scholarly journals Optimization of the Preparation Process for an Oral Phytantriol-Based Amphotericin B Cubosomes

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Zhiwen Yang ◽  
Xinsheng Peng ◽  
Yinhe Tan ◽  
Meiwan Chen ◽  
Xingqi Zhu ◽  
...  
Keyword(s):  
Particle Size ◽  
Amphotericin B ◽  
Liquid Crystalline ◽  
Uv Spectroscopy ◽  
Drug Loading ◽  
Narrow Particle Size Distribution ◽  
Drug Solubility ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Bicontinuous Cubic

In order to develop an oral formation of Amphotericin B (AmB) using phytantriol- (PYT-) based cubosomes with desirable properties, homogenization conditions were firstly investigated to determine their effects on the morphological and dimensional characteristics of cubosomes. Under the optimized homogenization conditions of 1200 bar for 9 cycles, cubosomes with reproducible, narrow particle size distribution and a mean particle size of 256.9 nm ± 4.9 nm were obtained. The structure of the dispersed cubosomes was revealed by SAXS (small-angle X-ray scattering) and Cryo-TEM (cryogenic transmission electron microscopy) as a bicontinuous cubic liquid crystalline phase with Pn3m geometry. To overcome the poor drug solubility and increase the drug-loading rate, a solubilization method was firstly used to develop cubosomes containing AmB. The encapsulation efficiency determined by HPLC assay was87.8%±3.4%, and UV spectroscopy and stability studies in simulated gastric fluids further confirmed that AmB was successfully encapsulated in cubosomes.

Silica Nanoparticle Synthesis and Multi-Method Characterisation

2019 ◽  
Vol 947 ◽  
pp. 82-90
Author(s):  
Pirutchada Musigapong ◽  
Sophie Marie Briffa ◽  
Iseult Lynch ◽  
Siriwat Soontaranon ◽  
N. Chanlek ◽  
...  
Keyword(s):  
Particle Size ◽  
Sol Gel ◽  
Nanoparticle Synthesis ◽  
Size Control ◽  
Silica Nanoparticle ◽  
Radius Of Gyration ◽  
Hydrodynamic Diameter ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Diameter Core

The information provided by different characterisation methods when measuring particle size varies depending on the chosen technique and analytical approach (e.g. light scattering, transmission electron microscopy, spectroscopy, x-ray scattering). This in turn has an impact on the accuracy of the results as well as comparability between methods and overall confidence on the analyses. The present study used a common sol-gel reaction to synthesise amorphous silica nanoparticles (aSiNPs) and characterised the product purity and homogeneity. The reaction involved hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in the presence of lysine, which acted as catalyst for the silica production and also as a capping agent for particle size control in a suspension kept at pH 8-10. According to DLS data, the stock suspension was stable for at least 6 months in Milli Q water without surfactant when kept at 4°C. This study focused on multi-method size and shape characterisation of the aSiNPs, involving the following techniques: DLS, TEM, FTIR, STEM and SAXS. These techniques provided information on hydrodynamic diameter, core particle dimensions, sphere equivalent size, and radius of gyration. Our results show two particle populations, one around 2 nm and the other around 7 nm in diameter. Notably, these two populations are not resolved (i.e. “visible”) by all methods used.

Scalable Production of Carbon Encapsulated Ni Nanoparticles by Water Arc Discharge: Structural and Magnetic Properties

2005 ◽  
Vol 23 ◽  
pp. 87-90 ◽  
Author(s):  
K.H. Ang ◽  
I. Alexandrou ◽  
N.D. Mathur ◽  
R. Lacerda ◽  
I.Y.Y. Bu ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Arc Discharge ◽  
Narrow Particle Size Distribution ◽  
Ni Nanoparticles ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Water Container

