Nanoparticle formation by using shellac and chitosan for a protein delivery system

The potential of using two natural polymers (chitosan and shellac) for the formation of nanoparticles by the process of ionic cross-linking to encapsulate bovine serum albumin, a model protein was investigated. Depending on the concentrations of chitosan, shellac and bovine serum albumin, three physical states – nanoparticle, aggregation, and solution could be observed as a result of the electrostatic force. The formation of nanoparticles was due to the balance between the repulsion force and attractive force while the imbalance between both forces resulted in the formation of aggregation and solution. The Fourier transform infrared spectroscopy and differential scanning calorimetry were applied to prove the nanoparticle formation. The particle size was characterized by the light scattering technique and was found in the range between 100 and 300 nm. The morphology of the particles, detected by transmission electron microscopy was spherical shape. The result showed that the zeta potential of the nanoparticles possessed positive charges. The concentrations of chitosan, shellac and bovine serum albumin had an influence on the physicochemical properties of the nanoparticles such as the particle size, the zeta potential, the encapsulation, the loading efficiencies and the cumulative release. Therefore, chitosan and shellac could be used to form nanoparticles for protein delivery by the ionic cross-linking method.     

Silica nanoparticles on the oral delivery of insulin

Introduction: When intravenous or subcutaneous administration of insulin, various side effects or possible risks have been reported. Oral administration of insulin has significant advantages of convenience, painless and mimetic endogenous insulin pathway, and thus it presents patients compliance, protects pancreatic β cells and lessens adverse effects caused by long-term injection. This challenging oral delivery of insulin can be achieved by promising silica nanoparticles (SNs), especially mesoporous silica nanoparticles (MSNs), with controllable morphology and high loading efficiency. This review presents the synthesis and physiological behaviors of SNs such as in vivo and in vitro degradation, absorption, distribution, and excretion, as well as preparations of oral insulin based on SNs. As well, this review will provide insights for innovative oral delivery of SNs and insulin.

Areas covered: Promising SNs and MSNs have gained interests for application in oral drug delivery of insulin.

Expert opinion: After synthesis under proper conditions and methods, promising SNs with controllable structure and suitable stability can be synthesized. By improving permeability and penetration, achieving controlled release and adjusting physiological processes, functionalization on SNs by active groups, molecules, or polymers is necessary for oral delivery of insulin.     

Application of chitosan/alginate nanoparticle in oral drug delivery systems: prospects and challenges

Oral drug delivery systems (ODDSs) have various advantages of simple operation and few side effects. ODDSs are highly desirable for colon-targeted therapy (e.g. ulcerative colitis and colorectal cancer), as they improve therapeutic efficiency and reduce systemic toxicity. Chitosan/alginate nanoparticles (CANPs) show strong electrostatic interaction between the carboxyl group of alginates and the amino group of chitosan which leads to shrinkage and gel formation at low pH, thereby protecting the drugs from the gastrointestinal tract (GIT) and aggressive gastric environment. Meanwhile, CANPs as biocompatible polymer, show intestinal mucosal adhesion, which could extend the retention time of drugs on inflammatory sites. Recently, CANPs have attracted increasing interest as colon-targeted oral drug delivery system for intestinal diseases. The purpose of this review is to summarize the application and treatment of CANPs in intestinal diseases and insulin delivery. And then provide a future perspective of the potential and development direction of CANPs as colon-targeted ODDSs.     

Impact of chitosan composites and chitosan nanoparticle composites on various drug delivery systems: A review

Chitosan is a promising biopolymer for drug delivery systems. Because of its beneficial properties, chitosan is widely used in biomedical and pharmaceutical fields. In this review, we summarize the physicochemical and drug delivery properties of chitosan, selected studies on utilization of chitosan and chitosan-based nanoparticle composites in various drug delivery systems, and selected studies on the application of chitosan films in both drug delivery and wound healing. Chitosan is considered the most important polysaccharide for various drug delivery purposes because of its cationic character and primary amino groups, which are responsible for its many properties such as mucoadhesion, controlled drug release, transfection, in situ gelation, and efflux pump inhibitory properties and permeation enhancement. This review can enhance our understanding of drug delivery systems particularly in cases where chitosan drug-loaded nanoparticles are applied.     

