Solubility and Micronization of Ganciclovir

2011 ◽  
Vol 393-395 ◽  
pp. 1421-1426
Author(s):  
Feng Xiang Tang ◽  
Yun Zhang ◽  
Su Na Lin ◽  
Zhong Li Guo
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Particle Diameter ◽  
Absolute Bioavailability ◽  
Stabilizing Agents ◽  
Ph Values ◽  
Solubility Behavior ◽  
The Mean ◽  
Liquid Precipitation ◽  
Mean Particle Diameter

Ganciclovir (GCV) is only slightly soluble in water and hence oral GCV gives low absolute bioavailability. Liquid precipitation is an effective way to prepare micro-sized drug particles. The solubility of GCV in several solvents or in aqueous solution at different pH values was determined. According to its solubility behavior, reactive precipitation was suggested as the micronization method of GCV. The mean particle diameter of micronized GCV powder was around 15~20 μm, smaller than that of raw GCV powder, and the size distribution of micronized GCV was narrower than that of raw GCV. The stirring rate, the type and addition of stabilizing agents seemed to have no significant effect on the particle size of micronized GCV. Micronized GCV showed much faster dissolution rate than raw GCV.

Aerosol Synthesis of Aluminum Nitride Powders

1991 ◽  
Vol 249 ◽  
Author(s):  
Albert A. Adjaottor ◽  
Gregory L. Griffin
Keyword(s):  
Particle Size ◽  
Residence Time ◽  
Particle Diameter ◽  
Aerosol Formation ◽  
Yield Efficiency ◽  
Operating Variables ◽  
Aerosol Process ◽  
The Mean ◽  
Diffusive Mixing ◽  
Mean Particle Diameter

ABSTRACTWe describe a new laboratory-scale aerosol process for producing AIN powder. A two-stage reactor design is used. In the first stage, triethyl aluminum (TEA = AI(CC2H5 )3) and NH3 react to form an aerosol adduct in a laminar flow diffusive mixing zone. The aerosol then enters the furnace stage, where it is converted to AIN. We have examined the influence of the major operating variables (e.g., inlet TEA concentration, reactor residence time, and furnace temperature) on the particle size and distribution, yield, and efficiency. For example, increasing the TEA concentration from 0.12 to 1.30 µmol/cm3 causes an increase in the mean particle diameter (from 0.07 to 0.13 Pim), a slight increase in polydispersity (from 0.31 to 0.43), and a decrease in yield efficiency (from 90% to 73%). In contrast, decreasing the reactor residence time (by increasing the flow rate) has little effect on mean particle diameter, but causes a significant increase in yield efficiency (approaching 100%). The overall behavior of the reactor suggests a model in which the particle size distribution of the final product is determined primarily by the aerosol formation steps in the mixing stage (i.e., nucleation, growth, and coalescence), while the composition and crystallinity of the product are determined by furnace conditions.

Synthesis of Immiscible Alloys by the Mixalloying Process

1989 ◽  
Vol 111 (1) ◽  
pp. 70-78 ◽  
Author(s):  
S. Tu¨rker Oktay ◽  
Chong N. Chu ◽  
Nannaji Saka ◽  
Nam P. Suh
Keyword(s):  
Particle Size ◽  
Computational Simulation ◽  
Particle Diameter ◽  
Al Alloys ◽  
Size Distributions ◽  
Simulation Studies ◽  
Particle Size Distributions ◽  
The Mean ◽  
Log Normal ◽  
Mean Particle Diameter

Dispersed-phase microstructures of the immiscible Pb-Zn, Pb-Zn-Sn and Pb-Al alloys were produced by the Mixalloying Process [1]. The particle size was found to follow the log-normal statistical distribution and the mean particle diameter correlated well with the –3/5th power of the Weber number. Furthermore, computational simulation studies showed that the particle-size distributions became significantly broader due to Stokes coalescence during solidification.

Batch Precipitation of Lead Iodide

1994 ◽  
Vol 59 (6) ◽  
pp. 1301-1304
Author(s):  
Jaroslav Nývlt ◽  
Stanislav Žáček
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Crystal Size ◽  
Lead Nitrate ◽  
Lead Iodide ◽  
Constant Rate ◽  
Mean Size ◽  
The Mean

Lead iodide was precipitated by a procedure in which an aqueous solution of potassium iodide at a concentration of 0.03, 0.10 or 0.20 mol l-1 was stirred while an aqueous solution of lead nitrate at one-half concentration was added at a constant rate. The mean size of the PbI2 crystals was determined by evaluating the particle size distribution, which was measured sedimentometrically. The dependence of the mean crystal size on the duration of the experiment exhibited a minimum for any of the concentrations applied. The reason for this is discussed.