An electric arc discharge in de-ionised water between a solid graphite cathode and an anode made by compressing Ni and C containing powders in a mass ratio of Ni:C = 7:3 was used here to prepare carbon encapsulated Ni nanoparticles in the form of powder suspended in water. The morphology of the produced material was analysed using high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The magnetic properties of the samples were determined using a Princeton vibrating sample magnetometer (VSM). Collection of the powder produced from different depths in the water container has proved to be an effective method for obtaining samples with narrow particle size distribution. Further material purification by dry NH4 plasma etching was used to remove the amorphous carbon content of the samples. XRD and HRTEM analysis showed that the material synthesized is fcc Ni particles with mean particle size ranging from 14 to 30 nm encapsulated in 2 to 5 graphitic cages. The data suggests that the process reported has the ability to mass-produce carbon encapsulated ferromagnetic nanoparticles with desired particle size distribution, and hence with controlled size-dependent magnetic properties.

scholarly journals Effect of Reaction Temperature on Size and Optical Properties of NiTiO3Nanoparticles

2012 ◽  
Vol 9 (1) ◽  
pp. 282-288 ◽  
Author(s):  
R. Vijayalakshmi ◽  
V. Rajendran
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Uv Spectroscopy ◽  
Particle Size Effect ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Nickel Titanate ◽  
Different Temperatures ◽  
Wet Chemical

Nickel titanate (NiTiO3) nanoparticles were successfully prepared by wet-chemical method, using nickel acetate and titanium(IV) isopropoxide as Ni, Ti sources and citric acid as complexing reagent. The gel was calcined at different temperatures from 500-700 °C. Results of thermogravimetric analysis (TGA) are given. Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM),transmission electron microscopy (TEM), ultraviolet (UV) spectroscopy, vibrating sample magnetometer (VSM) were used to characterize the crystallization process, particle size, morphology, optical and magnetic properties of the calcined nanoparticles. TEM result reveals that the NiTiO3was homogeneous and hexagon morphology with the grain size of 30-70 nm. The band gap values of the NiTiO3nanoparticles were calculated to be 3.43, 3.39 and 3.31 eV. The magnetic property was confirmed that the NiTiO3nanoparticles of super paramagnetic behavior in nature. Our results suggested that the temperature plays an important role in the particle size effect of nanocrystalline NiTiO3.

Etude de la repartition de l'eau dans des argiles saturees Mg2+ aux fortes teneurs en eau

Clay Minerals ◽  
1990 ◽  
Vol 25 (2) ◽  
pp. 217-233 ◽  
Author(s):  
O. Touret ◽  
C. H. Pons ◽  
D. Tessier ◽  
Y. Tardy
Keyword(s):  
Particle Size ◽  
Aggregate Size ◽  
High Water ◽  
Hydration Mechanism ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Particle Aggregate ◽  
Sample Water ◽  
Particle Size And Shape ◽  
Water Contents

AbstractPowdered 2:1 Mg-clay samples were rehydrated up to the maximum hydration. Both scanning and transmission electron microscopy were used to characterize their structural organization i.e. particle arrangement, texture and crystal structure. Low-angle X-ray scattering experiments were carried out to quantify the microstructure of the system. The results showed that sample water contents reached at saturation are not directly related to changes in layer distance. The hydration mechanism is rather correlated to particle size and particle aggregate size. It is also shown that the a, b plane extension of the layers influences particle size and shape. Finally, it appears that for a better understanding of clay swelling mechanisms, at high water contents, it is necessary to take into account all organization levels and that the contribution of interlayer space to the total water content, for Mg-smectites, is small.

scholarly journals Ibuprofen Release from Poly(ethyl cyanoacrylate) Nanoparticles Prepared by Semicontinuous Heterophase Polymerization

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
J. A. Balleño ◽  
A. P. Mendizábal-Ruiz ◽  
H. Saade ◽  
R. Díaz de León-Gómez ◽  
E. Mendizábal ◽  
...  
Keyword(s):  
Surfactant Concentration ◽  
Uv Spectroscopy ◽  
Drug Loading ◽  
Weibull Model ◽  
Heterophase Polymerization ◽  
Transmission Electron ◽  
Ethyl Cyanoacrylate ◽  
Release Data ◽  
Ibuprofen Release ◽  
Semicontinuous Heterophase Polymerization

