Improvement Of Flowability Research Articles

The effect of styrene maleic anhydride compatibilizer on the performance of polycarbonate/acrylonitrile butadiene styrene blends

The effect of styrene maleic anhydride as compatibilizer on the performance of polycarbonate/acrylonitrile butadiene styrene blends (PC/ABS) have been studied. The blends with varying amounts viz., 40, 50 and 60 wt% of acrylonitrile butadiene styrene have been melt mixed with 5 phb of SMA using twin screw extruder. The blends were characterized for mechanical behaviour interms of tensile properties and impact strength. Structural behaviour of the PC/ABS blends were characterized by Fourier transform infrared spectroscopy. The flowability was tested using melt flow index tester. The thermal resistance was tested by carrying out heat deflection temperature test. The glass transition temperature (Tg) and crystalline melting point (Tm) of blends were determined using differential scanning calorimetry. The morphological behaviour of the PC/ABS blends were characterized by scanning electron microscopy. From the results obtained, it was observed that styrene maleic anhydride compatibilized blends exhibits a significant improvement in tensile and impact properties as compared to uncompatibilized polycarbonate/acrylonitrile butadiene styrene blends. The results obtained by the Fourier transform infrared spectroscopy confirmed the reaction of compatibilizer by the intensity and shifting of peaks in the compatibilized blend compositions. There was an improvement in flowability with increase in polycarbonate percentage and with compatibilizer compare to uncompatibilzed blends. There was an improvement HDT vlaues. The changes in Tg peak position in thermograms indicates that partial miscibility between the blend components. Scanning electron microscopy revealed the molecular level interactions between PC and ABS in presence of compatibilizer.

Effects of discharging vibration conditions and coating structures on improving discharge particle flowability in a smaller particle admixing system

Particle flowability can be improved by admixing particles smaller than the original particles (main particles). However, the effects of coating structures on the improvement of flowability are not yet fully understood. In this study, we focused on vibrating discharge particle flowability and investigated the effect of discharging vibration conditions and coating structures on improving the flowability. Main and admixed particles of 60.8 μm and 8 nm in diameter, respectively, were mixed in various mass ratios, and the discharge particle flow rates of the mixed particles were measured. Scanning electron microscopy and scanning probe microscopy images were used to analyze the coverage diameter, surface coverage ratio, and coverage height of the admixed particles on the main particle surfaces. As a result, the admixing mass ratio that gave maximum flowability was found to depend on the maximum value of the vibration acceleration. This could be explained by the relationship between the coating structures of admixed particles and the coated average surface distances due to the vibration acceleration.

Spheroidization behavior of water-atomized 316 stainless steel powder by inductively-coupled thermal plasma

In the additive manufacturing process, fine powders having spherical shape are used due to their high flowability and packing density. When powders are produced by the water atomization method, it is advantageous to prepare fine powders, but powders having irregular shape are prepared, which is not suitable for the AM process. Therefore, in this study, 316 stainless steel powder fabricated by water atomization method were spheroidized using inductively-coupled thermal plasma. The initial water atomized 316 stainless steel powders had an irregular shape; however after spheroidization, their morphology was changed to a perfect spherical shape, which results in the drastic improvement of flowability. Examining the composition changes after spheroidizing, it was confirmed that the concentrations of oxygen and Cr were decreased. The reason for the decrease in oxygen concentration was that the temperature in the plasma process is extremely high and the oxygen partial pressure in the plasma chamber is low. The decrease in Cr concentration was caused by the evaporation of Cr during the spheroidization process, and the vapor pressure and evaporation coefficient of Cr in 316 molten liquid were calculated to analyze the reason.

Flowability characterization and enhancement of aluminium powders for additive manufacturing

The present work aims at quantifying and enhancing the flowability of cohesive metal powders, in particular aluminium powders, for their use in Additive Manufacturing processes such as Laser Metal Deposition. A flowability criterion, the population-dependent granular Bond number, is calculated for various metal powder samples, which are then tested with a funnel flowmeter under vibrational assistance. It is demonstrated that vibrations at a specific frequency can help trigger and sustain the flow of cohesive metal powders. Another way of enhancing powder flowability is achieved through heat treatment. A significant improvement in flowability is measured for a specific time-temperature setting, thereby enabling the use of a cohesive Al-Cu powder with the Laser Metal Deposition process.