Removal of Phosphate Ions from Aqueous Solution Using Anthracite

2012 ◽  
Vol 60 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Mohammad Arifur Rahman ◽  
Tamanna Azam ◽  
A. M. Shafiqul Alam
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Flow Rate ◽  
Cost Effective ◽  
Phosphate Concentration ◽  
Phosphate Solution ◽  
Adsorption Study ◽  
Adsorption Column ◽  
Ph Values ◽  
Phosphate Ions

Anthracite was used as an adsorbent to remove excess phosphate from wastewater. Anthracite used in the present study is environmentally friendly and of cost effective. The adsorption study was carried out using different particle size of adsorbents, different concentration of phosphate solution ranging from 25.0 mg/L to 100.0 mg/L, different pH values ranging from 0.5 to 11.5 along with different adsorbent amount from 1.0 g to 5.0 g. Flow rate was also varied in the range of 0.6 mL/min to 1.8 mL/min. Adsorption column methods show the optimum removal of phosphate under the following conditions: initial phosphate concentration 25 mg/L, initial volume 25.0 mL, flow rate 1.0 mL/min adsorbent amount 2.0 g, particle size, < 90?m. This removal method may provide a solution to the removal phosphate from wastewater in Bangladesh as well as other countries of the world.DOI: http://dx.doi.org/10.3329/dujs.v60i2.11490 Dhaka Univ. J. Sci. 60(2): 181-184, 2012 (July)

Prediction of the deflagration index for organic dusts as a function of the mean particle diameter

2017 ◽  
Vol 50 ◽  
pp. 67-74 ◽  
Author(s):  
Anna Fumagalli ◽  
Marco Derudi ◽  
Renato Rota ◽  
Jef Snoeys ◽  
Sabrina Copelli
Keyword(s):  
Particle Diameter ◽  
Deflagration Index ◽  
The Mean ◽  
Mean Particle Diameter

Influence of nucleating agent type on the morphology of extruded polyetherimide foam for printed circuit boards*

2019 ◽  
Vol 56 (3) ◽  
pp. 317-341 ◽  
Author(s):  
Clemens Keilholz ◽  
Daniel Raps ◽  
Thomas Köppl ◽  
Volker Altstädt
Keyword(s):  
Surface Tension ◽  
Printed Circuit Boards ◽  
Particle Diameter ◽  
Nucleating Agent ◽  
Nucleating Agents ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Foam Morphology ◽  
The Mean ◽  
Mean Particle Diameter

This work focuses on the development of foamed high temperature thermoplastic substrates for printed circuit boards. For this application it is necessary to achieve mean cell diameters smaller than 30 µm in order to be able to realize vias and high packaging densities (miniaturization). Different additives as nucleating agents, namely macro- and micro-crystalline talc, silica, calcium carbonate, and wollastonite, were melt-compounded with polyetherimide using a twin-screw extruder. Foamed samples are prepared by foam extrusion using a slit die and CO2 as physical blowing agent. The aim of this study is to analyze the influence of the mean particle size and the particle surface tension on the mean cell diameters. Therefore, the shape of the additives, the foam morphology, and the elongational viscosity were considered. The additives with a suitable particle size and surface tension exhibit a positive influence on the foam morphology, resulting in smaller cell diameters (<30 µm), a narrower cell size distribution and a foam density lower than 900 kg/m3. If the mean particle diameter of the nucleating agents is lower than 0.6 µm in this study, no nucleation effect could be observed. This is related to the fact that no heterogeneous nucleation occurs, if the particle diameter is too small. If the mean particle diameter of the used additives is larger than 1.5 µm, which could be demonstrated in this study in case of polyetherimide, then the additive acts as nucleating agent and heterogeneous nucleation occurs. Furthermore, it was observed that the mean cell diameter was affected by the different surface tensions of the studied nucleating agents.

scholarly journals Snow particle characteristics in the saltation layer

2014 ◽  
Vol 60 (221) ◽  
pp. 431-439 ◽  
Author(s):  
Christof Gromke ◽  
Stefan Horender ◽  
Benjamin Walter ◽  
Michael Lehning
Keyword(s):  
Particle Size ◽  
Particle Number ◽  
Particle Diameter ◽  
Wind Tunnel Experiments ◽  
Scale Parameters ◽  
Particle Characteristics ◽  
Maximum Particle ◽  
The Mean ◽  
Snow Particle ◽  
Measurement Area

AbstractShadowgraphy was employed to study snow saltation in boundary-layer wind tunnel experiments with fresh, naturally deposited snow. The shadowgraphy method allowed for a temporally and spatially high-resolution investigation of snow particle characteristics within a measurement area of up to 50 mm × 50 mm. Snow particle size and number characteristics, and their variation with height in the saltation layer, were analysed. The following observations and findings were made for the saltation layer: (1) the particle number decreases exponentially with height, (2) the mean particle diameter is fairly constant, with a very slight tendency to decrease with height, (3) the maximum particle diameter decreases linearly with height, and (4) the snow particle size distribution can be adequately described by gamma probability density functions. The shape and scale parameters of the gamma distribution were found to vary systematically, though only slightly, with height over ground and between experiments with different snowpack characteristics.

Effect of Ion Exchange Resin Particle Size on X-Ray Fluorescent Analysis

1971 ◽  
Vol 15 ◽  
pp. 534-538
Author(s):  
A. L. Allen ◽  
V. C. Rose
Keyword(s):  
Particle Size ◽  
Copper Concentration ◽  
Exchange Resin ◽  
Particle Diameter ◽  
Ion Exchange Resin ◽  
General Shape ◽  
X Ray ◽  
A Minor ◽  
The Relationship ◽  
Mean Particle Diameter

The effect of resin particles on copper x-ray fluorescence was studied. For any given resin size the relationship between copper concentration and x-ray intensity was linear. As the particle size decreased, the x-ray intensity increased for any given copper concentration. The general shape of the curves are similar to the ones predicted by Bernstein for a minor constituent in a power sample. This study indicates that the variation in intensity with particle size can be eliminated by using resins with a mean particle diameter of 56 microns or less.

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