蛋白多肽类药物纳米粒口服给药系统的研究进展

目的综述近年来纳米粒作为蛋白质多肽类药物口服传递系统方面的研究现状和进展。方法分析有关文献资料,从纳米粒给药系统的载体材料、口服药效等方面进行了概述。结果纳米粒给药系统可提高蛋白质和多肽类药物的口服吸收效率,提高此类药物的生物利用度。结论纳米粒给药系统在口服传递蛋白质和多肽类药物方面有着广阔的研究和应用前景。     

负载pVAX1-wapA的壳聚糖及季铵化壳聚糖纳米粒的制备研究

目的 制备负载抗龋DNA疫苗pVAX1-wapA质粒的壳聚糖和季铵化壳聚糖纳米粒,优化其制备工艺,测定其细胞转染效率。 方法 以包封率和粒径为主要指标,单因素法考察载体浓度、pH值、N/P、TPP浓度等因素的影响,Realtime-PCR检测细胞对质粒编码蛋白的转录表达水平以评价载质粒纳米粒的促转染作用。 结果 制得的载DNA疫苗纳米粒粒径均一,形态圆整。壳聚糖(CS)纳米粒粒径为(219.2±18.2) nm,Zeta电位为(24.7±3.5) mV,包封率为91.24%。季铵化壳聚糖(CSTM)纳米粒粒径为(222.5±15.6) nm,Zeta电位为(19.6±1.2) mV,包封率为87.66%。纳米粒可以促进pVAX1-wapA进入细胞,并成功被转录。 结论 制备的包载pVAX1-wapA的季铵化壳聚糖纳米粒可用于重组基因疫苗的运送。     

口服纳米粒递送胰岛素研究进展

药物治疗糖尿病的最新进展当属口服胰岛素,而制备口服胰岛素需要将胰岛素包埋进载体使其避免胃肠降解。可突破肠上皮屏障达到良好降糖效果的口服载体多种多样,其中利用纳米材料制备胰岛素载体(INS-NPs)的研究最热,主要有以下优势:加强药物稳定性,大大提升生物利用率;实现靶向定位释药,降低药物对机体的毒副作用;控制释放药物时量,使药物在体内的作用更加明显等。针对上述优势并结合相关研究结论,本文从生物利用率、降糖时效和控释作用3个方面简述口服纳米粒在糖尿病治疗中的新进展。     

口服胰岛素羧甲基壳聚糖纳米粒的制备及评价

目的:研制一种生物利用度高且具有缓释作用的口服胰岛素制剂。方法:通过钙离子交联制备羧甲基壳聚糖纳米粒,采用正交试验优化纳米粒制备条件,以透射电镜观察纳米粒形态,激光粒度分析仪测定粒度,高效液相色谱法测定纳米粒包封率和载药量,并对胰岛素的体外释放性能进行考察。结果:优化工艺制备的纳米粒外观形态圆整,平均粒径为(256.1±11.2)nm,包封率为(45±0.41)%,载药量为(17.2±0.33)%,药理相对生物利用度为14.71%。结论:口服载胰岛素羧甲基壳聚糖纳米粒具有降血糖作用和显著的缓释作用,药理相对生物利用度高。     

Polymeric nanoparticle drug delivery technologies for oral delivery applications

Introduction: Many therapeutics are limited to parenteral administration. Oral administration is a desirable alternative because of the convenience and increased compliance by patients, especially for chronic diseases that require frequent administration. Polymeric nanoparticles (NPs) are one technology being developed to enable clinically feasible oral delivery.

Areas covered: This review discusses the challenges associated with oral delivery. Strategies used to overcome gastrointestinal (GI) barriers using polymeric NPs will be considered, including mucoadhesive biomaterials and targeting of NPs to transcytosis pathways associated with M cells and enterocytes. Applications of oral delivery technologies will also be discussed, such as oral chemotherapies, oral insulin, treatment of inflammatory bowel disease, and mucosal vaccinations.

