Particle size reduction

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Particle size reduction to the nanometer range: a promising approach to improve buccal absorption of poorly water-soluble drugs

Particle size reduction to the nanometer range: a promising approach to improve buccal absorption of poorly water-soluble drugs

Solubility is generally defined as a compound-specific constant depending only on the temperature and the crystalline structure. However, the rate of dissolution and thus the appar- ent solubility of phenylephrine were remarkably improved by the formation of a hydroxypropyl- β -cyclodextrin complex with phenylephrine or the development of a phenylephrine nanosuspension. The increase in apparent solubility then brought a significant increase in transmucosal permeation. A 30% increase in apparent solubility by cyclodextrin compl- exation led to a doubling of transmucosal flux through porcine buccal mucosa, and an 80% increase in apparent solubility via nanosuspension was accompanied by approximately a 4-fold increase in the transmucosal flux. It is postulated that with the increase in apparent solubility, more dissolved drug is presented to the porcine buccal mucosal surface, resulting in a higher concentration gradient across the membrane. Since phenylephrine permeates through buccal mucosa via passive diffusion (confirmed by the linearity between transmucosal flux and donor concentration, Figure 2), the increase in con- centration gradient across the membrane contributed to the improved permeability of phenylephrine. Therefore, cyclo- dextrin inclusion and particle size reduction to the nanometer range were confirmed as two effective techniques to improve buccal transmucosal permeability of phenylephrine via increasing apparent solubility. The feature of mucosal adhe- siveness and the consequent prolonged retention at mucosal surface further suggests the use of nanosuspensions for buccal drug delivery may be a promising technique.
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CELF significantly reduces milling requirements and improves soaking effectiveness for maximum sugar recovery of Alamo switchgrass over dilute sulfuric acid pretreatment

CELF significantly reduces milling requirements and improves soaking effectiveness for maximum sugar recovery of Alamo switchgrass over dilute sulfuric acid pretreatment

Most biological operations for biomass conversion require particle size reduction prior to pretreatment to realize high sugar yields by subsequent enzymatic hydrolysis. Biomass is also presoaked prior to most pre- treatments to provide adequate reactant contact. Thus, both particle size reduction and presoaking can increase reactant diffusion into the biomass particle. However, the high milling energy required to reduce particle size suf- ficiently to realize high yields is a significant contributor to processing costs, and extended presoaking increases processing times. In this study, the effect of presoak- ing times and particle size reduction by knife milling on DSA and CELF pretreatment of Alamo switchgrass was investigated. Biomass presoaking slightly increased glu- cose yields from enzymatic hydrolysis for DSA and CELF solids. Significantly, CELF pretreatment is shown to be capable of achieving high glucose yields from subsequent enzymatic hydrolysis of solids from CELF pretreatment of switchgrass without size reduction even at low enzyme loadings, in definite contrast to DSA. The latter results indicate that particle size reduction of biomass could be eliminated prior to CELF pretreatment without a reduc- tion in sugar yields, thus potentially reducing processing costs for biofuels production.
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Nanocrystal Technology as a Tool for Improving Dissolution of Poorly Soluble Drugs

Nanocrystal Technology as a Tool for Improving Dissolution of Poorly Soluble Drugs

This technology called opposite stream or nanojet technology. This method consists of micro fluidizer which uses a chamber where a stream of suspension is divided into two or more parts, which colloid with each other at high pressure. The high shear force produced during the process due particle collision and high pressure results in particle size reduction. Equipment using this principle includes the M110L and M110S micro fluidizers. Dearn prepared Nano suspensions of atovaquone using the micro fluidization process [21].The major disadvantage of this technique is the high number of passes through the micro fluidizer and that the product obtained contains a relatively larger fraction of microparticles [24].
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Preliminary study of nanonized lamotrigine containing products for nasal powder formulation

Preliminary study of nanonized lamotrigine containing products for nasal powder formulation

NaHA (from 8.96 to 26 µ m) also increased after milling; its sponge-like structure and surface became smooth. How- ever, the PVA (from 124.97 to 49.96 µ m) and PVP_K25 (from 21.26 to 13.06 µ m) particles became smaller. This particle size reduction is associated with the cataract and cascade effects that occur during milling. The temperature rise during milling is not remarkable because the measured temperatures (25 ° C–37 ° C) do not reach the glass transition temperatures of the polymers. The morphology of initial LAM crystals was large, mainly columned, and they had a rough surface compared to the ground LAM, because those particles were nearly spherical and aggregated, which are factors responsible for the particle size increasing. The surface of the additives remained uneven after milling – except for PVP_K25 (because its surface in the beginning was nearly spherical) – but as their particle size decreased, due to the higher specific and uneven surface, they could offer an optimal polymer matrix, where the individual LAM particles can adhere.
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Preparation, solid state characterization and evaluation of ketoprofen-glucosamine HCl solid dispersions

