The Application of Sodium Citrate in Co3O4 Nano-Particle Dispersing System

2013 ◽  
Vol 634-638 ◽  
pp. 2284-2287
Author(s):  
Wen Ze Li ◽  
Lin Jiu Xiao ◽  
Ying Xie ◽  
Xuan Qi ◽  
Hong Bin Sun

Based on the profound application, the Co3O4 was chosen to be research object; the optimized dispersing condition was studied and determined as: dosage of Co3O4 nano particle varied from 0.01 to 0.02mg/ml, sodium citrate was determined to be dispersing adjuvant with a dosage of 0.0005g/ml, ultrasonic time: 10min, and pH value was 7 to 8 when the Zeta potential was –57.1mv. After a detailed discussion of size distribution and dispersing condition, the size distribution of Co3O4 nano particle was measured with Malvern Nano Zetasizer to be 217nm.

2013 ◽  
Vol 790 ◽  
pp. 542-545
Author(s):  
Zhao Hui Zhen ◽  
Cui Hua Dong

The paper studied the effects of SMA as protective colloid on emulsification and micro-encapsulation process in the preparation of MF-resin microcapsules. The results indicated that pH value and the dosage of the SMA had important effects on zeta value and micro-encapsulation. The SMA dosage, emulsifying time and stirring rate influenced the capsule preparation, mean particle size and particle size distribution of microcapsules. The diameter became smaller with the increase of the amount of protective colloid. The applying amount of the SMA had an optimum value. The zeta potential just after emulsification was much larger than after reaction of MF in the preparation of microcapsules.


2017 ◽  
Vol 68 (7) ◽  
pp. 1518-1423
Author(s):  
Adina Turcu Stiolica ◽  
Mariana Popescu ◽  
Maria Viorica Bubulica ◽  
Carmen Nicoleta Oancea ◽  
Claudiu Nicolicescu ◽  
...  

Gold nanoparticles are considered the newest drug carriers for different diseases. Therefore it is appropriate continuous optimization of their preparation. In this study, gold colloids with an average size of 1 - 26 nm were obtained by the reduction of tetrachloroauric acid with trisodium citrate. The nanomaterials were characterized by UV-Vis spectroscopy and dynamic light scattering technique. In addition, zeta potential was measured for samples synthesized in order to determine the stability of the colloids. A Two-level Full Factorial design was chosen to determine the optimum set of process parameters (chloroauric acid concentration and sodium citrate concentration) and their effect on various gold nanoparticles characteristics (size and zeta potential). These effects were quantified using Design of Experiments (DoE) with 5 runs and 1 centerpoint. The selected objective and process model in this investigation are screening and interaction. Findings from this research show that to obtain particles larger than 35 nm, it is recommended to increase sodium citrate concentration, at low chloroauric acid values. These conditions will help to achieve smaller zeta potential, too.


2020 ◽  
Vol 26 (14) ◽  
pp. 1543-1555 ◽  
Author(s):  
Meltem E. Durgun ◽  
Emine Kahraman ◽  
Sevgi Güngör ◽  
Yıldız Özsoy

Background: Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers. Objective: In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions. Method: Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells. Results: Pre-formulation studies indicated that single D-ɑ-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension. Conclusion: The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.


2012 ◽  
Vol 512-515 ◽  
pp. 261-264
Author(s):  
Li Shen ◽  
Jin Hu ◽  
Da Ping Wu

As anionic surfactant, a commercial salt of lauryl sodium sulfate was used. The effects of different amounts of dispersant on the measurement of particle size distribution between two titanium dioxide powders (anatase and rutile) in aqueous media were discussed. Diluted aqueous suspensions were characterized in terms of particle size distribution and zeta potential. The results demonstrate that the measurement of particle size distribution strongly depends on the amounts of dispersant. The amounts of dispersant have a significant effect on the behavior of the rutile-TiO2 particles. The particle size first decreases significantly with an increase in the amounts of dispersant and then lesser increases with a further increase in the amounts of dispersant. The tendency show significant differences between two particles.


2015 ◽  
Vol 51 (4) ◽  
pp. 823-832 ◽  
Author(s):  
Francine Rodrigues Ianiski ◽  
Luciane Varini Laporta ◽  
Alexandre Machado Rubim ◽  
Cristiane Luchese