Expert opinion: There have been many approaches used to overcome the transport barriers presented by the GI tract, but most have been limited by low bioavailability. Recent strategies targeting NPs to transcytosis pathways present in the intestines have demonstrated that it is feasible to efficiently transport both therapeutics and NPs across the intestines and into systemic circulation after oral administration. Further understanding of the physiology and pathophysiology of the intestines could lead to additional improvements in oral polymeric NP technologies and enable the translation of these technologies to clinical practice.     

以N-三甲基壳聚糖为载体的纳米粒研究进展

N-三甲基壳聚糖（TMC）是壳聚糖的一种季胺盐衍生物,与壳聚糖具有相似的生物学性质,但TMC在中性及弱碱性条件下具有很好的溶解性。TMC作为载药体系其毒性较低、无抗原性且运载药物和基因的效率较高。离子交联法制备纳米粒操作简单,可避免因使用有机溶剂和超声等造成污染与破坏。本文综述TMC为载体的纳米粒研究进展。     

注射用紫杉醇纳米制剂的研究进展

紫杉醇广泛用于卵巢癌、乳腺癌、肺癌等多种肿瘤的治疗。传统的紫杉醇制剂生物利用度低,临床应用有限。纳米给药系统是现代药物制剂的研究热点,近年来临床上陆续开发了紫杉醇的纳米新剂型。纳米乳、纳米粒、胶束等也正在实验研究之中。本文就紫杉醇纳米制剂的开发和应用进展进行综述。     

Effect of formulation variables on cis-platin loaded chitosan microsphere properties

Chitosan microspheres containing cis-platin were prepared using a w/o emulsion system. Variables important for microsphere properties were investigated: these include; chitosan, cis-platin and glutaraldehyde concentrations, the types of chitosan and oil, the cross-linking process and stirring rate. Chitosan and glutaraldehyde concentrations, the types of oil and chitosan have a significant effect on cis-platin entrapment in chitosan microspheres. In general, incorporation efficiency was high and ranged from 28-99%. The type and concentration of chitosan affected cis-platin release from microspheres. The type of oil was also important for release properties. Cis-platin release from microspheres is characterized by an initial burst effect.     

Design and evaluation of novel pH-sensitive chitosan nanoparticles for oral insulin delivery

Chitosan nanoparticles (CS NPs) have been commonly regarded as potential carriers for the mucosal delivery of therapeutic peptides because of their biocompatibility, bioadhesion and permeation enhancing properties. However, they have limited colloidal stability and readily dissociate and dissolve in the acidic gastric conditions. In the current study, CS NPs were formulated by ionic cross-linking with hydroxypropyl methylcellulose phthalate (HPMCP) as a pH-sensitive polymer and evaluated for the oral delivery of insulin. In vitro results revealed a superior acid stability of CS/HPMCP NPs with a significant control over insulin release and degradation in simulated acidic conditions with or without pepsin. Furthermore, fluorescently-labeled CS/HPMCP NPs showed a 2- to 4-fold improvement in the intestinal mucoadhesion and penetration compared to CS/TPP NPs as evidenced by quantitative fluorescence analysis and confocal microscopy. After s.c. injection to rats, no significant difference in the hypoglycemic effect of insulin solution or insulin-loaded CS/HPMCP NPs was observed, confirming the physico-chemical stability and biological activity of the entrapped peptide. Following peroral administration, CS/HPMCP NPs increased the hypoglycemic effect of insulin by more than 9.8 and 2.8-folds as compared to oral insulin solution and insulin-loaded CS/tripolyphosphate (TPP) NPs, respectively.     

Microencapsulated chitosan nanoparticles for lung protein delivery

It has already been demonstrated that spray drying is a very valuable technique for producing dry powders adequate for pulmonary delivery of drugs. We have developed chitosan/tripolyphosphate nanoparticles that promote peptide absorption across mucosal surfaces. The aim of this work was to microencapsulate protein-loaded chitosan nanoparticles using typical aerosol excipients, such as mannitol and lactose, producing microspheres as carriers of protein-loaded nanoparticles to the lung. The results showed that the obtained microspheres are mostly spherical and possess appropriate aerodynamic properties for pulmonary delivery (aerodynamic diameters between 2 and 3 μm, apparent density lower than 0.45 g/cm³). Moreover, microspheres morphology was strongly affected by the content of chitosan nanoparticles. These nanoparticles show a good protein loading capacity (65–80%), providing the release of 75–80% insulin within 15 min, and can be easily recovered from microspheres after contact with an aqueous medium with no significant changes in their size and zeta potential values. Therefore, this work demonstrated that protein-loaded nanoparticles could be successfully incorporated into microspheres with adequate characteristics to reach the deep lung, which after contact with its aqueous environment are expected to be able to release the nanoparticles, and thus, the therapeutic macromolecule.     