Preparation, solid state characterization and evaluation of ketoprofen-glucosamine HCl solid dispersions

The SDs were prepared of Ketoprofen, using Glucosamine HCl as hydrophilic carrier by solvent evaporation method with drug carrier ratio 1:1, 1:2, and 1:3. The results depicted that 1:3 (F6 KTP) solid dispersions have the highest dissolution pro ile as compared to pure Ketoprofen and other formulations. The order of dissolution rates of pure Ketoprofen and different formulations is, pure Ketoprofen ˂ F1 KPT ˂ F2 KPT ˂ F3 KPT ˂ F4 KPT ˂ F5 KPT ˂ F6 KPT. The enhancement of the dissolution rate of solid dispersions can be ascribed to various factors such as lack of crystallinity (amorphization), particle size reduction, increased wettability and dispersability [21,22]. As shown by dissolution data of the PMs, improvement could be attributed higher dispersability and wettability. Therefore, PMs of drug with hydrophilic carrier result in greater wetting as compared to pure Ketoprofen. Different techniques were used for solid state characterizations and determination of interactions between drug and carrier. Differential scanning caloromitry studies, on the basis of melting point of
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Mechanical Modification of Khulays Clay; Structural and Textural Effects

Mechanical Modification of Khulays Clay; Structural and Textural Effects

The results from this study showed that the physical disintegration of the clay minerals by manual milling consisted of many processes: particle size reduction, morphological and structural changes, accompanied by changes of the surface properties. Many aspects should be addressed here. The first process applies to all investigated solids during the milling treatment, refers to the intensive decrease of the initial particle size, associated with morphological changes and the formation of a poly dispersed powder as shown from SEM and TEM results [1-3]. Similar to other studies [13,14, 22, 25], the fracturing and size reduction of the clay mineral particles during this process was accompanied by an increase in the surface area. In the present study there is an agreement in the results from DLS (Fig. 3) after 30 minutes of grinding and BET results (Fig. 4.). This implies that the intensive mechanical treatment of different clay minerals causes the formation of aluminosilicates with similar structural (XRD), morphological and surface area properties.
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NANOSUSPENSION: A PROMISING DRUG DELIVERY SYSTEM

NANOSUSPENSION: A PROMISING DRUG DELIVERY SYSTEM

In piston gap homogenizer, particle size reduction is based on the cavitation principle. A Piston-gap homogenizers like APV Gaulin types has been shown. Particles are also reduced due to high shear forces and the collision of the particles against each other. The dispersion contained in 3cm diameter cylinder; suddenly passes through a very narrow gap of 25µm. The reduction in diameter from 3cm to 25µm leads to increase in dynamic pressure and decrease of static pressure below the boiling point of water at room temperature. Due to this, water starts boiling at room temperature and forms gas bubbles, which implode when the suspension leaves the gap (called cavitation) and normal air pressure, are reached. The size of the drug nanocrystals that can be achieved mainly depends on factors like temperature, number of homogenization cycles, and power density of homogenizer and homogenization Pressure. 2 DissoCubes technology is an example of this technology developed by R.H. Muller in 1999 e.g. Omeprazole.
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COLLOIDS   FIELD FLOW FRACTIONATION pdf

COLLOIDS FIELD FLOW FRACTIONATION pdf

A general methodology for the analysis of a collo- idal mixture by PB SdFFF consists of injecting into the column the mixture with a carrier solution in which the ionic strength is too high to ensure total adhesion of all the components of the mixture, except for one with the lower attractive force with the chan- nel wall. Then a programmed variation (decrease) of the ionic strength of the carrier solution is applied to release, in time, the adherent particles according to their size and / or surface characteristics. As the PBSdFFF technique is based on particle } wall interac- tions, its applications can be extended by using differ- ent materials, such as stainless steel, Te S on and polyimide. PBSdFFF is also a convenient and accurate method for the concentration and analysis of dilute colloidal samples. This makes PBSdFFF a highly attractive technique for the characterization of sam- ples where even particles of the same size but of different chemical composition are present in low concentration.
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Morphology and electronic structure of nanoscale powders of calcium hydroxyapatite

Morphology and electronic structure of nanoscale powders of calcium hydroxyapatite

structure of which approaches the mineral component of bones, are widely used in medical practice over the past 20 years. All the time, the researches continue to work for improvement of these materials [1-4]. However, the pro- spect of their application may not be quite complete with- out clarifying the relationship of morphological, physical and chemical properties, and atomic architecture surfaces of these materials because biocompatibility is dependent not only on their chemical composition but also to a large extent on the morphology of the particles, which affect the interaction of mineral constituent of bones with the organic matrix. In view of the fact that such material should be included in the metabolism of the body and be replaced with a full bone tissue, it remains relevant to ob- tain nanodispersed calcium hydroxyapatite with parame- ters that match the parameters of particle maximum mineral component of bones [5-8]. This article presents the results of a study of morphological and physicochemi- cal properties of calcium hydroxyapatite powders obtained at various temperature parameters of synthesis.
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Synthesis, Characterization and Photocatalytic Application of Different Sizes of Gold Nanoparticles on 4 Nitrophenol

