Preparation and characterization of venlafaxine hydrochloride‐loaded chitosan nanoparticles and in vitro release of drug

The venlafaxine hydrochloride (VHL)‐loaded chitosan nanoparticles were prepared by ionic gelation of chitosan (CS) using tripolyphosphate (TPP). The nanoparticles were characterized using FTIR, differential scanning calorimetry, X‐ray diffraction, dynamic light scattering, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The effect of concentration of CS, polyethylene glycol (PEG), VHL and CS/TPP mass ratio on the particle size and zeta potential of nanoparticles was examined. The particle size of CS/TPP nanoparticles and VHL‐loaded CS/TPP nanoparticles was within the range of 200–400 nm with positive surface charge. In the case of VHL‐loaded nanoparticles and PEG‐coated CS/TPP nanoparticles, the particle size increases and surface charge decreases with increasing concentration of VHL and PEG. Both placebo and VHL‐loaded CS/TPP nanoparticles were observed to be spherical in nature. PEG coating on the surface of CS/TPP nanoparticles was confirmed by XPS analysis. Maximum drug entrapment efficiency (70%) was observed at 0.6 mg/mL drug concentration. In vitro drug release study at 37°C ± 0.5°C and pH 7.4 exhibited initial burst release followed by a steady release. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Depolymerized chitosan nanoparticles for protein delivery: Preparation and characterization

In this article we describe our preliminary work involving the use of depolymerized, low molecular weight chitosan nanoparticles as carriers for proteins and peptides. We hypothesized that the molecular weight of chitosan could favorably modulate the particle and protein release characteristics for the delivery of certain bioactive macromolecules. Our primary objectives were to develop nanoparticle formulations that were stable and reproducible across a range of chitosan molecular weights and then characterize the physicochemical and in vitro release properties as functions of the polymer size. Using depolymerized fragments generated by NaNO₂ degradation of different chitosan salts, we prepared nanoparticle formulations based on ionotropic gelation with sodium tripolyphosphate (TPP). Regardless of the formulation, the nanoparticle size decreased with decreasing molecular weight and the ζ‐potential values remained unchanged. Similar comparisons were made with the encapsulation of insulin and tetanus toxoid as model proteins. The results indicated that the quantity of TPP in a given formulation has a greater effect on the protein encapsulation than the chitosan molecular weight. In fast release environments (i.e., buffered media), there was no significant molecular weight effect that could be discerned. These data lead to the conclusion that, under these experimental conditions, the chitosan molecular weight has a measurable effect on the particle properties, although this effect is modest relative to other formulation parameters (e.g., TPP content, type of protein loaded). Because these subtle differences could have dramatic effects physiologically, work is currently underway to elucidate the possible applications of depolymerized chitosans for peptide delivery in vivo. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 12: 2769–2776, 2003     

Preparation,evaluation, and in vitro release study of O‐carboxymethyl chitosan nanoparticles loaded with gentamicin and salicylic acid

To inhibit the ototoxicity of gentamicin (GM) and overcome the drawback related to chitosan (CS) nanoparticles preparation in acid solution, O‐carboxymethyl chitosan (O‐CMC) nanoparticles loaded with GM and salicylic acid (SA) were prepared by ionic cross‐linking method using calcium chloride as crosslinking agent. The Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) were used to analyze the reaction of O‐CMC and crosslinking agent. The parameters of preparation of the compound nanoparticles including the concentration of O‐CMC, the mass ratio of O‐CMC to calcium chloride, and the feed ratio of SA to GM were investigated. The results showed that the obtained nanoparticles had a high zeta potential and drug‐loading capacity. The nanoparticles were characterized by a spherical morphology, with average size ranging from 148 to 345 nm and a narrow particle size distribution. In vitro release studies in phosphate buffer saline (pH 7.4) evidenced a burst release in the first 1 h, followed by a sustained release in the residual time. The release amount of SA and GM were approximately equal in 24 h, which indicated that the SA‐ and GM‐loaded O‐CMC nanoparticles are a promising carrier system for inhibiting the ototoxicity of GM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