The importance of nanoparticle shape in cancer drug delivery

Introduction: Nanoparticles have been successfully used for cancer drug delivery since 1995. In the design of commercial nanoparticles, size and surface characteristics have been exploited to achieve efficacious delivery. However, the design of optimized drug delivery platforms for efficient delivery to disease sites with minimal off-target effects remains a major research goal. One crucial element of nanoparticle design influencing both pharmacokinetics and cell uptake is nanoparticle morphology (both size and shape). In this succinct review, the authors collate the recent literature to assess the current state of understanding of the influence of nanoparticle shape on the effectiveness of drug delivery with a special emphasis on cancer therapy.

Areas covered: This review draws on studies that have focused on the role of nonspherical nanoparticles used for cancer drug delivery. In particular, the authors summarize the influence of nanoparticle shape on biocirculation, biodistribution, cellular uptake and overall drug efficacy. By comparing spherical and nonspherical nanoparticles, they establish some general design principles to serve as guidelines for developing the next generation of nanocarriers for drug delivery.

Expert opinion: Pioneering studies on nanoparticles show that nonspherical shapes show great promise as cancer drug delivery vectors. Filamentous or worm-like micelles together with other rare morphologies such as needles or disks may become the norm for next-generation drug carriers, though at present, traditional spherical micelles remain the dominant shape of nanocarriers described in the literature due to synthesis and testing difficulties. The few reports that do exist describing nonspherical nanoparticles show a number of favorable properties that should encourage more efforts to develop facile and versatile nanoparticle synthesis methodologies with the flexibility to create different shapes, tunable sizes and adaptable surface chemistries. In addition, the authors note that there is a current lack of understanding into the factors governing (and optimizing) the inter-relationships of size, surface characteristics and shapes of many nanoparticles proposed for use in cancer therapy.     

Tocol modified glycol chitosan for the oral delivery of poorly soluble drugs

The aim of this study was to develop tocol derivatives of chitosan able (i) to self-assemble in the gastrointestinal tract and (ii) to enhance the solubility of poorly soluble drugs. Among the derivatives synthesized, tocopherol succinate glycol chitosan (GC-TOS) conjugates spontaneously formed micelles in aqueous solution with a critical micelle concentration of 2 μg mL⁻¹. AFM and TEM analysis showed that spherical micelles were formed. The GC-TOS increased water solubility of 2 model class II drugs. GC-TOS loading efficiency was 2.4% (w/w) for ketoconazole and 0.14% (w/w) for itraconazole, respectively. GC-TOS was non-cytotoxic at concentrations up to 10 mg mL⁻¹. A 3.4-fold increase of the apparent permeation coefficient of ketoconazole across a Caco-2 cell monolayer was demonstrated. Tocol polymer conjugates may be promising vehicles for the oral delivery of poorly soluble drugs.     

Preparation and optimization of N-trimethyl-O-carboxymethyl chitosan nanoparticles for delivery of low-molecular-weight heparin