Ibuprofen-loaded poly(ethyl cyanoacrylate) nanoparticles were prepared by semicontinuous heterophase polymerization of ethyl cyanoacrylate in the presence of ibuprofen; different surfactant concentration, pH, and temperature were used. Particle size was measured by quasi-light scattering and transmission electron microscopy, while the amount of drug released was determined by UV spectroscopy. Nanoparticles with diameters between 10 and 58 nm, loaded with ibuprofen, were obtained. The smallest particles and the higher drug loading were obtained at the highest pH tested. The analysis of the release data showed that the drug release profiles correspond to the Weibull model. Moreover, it was found that most of the ibuprofen is released within the first 80–120 min; initially the release rate is slow, but then it increases to finally decrease. This behavior contrasts with the reported burst of drug concentration in the plasma after oral administration of IB.

scholarly journals Continuous Microfluidic Production of Citrem-Phosphatidylcholine Nano-Self-Assemblies for Thymoquinone Delivery

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1510
Author(s):  
Esra Ilhan-Ayisigi ◽  
Aghiad Ghazal ◽  
Barbara Sartori ◽  
Maria Dimaki ◽  
Winnie Edith Svendsen ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Continuous Production ◽  
Structural Features ◽  
Microfluidic Platforms ◽  
Lipid Mixture ◽  
X Ray Scattering ◽  
Bicontinuous Cubic ◽  
Bio Imaging ◽  
Nanoparticle Sizes ◽  
Insight Into

Lamellar and non-lamellar liquid crystalline nanodispersions, including liposomes, cubosomes, and hexosomes are attractive platforms for drug delivery, bio-imaging, and related pharmaceutical applications. As compared to liposomes, there is a modest number of reports on the continuous production of cubosomes and hexosomes. Using a binary lipid mixture of citrem and soy phosphatidylcholine (SPC), we describe the continuous production of nanocarriers for delivering thymoquinone (TQ, a substance with various therapeutic potentials) by employing a commercial microfluidic hydrodynamic flow-focusing chip. In this study, nanoparticle tracking analysis (NTA) and synchrotron small-angle X-ray scattering (SAXS) were employed to characterize TQ-free and TQ-loaded citrem/SPC nanodispersions. Microfluidic synthesis led to formation of TQ-free and TQ-loaded nanoparticles with mean sizes around 115 and 124 nm, and NTA findings indicated comparable nanoparticle size distributions in these nanodispersions. Despite the attractiveness of the microfluidic chip for continuous production of citrem/SPC nano-self-assemblies, it was not efficient as comparable mean nanoparticle sizes were obtained on employing a batch (discontinuous) method based on low-energy emulsification method. SAXS results indicated the formation of a biphasic feature of swollen lamellar (Lα) phase in coexistence with an inverse bicontinuous cubic Pn3m phase in all continuously produced TQ-free and TQ-loaded nanodispersions. Further, a set of SAXS experiments were conducted on samples prepared using the batch method for gaining further insight into the effects of ethanol and TQ concentration on the structural features of citrem/SPC nano-self-assemblies. We discuss these effects and comment on the need to introduce efficient microfluidic platforms for producing nanocarriers for delivering TQ and other therapeutic agents.