Enteric Release Essential Oil Prepared by Co-Spray Drying Methacrylate/Polysaccharides-Influence of Starch Type.

Oregano essential oil (EO) enteric release powder was formulated by spray drying feed emulsions stabilized with polysaccharides (PSC) and Eudragit® L100 (PLM). Different modified starches were used in the PSC component. Spray-dried powders were evaluated for particle size and morphology, dynamic packing, flowability, chemical interactions, reconstitution, and gastric protection. Feed emulsions were stable, indicating the good emulsification ability of the PLM/PSC combination. The presence of polymer in the encapsulating wall neutralized electrostatic charges indicating physical attraction, and FTIR spectra showed peaks of both PLM and PSC without significant shifting. Furthermore, the presence of polymer influenced spray drying, resulting in the elimination of surface cavities and the improvement of powder packing and flowability, which was best when the surface-active, low-viscosity sodium octenyl succinate starch was used (angle of repose 42°). When a PLM/PSC ratio of 80/20 was used in the encapsulating wall, the spray-dried product showed negligible re-emulsification and less than 15% release in pH 1.2 medium for 2 h, confirming gastric protection, whereas at pH 6.8, it provided complete re-emulsification and release. In conclusion, (1) polymer–PSC physical interaction promoted the formation of a smoother particle surface and product with improved technological properties, which is important for further processing, and (2) the gastro protective function of Eudragit® L100 was not impaired due to the absence of significant chemical interactions.

Impact of formulation on reconstitution and flowability of spray-dried milk powders

The present study focuses on the impact of lipid content (1.5, 13.8, and 26 % (w/w)) and pretreatment of dairy concentrates (air incorporation by whipping prior to spray-drying) on the physicochemical and technofunctional characteristics of dairy powders. Spray-drying was performed according to the following conditions: 200 °C inlet air temperature and 85 °C outlet air temperature. Physicochemical properties (particle size distribution, shape factors, moisture content, water activity, and surface composition) of spray-dried powders were characterized in order to explain their reconstitution properties and flowability.The first part of the study revealed that changing the lipid content induced no significant difference of powder reconstitution. It was evidenced that median particle size of fatty powders was higher, thus counteracting the negative effect of powder surface hydrophobicity on its reconstitution behavior. Air incorporation in feed dairy concentrates did not significantly affect powder reconstitution properties, even if surface lipid content and median particle size were both decreased. Standard wettability and dispersibility tests were not relevant to evaluate the reconstitutability of investigated powders and all studied powders were classified as non-wettable and poorly dispersible.The second part of the study revealed that changing the lipid content induced a decrease in powder flowability both in unconfined conditions and under high normal stress. Powders were cohesive due to their low median particle size and their surface lipid coverage, nevertheless feed concentrates aeration induced an improvement of powder flowability by the decrease in surface lipid content. The bulk density (BD) and the compressed bulk density (CBD) both decreased with the lipid content, and the aeration of feed concentrates did not impact the BD but led to a decrease in CBD. Last, the compressibility increased with the lipid content and the aeration of feed concentrates, as the former increased particle cohesion and the latter induced the formation of smaller particles.

Effects of mixing ratio and order of admixed particles with two diameters on improvement of compacted packing fraction

To improve particle flowability, a technique is used in which fine particles are admixed with the main particles. However, the effects of coating structure on the improvement in flowability are not yet fully understood. Thus, predicting the improvement resulting from this technique is difficult. In this study, we focused on the effects of the particle diameter distribution of the admixed particles on coating structures and improvement of flowability in terms of the compacted packing fraction in a particle bed. Main particles of size 397 nm with admixed particles of sizes 8 and 104 nm were used. Bimodal particle diameter distributions were adjusted by changing the mixing ratios of the two admixed particles. Furthermore, the main and admixed particles were mixed in various orders. We examined the compacted packing fractions for these different mixing ratios and orders. Scanning electron microscopy images were obtained in order to analyze the coating structures on the main particle surfaces. The results show that the main particle packing fraction was most greatly improved by pre-mixing the two admixed particles. This can be explained by a linked rigid-3-bodies model with leverage based on increasing the apparent diameter of the main particles.