水溶性壳聚糖纳米粒子的制备及其BSA载药性能

为了避免高分子量壳聚糖水溶性差以及增溶剂乙酸可能带来的负面作用,本文选择低分子量水溶性壳聚糖 (WSC)作研究对象,采用三聚磷酸(TPP)作交链剂制备不同WSC/TPP比率的WSC纳米粒子,并用于牛血清白蛋白 (BSA)的释放载体。经测得为球形形貌的纳米粒子空载和载药时粒径、Zeta电位分别在35～190 nm、35～42 mV。红外光谱及X–射线衍射证实了纳米粒子中WSC的氨基与TPP的磷酸基团发生了交联反应。纳米粒子载药性能试验表明在0.05～1 mg/mL范围内随着BSA浓度的增大,纳米粒子的载药量增加而负载率降低。体外释放实验表明水溶性壳聚糖纳米载体对蛋白质药物具有缓释特征。因此,水溶性壳聚糖有望成为新的载体应用于蛋白质药物的控制释放。     

In vitro nifedipine release from poly(lactic acid)/chitosan nanoparticles loaded with nifedipine

In this study, nanoparticles based on poly(lactic acid) (PLA), chitosan (CS), and nifedipine (NIF) were prepared by an emulsion method with poly(ethylene oxide) (PEO) as an emulsifier. We investigated the most suitable conditions for preparing the poly(lactic acid)/chitosan/nifedipine nanoparticles (PCNs) by changing the distilled water volume, PEO content, and PLA/CS ratio. NIFs with different contents were loaded into poly(lactic acid)/chitosan nanoparticles (PCs) to study in vitro drug‐delivery systems. The PCNs were characterized with a Zetasizer particle size analyzer, field emission scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and X‐ray diffraction (XRD) methods. From the obtained results of the particle size parameters of the PCNs, the most suitable conditions for the preparation of the PCNs were found. The FTIR spectroscopy and XRD results show that NIF was loaded into the PCs. The PCNs had major basic particle sizes in the range 20–40 nm. NIF release from the PCNs was studied as a function of the pH of the immersed solution, the immersion time, and the NIF content. The kinetics of drug release were investigated and are reported to determine the type of release mechanism. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43330.     

Preparation of polymer nanoparticles loaded with doxorubicin for controlled drug delivery

The preparation of polymer nanoparticles loaded with an active principle, commonly used in cancer treatment, is investigated here from the experimental point of view. The main novelty of this work stands in the use of continuous confined impinging jets mixers in combination with realistic materials, notably the biodegradable and biocompatible copolymer poly(methoxypolyethyleneglycolcyanoacrylate-co-hexadecylcyanoacrylate) together with two forms of the drug doxorubicin. To our knowledge this is the first attempt to use for such a system a device that can be operated continuously and can be easily scaled up. Nanoparticles are produced via solvent-displacement experimenting different solvents; the effect of the other operating parameters is also investigated. Nanoparticles are characterized in terms of their size distribution and surface properties; for a limited number of samples prepared with the optimized preparation protocol further characterization (in terms of drug loading, incorporation and release profiles) is also carried out. Collected results show that the overall approach is capable of producing nanoparticles with controlled particle size distribution, drug loading and good reproducibility and that on the contrary of what reported in the literature the presence of the active principle does play an important role.     

Preparation of chitosan nanoparticles for encapsulation and release of protein

Chitosan nanoparticles were prepared by ionic cross-linking with tripolyphosphate (TPP). The major effect on encapsulation and release of protein in chitosan-TPP nanoparticles was investigated in order to control the loading and release efficiency. A set of the same molecular weight (MW) proteins with different pI and a set of the same pI proteins with different MW were studied. The influence of protein concentration, pH of solution, and the activity of released protein were examined. It was found that the encapsulation efficiency (EE) of a set of the different MW protein decreased with increasing of MW of protein and protein concentration. The protein with having pI higher than pH of solution was attracted to the positively charged chitosan, resulting in increasing of EE. The release of protein from the nanoparticles showed that the protein release decreased with increasing of chitosan concentration, high MW protein, low pH, and less swelling of the particle. The released protein in chitosan-TPP matrix was still active in the buffer solution.     

Preparation and characterization of mucoadhesive gels containing pentoxifylline loaded nanoparticles for vaginal delivery of genital ulcer

Iranian Polymer Journal - Mucoadhesive gel formulations containing pentoxifylline (PTX)-loaded nanoparticle (NP) for the treatment of genital ulcer were prepared and evaluated. In that context,...     

