechanisms and effectiveness of these drug delivery systems are described in order to guide the development of specific and effective therapies for the future development of peptide preparations and other drugs that otherwise should be administered parenterally. As a consequence, bioavailability and residence time of the drugs that are administered via the nasal route can be increased by bioadhesive drug delivery systems. Although the majority of this work involving the use of microspheres, liposomes and gels is limited to the delivery of macromolecules (e.g., insulin and growth hormone), the general principles involved could be applied to other drug candidates. It must be emphasized that many drugs can be absorbed well if the contact time between formulation and the nasal mucosa is optimized.     

Nasal route: an alternative approach for antiemetic drug delivery

INTRODUCTION: Antiemetic drugs are used in the treatment of nausea and emesis. Development of novel delivery systems for antiemetic drugs, as an alternative to conventional preparations, is important in terms of good patient compliance and improving bioavailability. The nasal route offers unique superiorities, such as fast and high drug absorption, and high patient compliance. Therefore, a considerable amount of research has been carried out on the development of nasal delivery systems for antiemetic drugs. AREAS COVERED: This review deals with the importance of nasal delivery of antiemetic drugs and the studies performed on this subject. The first part of this review summarizes the properties of the nasal route, its advantages and limitations, parameters affecting drug absorption through nasal mucosa, nasal passage pathways and general approaches to improve nasal transport. The second part reviews the studies conducted on the development of nasal delivery systems. EXPERT OPINION: Due to its superiorities, the nasal route could be considered as an attractive alternative to oral and parenteral routes. To overcome the barrier properties of the nasal epithelium and to enhance transport of antiemetic drugs, several approaches, including permeation enhancers, in situ gel formulations and micro- and nanoparticulate systems, have been evaluated. The results obtained are promising and indicate that nasal formulations of some antiemetic drugs may enter the market in the near future.     

The biopharmaceutical aspects of nasal mucoadhesive drug delivery

Nasal drug administration has frequently been proposed as the most feasible alternative to parenteral injections. This is due to the high permeability of the nasal epithelium, allowing a higher molecular mass cut‐off at approximately 1000 Da, and the rapid drug absorption rate with plasma drug profiles sometimes almost identical to those from intravenous injections. Despite the potential of nasal drug delivery, it has a number of limitations. In this review, the anatomy and physiology of the nasal cavity, as well as ciliary beating and mucociliary clearance as they relate to nasal drug absorption, are introduced. The rationale for nasal drug delivery and its limitations, some factors that influence nasal drug absorption, and the experimental models used in nasal drug delivery research are also reviewed. Nasal mucoadhesion as a promising method of nasal absorption enhancement is discussed, and factors that influence mucoadhesion, as well as safety of nasal mucoadhesive drug delivery systems are reviewed in detail. Nasal drug administration is presently mostly used for local therapies within the nasal cavity. Anti‐allergic drugs and nasal decongestants are the most common examples. However, nasal drug administration for systemic effects has been practised since ancient times. Nasally‐administered psychotropic drugs by native Americans, the use of tobacco snuffs, and nasal administration of illicit drugs such as cocaine are all well known (Illum & Davis 1992). Nowadays, the nasal cavity is being actively explored for systemic administration of other therapeutic agents, particularly peptides and proteins (Illum 1992; Edman & Bjork 1992), as well as for immunization purposes (Lemoine et al 1998). To better understand the basis for nasal drug absorption and factors that can influence it, a brief review of the anatomy and physiology of the nose is appropriate.     

