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131.
Ishikawa T Mukai B Shiraishi S Utoguchi N Fujii M Matsumoto M Watanabe Y 《Chemical & pharmaceutical bulletin》2001,49(2):134-139
To decrease the sensation of roughness when a tablet, which is rapidly disintegrated by saliva (rapidly disintegrating tablet), is orally taken, we prepared rapidly disintegrating tablets using microcrystalline cellulose (Avicel PH-M series), a new type of pharmaceutical excipient that is spherical and has a very small particle size (particle size, 7-32 microm), instead of conventional microcrystalline cellulose (PH-102) used in the formulation of tablets containing acetaminophen or ascorbic acid as model drugs for tableting study. Tablets (200 mg) prepared using spherical microcrystalline cellulose, PH-M-06, with the smallest particle size (mean value, 7 microm) had sufficient crushing tolerance (approximately, 8 kg) and were very rapidly, disintegrated (within 15 s) when the mixing ratio of PH-M-06 to low-substituted hydroxypropylcellulose (L-HPC) was 9:1. Sensory evaluation by volunteers showed that PH-M-06 was superior to PH-102 in terms of the feeling of roughness in the mouth. Consequently, it was found that particle size is an important factor for tablet preparation using microcrystalline cellulose. It is possible to prepare drugs such as acetaminophen and ascorbic acid (concentration of approximately 50%) in the tablet form using PH-NM-06 in combination with L-HPC as a good disintegrant at a low compression force (1-6 kN). To solve the problem of poor fluidity in the preparation of these tablets, we investigated the use of spherical sugar granules (Nonpareil, NP-101 (sucrose and starch, composition ratio of 7:3), NP-103 (purified sucrose), NP-107 (purified lactose) and NP-108 (purified D-mannitol)). Rapidly disintegrating tablets can be prepared by the direct compression method when suitable excipients such as fine microcrystalline cellulose (PH-M-06) and spherical sugar granules (NP) are used. 相似文献
132.
Yoshio Fuchita Katsuma Hiraki Yasuhiro Matsumoto 《Journal of organometallic chemistry》1985,280(2):c51-c54
N,N-Dimethylneopentylamine reacts with Pd(MeCO2)2 to give a novel trinuclear cyclopalladated complex [Me2NCH2CMe2CH2Pd(μ-MeCO2)2Pd(μ-MeCO2)2PdCH2CMe2CH2NMe2]?-0.5C6H6 (I). The reaction of I with PPh3 affords both trans-[Pd(MeCO2)2(PPh3)2] (II) and [Pd(CH2CMe2CH2NMe2)(MeCO2)(PPh3)] (III). The reaction of III with LiCl yields a mononuclear cyclopalladated complex, [Pd(CH2CMe2CH2NMe2)Cl(PPh3)] (IV). 相似文献
133.
Shinsuke Nakamoto Kohji Tashiro Akikazu Matsumoto 《Journal of Polymer Science.Polymer Physics》2003,41(5):444-453
The Raman shift and crystallite modulus were measured under the application of tensile force for a giant single crystal and a series of uniaxially oriented semicrystalline samples of poly(trans‐1,4‐diethyl muconate) (polyEMU). The apparent Raman shift factor αapp or a vibrational frequency shift per 1 GPa tensile stress was higher for the semicrystalline samples with lower crystallinity or lower bulk modulus. The apparent crystallite modulus E or Young's modulus along the chain axis in the crystalline region was not constant but varied remarkably between the giant single crystal and semicrystalline samples. A systematic change in αapp and E among the polyEMU samples with different preparation history could be interpreted quantitatively on the basis of a mechanical series parallel model consisting of crystalline and amorphous phases. The origin of different E and αapp was speculated to be a stress concentration on the taut‐tie chain contained as a parallel crystalline component in the mechanical model. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 444–453, 2003 相似文献
134.
135.
Tatsuaki Yamaguchi Kimitoshi Saito Toshio Tsujimoto Hidetaka Yuki 《Journal of heterocyclic chemistry》1976,13(3):533-537
Nmr spectra of structural analogs of tenuazonic acid such as 3-acetyltetramic acid, 3-acetyltetronic acid, 3-acetylthiotetronic acid and others were investigated for elucidation of the tautomeric structures. These compounds have completely enolized β,β′-triketone systems, and the position of the nmr signals for the enolic proton shows that the strength of their intramolecular hydrogen-bonding is weaker than those of acyclic β,β′-triketones and six-membered cyclic triketones. The assignment was made for nmr signals split by the difference of the diamagnetic anisotropic effect in each tautomers. The percentages of each of the tautomers were calculated from the intensities of the corresponding nmr signals. The results were confirmed by means of 13C-nmr spectroscopy. 相似文献
136.
