Country：Japan

Country：Japan

Country：Japan

Country：Japan

Country：Japan

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.cej.2023.146166

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.apt.2023.104045

Publishing type：Research paper (scientific journal)  

<p>Wet granulation plays an important role in the processing of fine ore powder. Water content is a critical process parameter that determines the granule properties during wet granulation. However, in the ironmaking industry, various types of iron ore powder imported from different regions are blended, quicklime powder is added as a binder, and used as raw materials. Therefore, the physicochemical properties of the raw powders are not always consistent, which makes it difficult to determine the optimum water content. In this study, we present a method to determine the optimum water content using the agitation torque of wet ore powder blended with quicklime. First, we investigated the agitation torque for blending of various types and ratios of ore powders and quicklime. Two types of torque profiles were observed: a unimodal torque profile (Type I) and a torque profile with a plateau region (Type II). From the agitation torque profile, the characteristic water content (<i>W</i>_torque) for estimating the optimum water content (<img align="middle" src="./Graphics/abst-63_ISIJINT-2022-498_eq_a.jpg"/>) was individually defined for the types I and II. The <i>W</i>_torque was well correlated with the <img align="middle" src="./Graphics/abst-63_ISIJINT-2022-498_eq_a.jpg"/>, regardless of the type and blending ratio of the original ore powders and quicklime. Finally, the optimum water content was estimated using the <i>W</i>_torque. The estimated water content was confirmed to be in good agreement with the experimental results, demonstrating that the optimum water content for the wet granulation of fine ore powder with quicklime can be determined using agitation torque.</p>

DOI： 10.2355/isijinternational.isijint-2022-498

Publishing type：Research paper (scientific journal)  

DOI： 10.1002/aesr.202200206

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jpowsour.2022.232379

Publishing type：Research paper (scientific journal)  

DOI： 10.1248/cpb.c23-00168

PubMed

Publishing type：Research paper (scientific journal)  

Because the cell membrane is the main barrier of intracellular delivery, it is important to facilitate and control the translocation of extracellular compounds across it.

DOI： 10.1039/d3cp03281g

PubMed

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.apt.2022.103822

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ijpharm.2022.122251

PubMed

Authorship：Lead author   International / domestic magazine：Domestic journal  

<p>Solid dispersion particles were prepared using an indomethacin (IND) as a model insoluble drug, poly-(vinylpyrrolidone-co-vinyl acetate) (VA64) as a water-soluble polymer and mannitol (Man) as an excipient. In case of hot-melt extrusion (HME) preparation, dissolution profile of every composition without Man was the same as others. The dissolution profile of composition including Man was much improved than others without Man. By contrast, the effect of Man addition was not recognized in case of spray drying (SD) preparation. Surface energy of the solid dispersion particles was measured by using an inverse gas chromatography surface analyzer (iGC-SEA). The surface energy of solid dispersion particles including Man prepared by the HME is much smaller than that without Man. However, in the SD preparation, there was no clear difference in the surface energy of solid dispersion particles with and without Man. The characteristic of the solid dispersion particles by the different manufacturing methods implied the difference of the dissolution improvement, in spite of the same composition.</p>

DOI： 10.4164/sptj.59.438

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ica.2022.121143

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.apt.2022.103705

<p>Solid dispersion is a common useful technique which makes a crystal drug into amorphous. It improves the dissolution of the insoluble drug by using a rise in solubility, to increase the gastrointestinal tract absorption. In this study, dissolution characteristics of solid dispersion were improved by adding mannitol to the solid dispersion. The effect of mannitol addition to the solid dispersion formulation including PVP-K30 on the dissolution property was investigated. A large difference was observed between two manufacturing methods, a solvent distillation by an evaporator and a spray drying. The different effect of the mannitol addition appeared in the influence of the particle size of solid dispersion particles, although the composition of solid dispersion manufactured by both methods was the same.</p>

DOI： 10.4164/sptj.59.331

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.apt.2022.103633

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.cej.2022.138298

<p>All-solid-state lithium-ion batteries are expected as next-generation batteries for electric vehicles due to high energy densities and high safety. Approaches to a further improvement of energy densities include the analysis of electrode structure. In this study, DEM simulations were performed to calculate under compression process. The effect of the particle size ratio and plasticity ratio on the packing property was investigated.</p>

