Evaluation and modification of N-trimethyl chitosan chloride nanoparticles as protein carriers

N-Trimethyl chitosan chloride (TMC) nanoparticles were prepared by ionic crosslinking of TMC with tripolyphosphate (TPP). Two model proteins with different pI values, bovine serum albumin (BSA, pI=4.8) and bovine hemoglobin (BHb, pI=6.8), were used to investigate the loading and release features of the TMC nanoparticles. TMC samples with different degrees of quaternization were synthesized to evaluate its influence on the physicochemical properties and release profiles of the nanoparticles. Sodium alginate was used to modify the TMC nanoparticles to reduce burst release. The results indicated that the TMC nanoparticles had a high loading efficiency (95%) for BSA but a low one (30%) for BHb. The particle size and zeta potential were significantly affected by the BSA concentration but not by the BHb concentration. Nanoparticles of TMC with a lower degree of quaternization showed an increase in particle size, a decrease in zeta potential and a slower drug-release profile. As for the alginate-modified nanoparticles, a smaller size and lower zeta potential were observed and the burst release of BSA was reduced. These studies demonstrated that TMC nanoparticles are potential protein carriers, and that their physicochemical properties and release profile could be optimized by means of various modifications.     

Effect of molecular structure of chitosan on protein delivery properties of chitosan nanoparticles

Chitosan nanoparticles (CS NP) with various formations were produced based on ionic gelation process of tripolyphosphate (TPP) and chitosan. They were examined with diameter 20-200 nm and spherical shape using TEM. FTIR confirmed tripolyphosphoric groups of TPP linked with ammonium groups of chitosan in the nanoparticles. Factors affecting delivery properties of bovine serum albumin (BSA) as model protein have been tested, they included molecular weight (Mw) and deacetylation degree (DD) of chitosan, the concentration of chitosan and initial BSA, and the presence of polyethylene glycol (PEG) in encapsulation medium. Increasing Mws of chitosan from 10 to 210 kDa, BSA encapsulation efficiency was enhanced about two times, BSA total release in PBS (phosphate buffer saline) pH 7.4 in 8 days was reduced from 73.9 to 17.6%. Increasing DD from 75.5 to 92% promoted slightly the encapsulation efficiency and decelerated the release rate. The encapsulation efficiency was highly decreased by increase of initial BSA and chitosan concentration; higher loading capacity of BSA speeded the BSA release from the nanoparticles. Adding PEG hindered the BSA encapsulation and accelerated the release rate.     

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。     

离子凝胶法制备壳聚糖纳米粒的影响因素研究

目的 探讨离子凝胶法制备壳聚糖纳米粒(CS-NPs)的影响因素.方法 用碱降解法制备高脱乙酰度的壳聚糖(CS),并以之为材料,采用离子凝胶法制备CS-NPs,以微粒的平均粒径、分散度和Zeta电位为指标,考察CS及三聚磷酸钠(TPP)的质量浓度、CS/TPP质量比、CS溶液pH值和CS溶液温度对制备CS-NPs的影响....     

壳聚糖纳米粒表面游离氨基与纳米粒特性研究

为研究对三聚磷酸钠(TPP)交联的壳聚糖纳米粒的表面游离氨基与纳米粒的性质之间的关联性,采用胶体滴定法测定壳聚糖纳米粒表面氨基游离率，考察表面游离氨基的数量及离解程度对纳米粒粒径、电位、形态及对药物包封率和体外释药特性的影响，并阐述这种变化机制。结果表明，随TPP浓度增加，表面游离氨基逐步减少，在一定TPP浓度范围内，纳米粒粒径减小，表面zeta电位降低，稳定性也随之下降，粒子易聚集，释药速度和程度也随之降低，但药物包封率未受到影响；随着pH升高，表面游离氨基离解程度降低，纳米粒粒径亦随之减小，表面zeta电位降低。酸性介质提高纳米粒的释药速度和程度，在中性和碱性介质中纳米粒的释药速度和程度明显降低。交联程度和pH影响表面游离氨基的数量或离解程度，进而影响纳米粒的体积相转变(溶胀/收缩过程)等重要性质。表面游离氨基与纳米粒性质间有密切的联系。     

