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Koura A, Shimojo F. Intermediate range structure of amorphous Cu 2GeTe 3: ab initio molecular dynamics study. J Phys Condens Matter 2020; 32:244001. [PMID: 32196481 DOI: 10.1088/1361-648x/ab7b1b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We have investigated the intermediate range structure of amorphous Cu2GeTe3 based on ab initio molecular dynamics simulations. The highest population of ring size is three, which makes the triangle structure. This ring consists of mainly Cu2Te. Rings may also consist of CuCuCu, Cu2Ge, and CuGeTe, where approximately 88% of Cu atoms in the system are related with the three-membered ring. The second highest population of ring size is five. Three- and five-membered rings in the amorphous phase originate from six-membered ring in the crystalline phase. This situation can enhance the phase transition between crystalline and amorphous phases. In the phase change process, Cu atoms may diffuse in the amorphous state with changing bonds. The diffusion coefficient of Cu D Cu is estimated to be approximately 0.12 × 10-9 m2 s-1. Such high diffusion coefficient of Cu atoms is contributed from only 10% of Cu atoms in the amorphous phase.
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Affiliation(s)
- A Koura
- Department of Physics, Kumamoto University, Kumamoto, Japan
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2
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Ohmura S, Shimojo F. Structural change in liquid sulphur from chain polymeric liquid to atomic simple liquid under high pressure. J Phys Condens Matter 2019; 31:215101. [PMID: 30897066 DOI: 10.1088/1361-648x/ab0a35] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The structural properties of liquid sulphur under high pressure up to approximately 500 GPa have been investigated by means of ab initio molecular-dynamics (MD) simulations. The obtained pair distribution functions and spatial distribution of electron density under high pressure indicate the existence of a covalent-like interaction even in the metallic state and the covalent-like interaction gradually decreases with increasing pressure. By analyzing the static structure factor, it is found that the covalent-like interaction still remains at approximately 200 GPa, and liquid sulphur has a simple liquid structure at 320 GPa and higher pressures. These results indicate that the covalent-like interaction disappears at a pressure between 200 and 320 GPa. In this study, we also estimate the pressure range of structural change in other liquid chalcogens in a similar manner as liquid S. The pressures at which liquid Se and Te have simple liquid structure are estimated to be larger than approximately 100 and 20 GPa, respectively.
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Affiliation(s)
- S Ohmura
- Research Center for Condensed Matter Physics, Hiroshima Institute of Technology, Hiroshima 731-5193, Japan
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3
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Inui M, Baron AQR, Kajihara Y, Matsuda K, Hosokawa S, Kimura K, Tsuchiya Y, Shimojo F, Yao M, Tsutsui S, Ishikawa D, Tamura K. Viscoelastic anomaly accompanying anti-crossing behaviour in liquid As 2Se 3. J Phys Condens Matter 2018; 30:28LT02. [PMID: 29873306 DOI: 10.1088/1361-648x/aacab5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We investigate the dynamic structure factor of the melt of the well known glass former, As2Se3, using inelastic x-ray scattering for temperatures, T, [Formula: see text] K and momentum transfers Q from [Formula: see text] nm-1. An anomaly was observed at Q = 2.7 nm-1 ([Formula: see text] K) with, in the context of a simple model, both an abrupt change in frequency and an increased linewidth reminiscent of an anti-crossing in a solid. Comparison with structural information from reverse Monte Carlo modeling of x-ray diffraction data allows us to associate the disappearance of the anomaly at higher temperatures with a drop in the number of mechanical constraints per atom, n mc, to [Formula: see text] reminiscent of the threshold applicable for glass formation in rigidity theory. It is inferred that the surprising jump in the dispersion in the liquid may be correlated with a stiffness transition in a network glass.
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Affiliation(s)
- M Inui
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8521, Japan
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4
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Arifin R, Shibuta Y, Shimamura K, Shimojo F. First principles molecular dynamics simulation of graphene growth on Nickel (111) surface. ACTA ACUST UNITED AC 2016. [DOI: 10.1088/1757-899x/128/1/012032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Shimamura K, Shibuta Y, Ohmura S, Arifin R, Shimojo F. Dissociation dynamics of ethylene molecules on a Ni cluster using ab initio molecular dynamics simulations. J Phys Condens Matter 2016; 28:145001. [PMID: 26953616 DOI: 10.1088/0953-8984/28/14/145001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The atomistic mechanism of dissociative adsorption of ethylene molecules on a Ni cluster is investigated by ab initio molecular-dynamics simulations. The activation free energy to dehydrogenate an ethylene molecule on the Ni cluster and the corresponding reaction rate is estimated. A remarkable finding is that the adsorption energy of ethylene molecules on the Ni cluster is considerably larger than the activation free energy, which explains why the actual reaction rate is faster than the value estimated based on only the activation free energy. It is also found from the dynamic simulations that hydrogen molecules and an ethane molecule are formed from the dissociated hydrogen atoms, whereas some exist as single atoms on the surface or in the interior of the Ni cluster. On the other hand, the dissociation of the C-C bonds of ethylene molecules is not observed. On the basis of these simulation results, the nature of the initial stage of carbon nanotube growth is discussed.