The aim of this study was preparation, optimization and in vitro characterization of nanoparticles composed of 6-[O-carboxymethyl]-[N,N,N-trimethyl] (TMCMC) for oral delivery of low-molecular-weight heparin. The chitosan derivative was synthesized. Nanoparticles were prepared using the polyelectrolyte complexation method. Box–Behnken response surface experimental design methodology was used for optimization of nanoparticles. The morphology of nanoparticles was studied using transmission electron microscopy. In vitro release of enoxaparin from nanoparticles was determined under simulated intestinal fluid. The cytotoxicity of nanoparticles on a Caco-2 cell line was determined, and finally the transport of prepared nanoparticles across Caco-2 cell monolayer was defined. Optimized nanoparticles with proper physico-chemical properties were obtained. The size, zeta potential, poly-dispersity index, entrapment efficiency and loading efficiency of nanoparticles were reported as 235?±?24.3?nm, +18.6?±?2.57?mV, 0.230?±?0.03, 76.4?±?5.43% and 12.6?±?1.37%, respectively. Morphological studies revealed spherical nanoparticles with no sign of aggregation. In vitro release studies demonstrated that 93.6?±?1.17% of enoxaparin released from nanoparticles after 600?min of incubation. MTT cell cytotoxicity studies showed no cytotoxicity at 3?h post-incubation, while the study demonstrated concentration-dependent cytotoxicity after 24?h of exposure. The obtained data had shown that the nanoparticles prepared from trimethylcarboxymethyl chitosan may be considered as a good candidate for oral delivery of enoxaparin.     

蛋白多肽类口服给药微粒载体研究进展

蛋白多肽类药物已经成为国内外药学研究和开发的热点,文中介绍几种给药微粒载体在多肽蛋白类药物口服中的应用,分别阐述了纳米粒、微球、脂质体、微乳等的应用和研究新成果。上述新型给药微粒载体研究在蛋白多肽药物制备中取得较大进展,明显改善了蛋白多肽药物的稳定性和体内药动学性质,在蛋白多肽药物研究中有广阔的应用前景。     

The potential of cystine-knot microproteins as novel pharmacophoric scaffolds in oral peptide drug delivery

Within this study, the potential of three clinically relevant microproteins (SE–AG–AZ, SE–EM and SE–EP) with cystine-knot architecture as pharmacophoric scaffolds for oral peptide delivery was investigated. Cystine-knot microproteins (CKM) were analysed regarding their stability towards the most important gastrointestinal secreted and membrane bound proteases in physiological concentrations. In addition, their permeation behaviour through freshly excised rat intestinal mucosa as well as important parameters such as aggregation behaviour, stability in rat plasma and isoelectric point were evaluated and compared to the properties of the model peptide drugs bacitracin and insulin. Aggregation studies indicate that under physiological conditions between 25 and 70% of the CKMs occur as monomers, whereas the rest forms di- and trimers. Pepsin and elastase cause no or only minor degradation to CKMs, whereas trypsin and chymotrypsin degrade CKMs extensively. Removing the theoretical chymotrypsin cleavage site from a CKM, however, led to stabilization towards this protease. Two of the three evaluated CKMs are stable against membrane bound proteases. P_app values were determined to be 5.96 ± 0.98 × 10^{? 6} and 6.63 ± 0.47 × 10^{? 6} cm/s. In conclusion, this study indicates that CKM are promising novel pharmacophoric scaffolds for oral peptide delivery.     

Nasal delivery of insulin using chitosan microspheres

Nasal delivery of insulin is an alternative route for administration of this drug. The objective of this study was preparation of chitosan microspheres for insulin nasal delivery. After preparation of insulin chitosan microspheres by emulsification-cross linking process, the effect of chitosan quantity (200–400?mg), cross-linker type (ascorbic acid or ascorbyl palmitate) and amount (70–140?mg) were studied on the morphology, particle size, loading efficiency, flow and release of insulin from the microspheres by a factorial design. Optimized formulation was administered nasally in four groups of diabetic rats and their serum insulin levels were analysed by the insulin enzyme immunoassay kit and the serum glucose by the glucose oxidase kits. Insulin loading in microspheres was between 4.7–6.4% w/w, preparation efficiency more than 65% and mean particle size was 20–45?µm. In most cases, drug released followed a Higuchi model. Ascorbic acid caused an increase in stability, particle size and T_50% while decreased the loading efficiency and production efficiency. Increasing the chitosan content, increased particle size, flow and insulin release rate form the microspheres. The increase of cross-linking percentage decreased the flow and size of the microspheres while increase of cross-linking percentage promoted the stability and decreased DE₈% of insulin. Microspheres containing 400?mg of chitosan and 70?mg ascorbyl palmitate caused a 67% reduction of blood glucose compared to i.v. route and absolute bioavaliability of insulin was 44%. The results showed that chitosan microspheres of insulin are absorbable from nasal route.