Drug Metabolism in the Nasal Mucosa

Nasal delivery is a potential alternative for systemic availability of drugs restricted to intravenous administration, such as peptide and protein drugs. Although nasal delivery avoids the hepatic first-pass effect, the enzymatic barrier of the nasal mucosa creates a pseudo-first-pass effect. The xenobiotic metabolic activity in the nasal epithelium has been investigated in several species including humans. The Phase I, cytochrome P-450 enzymes have been studied extensively for their toxicological significance, since these enzymes metabolize inhaled pollutants into reactive metabolites which may induce nasal tumors. The cytochrome P-450 activity in the olfactory region of the nasal epithelium is higher even than in the liver, mainly because of a three- to fourfold higher NADPH–cytochrome P-450 reductase content. Phase II activity has also been found in the nasal epithelium. The delivery of peptides and proteins has been hindered by the peptidase and protease activity in the nasal mucosa. The predominant enzyme appears to be aminopeptidase among other exopeptidases and endopeptidases. The absorption of peptide drugs can be improved by using aminoboronic acid derivatives, amastatin, and other enzyme inhibitors as absorption enhancers. It is possible that some of the surfactants, e.g., bile salts, increase absorption by inhibiting the proteolytic enzymes. Thus, in addition to the permeation barriers, there also exists an enzymatic barrier to nasal drug delivery, which is created by metabolic enzymes in the nasal epithelium.     

Nasal mucoadhesive drug delivery: background, applications, trends and future perspectives

Nasal drug delivery has now been recognized as a very promising route for delivery of therapeutic compounds including biopharmaceuticals. It has been demonstrated that low absorption of drugs can be countered by using absorption enhancers or increasing the drug residence time in the nasal cavity, and that some mucoadhesive polymers can serve both functions. This article reviews the background of nasal mucoadhesive drug delivery with special references to the biological and pharmaceutical considerations for nasal mucoadhesive drug administration. Applications of nasal mucoadhesives for the delivery of small organic molecules, antibiotics, proteins, vaccines and DNA are also discussed. Furthermore, new classes of functionalized mucoadhesive polymers, the characterization and safety aspects of nasal drug products as well as the opportunities presented by nasal drug delivery are extensively discussed.     

吸收促进剂的作用机制及其在鼻腔给药中的研究进展

随着新的蛋白质及肽类治疗药物的开发,非侵入性给药途径-鼻腔给药日益受到关注。与口服给药和注射给药相比,鼻腔给药既可避免注射给药带来的生理和心理创伤,也可消除口服给药过程中肝脏的首过效应;且鼻腔黏膜下血管丰富,有助于药物的吸收,也更加便于患者的抢救和自救。然而,由于鼻黏膜屏障的存在,药物很难达到理想的治疗效果,因此需要加入鼻黏膜吸收促进剂来增强药物的吸收。该文主要探讨鼻黏膜吸收促进剂的作用机制及分类,并对FDA已上市鼻腔制剂中的吸收促进剂进行汇总,同时对新型黏膜吸收促进剂在鼻腔给药制剂中的应用进行阐述,以期为鼻腔给药制剂的开发提供依据。     

Nasal route: an alternative approach for antiemetic drug delivery

Introduction: Antiemetic drugs are used in the treatment of nausea and emesis. Development of novel delivery systems for antiemetic drugs, as an alternative to conventional preparations, is important in terms of good patient compliance and improving bioavailability. The nasal route offers unique superiorities, such as fast and high drug absorption, and high patient compliance. Therefore, a considerable amount of research has been carried out on the development of nasal delivery systems for antiemetic drugs.

Areas covered: This review deals with the importance of nasal delivery of antiemetic drugs and the studies performed on this subject. The first part of this review summarizes the properties of the nasal route, its advantages and limitations, parameters affecting drug absorption through nasal mucosa, nasal passage pathways and general approaches to improve nasal transport. The second part reviews the studies conducted on the development of nasal delivery systems.

Expert opinion: Due to its superiorities, the nasal route could be considered as an attractive alternative to oral and parenteral routes. To overcome the barrier properties of the nasal epithelium and to enhance transport of antiemetic drugs, several approaches, including permeation enhancers, in situ gel formulations and micro- and nanoparticulate systems, have been evaluated. The results obtained are promising and indicate that nasal formulations of some antiemetic drugs may enter the market in the near future.