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Affiliation(s)
- K Shimamura
- Department of Physics, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan. Graduate School of System Informatics, Kobe University, 1-1 Rokkodai, Nada-ku, 657-8501, Japan
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Hosokawa S, Munejiri S, Inui M, Kajihara Y, Pilgrim WC, Ohmasa Y, Tsutsui S, Baron AQR, Shimojo F, Hoshino K. Transverse excitations in liquid Sn. J Phys Condens Matter 2013; 25:112101. [PMID: 23378432 DOI: 10.1088/0953-8984/25/11/112101] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Transverse acoustic (TA) excitation modes were observed in inelastic x-ray scattering (IXS) spectra of liquid Sn. The excitation energies and widths of the TA modes are in good agreement with results of an ab initio molecular dynamics simulation. By comparing current correlation spectra between the experimental and theoretical results quantitatively, we have concluded that the TA modes can be detected experimentally through the quasi-TA branches in the longitudinal current correlation spectra. The lifetime and propagation length of the TA modes were determined to be ~0.7 ps and 0.8-1.0 nm, respectively, corresponding to the size of cages formed instantaneously in liquid Sn.
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Affiliation(s)
- S Hosokawa
- Department of Physics, Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan.
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7
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Ohmura S, Shimojo F. Atomic diffusion in liquid B 2O 3under pressure from ab initiomolecular dynamics. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311082717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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8
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Yamane A, Shimojo F, Hoshino K, Ichikawa T, Kojima Y. Ab initio study on the hydrogen desorption from MH-NH3 (M = Li, Na, K) hydrogen storage systems. J Chem Phys 2011; 134:124515. [PMID: 21456684 DOI: 10.1063/1.3562122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hydrogen storage system LiH + NH(3) ↔ LiNH(2) + H(2) is one of the most promising hydrogen storage systems, where the reaction yield can be increased by replacing Li in LiH with other alkali metals (Na or K) in order of Li < Na < K. In this paper, we have studied the alkali metal M (M = Li, Na, K) dependence of the reactivity of MH with NH(3) by calculating the potential barrier of the H(2) desorption process from the reaction of an M(2)H(2) cluster with an NH(3) molecule based on the ab initio structure optimization method. We have shown that the height of the potential barrier becomes lower in order of Li, Na, and K, where the difference of the potential barrier in Li and Na is relatively smaller than that in Na and K, and this tendency is consistent with the recent experimental results. We have also shown that the H-H distance of the H(2) dimer at the transition state takes larger distance and the change of the potential energy around the transition state becomes softer in order of Li, Na, and K. There are almost no M dependence in the charge of the H atom in NH(3) before the reaction, while that of the H atom in M(2)H(2) takes larger negative value in order of Li, Na, and K. We have also performed molecular dynamics simulations on the M(2)H(2)-NH(3) system and succeeded to reproduce the H(2) desorption from the reaction of Na(2)H(2) with NH(3).
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Affiliation(s)
- A Yamane
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521, Japan.