Evaluation of the physical properties of dry surface-modified ibuprofen using a powder rheometer (FT4) and analysis of the influence of pharmaceutical additives on improvement of the powder flowability.

In this study, we examined the characteristics of glidant that affect the improvement of the flowability of APIs by using the dry surface modification of ibuprofen. In addition, the screening method of glidant suitable for improving flowability of APIs was examined. As a result of evaluation of mixed powder with surface modification using various inorganic fine particles with different physical properties, it became clear that the packing fraction had the most influence regardless of the component. This was thought to able to coat the surface with small quantities because the smaller the packing fraction, the more it was able to dispersed from the less contacts between the glidant particles. The packing fraction of glidant was correlated with the (SE/CBD)-1 which was calculated value from the results measured with powder rheometer. From this results, when using any excipient as a glidant for dry surface modification, it is now possible to estimate the effect of improving flowability simply by measuring with a powder rheometer. Based on this study, it is possible to select excipients suitable for improving APIs flowability and to estimate the improvement effect, and therefore, it is expected to improve the efficiency of prescription design work.

Preparation and characterization of co-processed starch/MCC/chitin hydrophilic polymers onto magnesium silicate

It was aimed to investigate the compressibility, compactibility, powder flow and tablet disintegration of a new excipient comprising magnesium (Mg) silicate co-processed (5%–85% w/w) onto chitin, microcrystalline cellulose (MCC) and starch as the hydrophilic polymers of interest. Initially, the mechanism of tablet disintegration was studied by measuring water infiltration rate, moisture sorption, swelling capacity and hydration ability. Moreover, the powders compression behavior was carried out by applying Kawakita model of compression analysis in addition to porosity and radial tensile strength measurements. In vitro drug release of compacts made of 400 mg ibuprofen and 300 mg of the hydrophilic polymers containing 30% w/w Mg silicate co-precipitate was investigated in phosphate buffer (pH 7.8). This work demonstrated that the incorporation of Mg silicate to the hydrophilic polymers lead to the improvement of powder flowability, compactibility, stability (with regard to storage conditions), compacts crushing strength, and disintegration time in addition to faster drug release. The overall findings are practically advantageous in the context of finding a low cost and multifunctional co-processed excipient of natural origins.

Nanoporous CD-MOF particles with uniform and inhalable size for pulmonary delivery of budesonide

It is essential to optimize a carrier of dry powder inhalation (DPI) for the aerodynamic deposition in vitro to achieve pulmonary delivery of drug molecules in vivo. In this study, neutralized nanoporous γ-cyclodextrin metal-organic framework (CD-MOF) crystals with cubic morphology and uniform inhalation size were developed and modified as a DPI carrier for budesonide (BUD). Cholesterol (CHO) and leucine (LEU)-poloxamer were used to modify the CD-MOF powder for the improvement of flowability and particle aerodynamic behaviour, for which the particle size distribution, Carr's index and in vitro pulmonary deposition were assessed. Compared to CD-MOF or LEU-CD-MOF-BUD, CHO-CD-MOF had a superior mass median aerodynamic diameter (4.35 ± 0.04 μm) and inhalable performance (fine particle fraction of 30.60 ± 0.76%), which were maintained after budesonide loading (4.47 ± 0.30 μm, 24.95 ± 4.33%). The crystallinity, cytotoxicity and in vivo deposition of drug loaded samples (CHO-CD-MOF-BUD) were then investigated by powder X-ray diffraction (PXRD), cell viability study, in vivo fluorescence imaging and pharmacokinetic studies in rats. The characteristic PXRD crystallinity peaks of budesonide disappeared after being loaded into CHO-CD-MOF, potentially indicating the molecular incorporation of budesonide into the pores of CD-MOF. The cell viability of A549 cell was more than 90% for CHO-CD-MOF-BUD as a result of the good biocompatibility of CD-MOF. When Rhodamine B was carried by the DPI particles, the fluorescence signal at the lung tissue was markedly improved after cholesterol modification compared with CD-MOF, whilst the bioavailability of CHO-CD-MOF-BUD in rat was equivalent with that of the commercial product of Pulmicort Turbuhaler. Therefore, the CD-MOF powders modified by cholesterol can be used as a promising inhalable carrier for pulmonary delivery of drugs with small dose.

