The Dissolution of Zinc Oxide Ore in Sulfamic Acid Solution

2014 ◽  
Vol 881-883 ◽  
pp. 1554-1557
Author(s):  
Dan Dan Wu ◽  
Shu Ming Wen ◽  
Jing Yang ◽  
Qi Cheng Feng ◽  
Ying Bo Mao
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Acid Solution ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Sulfamic Acid ◽  
Solution Temperature ◽  
Average Particle ◽  
Zinc Extraction ◽  
Effects Of Temperature

In this study, the dissolution effect of zinc oxide ore was investigated using sulfamic acid solution as leaching agent. The effects of temperature, concentration of sulfamic acid, average particle size and stirring speed on the dissolution of zinc oxide ore were investigated. The dissolution rate increased with increasing solution temperature, concentration, and stirring speed as well as with decreasing average particle size. Sulfamic acid solution can therefore be used as an effective leaching agent for zinc extraction from zinc oxide ore.

A Study on Leaching of Zinc Oxide Ore in Ammonium Sulfate Solution

2014 ◽  
Vol 522-524 ◽  
pp. 1463-1466
Author(s):  
Dan Dan Wu ◽  
Shu Ming Wen ◽  
Jing Yang ◽  
Yi Jie Wang ◽  
Chao Lv
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Ammonium Sulfate ◽  
Average Particle Size ◽  
Sulfate Solution ◽  
Solution Temperature ◽  
Average Particle ◽  
Leaching Rate ◽  
Ammonium Sulfate Solution ◽  
Effects Of Temperature

In this paper, the leaching effect of zinc oxide ore was investigated using ammonium sulfate solution as leaching agent. The effects of temperature, concentration of ammonium sulfate, average particle size and stirring speed on the leaching of zinc oxide ore were studied. The leaching rate increased with increasing solution temperature, concentration, and stirring speed as well as with decreasing average particle size. Ammonium sulfate solution can therefore be used as an effective leaching agent for zinc extraction from zinc oxide ore.

Azithromycin nanosuspension preparation using evaporative precipitation into aqueous solution (EPAS) method and its comparative dissolution study

2020 ◽  
Vol 17 ◽  
Author(s):  
Mohammad Hossain Shariare ◽  
Tonmoy Kumar Mondal ◽  
Hani Alothaid ◽  
Md. Didaruzzaman Sohel ◽  
MD Wadud ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Scale Up ◽  
Average Particle ◽  
Total Drug ◽  
Residual Solvent ◽  
Dissolution Study ◽  
Drug Content

Aim: EPAS (evaporative precipitation into aqueous solution) was used in the current studies to prepare azithromycin nanosuspensions and investigate the physicochemical characteristics for the nanosuspension batches with the aim of enhancing the dissolution rate of the nanopreparation to improve bioavailability. Methods: EPAS method used in this study for preparing azithromycin nanosuspension was achieved through developing an in-house instrumentation method. Particle size distribution was measured using Zetasizer Nano S without sample dilution. Dissolved azithromycin nanosuspensions were also compared with raw azithromycin powder and commercially available products. Total drug content of nanosuspension batches were measured using an Ultra-Performance Liquid Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent was measured using gas chromatography (GC). Results: The average particle size of azithromycin nanosuspension was 447.2 nm and total drug content was measured to be 97.81% upon recovery. Dissolution study data showed significant increase in dissolution rate for nanosuspension batch when compared to raw azithromycin and commercial version (microsuspension). The residual solvent found for azithromycin nanosuspension is 0.000098023 mg/ mL or 98.023 ppb. Conclusion: EPAS was successfully used to prepare azithromycin nanoparticles that exhibited significantly enhanced dissolution rate. Further studies are required to scale up the process and determine long term stability of the nanoparticles.

Formulation and Characterization of Nateglinide Nanosuspension by Precipitation Method

2014 ◽  
Vol 7 (4) ◽  
pp. 2685-2691
Author(s):  
Amruta Papdiwal ◽  
Kishor Sagar ◽  
Vishal Pande
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Water Solubility ◽  
Average Particle Size ◽  
Biologically Active ◽  
In Vitro Dissolution ◽  
Precipitation Method ◽  
Average Particle ◽  
Scanning Calorimetry

Poor water solubility and slow dissolution rate are major issues for the majority of upcoming and existing biologically active pharmaceutical compounds. Nateglinide is Biopharmaceutical Classification System Class-II drug that has low solubility and high permeability. The purpose of the present study was to improve the solubility and dissolution rate of Nateglinide by the preparation of nanosuspension by the nanoprecipitation technique. Nateglinide nanosuspension was evaluated for its particle size, in vitro dissolution study, and characterized by differential scanning calorimetry and scanning electron microscopy. The optimized formulation showed an average particle size of 207 nm and zeta potential of -25.8 mV. The rate of dissolution of the optimized nanosuspension was enhanced by 83% in 50 min relative to micronized suspension of nateglinide (37% in 50 min). This improvement was mainly due to the formulation of nanosized particles of Nateglinide. Stability study revealed that nanosuspension was more stable at room temperature and refrigerator condition with no significant change in particle size distribution. These results indicate that the nateglinide loaded nanosuspension may significantly improve in vitro dissolution rate and thereby possibly enhance the onset of therapeutic effect.