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Yamane A, Shimojo F, Hoshino K. Effects of system-size and inner-core 2p states on melting of dense sodium at high pressure: ab initiomolecular-dynamics simulation. EPJ Web of Conferences 2011. [DOI: 10.1051/epjconf/20111501009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Yoshimura R, Ohmura S, Shimojo F. Ab initiomolecular-dynamics study of structural and electronic properties of liquid MgSiO 3under pressure. EPJ Web of Conferences 2011. [DOI: 10.1051/epjconf/20111502004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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11
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Shimojo F, Ohmura S, Nakano A, Kalia RK, Vashishta P. Large-scale atomistic simulations of nanostructured materials based on divide-and-conquer density functional theory. EPJ Web of Conferences 2011. [DOI: 10.1051/epjconf/20111503005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Ohmura S, Yoshimura R, Shimojo F. Atomic diffusion in covalent liquids under pressure from ab initiomolecular dynamics. EPJ Web of Conferences 2011. [DOI: 10.1051/epjconf/20111502003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Kowaki Y, Harada A, Shimojo F, Hoshino K. Reconstruction of carbon atoms around a point defect of a graphene: a hybrid quantum/classical molecular-dynamics simulation. J Phys Condens Matter 2009; 21:064202. [PMID: 21715905 DOI: 10.1088/0953-8984/21/6/064202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have investigated the rearrangement of carbon atoms around a point defect of a graphene using a hybrid ab initio/classical molecular-dynamics (MD) simulation method, in which 36 carbon atoms surrounding a point defect are treated by the ab initio MD method and the other 475 carbon atoms relatively far from the point defect are treated by the classical MD method. We have confirmed a formation of a 5-1DB defect (a pentagon and a dangling bond) from the time dependence of atomic configurations and electron density distributions obtained by our simulation. We have found that the pentagon is formed in two different positions around the point defect, and that the two positions appear alternately during the simulation, the frequency of which increases with increasing temperature.
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Affiliation(s)
- Y Kowaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
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14
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Harada A, Shimojo F, Hoshino K. Hydrogen desorption from nanostructured graphite: ab initio molecular-dynamics studies. J Phys Condens Matter 2007; 19:365209. [PMID: 21694155 DOI: 10.1088/0953-8984/19/36/365209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have carried out hybrid ab initio/classical molecular-dynamics simulations for the model system of hydrogen-adsorbed nanostructured graphite. We have investigated the effect of the recrystallization of the nanostructured graphite to the bonding states of hydrogen atoms at 1000 K and the desorption mechanism of the hydrogen dimer from the graphite at 2000 K. We have shown that the recrystallization weakens the bond between the hydrogen and the carbon atoms and the desorption of hydrogen atoms, as the hydrogen dimer occurs at 2000 K.
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Affiliation(s)
- A Harada
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan
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Kodiyalam S, Kalia RK, Kikuchi H, Nakano A, Shimojo F, Vashishta P. Grain Boundaries in Gallium Arsenide Nanocrystals Under Pressure: A Parallel Molecular-Dynamics Study. Phys Rev Lett 2001; 86:55-58. [PMID: 11136092 DOI: 10.1103/physrevlett.86.55] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2000] [Indexed: 05/23/2023]
Abstract
Structural transformation in gallium arsenide nanocrystals under pressure is studied using molecular-dynamics simulations on parallel computers. It is found that the transformation from fourfold to sixfold coordination is nucleated on the nanocrystal surface and proceeds inwards with increasing pressure. Inequivalent nucleation of the high-pressure phase at different sites leads to inhomogeneous deformation of the nanocrystal. This results in the transformed nanocrystal having grains of different orientations separated by grain boundaries. A new method based on microscopic transition paths is introduced to uniquely characterize grains and deformations.
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Affiliation(s)
- S Kodiyalam
- Concurrent Computing Laboratory for Materials Simulations, Department of Physics & Astronomy and Department of Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803-4001
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Nakano A, Bachlechner M, Kalia R, Lidorikis E, Vashishta P, Voyiadjis G, Campbell T, Ogata S, Shimojo F. Multiscale simulation of nanosystems. Comput Sci Eng 2001. [DOI: 10.1109/5992.931904] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Shimojo F, Ebbsjo I, Kalia RK, Nakano A, Rino JP, Vashishta P. Molecular dynamics simulation of structural transformation in silicon carbide under pressure. Phys Rev Lett 2000; 84:3338-3341. [PMID: 11019084 DOI: 10.1103/physrevlett.84.3338] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/1999] [Indexed: 05/23/2023]
Abstract
Pressure-induced structural transformation in cubic silicon carbide is studied with the isothermal-isobaric molecular-dynamics method using a new interatomic potential scheme. The reversible transformation between the fourfold coordinated zinc-blende structure and the sixfold coordinated rocksalt structure is successfully reproduced by the interatomic potentials. The calculated volume change at the transition and hysteresis are in good agreement with experimental data. The atomistic mechanisms of the structural transformation involve a cubic-to-monoclinic unit-cell transformation and a relative shift of Si and C sublattices in the 100 direction.