Synthesis of n-Hexadecylphosphonic Acid-Coated Monodisperse Fe3O4 Superparamagnetic Nanoparticles

2012 ◽  
Vol 512-515 ◽  
pp. 170-173
Author(s):  
Xue Song Tang ◽  
Ming Li
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Drug Loading ◽  
Average Particle Size ◽  
Superparamagnetic Nanoparticles ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Cubic Crystal ◽  
Transmission Electron ◽  
Potential Applications

Monodisperse Fe3O4 Superparamagnetic Nanoparticles Were Synthesized in N-Hexadecylphosphonic Acid/ Cyclohexane/ Water/ Ethanol Microemulsion under Solvothermal Conditions at 100°C. the Crystal Structure and Particle Size of Synthesized Fe3O4 Were Observed by X-Ray Diffraction (XRD) as Well as Transmission Electron Microscopy (TEM). the Results Show that the Nanoparticles Have a Cubic Crystal System and a Average Particle Size of about 10nm. each Nanoparticle Has a Single Crystal Structure. the Surface Chemistry of Synthesized Fe3O4 Nanoparticles Was Characterized by Fourier Transform Infrared Spectroscopy (FTIR), Indicating that the Nanoparticles Were Covered by a Layer of N-Hexadecylphosphonic Acid, which Made the Nanoparticles Totally Lipophilic. Magnetic Properties of the Nanoparticles Were Investigated by Using Vibrating Sample Magnetometer (VSM). the Result Reveals that the Saturation Magnetization (Ms) of the Nanoparticles Is Higher than 40 Emu/G and the Coercive Force Is near to 0. the Monodisperse Fe3O4 Nanoparticles Have Superparamagnetic Property and May Find Potential Applications in many Fields, such as Ferrofluids, Drug Loading and Release, Selective Biomolecular Separation and MRI.

Preparation of Nanostructured Lipid Drug Delivery Particles Using Microfluidic Mixing

2019 ◽  
Vol 7 (6) ◽  
pp. 484-495 ◽  
Author(s):  
Linda Hong ◽  
Yao-Da Dong ◽  
Ben J. Boyd
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Liquid Crystalline ◽  
High Energy ◽  
Microfluidic System ◽  
Stimuli Responsive ◽  
Microfluidic Mixing ◽  
X Ray Scattering ◽  
The Impact

Background: Cubosomes are highly ordered self-assembled lipid particles analogous to liposomes, but with internal liquid crystalline structure. They are receiving interest as stimuli responsive delivery particles, but their preparation typically requires high energy approaches such as sonication which is not favourable in many applications. Objective: Here we investigated the impact of microfluidic preparation on particle size distribution and internal structure of cubosomes prepared from two different lipid systems, phytantriol and glyceryl monooleate (GMO). Methods: The impact of relative flow rates of the aqueous and organic streams, the total flow rate and temperature were investigated in a commercial microfluidic system. The particle size distribution and structure were measured using dynamic light scattering and small angle X-ray scattering respectively. Results: Phytantriol based particles were robust to different processing conditions, while cubosomes formed using GMO were more sensitive to composition both locally and globally, which reflects their preparation using other techniques. Conclusion: Thus, in summary microfluidics represents a reproducible and versatile method to prepare complex lipid particle dispersions such as cubosomes.

scholarly journals Alginate microspheres obtained by the spray drying technique as mucoadhesive carriers of ranitidine

2015 ◽  
Vol 65 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Marta Szekalska ◽  
Aleksandra Amelian ◽  
Katarzyna Winnicka
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Spray Drying ◽  
Drug Loading ◽  
Entrapment Efficiency ◽  
Narrow Particle Size Distribution ◽  
In Vitro Drug Release ◽  
Adhesive Layers ◽  
First Order Kinetics

Abstract The present study is aimed at formulation of alginate (ALG) microspheres with ranitidine (RNT) by the spray drying method. Obtained microspheres were characterized for particle size, surface morphology, entrapment efficiency, drug loading, in vitro drug release and zeta potential. Mucoadhesive properties were examined by a texture analyser and three types of adhesive layers - gelatine discs, mucin gel and porcine stomach mucosa. Microspheres showed a smooth surface with narrow particle size distribution and RNT loading of up to 70.9 %. All formulations possessed mucoadhesive properties and exhibited prolonged drug release according to the first-order kinetics. DSC reports showed that there was no interaction between RNT and ALG. Designed microspheres can be considered potential carriers of ranitidine with prolonged residence time in the stomach

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