Study of Synthesis of Nanoparticulate Zinc Oxide Aiming at the Confection of Appropriated Targets for the Production of Radioisotopes

2016 ◽  
Vol 881 ◽  
pp. 485-490
Author(s):  
Nelcy D.S. Mohallem ◽  
Juliana B. da Silva ◽  
Cristiana P. Rezende
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Gamma Spectroscopy ◽  
Low Cost ◽  
Average Particle Size ◽  
Average Particle ◽  
Radioisotope Production ◽  
Target Preparation ◽  
Multifunctional Material ◽  
Freeze Dried

Zinc Oxide (ZnO) is a multifunctional material, which produces radionuclides of gallium by irradiation, widely used in diagnosis and nuclear medicine. In this work, two precursors were tested as well as two routes of synthesis, with the objective of obtaining nanoparticles appropriate to the production of pellets with grain size and porosity suitable for target preparation used in the radioisotope production by irradiation. The sintered pellets obtained from zinc acetate and NH4OH, and freeze-dried presented density of 90% of the theoretical density, average particle size of 1 μm and macropore size of 500 nm. These targets generated radionuclide of gallium (67Ga and 66Ga) inside the pores, without rupture of the pellets, confirmed by gamma spectroscopy, at low cost of production.

Formulation and Evaluation of Nanosuspension Formulations of Ramipril using Hydrophilic Polymers

2015 ◽  
Vol 8 (1) ◽  
pp. 2735-2741
Author(s):  
Pankaj P Nerker ◽  
Hitendra Mahajan ◽  
Sagar Deore ◽  
Pradyumn Ige
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Entrapment Efficiency ◽  
Hydrophilic Polymers ◽  
In Vitro Dissolution ◽  
Average Particle ◽  
Antisolvent Precipitation ◽  
Enhanced Dissolution

Nanosuspensions provide convenient formulations for improving the bioavailability and drug delivery. The objective of the investigation was to develop stable nanosuspension formulation of ramipril, with minimum surfactant concentration that could improve its solubility, stability and oral bioavailability. Ramipril is a potent antihypertensive drug, which act by inhibiting the angiotensin-converting enzyme. Nanosuspension was developed by antisolvent precipitation followed by high-pressure homogenization using hydrophilic polymers such as HPMC E5, HPMC E15, PVP K30, PVP K25, and PVA. The resulting nanosuspension was transformed into dry powder by freeze-drying process. Among all five formulations a formulation was choosen on the basis of results obtained from comparative study between different polymers based nanosuspension formulation of ramipril. The nanosuspension prepared was then evaluated for particle size, polydispesivity index, zeta potential, entrapment efficiency, saturated solubility study, scanning electron microscopy, differential scanning colorometry, and X ray diffraction. The combination of soya lecithin and pluronic F-68 as stabilizers yield nanosuspension with the smallest average particle size. The formulation of ramipril based on HPMC E 15 (Formulation B) shown enhanced dissolution rate. In which more than 60% of the drug was dissolved in the first 20 min compared to less than 25% of the pure drug within the same time period. The increase in the in vitro dissolution rate, nano size may favourably affect bioavailability.

Preparation of Nano-curcumin with Enhanced Dissolution Using Ultrasonic-Assisted Supercritical Anti-solvent Technique

2015 ◽  
Vol 11 (5) ◽  
pp. 609-617 ◽  
Author(s):  
Fatemeh Zabihi ◽  
Na Xin ◽  
Jingfu Jia ◽  
Tao Cheng ◽  
Yaping Zhao
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Aqueous Suspension ◽  
Average Particle Size ◽  
Nano Particles ◽  
In Vitro Dissolution ◽  
Solution Flow Rate ◽  
Average Particle ◽  
Solution Flow ◽  
Ultrasonic Assisted

Abstract Curcumin is the main gradient of “Turmeric” a famous Indian spice and food additive. The marvelous nutritional and medicinal effects of curcumin made it a good alternative to some conventional drugs and food flavoring or coloring materials. However, the low solubility of curcumin is a challenging hindrance which should be seriously addressed. In this work, we prepared nano-curcumin with enhanced aqueous dispersion and dissolution rate. Ultrasonic-assisted supercritical anti-solvent (UA-SAS) technique was used to convert the commercial curcumin to uniform distributed nano-particles with the average size of 20 nm and yielding of 65%. The effect of process parameters including pressure, temperature, solution flow rate, and nature of organic solvent on the average particle size and yielding of products was investigated. The morphology, size, and crystalline pattern of processed curcumin particles were characterized by scanning electron microscopy, mean particle size analyzer, and X-ray diffraction. The champion specimen was achieved when the supercritical fluid was employed at 16 MPa and 35°C. Aqueous suspension of processed nano-curcumin can be stable for more than 2 months. In vitro dissolution experiments showed a remarkable enhancement in dissolution rate of UA-SAS-treated curcumin respecting to the commercial curcumin powder.