Preparation of chitosan nanoparticles containing Naja naja oxiana snake venom

Hydrophilic nanoparticles have received much attention for delivery of therapeutic peptides, proteins, and antigens. Chitosan (CS) is a biodegradable and nontoxic polysaccharide, as a carrier for drug delivery. The study purpose was to evaluate the influence of a number of factors on the encapsulation of Naja naja oxiana (Indian or speckled cobra) venom and loading capacity, as well as to investigate the physicochemical structure of nanoparticles. CS nanoparticles were produced based on the ionic gelation process of tripolyphosphate (TPP) and CS. All the preparations were estimated with diameter 120–150 nm and spherical shape using transmission electron microscopy. Fourier transform–infrared spectroscopy confirmed that tripolyphosphoric groups of TPP linked with ammonium groups of CS in the nanoparticles. Our results showed that CS can react with TPP to form stable cationic nanoparticles. Therefore, when chitosan concentration was increased to 1.5 mg/mL the aggregates with large diameter were formed. Optimum loading capacity and encapsulation efficiency of venom at a concentration of 500 μg/mL were achieved for low-molecular-weight (low-MW) CS at a concentration of 2 mg/mL and high-MW CS at a concentration of 3 mg/mL.From the Clinical EditorIn this study a hydrophilic nanoparticle chitosan was investigated as a protein delivery system, and optimum conditions were established for future use of this technology.     

Synthesis and characterization of chitosan quaternary ammonium salt and its application as drug carrier for ribavirin

Abstract

N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) is hydro-soluble chitosan (CS) derivative, which can be obtained by the reaction between epoxypropyl trimethyl ammonium chloride (ETA) and CS. The preparation parameters for the synthesis of HTCC were optimized by orthogonal experimental design. ETA was successfully grafted into the free amino group of CS. Grafting of ETA with CS had great effect on the crystal structure of HTCC, which was confirmed by the XRD results. HTCC displayed higher capability to form nanoparticles by crosslinking with negatively charged sodium tripolyphosphate (TPP). Ribavrin- (RIV-) loaded HTCC nanoparticles were positively charged and were spherical in shape with average particle size of 200?nm. More efficient drug encapsulation efficiency and loading capacity were obtained for HTCC in comparison with CS, however, HTCC nanoparticles displayed faster release rate due to its hydro-soluble properties. The results suggest that HTCC is a promising CS derivative for the encapsulation of hydrophilic drugs in obtaining sustained release of drugs.     

Preparation and characterization of drug‐loaded chitosan–tripolyphosphate microspheres by spray drying

The present study reports on the preparation of chitosan–tripolyphosphate (TPP) microspheres by the spray‐drying method using acetaminophen as a model drug substance. Chitosan–TPP microspheres were spherical and had a smooth surface. Perfectly spherical chitosan–TPP microparticles loaded with acetaminophen were obtained in the size range of 3.1–10.1 µm. Spray‐dried chitosan–TPP microspheres were positively charged (zeta potential ranged from +18.4 to +31.8). The encapsulation efficiency of these microspheres was in the range of 48.9–99.5%. The swelling capacity of chitosan–TPP microspheres increased with increases in the molecular weight of chitosan and decreases with increasing volume of 1% wt/vol TPP solution used for the cross‐linking reaction. The effect of chitosan concentration, drug loading, volume of TPP solution used for cross‐linking, and chitosan molecular weight on surface morphology and drug release rate was extensively investigated. Microparticles with spherical shape and slower release rates were obtained from chitosan–TPP microspheres prepared using a higher concentration of chitosan, higher volume of TPP solution, a higher molecular weight chitosan and/or a higher drug loading. Most importantly, the drug release rate was mainly controlled by the chitosan–TPP matrix density and, thus, by the degree of swelling of the hydrogel matrix. Drug release from chitosan–TPP microspheres occurred via diffusion as the best fit for drug release was obtained using the Higuchi equation. Drug Dev. Res. 64:114–128, 2005. © 2005 Wiley‐Liss, Inc.     