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Affiliation(s)
- F Shimojo
- Concurrent Computing Laboratory for Materials Simulations, Department of Physics and Astronomy and Department of Computer Science, Louisiana State University, Baton Rouge, Louisiana 70803 and Faculty of Integrated Arts and Sciences, H
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Kuwata A, Ri S, Shimizu H, Nakano A, Morinaga K, Gesu T, Ueda T, Shirosaki A, Kimura H, Suzuki A, Shimojo F. [Case of chronic renal failure with sudden progression of renal dysfunction due to furosemide hypersensitivity]. Nihon Naika Gakkai Zasshi 1999; 88:130-2. [PMID: 10341572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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20
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Fujisaki J, Tokunaga Y, Takahashi T, Shimojo F, Kimura S, Hata T. Osteotropic drug delivery system (ODDS) based on bisphosphonic prodrug. I.v. effects of osteotropic estradiol on bone mineral density and uterine weight in ovariectomized rats. J Drug Target 1998; 5:129-38. [PMID: 9588869 DOI: 10.3109/10611869808995866] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
An osteotropic drug delivery system (ODDS) based on the bisphosphonic prodrug was designed for 17beta-estradiol (E2) in order to improve patient compliance in estrogen replacement therapy of postmenopausal osteoporosis. The bisphosphonic prodrug of E2, disodium [17beta-(3 '-hydroxy- 1',3',5'-estratrienyloxy) carbonylpropyl carboxamidomethylene] bisphosphonate (E2-BP) was synthesized and its effects on bone mineral density and uterine weight were investigated in ovariectomized (OVX) rats. E2-BP was injected intravenously once a week (4 injections/experiment), and E2 was administrated orally 5 times a week (20 administrations/experiment). Once a week treatment with 0.1 mg/kg E2-BP significantly restored bone mineral reduction by 61.8% without significantly increasing uterine weight. Similarly, once in 4 weeks treatment with 1.0 mg/kg E2-BP (1 injection/experiment) showed almost the same therapeutic effects. On the other hand, 5 times a week oral treatment with 1.0 mg/kg E2 significantly improved bone mineral density by 90.5%, but increased uterine weight up to 98.2% of that of the sham group. In vitro bone resorption analysis revealed that E2-BP exhibits antiresorptive activity not as a bisphosphonate but as a prodrug of E2. These results demonstrated that E2-BP has the potential to improve patient compliance in estrogen therapy by its minimal adverse effects and less frequent medication.
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Affiliation(s)
- J Fujisaki
- Pharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Company Ltd., Osaka, Japan
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21
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Katashima M, Irino T, Shimojo F, Kawamura A, Kageyama H, Higashi N, Miyao Y, Tokuma Y, Hata T, Yamamoto K, Sawada Y, Iga T. Pharmacokinetics and pharmacodynamics of FK143, a nonsteroidal inhibitor of steroid 5 alpha-reductase, in healthy volunteers. Clin Pharmacol Ther 1998; 63:354-66. [PMID: 9542479 DOI: 10.1016/s0009-9236(98)90167-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The pharmacokinetics and pharmacodynamics of FK143, a new nonsteroidal inhibitor of steroid 5 alpha-reductase, were investigated in healthy volunteers, with use of plasma FK143 concentrations and serum dihydrotestosterone levels as an index for pharmacologic effects. The area under the plasma concentration-time curve from zero to infinity [AUC(0-infinity)] and maximum plasma concentration [Cmax] were increased dose proportionally after oral administration (100 to 500 mg) while subjects were in the fed state. The AUC(0-infinity) and Cmax after 500 mg oral administration during fed conditions were significantly larger than those during the fasted state, suggesting an increase of the absorption of FK143. Dihydrotestosterone concentrations after a single administration of FK143 (100 to 500 mg) during fed conditions decreased to about 65% of predose values and thereafter slowly recovered to the same levels as predose values at 168 hours. A combined pharmacokinetic-pharmacodynamic model was constructed with use of changes in dihydrotestosterone concentrations. The pharmacokinetic-pharmacodynamic profiles of FK143 after repeated administration were predictable with use of the pharmacokinetic-pharmacodynamic parameters obtained after a single administration of FK143.