pH值响应聚乙二醇化壳聚糖基隐形纳米胶束的制备及其载药性能

聚乙二醇单甲醚(mPEG)先经过氯乙酸羧化后,再通过酰化反应接枝到双烷基壳聚糖上,制备高接枝度的N,N-双十二烷基-3,6-O-mPEG-壳聚糖(PEDLCS)双亲性衍生物,用¹H NMR、FTIR、EA等对产物进行表征,并用透析法制得PEDLCS载酮洛芬(KP)胶束。结果表明,PEDLCS在水溶液中能自组装形成胶束,CMC值为0.1170mg/mL;载药胶束的最优投料比为KP/PEDLCS=0.8:1,载药量34.48%,包封率65.78%,粒径155.1nm,Zeta电位-31.6mV。载药胶束在不同pH值条件下的响应性实验表明,随着pH值的减小,胶束的稳定性降低,胶束粒径变大,具有可逆性。pH值响应范围符合肿瘤细胞微环境(pH值为7.2～6.0),有望成为具有pH值响应主动靶向的隐形纳米胶束。     

甲氨蝶呤囊泡的制备和体外释放性能研究

用非离子表面活性剂和胆固醇为原料,采用薄膜分散法制备甲氨蝶呤囊泡,通过透析法分离未包封的药物,紫外分光光度法测定包封率和体外释药性。结果显示,Span 60与胆固醇形成的囊泡(VSpan 60∶VCHOL=5∶3),在50℃超声40 m in的条件下,对0.60 g/L的甲氨蝶呤包封率可达65%以上,在模拟胃流体和模拟肠流体中均有良好的缓释作用。     

Physicochemical characterization and antioxidant activity of quercetin‐loaded chitosan nanoparticles

Quercetin is an abundant flavonoid in food plants with numerous biological activities and widely used as a potent antioxidant. Being sparingly soluble in water and subject to degradation in aqueous intestinal fluids, the absorption of quercetin is limited upon oral administration. In the present study, chitosan nanoparticles and quercetin‐loaded nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. The encapsulation of quercetin in the chitosan nanoparticles were confirmed by differential scanning calorimetry, X‐ray powder diffractometry, Fourier transformed infrared spectroscopy, ultraviolet‐visible spectrum, and fluorescence spectrum. The morphology of the nanoparticles was characterized by atomic force microscopy. The antioxidant activity of the quercetin‐nanoparticles was also evaluated in vitro by two different methods (free radical scavenging activity test and reducing power test), which indicates that inclusion of quercetin in chitosan nanopaticles may be useful in improving the bioavailabilty of quercetin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Synthesis,characterization of biomimetic phosphorylcholine‐bound chitosan derivative and in vitro drug release of their nanoparticles

Novel water‐soluble biomimetic phosphorylcholine (PC)—bound chitosan derivatives (N‐PCCs) with different degree of substitution (DS) via a phosphoramide linkage between glucosamine and PC were synthesized through Atherton‐Todd reaction under the mild conditions, and structurally characterized by ¹H‐NMR, Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), X‐ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Their DS ranged from ～ 16 to ～ 42 mol % based on the ¹H‐NMR spectra. All these N‐PCCs with decreased crystallization showed excellent solubility in the aqueous solutions within a wide pH range (1–12). DSC and TGA results revealed that the thermal stability of N‐PCCs decreased with the increase of DS value. Further, N‐PCCs nanoparticles could be still formed in a spherical shape similar to chitosan nanoparticles by ionic gelation technique, observed by atomic force microscopy (AFM). Dynamic light scattering (DLS) results suggested that the zeta potential value of N‐PCCs nanoparticles decreased with the DS value increasing. Using 5‐fluorouracil (5‐Fu) as a model drug, in vitro drug release studies indicated that N‐PCCs nanoparticles exhibited a similar prolonged release profile as chitosan nanoparticles. The results suggested that N‐PCCs nanoparticles could be used as promising nanocarriers for drug delivery applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

pH敏感O-羧甲基壳聚糖自组装纳米粒的制备及表征

用5β-胆烷酸(5β-CHA)对O-羧甲基壳聚糖(OCMC)进行疏水改性,接枝磺胺地托辛(SDM)以增强其pH敏感性,在pH=9的磷酸盐缓冲溶液中制备了对肿瘤组织具有靶向潜力的自组装纳米粒子.所得纳米粒粒径在100hm左右,且随5β-CHA接枝量的增加5β-CHA/OCMC纳米粒的粒径减小.自组装纳米粒有较低的临界聚集浓度(10-2 mg/mL),在pH=7.4(人体正常pH)的水溶液中表现出高度稳定性.而当溶液的pH<6.8(肿瘤组织pH)时,接枝SDM的纳米粒子会迅速聚集,粒径剧增,且随SDM接枝量的增加pH敏感性增强.     