壳聚糖负载肉桂挥发油纳米粒制备工艺响应面法优化及质量评价

目的:优化壳聚糖负载肉桂挥发油纳米粒的制备工艺和处方,并对其质量进行评价。方法:采用单因素考察壳聚糖纳米粒制备的处方和工艺,以粒径、包封率和载药量为评价指标,应用星点设计-响应面法优化负载肉桂挥发油的壳聚糖纳米颗粒的制备工艺,采用透射电镜观察肉桂挥发油壳聚糖纳米粒形态,并对其稳定性进行研究。结果:壳聚糖负载肉桂挥发油纳米粒优化后的工艺为壳聚糖浓度0.2%,均质压力为500 bar(1 bar=0.1 MPa),循环次数为20次,TPP含量0.2 mg·mL^-1,在该条件下平均包封率为(83.37±0.40)%、平均载药量为(26.42±0.65)%、平均粒径为(248.5±12.2) nm, Zeta电位为(52.3±1.1) mV。透射电镜结果显示其呈粒径均匀的类球形,且肉桂油外包裹着一层壳聚糖。稳定性结果显示壳聚糖负载肉桂挥发油纳米粒混悬液在低温条件下贮存最佳。结论:负载肉桂挥发油壳聚糖纳米粒,制备工艺简单,可重复性较好,物理稳定性较好。     

Preparation, characterization and protein loading of hexanoyl-modified chitosan nanoparticles

Hexanoyl chitosan was synthesized through a coupling reaction between chitosan and hexanoic anhydride. Proton nuclear magnetic resonance (¹HNMR) and fourier-transform infrared (FTIR) spectroscopy studies showed the formation of hexanoyl chitosan. The nanoparticles of hexanoyl chitosan were prepared through ionotropic gelation with tripolyphosphate (TPP) followed by sonication. The hexanoyl chitosan-TPP nanoparticles exhibited uniform spherical shape with smooth surface as observed by atomic force microscopy and transmission electron microscopy. The particle size of nanoparticles was between 54.1 to 724 nm with a mean diameter of 324 nm. At 0.2, 0.4, and 0.6 mg/mL bovine serum albumin initial concentration, the encapsulation efficiency and loading capacity of hexanoyl-chitosan-TPP nanoparticles were 58.2, 44.5, and 28.1%, and 14.1, 23.4, and 30.3%, respectively.     

Preparation,Characterization and Protein Loading of Hexanoyl-Modified Chitosan Nanoparticles

Hexanoyl chitosan was synthesized through a coupling reaction between chitosan and hexanoic anhydride. Proton nuclear magnetic resonance (¹HNMR) and fourier-transform infrared (FTIR) spectroscopy studies showed the formation of hexanoyl chitosan. The nanoparticles of hexanoyl chitosan were prepared through ionotropic gelation with tripolyphosphate (TPP) followed by sonication. The hexanoyl chitosan-TPP nanoparticles exhibited uniform spherical shape with smooth surface as observed by atomic force microscopy and transmission electron microscopy. The particle size of nanoparticles was between 54.1 to 724 nm with a mean diameter of 324 nm. At 0.2, 0.4, and 0.6 mg/mL bovine serum albumin initial concentration, the encapsulation efficiency and loading capacity of hexanoyl-chitosan-TPP nanoparticles were 58.2, 44.5, and 28.1%, and 14.1, 23.4, and 30.3%, respectively.     