Synthesis, Characterization and Photocatalytic Application of Different Sizes of Gold Nanoparticles on 4 Nitrophenol

Figure 1 shows the transmission electron microscopy (TEM) images of AuNPs prepared with different molar ratios of trisodium citrate. All the nanoparticles synthesized were roughly spherical in shape and morphologies were irregularly distributed in two of the samples (S1 and S3) and regularly distributed in sample S2. The di- ameter of the particles was measured using a millimetre scale and the number of particles within a bin of 5 mm with different average diameters was counted [16]. It was noted that the particle size decreased with decreasing concentration of tri-sodium citrate. The results agree with the previous work of Zabetakis et al. (2012) [17]. The negatively charged layer of citrate ions act as electrostatic stabilization and it is prevent the agglomeration of AuNPs. Lower level of citrate favor increased growth/agglomeration of the nanoparticles. Aggregated species can be attributed to the rapid reduction of AuIII by large excess of citrate. So that strongly reduction nature of tri-sodium citrate inducing rapid nucleation is followed by agglomeration rather than an extended particles growth phase. The average size of the Au nanoparticles was found to be ≈4 nm, 7 nm and 11 nm for samples S1, S2 and S3, respectively. TEM measurements of the three AuNPs samples exhibit a narrow size polydisprisity and it decrease with increasing the particle sizes due to the seeding growth process and sefl-focusing formation of AuNPs. Moreover the size polydispersity changed with the change of trisodium citrate concentrations. Figure 2 shows the UV-VIS absorption spectra of the gold nanoparticles synthesized with different particle sizes: 4 nm (S1), 7 nm (S2) and 11 nm (S3). From this figure we see that a sharp peak was observed at three wavelengths (512, 513 and 514 nm) for the three samples (S1-S3), respectively. The band shifted to a higher wavelength with increasing size
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Effect of Particle Size of NaX Zeolite on Adsorption of CO2/CH4

Effect of Particle Size of NaX Zeolite on Adsorption of CO2/CH4

Therefore, lower crystallization temperatures and strong shaking conditions prepare the small crystal sizes. The average crystal size of the prepared zeolites was calculated using Scherrer’s equation. The BET analysis was used to determine the external surface area,

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GLIBENCLAMIDE LOADED FLOATING BEADS –INVITRO CHARECTERIZATION

GLIBENCLAMIDE LOADED FLOATING BEADS –INVITRO CHARECTERIZATION

For size distribution analysis58, 250 mg of the floating beads of different sizes in a batch were separated by sieving, using a range of standard sieves. The amount of floating beads retained on each sieve is weighed. The mean particle size of the floating beads is calculated by the formula &results were shown in table no7&fig n0 5. [6]

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Influence of Temperature, Basiscity and Particle Size on MnO Reduction

Influence of Temperature, Basiscity and Particle Size on MnO Reduction

A mixture of a source of Manganese oxide, e.g., high- purity MnO or Mn ore and graphite was made so as to obtain the most uniform carbon distribution. During the experi- ments, no graphite segregation was observed on the oxide surface. The amount of ore was 150 g. Also, 37 g of graphite powder was mixed with the ore, which corresponds to the necessary stoichiometric mass to reduce the entire oxide. There is 63 g of Mn in 150 g of ore. This amount is equivalent to 83 g of high purity MnO. In this case, 14 g of graphite, the stoichiometric amount, was mixed with the high purity MnO. After all tests were performed, a thin layer of slag was always observed. Table 3 shows the experiments carried out to study the influence of temperature on reducing high-purity MnO. Analogously, Table 4 shows tests performed to investigate the effect of temperature on the MnO ore reduction. Similarly these experiments were done to measure the reaction rates and the apparent activation energy. The tests performed to investigate the effect of basicity on the reduction process are presented in Table 5. The basicity
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Cassava Leaf Nanoparticles (CLNPs) as a Potential Additive to Anti-Corrosion Coatings for Oil and Gas Pipeline

