Effect of water-soluble carriers on dissolution characteristics of nifedipine solid dispersions

Solid dispersions of nifedipine (NP) with polyethylene glycols (PEG4000 and PEG6000), hydroxypropyl-β-cyclodextrin (HPβCD), and poloxamer 407 (PXM 407) in four mixing ratios were prepared by melting, solvent, and kneading methods in order to improve the dissolution of NP. The enhancement of the dissolution rate and the time for 80% NP dissolution T_80% depended on the mixing ratio and the preparation method. The highest dissolution rate and the T_80% as short as 15 min were obtained from PXM 407 solid dispersion prepared by the melting method at the mixing ratio of 1:10. The X-ray diffraction (XRD) patterns of solid dispersions at higher proportions of carriers demonstrated consistent with the results from differential scanning calorimetric (DSC) thermograms that NP existed in the amorphous state. The wettability and solubility were markedly improved in the PXM 407 system. The presence of intermolecular hydrogen bonding between NP and PEGs and between HPβCD and PXM 407 was shown by infrared (IR) spectroscopy.     

Experiences of 23 patients > or = 90 years of age treated with radiation therapy

Previous studies showed that the 5-HT2 receptor antagonist, amperozide, is somewhat more potent than the opiate antagonist, naltrexone, in reducing alcohol drinking in high alcohol-preferring (P) rats. The purpose of this study was to determine in the P rat whether the effect of either drug could be due, in part, to an alteration in gustatory function. In an unlimited, 24-h free choice paradigm, P rats were offered water simultaneously with either a highly palatable 0.1% saccharin solution or a 1:4 dilution of Nestlé Sweet Success chocolate drink. Throughout all phases of the study, the P rats always consumed significantly greater volumes of the chocolate drink than of the saccharin solution, i.e., 526 ml/kg vs. 181 ml/kg, respectively. Successive 12-day experimental periods consisted of three phases: a 4-day predrug control interval; 4 days of administration of saline control vehicle or either drug; and a final 4 day postdrug interval. In a counterbalance design, saline, amperozide (1.0 or 5.0 mg/kg) or naltrexone (2.5 or 5.0 mg/kg) was administered subcutaneously twice daily at 1600 and 2200 h for 4 days. Amperozide and naltrexone significantly reduced the drinking of chocolate in a dose-dependent manner. Conversely, only the two higher doses of amperozide and naltrexone decreased the intake of saccharin significantly. Thus, these findings suggest that different populations of central serotonin and opioid receptors concurrently underpin, in part, the preferences for both palatable and/or nutrient fluids. Finally, because both the opiate and 5-HT2A antagonists reduce the ingestion of saccharin and chocolate solutions differentially, it is apparent that preferences for alternative palatable fluids should be examined when candidate drugs are screened for suppressing alcohol drinking and ultimately the treatment of alcohol abuse.     

Interlaboratory validation of quantitative duplex real-time PCR method for screening analysis of genetically modified maize

To reduce the cost and time required to routinely perform the genetically modified organism (GMO) test, we developed a duplex quantitative real-time PCR method for a screening analysis simultaneously targeting an event-specific segment for GA21 and Cauliflower Mosaic Virus 35S promoter (P35S) segment [Oguchi et al., J. Food Hyg. Soc. Japan, 50, 117-125 (2009)]. To confirm the validity of the method, an interlaboratory collaborative study was conducted. In the collaborative study, conversion factors (Cfs), which are required to calculate the GMO amount (%), were first determined for two real-time PCR instruments, the ABI PRISM 7900HT and the ABI PRISM 7500. A blind test was then conducted. The limit of quantitation for both GA21 and P35S was estimated to be 0.5% or less. The trueness and precision were evaluated as the bias and reproducibility of the relative standard deviation (RSD(R)). The determined bias and RSD(R) were each less than 25%. We believe the developed method would be useful for the practical screening analysis of GM maize.     

A combinatorial characterization scheme for high-throughput investigations of hydrogen storage materials

In order to increase measurement throughput, a characterization scheme has been developed that accurately measures the hydrogen storage properties of materials in quantities ranging from 10 ng to 1 g. Initial identification of promising materials is realized by rapidly screening thin-film composition spread and thickness wedge samples using normalized IR emissivity imaging. The hydrogen storage properties of promising samples are confirmed through measurements on single-composition films with high-sensitivity (resolution <0.3 μg) Sievert’s-type apparatus. For selected samples, larger quantities of up to ∼100 mg may be prepared and their (de)hydrogenation and micro-structural properties probed via parallel in situ Raman spectroscopy. Final confirmation of the hydrogen storage properties is obtained on ∼1 g powder samples using a combined Raman spectroscopy/Sievert’s apparatus.     

