In the present work, methyl viologen (1,1′-dimethyl-4,4′-bipyridinium dichloride) is used as a scavenger to estimate the radiolytic yields of water decomposition products from room temperature to 400 °C by pulse radiolysis method. {G(e aq -) + G(OH) + G(H)} has been studied using a 0.5 mM MV 2+ solution in the presence of 10 mM NaCOOH up to 200 °C and in the presence of 0.2 M ethanol up to 400 °C. The results show that the {G(e aq -) + G(OH) + G(H)} increases with temperature up to 350 °C at 25 MPa, while it depends also on pressure in supercritical conditions. The G(e aq -) was estimated using MV 2+ solutions in the presence of 0.2 M tert-butyl alcohol. The results agree well with the reported data up to around 300 °C at 25 MPa; however, in supercritical conditions a very significant density effect was observed. At a given temperature, G(e aq -) and {G(e aq -) + G(OH) + G(H)} decrease with increasing density while at a fixed density they decrease with increasing temperature.

We report on the fabrication and characterization of dry hybrid lipid-silica nanoparticle based microcapsules with an internal porous matrix structure for encapsulation of poorly soluble drugs, and their delivery properties (in vitro release and lipolysis and in vivo pharmacokinetics demonstrated for indomethacin as a model drug). Microcapsules were prepared by spray drying of Pickering o/w emulsions containing either negatively or positively charged lipophilic surfactant in the oil phase and hydrophilic silica nanoparticles in the aqueous phase. Effective microcapsule formation is critically dependent on the interfacial structure of the nanoparticle containing emulsions, which are in turn controlled by the surfactant charge and the nanoparticle to lipid ratio. Microcapsules (containing 50-85% oil) can be prepared with 10 times fewer silica nanoparticles when a droplet-nanoparticle charge neutralizing mechanism is operative. Cross-sectional SEM imaging has confirmed the internal porous matrix structure and identified pore sizes in the range 20-100 nm, which is in agreement with BET average pore diameters determined from gas adsorption experiments. Differential scanning calorimetry and X-ray diffraction analysis have confirmed that the model drug indomethacin remains in a noncrystalline form during storage under accelerated conditions (40 degrees C, 75% RH). Dissolution studies revealed a 2-5-fold increase in dissolution efficiency and significantly reduced the time taken to achieve 50% of drug dissolution values (> or =2- or 10-fold) for indomethacin formulated as microcapsules in comparison to o/w submicron emulsions and pure drug, respectively. Orally dosed in vivo studies in rats have confirmed superior pharmacokinetics for the microcapsules. Specifically, the fasted state absolute bioavailability (F) was statistically higher (93.07 +/- 5.09%) (p < 0.05) than for aqueous suspension (53.54 +/- 2.91%) and o/w submicron emulsion (64.57 +/- 2.11%). The microcapsules also showed the highest maximum plasma concentration (C(max)) among the investigated formulations (p < 0.05). In vitro lipolysis showed statistically higher (p < 0.05) fasted digestion (75.8% after 5 min) and drug solubilization (98% after 5 min) in digestive products for microcapsules than o/w emulsions. The hybrid lipid-silica microcapsules improve oral absorption by enhancing lipolysis and drug dissolution.

Surface functionalized mesoporous silicon (pSi) microparticles are reported as a solid dispersion carrier for improving dissolution and enhancing the orally administered pharmacokinetics (fasted rat model) of indomethacin (IMC), employed as a model poorly soluble BCS type II drug. IMC was loaded via immersion/solvent evaporation onto the thermally oxidized pSi particles, which provide a stable hydrophilic matrix with a nanoporous structure. The solid state properties of IMC loaded pSi were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, differential scanning calorimetry and thermogravimetric analysis. IMC molecules are encapsulated in a noncrystalline state due to geometric confinement in the nanopores; stability of the noncrystalline state has been demonstrated for several months under accelerated storage conditions. The pSi carrier facilitates accelerated immediate release of IMC and enhanced oral delivery performance in comparison with crystalline indomethacin and Indocid i.e. a 4-times reduction on T(max), a 200% increase on C(max) and a significant increase in bioavailability. The in vitro-in vivo correlation is discussed based on the noncompartment model and gives insight into the delivery mechanism for the pSi carrier.

The mole fraction solubility data of l-proline in five monosolvents (water, methanol, ethanol, acetone, and acetonitrile) and four binary solvent systems (methanol + acetone, ethanol + acetone, methanol + acetonitrile, and ethanol + acetonitrile) were experimentally measured by gravimetric method at temperatures ranging from 283.15 to 323.15 K. The results showed that l-proline solubility and experimental temperature were positively correlated when the solvent composition was constant. On the basis of the solubility scatter diagrams and our investigation of solvent properties, the solubility behavior of l-proline in the pure and binary solvent systems was influenced by a combination of many factors. The solubility data were correlated by the modified Apelblat model, CNIBS/R-K model, and Apelblat-Jouyban-Acree model. The fitting results were generally acceptable.

A universal 3D printing technique for metals, ceramics and multi-materials with complex geometries for resultant dense high-quality structures.