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Affiliation(s)
- M Katashima
- Biopharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Co. Ltd., Osaka, Japan
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Fujisaki J, Tokunaga Y, Takahashi T, Kimura S, Shimojo F, Hata T. Osteotropic drug delivery system (ODDS) based on bisphosphonic prodrug. V. Biological disposition and targeting characteristics of osteotropic estradiol. Biol Pharm Bull 1997; 20:1183-7. [PMID: 9401729 DOI: 10.1248/bpb.20.1183] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An osteotropic drug delivery system (ODDS) based on a bisphosphonic prodrug has been developed for 17 beta-estradiol (E2) to improve patient compliance in estrogen replacement therapy of postmenopausal osteoporosis. The biological disposition and the targeting efficiency of a bisphosphonic prodrug of E2, disodium [17 beta-(3'-hydroxy-1',3',5'-estratrienyloxy)carbonylpropyl carboxamidomethylene]bisphosphonate (E2-BP), was investigated in ovariectomized rats. After intravenous injection, E2-BP was rapidly taken up into the bone and subsequently cleared from the bone at a half-life of 13.5 d. The bone concentration of regenerated E2 was maintained throughout 28 d. In contrast, E2 injected intravenously showed extremely low bone distribution and rapid clearance from the bone, and E2 administered orally showed even lower bone distribution. Therapeutic availability (TA) and drug targeting index (DTI), which were calculated on the basis of the AUCs for E2 in the bone and plasma after injection of E2-BP and E2, were 64.6 and 451, respectively. These results suggest that ODDS has a potential to improve not only the apparent potency but also the therapeutic index of E2. As compared with the conventional estrogenic products, E2-BP should improve patient compliance with lower adverse effects and less frequent medication in long-term estrogen replacement therapy.
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Affiliation(s)
- J Fujisaki
- Biopharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Company, Ltd., Osaka, Japan
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Tsuji K, Konishi N, Spears GW, Ogino T, Nakamura K, Tojo T, Ochi T, Shimojo F, Senoh H, Matsuo M. Studies on anti-inflammatory agents. V. Synthesis and pharmacological properties of 3-(difluoromethyl)-1-(4-methoxyphenyl)-5- [4-(methylsulfinyl)phenyl]pyrazole and related compounds. Chem Pharm Bull (Tokyo) 1997; 45:1475-81. [PMID: 9332000 DOI: 10.1248/cpb.45.1475] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A series of novel 1,5-diphenylpyrazole derivatives bearing hydrophilic substituents was prepared. The anti-inflammatory and analgesic activities of these compounds were evaluated by using the adjuvant arthritis and Randall-Selitto assays in rats, and the structure-activity relationships were studied. The optimal compound was 3-(difluoromethyl)-1-(4-methoxyphenyl)-5-[4-(methylsulfinyl)phenyl]pyraz ole (10) with oral ED50 values of 0.31 and 2.6 mg/kg on adjuvant-induced arthritis and carrageenin-induced foot edema, respectively. Compound 10 showed analgesic activities not only toward inflamed paw but also toward normal paw (ED30 = 0.55 and 1.8 mg/kg, respectively) in the Randall-Selitto assay, and moreover, 10 was effective in the tail-pinch assay (ED50 = 21 mg/kg) similarly to morphine. The asymmetric synthesis and pharmacological properties of the enantiomers of 10 are also reported.
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Affiliation(s)
- K Tsuji
- New Drug Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan
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Fujisaki J, Tokunaga Y, Takahashi T, Murata S, Shimojo F, Hata T. Physicochemical characterization of bisphosphonic carboxyfluorescein for osteotropic drug delivery. J Pharm Pharmacol 1996; 48:798-800. [PMID: 8887727 DOI: 10.1111/j.2042-7158.1996.tb03976.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Disodium (fluorescein-6-carbonyloxy)acetoaminomethylene bisphosphonate (CF-BP), a prodrug of 6-carboxy-fluorescein, is efficiently absorbed by the skeleton where it hydrolyses to carboxyfluorescein. An osteotropic drug-delivery system based on this bisphosphonic prodrug has been developed as a novel method for site-specific and controlled delivery of drugs to the bone. In this study the physicochemical properties of the prodrug have been characterized by investigating the affinity of CF-BP for hydroxyapatite and the hydrolysis of the compound to carboxyfluorescein. In the binding study, CF-BP bound very rapidly to hydroxyapatite without degradation and carboxyfluorescein was subsequently gradually released by hydrolysis of bound CF-BP. Hydrolysis of CF-BP in buffer solutions followed pseudo-first-order kinetics, and quantitative regeneration of carboxyfluorescein was observed. In addition, regeneration of carboxyfluorescein from CF-BP was accelerated in the presence of fresh rat plasma. These results suggest that CF-BP has the physicochemical properties required for site-specific and controlled delivery of carboxyfluorescein to bones.