Thiomers: preparation and in vitro evaluation of a mucoadhesive nanoparticulate drug delivery system

It was the aim of this study to develop a mucoadhesive nanoparticulate delivery system. Nanoparticles were generated by in situ gellation of the thiomer chitosan-4-thiobutylamidine (chitosan-TBA) with tripolyphosphate (TPP) followed by stabilization via the formation of inter- and intrachain disulfide bonds by oxidation with H(2)O(2) in various concentrations. Afterwards TPP was removed by exhaustive dialysis at pH 1-2. Incorporation of the model compound fluorescein diacetate (FDA) was achieved by incubation of this fluorescence marker, dissolved in acetonitrile, with aqueous particle suspensions for 1h at room temperature. Mucoadhesion studies were performed on porcine intestinal mucosa. Results showed that the preparation method described above leads to nanoparticles of a mean diameter of 268+/-15 nm and a FDA load of 2%. Due to the removal of the anionic crosslinker TPP, the zeta potential of the nanoparticles was raised from 4+/-1 up to 19+/-2 mV without loosing stability of the nanoparticles. The more H(2)O(2) was added to the particles, the more inter- and intrachain disulfide bonds were formed. The more thiol groups were oxidized within the particles, however, the lower was the improvement in mucoadhesive properties. Nevertheless, even when 91% of all thiol groups on the nanoparticles were oxidized, their mucoadhesive properties were still twice as high as the mucoadhesive properties of unmodified nanoparticles. Thiolated chitosan nanoparticles show a two-fold higher zeta potential (I), improved stability (II) and more than doubled mucoadhesive properties (III) than corresponding unmodified chitosan nanoparticles. Therefore, they seem to be advantageous over ionically crosslinked chitosan nanoparticles.     

Encapsulation of vitamin C in tripolyphosphate cross-linked chitosan microspheres by spray drying

This paper describes vitamin C-encapsulated chitosan microspheres cross-linked with tripolyphosphate (TPP) using a new process prepared by spray drying intended for oral delivery of vitamin C. Thus, prepared microspheres were evaluated by loading efficiency, particles size analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), zeta potential and in vitro release studies. The microspheres so prepared had a good sphericity and shape but varied with the volume of cross-linking agent solution added. They were positively charged. The mean particle size ranged from 6.1-9.0 microm. The size, shape, encapsulation efficiency, zeta potential and release rate were influenced by the volume of cross-linking agent. With the increasing amount of cross-linking agent, both the particle size and release rate were increased. Encapsulation efficiency decreased from 45.05-58.30% with the increasing amount of TPP solution from 10-30 ml. FTIR spectroscopy study showed that the vitamin C was found to be stable after encapsulation. XRD studies revealed that vitamin C is dispersed at the molecular level in the TPP-chitosan matrix. Well-defined change in the surface morphology was observed with the varying volume of TPP. The sphericity of chitosan microspheres was lost at higher volume of cross-linking agent. The release of vitamin C from these microspheres was sustained and affected by the volume of cross-linking agent added. The release of vitamin C from TPP-chitosan microspheres followed Fick's law of diffusion.     

Critical physicochemical attributes of chitosan nanoparticles admixed lactose-PEG 3000 microparticles in pulmonary inhalation

Chitosan nanoparticles are exhalation prone and agglomerative to pulmonary inhalation. Blending nanoparticles with lactose microparticles (∼5 µm) could mutually reduce their agglomeration through surface adsorption phenomenon. The chitosan nanoparticles of varying size, size distribution, zeta potential, crystallinity, shape and surface roughness were prepared by spray drying technique as a function of chitosan, surfactant and processing conditions. Lactose-polyethylene glycol 3000 (PEG3000) microparticles were similarly prepared. The chitosan nanoparticles, physically blended with fine lactose-PEG3000 microparticles, exhibited a comparable inhalation performance with the commercial dry powder inhaler products (fine particle fraction between 20% and 30%). Cascade impactor analysis indicated that the aerosolization and inhalation performance of chitosan nanoparticles was promoted by their higher zeta potential and circularity, and larger size attributes of which led to reduced inter-nanoparticulate aggregation and favored nanoparticles interacting with lactose-PEG3000 micropaticles that aided their delivery into deep and peripheral lungs.     