Cassava Leaf Nanoparticles (CLNPs) as a Potential Additive to Anti-Corrosion Coatings for Oil and Gas Pipeline

precipitate that will serve as a protective film on the surface of the metal, thereby protecting the metal from corrosion. TEM image reveals more precise particle size compared to that obtained from SEM/Gwyddion software and XRD. FTIR result revealed the nature of bond that exist in the CLNPs and GC-MS result showed various organic compounds that were presence in the CLNPs. These organic compounds can be classified as fats, waxes, alkaloids, proteins, phenolics, simple sugars, pectins, mucilages, gums, resins, terpenes, starches, glycosides, saponins and essential oils. All of which helps improve the properties of metallic coatings. This work shows that the CLNPs can be produced, and they can be used as additives to coatings for corrosion protection, especially coatings for oil and gas applications. Therefore, CL should not be left to waste as they are useful for additives in coatings. These will add value to the CL that is usually dumped in the environment and also reduces environmental pollution.
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Hydrogen Assisted Magnesiothermic Reduction (HAMR) of Commercial TiO2 to Produce Titanium Powder with Controlled Morphology and Particle Size

Hydrogen Assisted Magnesiothermic Reduction (HAMR) of Commercial TiO2 to Produce Titanium Powder with Controlled Morphology and Particle Size

sphere. A further deoxygenation process was carried out to ensure the purity met the standard specification for titanium. The combination of the hydrogen assisted magnesium reduc- tion and deoxygenation (HAMR) process, is an integrated approach that made it possible to produce Ti powders that meet the ASTM specification for Ti based on a simple process of thermal reduction using Mg. In this study, particle sizes and morphology of Ti powder produced through three option- al routes are presented. From route I and route II, irregular shaped powders were produced, while from route III, a spher- ical powder was produced. They all met the ASTM B299 tita- nium sponge standard for general purpose applications.
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Impact of Particle Size on Content Uniformity

Impact of Particle Size on Content Uniformity

Copyright to IJIRSET DOI: 10.15680/IJIRSET.2015.0402100 9374 achieved just beyond 4 minutes of mixing. It implies that reducing the particles size reduces the mixing time. When the particle size is reduced by half, the mixing time is reduced by four times and it can be seen in mixing curve for salt with particle size less than 211 microns where the required content uniformity is obtained just after 2 minutes of mixing.

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Hemoglobin level and lipoprotein particle size

Hemoglobin level and lipoprotein particle size

Concentrations and sizes of lipoprotein subclass parti- cles were analyzed with high-throughput NMR spectros- copy of native serum samples [17, 18] in 2009. NMR data were measured at 37 °C using a Bruker AVANCE III spectrometer operating at 500.36 MHz using a new automated platform, as described previously [19]. The following 14 lipoprotein subclasses were calibrated using high-performance liquid chromatography: chylomi- crons (CMs) and largest VLDL particles (CM/ largest VLDL; average particle diameter ± 75 nm); five different VLDL subclasses, i.e., very large (average particle diameter 64.0 nm), large (53.6 nm), medium (44.5 nm), small (36.8 nm) and very small VLDL (31.3 nm); intermediate- density lipoprotein (IDL; 28.6 nm); three LDL subclasses, i.e., large (25.5 nm), medium (23.0 nm), and small LDL (18.7 nm); and four HDL subclasses, i.e., very large (14.3 nm), large (12.1 nm), medium (10.9 nm), and small HDL (8.7 nm).
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The Pollutant Particle Size and Chemistry Matters

The Pollutant Particle Size and Chemistry Matters

measure the particle surface area is based on measuring the particle number size distributions.. With 228.[r]

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Indoor particle size distribution in office

Indoor particle size distribution in office

than the eight-hour time weighted average (TWA) local office background particle exposure limit. Hence, these printers could increase the exposure of office workers to particles generated by printing activity at both one and two metres, respectively. The particle size distribution monitored during photocopying indicates that the emitted particles were much smaller than the original toner powders. Additionally, the number concentration of particles that were smaller than 0.5 μm was found to increase during the first hour of photocopying and it increased as the particle size decreased [7]. The ultrafine particle (UFP, < 100 nm) dominated the number concentration and the peak concentration appeared at sizes of under 50 nm. A high number concentration of UFP was found with a peak value of 1x10 8 particles cm -3 during
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Controlled release of 5-fluorouracil and progesterone from magnetic nanoaggregates

Controlled release of 5-fluorouracil and progesterone from magnetic nanoaggregates

The dependence of the drug release kinetics on the par- ticle diameter can be directly correlated to the variation on the drug loading. Figure S2 (Supplementary material) focuses on the effect of the average particle diameter on 5-fluorouracil release rate through nanoaggregates with approximately equal drug loading. The selected drug loading in all samples was adjusted to be 10%. It should be noted that there is little effect of the particle size on the drug release rate for the samples loaded by the in-situ method. A comparison between the release profiles of both the in-situ loaded and freeze-dried samples prepared at 10% drug loading is shown in Figure 2 (Supplementary section). Based on our previously discussed data, the drug loading, particle size and loading techniques all contribute to the release profile of examined samples. The drug loading techniques exhibited more significant roles in controlling the release rate.
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