DOI： 10.14356/hptf.20505

DOI： 10.14356/hptf.20001

<p>In human respiratory system, fluid behavior is complicated and drug particle behavior is unknown, since drug particle shape is irregular and its drag force is different from sphere particle. In this study, behavior of irregular shape particles in cascade impactor throat was analyzed by using DEM–CFD. Drag force model of irregular shape particle was applied for DEM–CFD. Based on the numerical simulation, drag force model suggested by Bagheri and Bonadonna agreed well with the experimental results. Also, it was found that many particles remained at inlet of cascade impactor throat due to the recirculation vortex.</p>

DOI： 10.14356/hptf.20503

Publishing type：Research paper (scientific journal)  

<p>Numerous efforts have been devoted to improving the solubility of poorly water-soluble drugs. Recently, it was reported that the use of metal-organic frameworks (MOFs), which are a new class of porous materials consisting of metal ions and organic ligands, is effective in improving the solubility of poorly water-soluble drugs. Our previous study demonstrated an improvement in the solubility of indomethacin (IDM) triggered by the zeolitic imidazolate framework-8 (ZIF-8). The present study aimed to elucidate the solubilization mechanism using the ZIF series, namely, ZIF-8, ZIF-67, and ZIF-L. It was confirmed that the solubility of ZIF-trapped IDM and ibuprofen (IBU) was enhanced compared to the raw drugs, regardless of the ZIF type. This study focused on 2-methylimidazole (2-MIM), which is commonly used as a ZIF organic ligand. Both IDM and IBU were easily dissolved by the addition of 2-MIM, suggesting that the presence of 2-MIM enhanced the solubility of the drugs. Inductively coupled plasma measurements also confirmed the presence of metal ions of ZIFs in the supernatant solution after the drug release tests, indicating the decomposition of ZIFs during drug release. The findings of this study demonstrated the solubilization mechanism of poorly water-soluble drugs using ZIF particles. We observed that the drugs loaded on the ZIFs were released simultaneously with the decomposition of some of the ZIFs. The 2-MIM molecules were also released concurrently. The presence of 2-MIM improved the solubility of poorly water-soluble drugs.</p>

DOI： 10.1248/cpb.c22-00020

PubMed

ゼオライト様イミダゾラート骨格系化合物ZIF-8、ZIF-67、ZIF-Lを用いて、その可溶化機序について検討した。ZIF捕捉性のインドメタシン(IDM)とイブプロフェン(IBU)では、ZIFの種類にかかわらずその原薬に比べて溶解度が向上した。一般的なZIF有機配位子としての2-メチルイミダゾール(2-MIM)を用いると、IDMとIBUの両者は2-MIMの添加によって容易に溶解し、2-MIMの存在が溶解度を高めることが示唆された。薬物放出試験後の上清溶液中にはZIFの金属イオンが存在し、薬物放出中にZIFが分解することが示唆された。以上より、ZIFに捕捉された薬物が、一部のZIFの分解と同時に放出されることを観察し、2-MIMは難水溶性薬の溶解度を改善すると考えられた。

Publishing type：Research paper (scientific journal)  

<p>The sustained-release formulations consist of many components, such as the active pharmaceutical ingredient, excipient, binder, lubricant, and polymer, leading to the complex dissolution process. The objective of this study is the elucidation of the rate-determining step in the dissolution process by direct optical observation. The composite particles of hydroxypropyl methylcellulose (HPMC) and brilliant blue FCF (model drug) were prepared, and the direct observation of the dissolution process and image analysis were conducted. The decrease in particle size and the penetration of solvent into the particles during the dissolution process had little impact on the sustained-release performance. On the other hand, the diffusion rate of the model drug in the HPMC gel strongly depended on the type of HPMC, suggesting that the rate-determining step in the dissolution process of the sustained-release formulations using HPMC would be the drug diffusion process in the polymer gel in the particles.</p>

DOI： 10.4164/sptj.59.160

Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.apt.2022.103470

Kind of work：Joint Work   International / domestic magazine：Domestic journal  

DOI： https://doi.org/10.4164/sptj.59.4

Publishing type：Research paper (scientific journal)  

DOI： 10.2355/isijinternational.isijint-2022-009

Publishing type：Research paper (scientific journal)  

DOI： 10.4164/sptj.58.414

Publishing type：Research paper (scientific journal)  

DOI： 10.4164/sptj.58.127

Publishing type：Research paper (scientific journal)  