scholarly journals Comparative Study of Different Crystallization Methods in the Case of Cilostazol Crystal Habit Optimization

Crystals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 295 ◽  
Author(s):  
Tímea Tari ◽  
Piroska Szabó-Révész ◽  
Zoltán Aigner
Keyword(s):  
Particle Size ◽  
Dissolution Rate ◽  
Mixing Time ◽  
Average Particle Size ◽  
Aqueous Solubility ◽  
Impinging Jet ◽  
Polymorphic Form ◽  
Crystal Habit ◽  
Narrow Particle Size Distribution ◽  
Average Particle

The therapeutic usage of cilostazol is limited owing to its poor aqueous solubility and oral bioavailability. Our aim was to produce cilostazol crystals with small average particle size; besides suitable roundness, narrow particle size distribution and stable polymorphic form to increase its dissolution rate and improve processability. Different conventional crystallization methods with or without sonication were compared with impinging jet crystallization combined with cooling, and the optimization of the various parameters was also implemented. The effects of post-mixing time and temperature difference were studied by means of a full factorial design. The physical properties of powder particles were characterized by, i.a., XRPD, DSC and SEM. The dissolution rate and the contact angle of solid surfaces were also determined to elucidate the relationship between wettability and dissolution. It was observed that impinging jet crystallization combined with cooling is a very effective and reproducible method for reducing the particle size of cilostazol. This method resulted in significantly smaller particle size (d(0.5) = 3–5 μm) and more uniform crystals compared to the original ground material (d(0.5) = 24 μm) or the conventional methods (d(0.5) = 8–14 μm), and it also resulted in a stable polymorphic form and enhanced the dissolution rate.

“Colloidal” Zinc Oxide

1937 ◽  
Vol 10 (2) ◽  
pp. 309-311
Author(s):  
H. A. Curran ◽  
T. R. Dawson
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Manufacturing Industry ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Zinc Oxides ◽  
Two Samples ◽  
Good Grade

Abstract Some ten years ago, when so-called “colloidal” zinc oxides were being introduced to the rubber manufacturing industry, two samples were investigated to determine their behavior in rubber compared with ordinary good quality zinc oxide used in rubber. According to accounts published at the time, “colloidal” zinc oxide possesses an average particle size just within the limit of resolution of high-power microscopes, and an average particle diameter of 0.15 micron. In rubber it has been claimed to impart superior reinforcement, higher tensile strength, greater resistance to abrasion, and enhanced activation of organic accelerators. In the following report, samples A and B represent two samples of the same grade of “colloidal” zinc oxide, and C a good grade of regular zinc oxide.

The Leaching of Copper Oxide Ore in Ammonium Chloride Solution

2014 ◽  
Vol 675-677 ◽  
pp. 1459-1462 ◽  
Author(s):  
Hua Sheng Dong ◽  
Jing Yang
Keyword(s):  
Particle Size ◽  
Copper Oxide ◽  
Ammonium Chloride ◽  
Chloride Solution ◽  
Average Particle Size ◽  
Ammonium Chloride Solution ◽  
Solution Temperature ◽  
Copper Extraction ◽  
Average Particle ◽  
Effect Of Copper

In this study, the leaching effect of copper oxide ore was investigated using ammonium chloride solution as leaching agent. The effects of temperature, concentration of ammonium chloride, average particle size and stirring speed on the leaching of copper oxide ore were investigated. The leaching rate increased with increasing solution temperature, concentration, and stirring speed as well as with decreasing average particle size. Ammonium chloride solution can therefore be used as an effective leaching agent for copper extraction from copper oxide ore.

Measurement of Average Particle Size of Fine Pigments

1932 ◽  
Vol 5 (2) ◽  
pp. 202-215 ◽  
Author(s):  
S. D. Gehman ◽  
T. C. Morris
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Wave Length ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Carbon Blacks ◽  
Count Method

Abstract A method of obtaining excellently dispersed suspensions of rubber pigments of accurate concentration is described in which the pigment is milled into rubber and the stock then dissolved in a solvent. The average particle sizes of carbon blacks measured by the Zsigmondy count method were found to range from 0.061μ for rubber gas black to 2.22μ for the coarsest one measured. The zinc oxide pigments had average particle sizes from 0.076μ to 0.57μ.. Measurements on several other pigments of interest are included. Because of the high visibility in the ultra-microscope, this method gives smaller values for average particle size than the photomicrographic methods. The results have been used to calibrate a microturbidimeter of the extinction type for use in measuring average particle size. Curves are included showing how the turbidities of suspensions of zinc oxide and carbon black vary with the average particle size, concentration, and wave length of light used.

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