Association of PLGA Microspheres to Carrier Pellets by Fluid Bed Coating: A Novel Approach towards Improving the Flowability of Microparticles.

Micro- and nanoparticles have been vastly studied due to their biopharmaceutical advantages. However, these particles generally display very weak packing and poor mechanical properties. Hereby, a new methodology is proposed to associate poorly flowing particles to macrostructures targeting the improvement of flowability and redispersibility of the particles. Cecropia glaziovii-loaded PLGA microspheres (4.59 ± 0.04 μm) were associated with carrier pellets by film coating in a top-spray fluid bed equipment. Optimal conditions were determined employing a IV-Optimal factorial design and RGB image analysis as 1% (w/v) Kollicoat® Protect as coating polymer (2:1 weight ratio of coating suspension to carrier pellets), containing 5 mg/mL microspheres (loading of 28.07 ± 1.01 mg/g). The method led to an improvement of the overall flowability. No relevant molecular interactions between PLGA microspheres and polymers were found. Microspheres detached rapidly from the surface of the pellets, without agglomeration, when exposed to hydrodynamic forces. In vitro release profiles, prior to and after fluid bed coating, showed no relevant changes in drug release rate and extent. The methodology developed is suitable for further applications when an improvement on the flow properties and redispersibility of the product is desired. We showed an easy-to-implement methodology that can be executed without significant increase in costs.

Effect of Fly Ash, Sinking Beads and Metakaolin on the Workability, Strength, Free Shrinkage and Chloride Resistance of Concretes: A Comparative Study

The aim of this study is to compare sinking beads (SB) with fly ash (FA) and metakaolin (MK) with regard to their ability to improve the performance of concretes. The workability, compressive strength, free shrinkage and chloride resistance of concretes with and without the above mineral admixtures are investigated. To explicate the differences of above results, the pore structure and pore solution chemistry were also studied. Besides, the Chapelle test was adopted to compare the pozzolanic activity of the mineral admixtures. The water-to-binder ratio of concretes and pastes was 0.35 by mass. The incorporation level of MK was 5 and 10 wt%, while that of FA and SB was 10, 20 and 30 wt%. A systematic improvement in flowability, compressive strength, chloride resistance, free shrinkage is observed for SB concretes compared with FA concretes due to the smaller particle size, more round particle shape and higher pozzolanic activity of SB. MK shows the overwhelming ability to improve compressive strength and chloride resistance ability of concretes compared with SB and FA for the same replacement level, but comparable compressive strength and chloride resistance for SB concretes can be obtained by increasing the content of SB. In addition, inclusion of 20 wt% SB demonstrates remarkable potential to reduce free shrinkage to 25% less than concretes with 10 wt% MK. It may be ascribed to the dense structure of SB, which brings less volume reduction or even some increase during pozzolanic reaction.

Spherical Crystallization: An Overview

Introduction: In 1986, Kawashima developed the spherical crystallization technique for size enlargement of drugs in the field of pharmacy. Spherical crystallization is defined as “An agglomeration process that transforms crystalline drug directly into compact spherical forms for improving the flowability, solubility and compactability”. Methods: General methods for preparing spherical crystallization are spherical agglomeration, emulsion solvent diffusion method, ammonia diffusion method and neutralization method. Factors controlling the process of agglomeration include solubility profile, mode and intensity of agitation, temperature of the system and residence time. Results: Spherical crystals can be characterized by Optical microscopy, X-ray powder diffraction, Electron scanning microscopy, Fourier Transform Infrared spectrometer (FTIR) and differential scanning calorimeter (DSC).Spherical crystallization has wide applications in pharmaceuticals like improvement of flowability and compressibility of poorly compressible drugs, masking bitter taste of drugs and improving the solubility and dissolution rate of poorly soluble drugs. Conclusion: Spherically agglomerated crystals can be directly converted into a tablet thus saving time and reducing cost.