Relationship between electron sensitivity and chemical structures of polymers as EB resists. III. Electron sensitivity of various polyamides using 3-amino perhydroazepine

Homopolyamides and copolyamides containing a variety of reactive and/or stabilizing groups, such as double bonds, epoxy groups, or naphthalene moieties, were synthesized using 3-amino perhydroazepine (APA) as a diamine monomer. These polymers were evaluated as electron beam (EB) resists, in order to investigate the relationship between EB sensitivity and chemical structure of the polyamides. It was found that polyamides containing double bonds were easily crosslinked by the EB exposure and that the sensitivity of a polyamide containing double bonds in the side chain was higher than that of a polyamide containing double bonds in the main chain. The sensitivity of a polyamide containing epoxy groups was lower than that of the above. Copolymer from APA, 77 mol % of trans-3-hexenedioyl chloride (HC) and 23 mol % of 2,6-naphthalenedioyl chloride (NC) had the same EB sensitivity as that of the homopolymer from APA and HC. The polyamides had excellent dry etching durability and were adaptable to EB lithography.     

Experimental study ofPVT properties of HFC-125 (CHF2CF3)

Pressure-volume-temperature (PVT) properties and vapor pressures of HFC125 (pentafuoroethane; CHF₂CF₃) have been experimentally obtained. Vapor pressures of HFC-125 have been measured in the range of temperatures from 223 to 338 K and pressures up to 3.54 M Pa with uncertainties of 5 mK and 2.5 kPa, respectively. The vapor pressure equation for this substance was correlated based on the present data. PVT properties of HFC-125 have been determined with a constant-volume apparatus in the range of temperatures from 280 to 473 K, pressures up to 17 M Pa, and densities up to 1145 kg · m^–3 with uncertainties of 5 mK, 2.5 kPa, and 0.01%, respectively. All of the available experimentalPVT property data were compared with the equation of state correlated by Wilson et al.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Production of Al-based amorphous sheets with large thickness by a supercooled liquid-quenching method

On leave from: Research and Development, Teikoku Piston Ring Co., Ltd.     

High-resolution magnetic resonance imaging of the intraorbital optic nerve and subarachnoid space in patients with papilledema and optic atrophy

OBJECTIVE: To evaluate the orbital portion of the optic nerve and the subarachnoid space using fast spin-echo magnetic resonance imaging in normal subjects and in patients with papilledema or optic atrophy. DESIGN: Measurements of the optic nerve complex on coronal images were made using high-resolution magnetic resonance imaging with fast spin-echo sequences. PATIENTS: Twenty-one patients, including 5 patients with papilledema due to congenital hydrocephalus, intracranial tumors, or meningitis, as well as 16 patients with optic atrophy, were studied. Sixteen healthy volunteers served as controls. MAIN OUTCOME MEASURES: The longitudinal diameter of the optic nerve, the longitudinal outer diameter of the subarachnoid space, the diameter ratio, and the area of the subarachnoid space were determined. RESULTS: In normal subjects, the ring-shaped area of high signal intensity that represented the subarachnoid space was widest behind the globe, then narrowed toward the orbital apex. In patients with papilledema, the area of the subarachnoid space was markedly dilated, the optic nerve was compressed, and the nerve sheath was widened, resulting in a small diameter ratio compared with that of controls. Patients with pallor of the temporal aspect of the optic disc appeared to exhibit dilation of the subarachnoid space; the size of the optic nerve was decreased more than that of the nerve sheath, resulting in a small diameter ratio compared with controls. Patients with complete pallor of the disc, however, exhibited hyperintense optic nerve complexes without a ring-shaped appearance toward the orbital apex. CONCLUSION: Fast spin-echo magnetic resonance imaging appears useful for objectively evaluating the optic nerve and surrounding subarachnoid space in patients with papilledema and optic atrophy.     

Improved hatching for in vitro quail embryo culture using surrogate eggshell and artificial vessel

One of the difficulties encountered in the study of aqueous humor is the relatively small volume generally available for analysis. The purpose of this study was to investigate the potential use of capillary zone electrophoresis (CE) for the analysis of nanolitre quantities of this fluid. Twelve samples of aqueous humor were obtained from patients undergoing cataract surgery and a further three samples were from non cataract post mortem subjects within 6 hr of death. CE was carried out in an uncoated fused silica glass capillary, 75 mu internal diameter and 100 cm long using a run buffer of 40 mM borate pH 9.4 containing 0.4 g l-1 methylcellulose. Detection of the separated zones was by ultra violet absorption at 200 nm. Preliminary identification of peaks was achieved by enzymatic hydrolysis and spiking with purified analytes. A number of very well resolved peaks were obtained from both cataract and post mortem samples using nanolitre quantities of unmodified fluid. Additional peaks were noted in the post mortem samples, most of which were likely to be due to a partial breakdown of the blood aqueous humor barrier. The profiles obtained were not significantly affected by various drugs routinely administered during cataract surgery. This preliminary study has demonstrated the potential value of CE in the analysis of aqueous humor in health and disease.