DOI： 10.2355/tetsutohagane.tetsu-2020-079

Publishing type：Research paper (scientific journal)  

© 2020 Elsevier Ltd Spray drying is a fundamental process in several industries. As many factors affect the particulate product property in complex manners, optimal operating conditions have been determined through trial and error. In a spray dryer, numerous sprayed droplets form a tear-shaped droplet aggregate (droplet group), in which each droplet evaporates at a different rate. Owing to the complicated evaporation behavior of a droplet group, a detailed mechanism of dried particle generation has yet to be sufficiently elucidated. The objective of this study is to investigate the effects of the operating conditions of spray drying processes on the evaporation rate of a droplet group. Numerical simulations were performed under various conditions to calculate the evaporation rates of a droplet group in a spray drying process. A method for estimating the evaporation rate of a droplet group based on the operating conditions, using the thermal efficiency and Nusselt number, is proposed.

DOI： 10.1016/j.ces.2020.115938

乾燥粉末吸入器(DPI)のカプセル(CAP)中の粒子付着機序を検討するため、付着モデルにJohnson-Kendall-Roberts理論を用い、数値流体力学と離散要素法(CFD-DEM)を併用して検討した。シミュレーション(SIM)と実験結果では、CAP出口に多くの粒子が残存したが、入口には殆ど残存しなかった。SIMではCAP内の粒子は片側から供給される空気で迅速に両側に分散し、CAPの入口から出口に輸送された。CAP出口側では過流を確認したが、入口側には過流を認めず、出口で多数の衝突を確認したが、入口では殆ど衝突を認めなかった。これらの結果から、CAP内の残存粒子の量を削減するためには過流が必要であることが示唆された。多くの粒子が残存した元のCAPを改変し過流が発生するよう改変したCAPは、元のCAPに比べて残存量が減少した。以上より、CFD-DEM手法は、粒子付着の理解とDPIの送達効率改善にとって有用であると考えられた。

ヒト呼吸器系の粒子沈着を評価するため、離散要素法(DEM)と計算流体力学法(CFD)を結合したモデルを用いたコンピュータシミュレーションを実施した。こうして開発した簡易呼吸モデル(SRM)により、粒子沈着挙動(DB)に及ぼす粒子特性と吸入パターンの影響を数値的に検討した。このDEM-CFD法では、小サイズで低比重の粒子がSRM内で高い到達可能性(REA)を示し、深部領域への粒子の到達速度はその空力的直径(ADD)に強く依存した。更に、RSMの深部への粒子REAとADDの間の指数関係を、要求されたREAを基にして粒子ADDを予測した。粒子形態も粒子DBに影響した。大きな縦横比の棒状粒子はSRMの深部内へのREAが高いことが示された。理由として、その長軸が深部領域を指向している粒子の高速運動に起因すると考えられた。

Publishing type：Research paper (scientific journal)  

© 2019 The Pharmaceutical Society of Japan. Dry powder inhalation (DPI) has attracted much attention as a treatment for respiratory diseases owing to the large effective absorption area in a human respiratory system. Understanding the drug particle motion in the respiratory system and the deposition behavior is necessary to improve the efficiency of DPI. We conducted computer simulations using a model coupling a discrete element method and a computational fluid dynamics method (DEM-CFD) to evaluate the particle deposition in human respiratory system. A simple artificial respiratory model was developed, which numerically investigated the effect of particle properties and inhalation patterns on the particle deposition behavior. The DEM-CFD simulations demonstrated that the smaller- and lower-density particles showed higher reachability into the simple respiratory model, and the particle arrival ratio to the deep region strongly depended on the aerodynamic diameter. The particle arrival ratio can be described as an exponential function of the aerodynamic diameter. Furthermore, the exponential relationship between the particle reachability into the depth of the simple respiratory model and the aerodynamic diameter predicted the particle aerodynamic diameter based on the required reachability. The particle shape also had an impact on the particle deposition behavior. The rod-like particles with a larger aspect ratio indicated higher reachability into the depth of the simple respiratory model. This was attributed to the high velocity motion of the particles whose long axis was in the direction of the deep region.

DOI： 10.1248/cpb.c19-00693

PubMed

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Kind of work：Joint Work  

Responsible for pages：101-110,141-177,210-221  

Responsible for pages：209-223  

Responsible for pages：479-484