Encapsulation of vitamin C in tripolyphosphate cross-linked chitosan microspheres by spray drying

This paper describes vitamin C-encapsulated chitosan microspheres cross-linked with tripolyphosphate (TPP) using a new process prepared by spray drying intended for oral delivery of vitamin C. Thus, prepared microspheres were evaluated by loading efficiency, particles size analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), zeta potential and in vitro release studies. The microspheres so prepared had a good sphericity and shape but varied with the volume of cross-linking agent solution added. They were positively charged. The mean particle size ranged from 6.1–9.0?µm. The size, shape, encapsulation efficiency, zeta potential and release rate were influenced by the volume of cross-linking agent. With the increasing amount of cross-linking agent, both the particle size and release rate were increased. Encapsulation efficiency decreased from 45.05–58.30% with the increasing amount of TPP solution from 10–30?ml. FTIR spectroscopy study showed that the vitamin C was found to be stable after encapsulation. XRD studies revealed that vitamin C is dispersed at the molecular level in the TPP-chitosan matrix. Well-defined change in the surface morphology was observed with the varying volume of TPP. The sphericity of chitosan microspheres was lost at higher volume of cross-linking agent. The release of vitamin C from these microspheres was sustained and affected by the volume of cross-linking agent added. The release of vitamin C from TPP-chitosan microspheres followed Fick's law of diffusion.     

Effect of chitosan on physicochemical properties of exenatide-loaded PLGA nanoparticles

The aim of this study was to test stability of exenatide and compare physicochemical properties of PLGA nanoparticles. To make small, stable, uniform and highly encapsulated nanoparticles, various factors such as the components (polymer and stabilizer) and preparation condition (organic phase, temperature or sonication time) were considered. We tested the effect of organic phase, acid/base, ultrasonication time or temperature on exenatide to decide preparation condition of PLGA nanoparticles. And, PLGA nanoparticles were prepared by the double emulsion-solvent evaporation method and chitosan was selected as stabilizer. PLGA nanoparticles were characterized by yield, encapsulation efficiency, drug loading, particle size, zeta potential, polydispersity index and morphology. In this study, PLGA nanoparticles showed different physicochemical properties according to chitosan molecular weight. In case of particle size, PLGA nanoparticles using 0.5 g chitosan (4 kDa) showed biggest particle size (781.4 ± 24.1 nm) among PLGA nanoparticles prepared in this study and PLGA nanoparticles using 1 g chitosan (2 kDa) showed highest encapsulation efficiency (52.8 ± 1.7 %) among PLGA nanoparticles prepared in this study. And, all of PLGA nanoparticles using chitosan showed that polydispersity index was low and zeta-potential was increased. These results suggest that chitosan molecular weight affects physicochemical properties of PLGA nanoparticle.     

Development and Characterization of Chitosan Cross-Linked With Tripolyphosphate as a Sustained Release Agent in Tablets,Part I: Design of Experiments and Optimization

Certain issues with the use of particles of chitosan (Ch) cross-linked with tripolyphosphate (TPP) in sustained release formulations include inefficient drug loading, burst drug release, and incomplete drug release. Acetaminophen was added to Ch:TPP particles to test for advantages of drug addition extragranularly over drug addition made during cross-linking. The influences of Ch concentration, Ch:TPP ratio, temperature, ionic strength, and pH were assessed. Design of experiments allowed identification of factors and 2-factor interactions that have significant effects on average particle size and size distribution, yield, zeta potential, and true density of the particles, as well as drug release from the directly compressed tablets. Statistical model equations directed production of a control batch that minimized span, maximized yield, and targeted a t₅₀ of 90 min (sample A); sample B that differed by targeting a t₅₀ of 240-300 min to provide sustained release; and sample C that differed from sample B by maximizing span. Sample B maximized yield and provided its targeted t₅₀ and the smallest average particle size, with the higher zeta potential and the lower span of samples B and C. Extragranular addition of a drug to Ch:TPP particles achieved 100% drug loading, eliminated a burst drug release, and can accomplish complete drug release.     