Effects of the spray drying conditions of chokeberry (Aronia melanocarpa L.) juice concentrate on the physicochemical properties of powders

SummaryA semi‐industrial spray drying process of chokeberry juice concentrate using maltodextrin was analysed. The influence of the content and dextrose equivalent (DE) of maltodextrin, inlet air temperature and rotary disc atomiser speed was studied on the physicochemical properties of the obtained powders. The size and structure of the powder particles, bulk density, moisture content, flowability, yield and total polyphenol content were analysed. An increase in carrier content from 50% to 70% caused a 4.9% increase in total polyphenol retention, better flowability (Hausner ratio decrease of 0.17) and greater yield of the powder (60%). An increase in the drying temperature (150–170 °C) caused larger particle size and improved powder flowability but also resulted in greater loss of total polyphenols. A decrease in rotary atomiser speed (11 000–15 000 rpm) had a moderate influence on particle size and improvement in flowability but had no effect on polyphenol retention. Changes in the DE (8–22) of maltodextrin as a carrier indicated a moderate growing dependence on particle size and worse flowability.

Application of Soluplus to Improve the Flowability and Dissolution of Baicalein Phospholipid Complex

In this study, a novel ternary complex system (TCS) composed of baicalein, phospholipids, and Soluplus was prepared to improve the flowability and dissolution for baicalein phospholipid complex (BPC). TCS was characterized using differential scanning calorimetry (DSC), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The flowability, solubility, oil–water partition coefficient, in vitro dissolution, and in vivo pharmacokinetics of the system were also evaluated. DSC, IR, PXRD, and SEM data confirmed that the crystal form of baicalein disappeared in BPC and TCS. Furthermore, the angle of repose of TCS of 35° indicated an improvement in flowability, and solubility increased by approximately eight-fold in distilled water when TCS was compared with BPC (41.00 ± 4.89 μg/mL vs. 5.00 ± 0.16 μg/mL). Approximately 91.24% of TCS was released at the end of 60 min in 0.5% SDS (pH = 6.8), which suggested that TCS could improve the dissolution velocity and extent. Moreover, TCS exhibited a considerable enhancement in bioavailability with higher peak plasma concentration (25.55 μg/mL vs. 6.05 μg/mL) and increased AUC0–∞ (62.47 μg·h/mL vs. 50.48 μg·h/mL) with 123.75% relative bioavailability compared with BPC. Thus, Soluplus achieved the purpose of improving the flowability and solubility of baicalein phospholipid complexes. The application of Soluplus to phospholipid complexes has great potential.

Spray freeze granulation of submicrometre alpha-alumina using ultrasonication

Granulation is a key factor towards improvement of the flowability of fine ceramic powders to make them suitable for industrial dry pressing. Controlled granulation of fine alumina particles with a primary particle size of ∼ 150 nm was carried out using spray-freeze drying, which led to the production of flowable granules with high crushability. The fracture surface of uniaxially die-pressed green bodies made from granules with density values of ≥ 50%of theoretical showed a uniform microstructure. Sintering experiments were performed using conventional single- and two-stage radiant heating methods followed by density and grain size measurement and characterisation of the final dense compacts to study the efficiency of two-stage sintering in grain growth elimination. The results have been compared with those of alumina bodies prepared using similar suspension by the slip-casting route.

Influence of Carbon Addition on Mechanical Properties of Thixomolded Magnesium Alloy

For the purpose of application for structural members such as the automobile, effect of carbon modification to the AZ91D magnesium alloy chip surface on fatigue property was examined by the rotary bending test. The carbon modification to the chip surface was quite useful for the control of the internal defect for the thick part on the thixomolding process. The depression of the internal defect by the carbon nanoparticle modification is closely related to the improvement of flowability, and that is presumed to be based on promoting the filling of the molten metal into the metal die inside. The tensile strength and elongation were respectively improved by the carbon addition. In addition, the fatigue strength also improved over 15%. This improvement of the mechanical property is based on the refinement of the crystal grain as well as the depression of the internal defects.

