High drug loading self-microemulsifying/micelle formulation: design by high-throughput formulation screening system and in vivo evaluation

Purpose: To design a high drug loading formulation of self-microemulsifying/micelle system. Methods: A poorly-soluble model drug (CH5137291), 8 hydrophilic surfactants (HS), 10 lipophilic surfactants (LS), 5 oils, and PEG400 were used. A high loading formulation was designed by a following stepwise approach using a high-throughput formulation screening (HTFS) system: (1) an oil/solvent was selected by solubility of the drug; (2) a suitable HS for highly loading was selected by the screenings of emulsion/micelle size and phase stability in binary systems (HS, oil/solvent) with increasing loading levels; (3) a LS that formed a broad SMEDDS/micelle area on a phase diagram containing the HS and oil/solvent was selected by the same screenings; (4) an optimized formulation was selected by evaluating the loading capacity of the crystalline drug. Aqueous solubility behavior and oral absorption (Beagle dog) of the optimized formulation were compared with conventional formulations (jet-milled, PEG400). Results: As an optimized formulation, d-α-tocopheryl polyoxyethylene 1000 succinic ester: PEG400?=?8:2 was selected, and achieved the target loading level (200?mg/mL). The formulation formed fine emulsion/micelle (49.1?nm), and generated and maintained a supersaturated state at a higher level compared with the conventional formulations. In the oral absorption test, the area under the plasma concentration-time curve of the optimized formulation was 16.5-fold higher than that of the jet-milled formulation. Conclusions: The high loading formulation designed by the stepwise approach using the HTFS system improved the oral absorption of the poorly-soluble model drug.     

Two-spherical-wave ultraviolet interferometer for making an antireflective subwavelength periodic pattern on a curved surface

An ultraviolet two-spherical-wave interferometer was developed in order to make a subwavelength structured surface on a curved surface. The change in fringe period on the curved surface was significantly suppressed compared with the two-plane-wave interferometer. The optical setup method for suppressing the change in fringe period is described. The effect of the two-spherical-wave interferometer was investigated by numerical simulations. In an experimental demonstration for a concave spherical surface with 11.1 mm radius of curvature and 10 mm diameter, the change in period of the photoresist pattern was reduced to 12 nm for the target period of 250 nm.     

Flow structure of steam–water mixed spray

In this study, the flow structure of a steam–water mixed spray is studied both numerically and experimentally. The velocity and pressure profiles of single-phase flow are calculated using numerical methods. On the basis of the calculated flow fields, the droplet behavior is predicted by a one-way interaction model. This numerical analysis reveals that the droplets are accelerated even after they are sprayed from the nozzle. Experimentally, the mixed spray is observed using an ultra-high-speed video camera, and the velocity field is measured by using the oarticle image velocimetry (PIV) technique. Along with this PIV velocity field measurement, the velocities and diameters of droplets are measured by phase Doppler anemometry. Furthermore, the mixing process of steam and water and the atomization process of a liquid film are observed using a transparent nozzle. High-speed photography observations reveal that the flow inside the nozzle is annular flow and that most of the liquid film is atomized at the nozzle throat and nozzle outlet. Finally, the optimum mixing method for steam and water is determined.     

Development of HVAC system simulation tool for life cycle energy management Part 1: Concept of life cycle energy management and outline of the developed simulation tool

The importance of LCEM (life cycle energy management) has been recognized from the view of life cycle energy savings for sustainable buildings. The purposes of this research are the proposal of an LCEM framework and development of prototype HVAC system simulation tools for LCEM. In this paper, the necessity of energy simulation tools for LCEM is discussed, and the outline and solution method of the simulation tool are shown.     

Inter-laboratory validation studies of biological method for determination of streptomycin in royal jelly

Inter-laboratory validation studies were conducted in 6 laboratories to validate the biological method for determination of streptomycin in royal jelly. Streptomycin spiked at the level of 0.2 and 1.0 ppm was analyzed. Mean recoveries were 89 and 96%, reproducibility relative standard deviations (RSD(R)) were 15.0 and 14.0%, HORRAT(R) values were 0.7 and 0.9. Samples containing residues at the levels of 0.25 and 0.80 ppm were analyzed. Mean recoveries were 113 and 99%, RSD(R) were 15.0 and 10.4%, and HORRAT(R) values were 0.8 and 0.6. The determination limit was 0.1 ppm. These results show that this method has good performance.     

Characteristics of partial discharges in artificial simulated treechannels during tree propagation

In order to clarify partial discharge (PD) mechanism in an electrical tree, we investigated PD pulse sequence and light emission from a single PD in an artificially-simulated tree channel during the tree propagation in low-density polyethylene (LDPE). For positive PD, the light emission was observed near the needle-tip and there was a positive correlation between the PD magnitude and the length of luminous region. The pulse-sequence analysis showed that PD took place at constant voltage increments. These results suggest that PD starts at the needle-tip and the PD magnitude is determined by the PD length. On the other hand, for negative PD, there was no correlation between the PD magnitude and the length of luminous region. The PD pulse sequence can be explained by a simple PD model, since the voltage increment is related to the magnitude of preceding PD. These results suggest that there is a difference between positive and negative PD characteristics and their mechanisms in an artificial channel during tree propagation     

Electrically active grain boundaries in ZnO varistors by liquid-infiltration method

The varistors were fabricated by spreading a thin layer of Pr₆O₁₁ powder paste on the surface of ZnO pellets and heating to various temperatures (1200–1400 °C) and times (0–60 min). Higher heat-treatment temperatures and/or times resulted in progressively higher breakdown voltages. Eventually the devices became varistor, which was attributed to the formation of a liquid (ZnO-PrO_x) layer between the grains. Microstructures of cross-sections of wetting pellets have shown that the infiltration rate was increased with the amount of Co₃O₄ and heat-treatment temperature. In addition, on the basis of the small variations of the varistor properties per grain boundary (e.g., threshold voltage, donor concentration, and barrier height), the number of active grain boundaries are believed to be increased when the samples were heat-treated above the liquid-phase temperature.     

Fracture mechanism characterization of cross-ply carbon-fiber composites using acoustic emission analysis

The sequence of microscopic fracture mechanisms in locally loaded cross-ply carbon-fiber composites was studied by analyzing acoustic emission (AE) signals in combination with the modal analysis of Lamb waves, using microscopic and ultrasonic examination of the specimen after load interruption. The first 70 AE events were analyzed, which were detected during the initial loading segment when the first sudden load drop and gradual load recovery were observed. Characteristics of the detected waves were compared with the S₀- and A₀-mode Lamb waves produced by a spot- or line-focused YAG laser. The internal damage progression of the composite specimen was determined to be the fiber fracture in the front lamina, transverse cracks in the mid-lamina, delamination and splitting.