Preparation and characterization of chitosan/sepiolite bionanocomposites for tetracycline release

Chitosan/sepiolite (CS/SEP) bionanocomposite films have been prepared and characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), X‐ray diffraction, and scanning electron microscopic analysis. The results indicated the formation of a phase separated microcomposite structure at low and high content of SEP. The point of zero charge was determined as neutral pH. The thermal behavior of the samples was examined by TGA/derivative thermogravimetric (DTG) analysis. The dispersed clay improved the thermal stability of the matrix systematically with the increase of clay loading. The release of Tetracycline (TC) was also studied in a batch system as function of pH, clay content, and contact time at 37°C. Increase in the clay content of the composite resulted decrease in the release of TC due to the interaction of the silanol groups ( SiOH) of the clay and the  OH groups of the drug by the formation of the hydrogen bonding. Diffusion rate of TC to aqueous medium decreased by increasing SEP content. POLYM. COMPOS., 38:1810–1818, 2017. © 2015 Society of Plastics Engineers     

pH响应性的虾青素壳聚糖微球制备及应用

以氯乙酸和壳聚糖为原料，通过N,O-羧甲基化化学改性方法制备了水溶性羧甲基壳聚糖，并以此为原料通过乳液法制备羧甲基壳聚糖微球和羧甲基壳聚糖负载虾青素微球。考察了羧甲基壳聚糖微球的形态、分散性和粒径。结果表明，微球最佳制备条件为：羧甲基壳聚糖含量（以水相即去离子水质量为基准，下同）1.0%，油水体积比1∶1，表面活性剂Span 80含量（以油相即液体石蜡体积为基准，下同）4.0%，交联剂戊二醛含量（以油相即液体石蜡体积为基准，下同）7.5%，剪切速率4000 r/min。红外测试表明，微球成功负载虾青素，在虾青素初始添加量为20mg的载药率和包封率分别为10.74%和67.24%。在模拟胃液和模拟肠液中，负载虾青素微球的释放率分别为10%和85%。羧甲基壳聚糖可以用作药物载体。     

包覆甲氧基肉桂酸辛酯固体脂质微粒的制备及性能

Preparation and properties of solid lipid nanoparticles carried octyl methoxycinnamate(OMC）were studiedThe influence of octyl methoxycinnamate（OMC）and pH value on the distribution, size, Zeta potential of solid lipid nanoparticle were studiedMeanwhile the configuration, particle size, composition and sunscreen properties were characterizedThe result showed that the Zeta potential of solid lipid nanoparticle was about 40 mV with optimizing composition and middle or weak basic pH condition The average particle size of solid lipid nanoparticle was about 150 nm and the particle distribution was homogeneousParticle configuration was spherical with or without OMC and little flocculationCarried OMC increased the particle sizeOMC with lipid material, emulsifier formed the solid lipid nanoparticle together but not carried in the coreThe solid lipid nanoparticle with OMC have good ultraviolet adsorption and the synergy function was between the solid lipid nanoparticles and sunscreen.     

Preparation and characterization of crosslinked PVAL membranes loaded with boehmite nanoparticles for fuel cell applications

Composite proton conducting membranes were prepared by doping the membrane, prepared by crosslinking poly(vinyl alcohol) with sulfosuccinic acid (SSA), with boehmite [aluminum oxyhydroxide or γ‐AlO(OH)]. The effect of the SSA and boehmite content on the membrane performance was studied and the results showed that the values for the ion exchange capacity (IEC) of the membranes were in the range of 0.45–4.80 mmol g^?1, the water content and the Young's modulus were dependent on the amount of SSA and nanoparticles. The proton conductivity was in the range of 10^?4 to 10^?2 S cm^?1 at 25°C and was directly related to the quantity of sulfonate groups present in the membrane, while the hydrogen permeability at 30°C was in the range of 10^?13 to 10^?12 mol cm s^?1 cm^?2 bar. The proton exchange membrane fuel cell tests indicated that the composite membranes have good proton conductivity and very low hydrogen permeability. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40148.     

明胶微球载药及其体外释放性能研究

以阿司匹林为药物模型分子,制备了载阿司匹林明胶微球。SEM研究表明,明胶微球在载药后,表面结构变得更为紧实。载药性能探讨表明,当阿司匹林的投药量为16mg时,明胶微球的载药性能较优（载药量为7．3％,包封率为57．5％）。对明胶微球在人工体液中的释药性能研究显示,载阿司匹林明胶微球具有良好的缓释性能。由于具有较大的酸性和胃蛋白酶的存在,微球在人工胃液中药物释放效率较高,在人工胃液和人工肠液中药物的释放率分别为40％和28％,且一级动力学模型对微球的体外药物释放情况拟合度较高。