abstract A method to ensure that an analytical method will produce reliable and interpretable information about the sample must first be validated, making sure that the results can be trusted and traced. In this study, we propose to validate an analytical high performance liquid chromatography (HPLC) method for the quantitation of meloxicam loaded PEGylated nanocapsules(M-PEGNC). We performed a validation study, evaluated parameters including specificity, linearity, quantification limit, detection limit, accuracy, precision and robustness. PEGylated nanocapsules were prepared by interfacial deposition of preformed polymer, and the particle size, polydispersity index, zeta potential, pH value and encapsulation efficiency were characterized. The proposed HPLC method provides selective, linear results in the range of 1.0-40.0 μg/mL; quantification and detection limits were 1.78 μg/mL and 0.59 μg/mL, respectively; relative standard deviation for repeatability was 1.35% and intermediate precision was 0.41% and 0.61% for analyst 1 and analyst 2, respectively; accuracy between 99.23 and 101.79%; robustness between 97.13 and 98.45% for the quantification of M-PEGNC. Mean particle diameters were 261 ± 13 nm and 249 ± 20 nm, polydispersity index was 0.15 ± 0.07 and 0.17 ± 0.06, pH values were 5.0 ± 0.2 and 5.2 ± 0.1, and zeta-potential values were -37.9 ± 3.2 mV e -31.8 ± 2.8 mV for M-PEGNC and placebo(B-PEGNC), respectively. In conclusion, the proposed analytical method is suitable for the quality control of M-PEGNC. Moreover, suspensions showed monomodal size distributions and low polydispersity index indicating high homogeneity of formulations with narrow size distributions, and appropriate pH and zeta potential. The extraction process was efficient for release of meloxicam from nanostructured systems.


2011 ◽  
Vol 402 ◽  
pp. 503-509
Author(s):  
Ze Hong Wang ◽  
Fu Jia Yu ◽  
Shan Cai ◽  
Shan Zhi Deng ◽  
Roger Horn

An extension of the classical Obriemoff experiments has been set up to measure the fracture energy of mica. This experimental system will be entirely independent of slurry rheology. CTAB (Cetyl Trimethyl Ammonium Bromide), sodium tripolyphosphate, sodium hexametaphosphate, and tri-sodium citrate are used as grinding aids in this study and the fracture energy has been measured for mica in air, water, and water with the addition of various concentrations of these grinding aids. The results show that the fracture energy of mica in water is about half of what it is in air. Grinding aids are shown to reduce the fracture energy of mica, but not dramatically. Addition of grinding aids reduces the fracture energy by a further 10-20%, with tri-sodium citrate appearing to be the most effective. For each grinding aid there appears to be an optimal concentration, typically around 10 mmol. An experiment is also done with sodium chloride at a range of concentrations to investigate the mechanism of these grinding aids, but no reduction in fracture energy (compared to water) was observed, hence the molecular-level mechanism of action of these grinding aids remains unclear. The effect of solution pH values on the fracture energy are also investigated using tri-sodium citrate and sodium chloride. The results show that the solution pH value may effect on the fracture energy of mica. So, in practice, both concentration and pH value of solution are important for getting better grinding results.


2018 ◽  
Vol 788 ◽  
pp. 83-88
Author(s):  
Oskars Leščinskis ◽  
Ruta Švinka ◽  
Visvaldis Švinka

Clays are materials consisting of clay minerals and non-clay minerals. Clay mineral fraction is considered to be a nanofraction. Clay minerals can be used for water purification and treatment. Description and characterization of 3 different Latvian clay nanosized minerals from 3 different geological periods (clay Liepa from Devonian period, clay Vadakste from Triassic period and clay Apriki from Quaternary period) as well as their adsorption capacity concerning organic compounds such as methyl orange and rhodamine B are summarized. Nanosized clay mineral particles were obtained using sedimentation method. Particle size distribution, zeta potential and FTIR spectra is given. The adsorption tests of above mentioned organic compounds were carried out in water solutions at 3 different pH values. The adsorption values were determined by means of UV-spectrophotometric technique. Zeta potential values for clay minerals Apriki, Liepa and Vadakste are -40.9 mV, -49.6 mV and -43.0 mV, respectively. FTIR spectra show similar tendencies for all 3 clay minerals. The best adsorption capacity concerning methyl orange and rhodamine B were in solutions with a pH value of 2, whereas at neutral and alkaline pH values adsorption in 24 hours was not observed.


Author(s):  
Aghiles Hammas ◽  
Gisèle Laure Lecomte-Nana ◽  
Nadjet Azril ◽  
Imane Daou ◽  
Claire Peyratout ◽  
...  

The present study aimed at investigating the influence of the concentration of sodium silicate and sodium hexametaphosphate on the dispersion of an aqueous kaolinitic clay slurry regarding further use for the tape casting process. The zeta potential of the kaolinitic clay slurry matched the requirements for tape casting. The addition of magnesite in the kaolinitic slurries tended to increase the zeta potential towards the required limit values. Despite, the further addition of surfactants allowed improving the zeta potential in agreement with the tape casting conditions. Accordingly, the rheological behavior, under continuous and oscillatory flow conditions, of various mixtures of magnesite and a kaolinitic clay was studied. Regarding the pH and the zeta potential measurements, the E–F attraction prevailed at low pH value, and F–F or E–E attraction was predominant at high pH value. All slurries exhibited a shear thinning behavior, which was well-correlated by Herschel–Bulkley model. It appeared that the best stability for the kaolinitic clay slurries was obtained while using 0.4 mass% and 1.2 mass% of sodium hexametaphosphate and sodium silicate respectively. An increase in the magnesite concentration above 6 mass% led to a complex behavior with low cohesion energy due to the occurrence of soluble complexes.


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