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Affiliation(s)
- J Fujisaki
- Pharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Company Ltd, Osaka, Japan
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Fujisaki J, Tokunaga Y, Sawamoto T, Takahashi T, Kimura S, Shimojo F, Hata T. Osteotropic drug delivery system (ODDS) based on bisphosphonic prodrug. III: Pharmacokinetics and targeting characteristics of osteotropic carboxyfluorescein. J Drug Target 1996; 4:117-23. [PMID: 8894972 DOI: 10.3109/10611869609046270] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An osteotropic drug delivery system (ODDS) based on a bisphosphonic prodrug has been developed as a novel method for site-specific and controlled delivery of drugs to the bone. The pharmacokinetics and the targeting efficiency of a bisphosphonic prodrug of carboxyfluorescein (CF), disodium (fluorescein-6-carbonyloxy) acetoaminomethylene bisphosphonate (CF-BP), was investigated in rats. After intravenous injection, CF-BP was rapidly taken up into the skeleton, and subsequently cleared from the bone by hydrolysis of its ester linkage at a half-life of 3.2 days. On the other hand, the bone concentration of regenerated CF gradually increased to reach the maximum at 14 days and slowly decreased up to 56 days. Kinetical analysis revealed that bone tissue acts as a reservoir of regenerated CF to supply the parent compound into the systemic circulation. In contrast with CF-BP, CF injected intravenously showed rapid clearance from the plasma and extremely low bone distribution. Therapeutic availability (TA) and drug targeting index (DTI), which were calculated on the basis of the AUCs for CF in the bone and plasma after injection of CF-BP and CF, were 1551 and 6689, respectively. These results suggest that ODDS has a potential to improve not only apparent potency but also therapeutic index of the drugs which exhibit their pharmacological effects in the bone.
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Affiliation(s)
- J Fujisaki
- Pharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Company Ltd., Osaka, Japan
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Shimojo F, Zempo Y, Hoshino K, Watabe M. First-principles molecular-dynamics simulation of expanded liquid rubidium. Phys Rev B Condens Matter 1995; 52:9320-9329. [PMID: 9979976 DOI: 10.1103/physrevb.52.9320] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Fujisaki J, Tokunaga Y, Takahashi T, Hirose T, Shimojo F, Kagayama A, Hata T. Osteotropic drug delivery system (ODDS) based on bisphosphonic prodrug. I: synthesis and in vivo characterization of osteotropic carboxyfluorescein. J Drug Target 1995; 3:273-82. [PMID: 8821001 DOI: 10.3109/10611869509015956] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An osteotropic drug delivery system (ODDS) based on a bisphosphonic prodrug was designed as a novel method for site-specific and controlled delivery of drugs to the bone. Due to the chemical adsorption of bisphosphonic promoiety to the mineral component, hydroxyapatite, a bisphosphonic prodrug is predominantly taken up into the bone. To verify the concept, bisphosphonic promoiety was chemically introduced into 6-carboxyfluorescein (CF) as a model compound and the disposition after intravenous injection was studied in rats. The bisphosphonic prodrug of CF, disodium (fluorescein-6-carbonyloxy) acetoaminomethylene bisphosphonate (CF-BP) was highly taken up to the skeleton (62.1% of dose) and the remainder was excreted into the urine (35.9% of dose). Subsequently, regeneration of CF by hydrolysis of CF-BP in the bone was observed. The microscopic observation showed that CF-BP was buried into the bone with a calcification of the bone. According to the remodeling of the bone, bisphosphonic prodrug buried was supposed to be released in the vicinity of the osteoclast or resorption surface of the bone. Thus, it is suggested that ODDS has a potential to achieve osteoclast-specific or resorption surface-specific targeting of the drugs.
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Affiliation(s)
- J Fujisaki
- Pharmaceutical and Pharmacokinetic Research Laboratories, Fujisawa Pharmaceutical Company Ltd., Osaka, Japan
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Abstract
The oral bioavailability of new formulations of ceftizoxime sodium was investigated in animals and humans. In rats, one of the formulations tested showed significant improvement, with a urinary excretion of 47.7% (0--24 hr). Good results were obtained also in dogs. In humans, the mean peak serum level was 3.6 micrograms/ml at 3.3 hr postadministration for formulation 10. The average ceftizoxime AUC at 0--8 hr was 17.3 micrograms hr/ml and urinary excretion of ceftizoxime was 9.6% (0--24 hr). The concentrations in the serum exceeded the minimum inhibitory concentrations for most of the commonly encountered bacterial pathogens.
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