Structural changes of the Langmuir-Blodgett (LB) films of azobenzene accompanied by photoisomerization are described. First, photoisomerization is explained in terms of 'free volume'. In the polyion complex monolayers of amphiphiles having two azobenzene units at the air-water interface, the area per molecule depends on the polycation species. The fraction of cis-azobenzene in the LB films at the photostationary state under the illumination with UV light increased with increasing area per molecule, which is consistent with the concept of free volume. Second, a counter example of the concept of free volume is presented. Three-dimensional cone-shaped structures developed with trans-to-cis photoisomerization in the polyion complex LB film of a water-soluble amphiphilic azobenzene. These structures appeared and disappeared reversibly by alternate illumination with UV and visible light. The results indicate that the two-dimensional LB film structure exerts significant modification by photoisomerization. This is against the concept of free volume because this concept does not consider the possibility that the two-dimensional LB film structures may change into three-dimensional ones. Finally, photo-induced J-aggregate formation of non-photochromic and photochromic dyes is described. Two cyanine dyes were each mixed with an amphiphilic azobenzene in the LB films. These cyanine dyes are known to form J-aggregates in single-component LB films. In the mixed LB films, the J-aggregate formation was suppressed to some extent. The alternate illumination of the films with UV and visible light caused the photoisomerization of azobenzene in the mixed LB films, which triggered the J-aggregate formation of the cyanine dyes. The J-aggregate formation was accompanied by the development of three-dimensional cone-shaped structures from the film surface. When an amphiphilic merocyanine was mixed with the azobenzene in the LB films, J-aggregate formation was also induced by the alternate illumination with UV and visible light. This J-aggregate formation was also accompanied by a large morphological change: circular domains changed into fractal-like ones. The J-aggregate formation of the dyes and the concomitant morphological change were irreversible. In these cases, the photoisomerization of azobenzene served as a trigger to induce self-organization of the dye molecules. 相似文献
137.
Tomohisa?Yamaguchi Keisuke?Kimura Akira?Tsuchida Tsuneo?OkuboEmail author Mitsuhiro?Matsumoto 《Colloid and polymer science》2005,283(10):1123-1130
Macroscopic and microscopic dissipative structural patterns formed in the course of drying the fractionated and monodisperse bentonite particles (plate-like in their shape) in aqueous deionized suspension and in the presence of NaCl have been studied on a cover glass. The patterns coexisted with the broad ring of the hill accumulated with the particles and with the round hills are formed around the outside edges of the film and in the center, respectively, in the macroscopic scale. By the addition of NaCl the pattern shifts from the broad ring to the round hill in the center. The spoke-like cracks, which have been observed for the suspensions of the spherical particles so often hitherto, are not observed at all for the bentonite suspensions. The characteristic convection flow of the particles and the interactions among the particles and substrate are important for the macroscopic pattern formation. Wrinkled, branch-like and/or star-like fractal patterns are observed in the microscopic scale. These patterns are determined mainly by the electrostatic and polar interactions between the particles and/or between the particle and the substrate in the course of drying. 相似文献
138.
The effect of pH on the molecular shape and dispersed state of native ovalbumin molecules in 20 mM phosphate and acetic acid buffer solutions has been studied using small-angle x-ray scattering (SAXS) and a rheological method The degree of association of the OA molecule at the 0.5% colloid system increases slightly with decreasing pH, i.e., 2.10 at pH 7.0, and 2.88 at pH 4.0, and the radius of the OA molecule decreases slightly with decreasing pH, i.e., 24.5 Å at pH 7.0, and 22.0 Å at pH 4.0.The OA colloid shows apparent yield stress and rigidity which are due to a certain ordered arrangement of the molecules. The yield stress and the rigidity increase abruptly at a pH value near to an isoelectric point (ca. pH 4.4). In the dilute system this increment is attributed to the change in the ordered arrangement or in the interparticle interaction, and not to the change in the association state of the OA molecules. The values of the yield stress and the rigidity remain almost constant over a wide concentration range and this feature (an auto-controlled mechanism) is kept over a certain range of pH. 相似文献
139.
N Kubodera K Miyamoto M Akiyama M Matsumoto T Mori 《Chemical & pharmaceutical bulletin》1991,39(12):3221-3224
Three vitamin D3 analogues, 1 alpha,25-dihydroxy-23-oxavitamin D3 (3), 1 alpha,25-dihydroxy-23-thiavitamin D3 (4) and 1 alpha,25-dihydroxy-23-azavitamin D3 (5) were synthesized. In the differentiation-inducing activity of human myeloid leukemia cells into macrophages in vitro, the 23-aza analogue (5) showed the least activity, while no remarkable differences were observed between the 23-oxa analogue (3) and the 23-thia analogue (4), which were less active than 1 alpha,25-dihydroxyvitamin D3 (1). 相似文献
140.
The photochromic ligand bis(terpyridyl)hexaarylbiimidazole (bistpy-HABI) and the Fe(II) complex of bistpy-HABI with formula [{Fe(tpy)}2.bistpy-HABI](PF6)4.4H2O were synthesized and characterized. Bistpy-HABI is readily cleaved into a pair of terpyridyltriphenylimidazolyl radicals (tpy-TPI*) on irradiation with UV light. This photochemical reaction is completely reversible, and the light-induced radicals can thermally recombine to form bistpy-HABI in the dark. [{Fe(tpy)}2.bistpy-HABI]4+ is the first example of a transition-metal complex of an HABI derivative and was found to show photochromic reaction in solution. The spin state of the light-induced radical pair in a frozen matrix was investigated by ESR spectroscopy. The triplet state of the light-induced radical pair from [{Fe(tpy)}2.bistpy-HABI]4+, as well as that from bistpy-HABI, was confirmed to be a ground state or nearly degenerated with a singlet state. Kinetic studies on the radical recombination reaction in solution elucidated the decrease in the activation energy by forming the Fe(II) complex. This is the first observation of a decrease in the activation energy of the radical recombination reaction by the formation of a metal-coordinated radical complex. The syntheses, photochemical properties, and spin states of bistpy-HABI and [{Fe(tpy)}2.bistpy-HABI](PF6)4 are discussed. 相似文献