Optimized polybutylene terephthalate powders for selective laser beam melting

Additive manufacturing processes like selective laser beam melting of polymers (LBM) are established for production of prototypes and individualized parts. The transfer to serial production currently is hindered by the limited availability of polymer powders with good processability.Within this contribution the effect of powder properties, such as particle size, shape and flowability on the processability in LBM and their influence on device quality is exemplified for polybutylene terephthalate (PBT) materials. A process chain for the production of spherical polymer microparticles has been developed to obtain PBT powder materials. The process chain consists of three steps: first, polymer microparticles are produced by wet grinding. Second, the particle shape is engineered by rounding in a heated downer reactor to improve the flowability of the product. Third, a further improvement of flowability of the still cohesive spherical PBT particles is realized by dry coating with fumed silica.Moreover, properties of the PBT powders obtained along the process chain are thoroughly characterized with respect to structure and crystallinity by infrared spectroscopy, X-ray diffraction and differential scanning calorimetry. The effect of flowability, shape and bulk density on the powders’ processabilities in LBM is assessed by characterization of the quality of thin layers built in a LBM device. It is demonstrated that the device quality is strongly determined by particle properties: powders of good flowability and high bulk density are mandatory to obtain dense devices.

INFLUENCE OF FREE-FLOW EXCIPIENTS ON FUNCTIONAL PERFORMANCE OF NOVEONAA1 IN CONTROLLED-RELEASE TABLETS

<p><strong>Objective: </strong>The aim of this work is the assessment of an eventual improvement in flowability of free flowing excipients on formulations containing Noveon AA1 and their influence on compactibility and release profile.</p><p><strong>Methods: </strong>Mixtures containing 20% Noveon AA1 and variable proportions of metronidazole and the free flowing excipients Prosolv EasyTab and GalenIQ 720 and 721were tested in their powder flow rate and the tablets compactibility and released profiles.</p><p><strong>Results: </strong>The powder flowability obtained with GalenIQ is about 20% better than that obtained with EasyTab. However, it is lesser than that considered as acceptable for a high-speed tableting machine. EasyTab reduces the drug release up to a half along with a continuing flattening of the release profile. This is attributed to an increasing tortuosity of the drug release path as the proportion EasyTab increases. GalenIQ restricts drug release in about a third with a lesser change in the release mechanism. This is attributed to competition for the available water inside the tablet, between the hydrating Noveon AA1 and the dissolving GalenIQ. The compactibility of the metronidazole/Noveon AA1 mixtures increases after addition of EasyTab in about 3.5 N per unit percentage of the added excipient while GalenIQ does it in about 2.6 N.</p><p><strong>Conclusion: </strong>The powder flowability of mixtures of metronidazole with Noveon AA1 was not suited for direct compression after addition of 40% of the free-flow excipient. The free-flow excipients reduce the metronidazole release rate and increase its compactibility. It was not observed a different clear functioning between both types of GalenIQ.</p>

Sustained drug release from electrostatic powder coated tablets with ultrafine ethylcellulose powders

In the present study, tablets were successfully coated with ultrafine ethylcellulose powders by using an electrostatic dry powder coating technology and sustained drug release was successfully achieved. The angle of repose (AOR) of the ultrafine powders of ethylcellulose was significantly reduced by adding nano sized colloidal silicon dioxide, indicating a significant improvement of flowability. Variations in charging voltage of the electrostatic gun had a significant influence on the coating powder adhesion and coating efficiency. Lactose and triethyl citrate (TEC) were used as the solid and liquid plasticizers to reduce the glass transition temperature (Tg) of ethylcellulose. The presence of liquid plasticizer could also increase the electrical conductivity of drug tablets so as to promote the coating powder adhesion. Other factors that affect the film formation include curing time and curing temperature. Dissolution tests indicated that the drug release from electrostatic dry powder coated tablets could be altered by adjusting coating level or pore former ratio in the coating formulation.