A 5% glucose infusion fluid provokes significant precipitation of phenytoin sodium injection via interruption of the cosolvent effect of propylene glycol

The precipitation of phenytoin sodium injection provoked by mixing with infusion fluids renders its use in clinical practice difficult, as rapid intravenous (i.v.) push and i.v. infusion are supposed to be avoided. As some of its aspects remain unclear, this study tried to elucidate this precipitation mechanism. In particular, this study focused on the significant precipitation induced by glucose infusion fluid. The precipitation provoked by 5% glucose infusion fluid was obviously different from the precipitation that accompanied simple pH reduction, in terms of the growth mode and morphology of crystals. In addition, the effect of glucose was partially unrelated to pH reduction. NMR measurements including a two-dimensional nuclear Overhauser effect spectroscopy (2D-NOESY) spectrum indicated the specific interaction between glucose and propylene glycol, which is incorporated into phenytoin sodium injection as a solubilizing agent. These results led to the conclusion that this interaction was crucial for the precipitation of phenytoin, as it diminished the solubilizing effect of propylene glycol, resulting in the enhancement of the crystallization of phenytoin. The determination of phenytoin solubility in aqueous solutions at different pH values revealed that phenytoin incorporated in the admixture could be dissolved completely, as long as the injection was diluted with saline or water. These findings offer a profound insight into the formulation design of phenytoin sodium injection and its use in clinical practice.     

Presentations of Grothendieck Constructions

We will give quiver presentations of the Grothendieck constructions of functors from a small category to the 2-category of 𝕜-categories for a commutative ring 𝕜.     

Dynamics of polyrotaxane investigated by neutron spin echo

The dynamics of a molecular necklace known as polyrotaxane (PR), in which α-cyclodextrins (CDs) are threaded into a poly (ethylene glycol) (PEG) chain, was investigated by means of neutron spin echo (NSE) measurements. We observed that threading CDs into PEG slowed down the local dynamics and changed its Q-dependence. A solution of PEG in DMSO-d₆ showed a dynamical crossover from collective diffusion dynamics to the Zimm mode, just as in conventional polymer solutions; however, the motion of PR in DMSO-d₆ was diffusive for the whole Q range. This may be because the persistence length l_p of PR was much larger than that of PEG and was similar to the mesh size of PR. The diffusive mode in a high Q regime, corresponding to a length scale of less than the l_p value of PR, contained the mode of the sliding of CDs along a rod-like PEG segment in one dimension.     

Dynamic light‐scattering measurement of sieving polymer solutions for protein separation on SDS CE

We evaluated the mesh size and homogeneity of polymer network by dynamic light scattering and discussed the relationship between the physical properties of polymer network and the protein separation behavior by capillary polymer electrophoresis. We compared three kinds of sieving polymers in solutions with a wide range of molecular weights and concentrations: polyacrylamide and polyethylene oxide as flexible polymers, and hydroxyethyl cellulose as a semiflexible polymer. We found that the mobility of protein was dominated primarily by the mesh size ξ, irrespective of the type of sieving polymers, and the peak spacing between protein peaks increased drastically in the range of ξ<10 nm, where the mobility also decreased. And the peak widths were dependent on the molecular species of sieving polymers and their homogeneity of polymer network. We proposed that a polymer network with a homogenous mesh size of less than 10 nm is the best sieving medium for separation of the proteins in the molecular weight range 14 300–97 200 Da from the view point of the resolution in protein separation.     

Synthesis of well-defined chain-end- and in-chain-functionalized polystyrenes with a definite number of benzyl chloride moieties and D-glucose residues

Novel well-defined chain-end- and in-chain-functionalized polystyrenes with six, eight, twelve, and sixteen benzyl chloride moieties and with four and eight D-glucose residues have been successfully synthesized by developing the methodology based on living anionic polymerization of using new functionalized agents derived from functionalized 1,1-diphenylethylene (DPE) derivatives. They are 1,10-dichloro-4,4-7,7-tetra(3-methoxymethylphenyl)decane, its iodide derivative, the dianion prepared from 1,1-bis(3-methoxymethylphenyl)ethylene and potassium naphthalenide, and 1,1-bis[3′,5′-bis(1,2:5,6-di-O-isopropylidene-α-D-glucofuranose-3-oxymethyl)phenyl]ethylene. The developed methodology involves diverse modes of reactions of polystyryllithium with new functionalized agents and either the subsequent transformation reaction with BCl₃ into benzyl chloride moieties or acid-hydrolysis to regenerate D-glucose residues. The resulting chain-multi-functionalized polystyrenes were precisely controlled with respect to chain length and quantitatively functionalized within experimental errors.     

An instability condition for the Hartree–Fock solution of the infinite one‐dimensional system with two‐crossing bands. I. Singlet‐instability check of metallic carbon nanotube

An instability condition is derived for the Hartree–Fock solution so that it can be applied to the system in which the highest occupied and the lowest unoccupied bands cross at the in‐between point in the Brillouin zone. The instability check developed here is further applied to a metallic single‐walled carbon nanotube having the two‐crossing bands toward prediction of its instability. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 76: 574–582, 2000     

Brewing characteristics of piezosensitive sake yeasts

Application of high hydrostatic pressure (HHP) treatment to food processing is expected as a non-thermal fermentation regulation technology that supresses over fermentation. However, the yeast Saccharomyces cerevisiae used for Japanese rice wine (sake) brewing shows high tolerance to HHP. Therefore, we aimed to generate pressure-sensitive (piezosensitive) sake yeast strains by mating sake with piezosensitive yeast strains to establish an HHP fermentation regulation technology and extend the shelf life of fermented foods. The results of phenotypic analyses showed that the generated yeast strains were piezosensitive and exhibited similar fermentation ability compared with the original sake yeast strain. In addition, primary properties of sake brewed using these strains, such as ethanol concentration, sake meter value and sake flavor compounds, were almost equivalent to those obtained using the sake yeast strain. These results suggest that the piezosensitive strains exhibit brewing characteristics essentially equivalent to those of the sake yeast strain.     

Unexpectedly cyclized products by reaction of N-tosyliminoisoquinolinium ylides with trimethylsilylketene

The reaction of N-tosyliminoisoquinolinium ylides with trimethylsilylketene as a C2 unit introducing reagent, giving unexpected [3+2] cycloadducts, pyrazolo[5,1-a]isoquinolines, is described.