Modification of solid lipid nanoparticles loaded with nebivolol hydrochloride for improvement of oral bioavailability in treatment of hypertension: polyethylene glycol versus chitosan oligosaccharide lactate

Nebivolol (NB)-loaded solid lipid nanoparticles (SLNs) were prepared and modified with chitosan oligosaccharide lactate (COL) and polyethylene glycol (PEG) stearate for improvement of its oral bioavailability. Compritol, poloxamer and lecithin were used for the preparation of SLNs by homogenisation method. After in vitro characterisation effect of lipase, pepsin, or pancreatin on degradation and release rate were investigated. Cytotoxicity and permeation were studied on Caco-2 cells. As COL concentration increased in SLNs, size and zeta potential increased. PEG concentration was reversely proportional to particle size with no change in zeta potential. Encapsulation efficiencies (EEs) were determined as 84–98%. DSC confirmed solubilisation of NB in lipid matrix. A sustained release with no burst effect was determined. The presence of enzymes affected the release. SLNs did not reveal cytotoxicity and highest permeability was obtained with PEG modification. PEG-modified SLNs could be offered as a promising strategy for oral delivery of NB.     

Cellular delivery of PEGylated PLGA nanoparticles

Objectives The objective of this study was to investigate the efficiency of uptake of PEGylated polylactide‐co‐gycolide (PLGA) nanoparticles by breast cancer cells. Methods Nanoparticles of PLGA containing various amounts of polyethylene glycol (PEG, 5%–15%) were prepared using a double emulsion solvent evaporation method. The nanoparticles were loaded with coumarin‐6 (C6) as a fluorescence marker. The particles were characterized for surface morphology, particle size, zeta potential, and for cellular uptake by 4T1 murine breast cancer cells. Key findings Irrespective of the amount of PEG, all formulations yielded smooth spherical particles. However, a comparison of the particle size of various formulations showed bimodal distribution of particles. Each formulation was later passed through a 1.2 µm filter to obtain target size particles (114–335 nm) with zeta potentials ranging from ?2.8 mV to ?26.2 mV. While PLGA‐PEG di‐block (15% PEG) formulation showed significantly higher 4T1 cellular uptake than all other formulations, there was no statistical difference in cellular uptake among PLGA, PLGA‐PEG‐PLGA tri‐block (10% PEG), PLGA‐PEG di‐block (5% PEG) and PLGA‐PEG di‐block (10% PEG) nanoparticles. Conclusion These preliminary findings indicated that the nanoparticle formulation prepared with 15% PEGylated PLGA showed maximum cellular uptake due to it having the smallest particle size and lowest zeta potential.     

正交试验优选羧甲基壳聚糖-醋甲唑胺纳米微球的制备方案

目的：制备羧甲基壳聚糖载药纳米微球,醋甲唑胺为模型药物,测量药物的包封率和纳米微球形态.方法：采用乳化交联法,在微乳液的基础上制备载药纳米微球,对可能影响药物包封率的处方因素进行优化设计,筛选出最优配方.结果：羧甲基壳聚糖溶液的浓度对包封率有显著性影响,三聚磷酸钠溶液浓度和醋甲唑胺药量对包封率未见影响.优化方案的载药纳米微球包封率为49.36％,其电镜下为较规整的球型纳米微球,平均粒径386.0 nm.结论：采用乳化交联法,可形成较高包封率的羧甲基壳聚糖-醋甲唑胺纳米微球.