I. Van Driessche

An oral controlled release matrix pellet formulation containing nanocrystalline ketoprofen.

A controlled release pellet formulation using a NanoCrystal colloidal dispersion of ketoprofen was developed. In order to be able to process the aqueous NanoCrystal colloidal dispersion into a hydrophobic solid dosage form a spray drying procedure was used. The in vitro dissolution profiles of wax based pellets loaded with nanocrystalline ketoprofen are compared with the profiles of wax based pellets loaded with microcrystalline ketoprofen and of a commercial sustained release ketoprofen formulation. Pellets were produced using a melt pelletisation technique. All pellet formulations were composed of a mixture of microcrystalline wax and starch derivatives. The starch derivatives used were waxy maltodextrin and drum dried corn starch. Varying the concentration of drum dried corn starch increased the release rate of ketoprofen but the ketoprofen recovery remained problematic. To increase the dissolution yield surfactants were utilised. The surfactants were either added during the production process of the NanoCrystal colloidal dispersion (sodium laurylsulphate) or during the pellet manufacturing process (Cremophor RH 40). Both methods resulted in a sustained but complete release of nanocrystalline ketoprofen from the matrix pellet formulations.

Bismuth molybdate catalysts synthesized using spray drying for the selective oxidation of propylene

Abstract In this study, a novel method—spray drying—was applied to synthesize bismuth molybdate catalysts for selective oxidation of propylene. The phenomena which occur during the synthesis of α, β and γ phases were examined by TGA/DTA, XRD, Raman and IR techniques allowing us to establish the best conditions to synthesize pure phases. The influences of temperature and time on their morphology and surface area were also investigated by BET and SEM. The pure phases obtained were tested for catalytic activities with the oxidation of propylene into acrolein. The results revealed that spray drying can be applied to replace for conventional synthesis methods, which opens interesting industrial applications. In addition, by permitting the synthesis of high purity single phase material, spray drying improves our understanding of the formation and interactions of these catalytic materials.

In vivo evaluation of matrix pellets containing nanocrystalline ketoprofen.

The aim of this study was to evaluate the in-vivo behaviour of matrix pellets formulated with nanocrystalline ketoprofen after oral administration to dogs. No significant differences in AUC-values were seen between pellet formulations containing nanocrystalline or microcrystalline ketoprofen and a commercial ketoprofen formulation (reference: Rofenid 200 Long Acting). C(max) of the formulations containing nano- or microcrystalline ketoprofen was significantly higher compared to reference, whereas t(max) was significantly lower. The in-vivo burst release observed for the spray dried nanocrystalline ketoprofen matrix pellets was reduced following compression of the pellets in combination with placebo wax/starch pellets. These matrix tablets sustained the ketoprofen plasma concentrations during 5.6 and 5.4 h for formulations containing nano- and microcrystalline ketoprofen, respectively.

Chemical solution deposition using ink-jet printing for YBCO coated conductors

This paper reports the successful application of ink-jet printing to the deposition of both continuous coatings and multi-filamentary structures of YBCO. Stable inks have been prepared using both the established TFA-MOD route and novel fluorine-free precursors with appropriate rheological properties for ink-jet printing. Continuous and well textured coatings with lengths exceeding 100?m and a thickness of 0.5??m have been deposited by electromagnetic ink-jet printing from TFA precursors on LZO-buffered Ni?W substrates and samples have achieved a Jc around 1.5?MA?cm?2 (self-field, 77?K). On single crystal substrates, continuous coatings and multi-filamentary structures have been deposited using piezoelectric ink-jet printing both from TFA-?and water-based precursors, achieving Jc values up to 3?MA?cm?2.

Evaluation of the phase composition of BPSCCO bulk samples by XRD- and susceptibility analysis

Abstract This paper describes the comparison of the phase purity analysis, using XRD and AC-susceptibility measurements, on a number of BPSCCO samples, containing different ratios of the Bi-2212 and Bi-2223 phase. The differences observed in the results of both techniques were correlated with the growth mechanism of the Bi-2223 phase. The higher values for the percentage of the Bi-2223 phase observed in AC-susceptibility analysis, could be explained by the assumption that there is a specific distribution of the Bi-2212 and Bi-2223 phase during particle growth, resulting in shielding effects.

Nonvacuum-based deposition techniques for superconducting ceramic coatings

The widespread use of vacuum-based techniques for the deposition of ceramic coatings with specific electric, magnetic, optical, and mechanical properties is well established in the research environment, and some of them have been implemented in a variety of industrial processes. However, obtaining uninterrupted deposition at high speed, increasing flexibility in composition and in film thickness, and attaining independence of geometric constraints are areas in which many vacuum techniques will need sustained development in order to answer industrial demands. The development of the next generation of deposition methods, which could alleviate some of these shortcomings and which are based on deposition under atmospheric environment and from aqueous precursor materials, is a real challenge for the community of solid-state chemists and delineates the subject of this overview.

A water-based sol–gel technique for chemical solution deposition of (RE)Ba2Cu3O7−y (RE = Nd and Y) superconducting thin films

The achievement of low-cost deposition techniques for high critical current (RE)Ba2Cu3O7?y-coated conductors is one of the major objectives in achieving a widespread use of superconductivity in power applications. Chemical solution deposition techniques are appearing as a very promising methodology to achieve highly textured oxide thin films at a low cost, so an intense effort is being carried out to develop routes for all chemically coated conductor tapes. In this work recent achievements will be presented towards the goal of the development of an environmentally friendly, completely water-based sol?gel technique for the deposition of thin superconducting films on SrTiO3 single-crystal substrates using the dip coat technique. A comparison is made between aqueous sol?gel synthesis of two (RE)Ba2Cu3O7?y superconducting systems: YBa2Cu3O7?y and its homologue NdBa2Cu3O7?y. Our conclusions are that YBa2Cu3O7?y still remains the material of choice for coated conductor development using this sol?gel technique, with a Tc,onset of 91?K and Jc of 0.3?MA?cm?2.

Elucidation of the Mechanism in Fluorine-Free Prepared YBa2Cu3O7−δ Coatings

In this work, the reaction mechanism used in the preparation of fluorine-free superconducting YBa(2)Cu(3)O(7-delta) (YBCO) was investigated. To determine which precursor interactions are dominant, a comprehensive thermal analysis (thermogravimetric analysis-differential thermal analysis) study was performed. The results suggest that a three step reaction mechanism, with a predominant role for BaCO(3), is responsible for the conversion of the initial state to the superconducting phase. In the presence of CuO, the decarboxylation of BaCO(3) is kinetically favored with the formation of BaCuO(2) as a result. BaCuO(2) reacts with the remaining CuO to form a liquid which ultimately reacts with Y(2)O(3) in a last step to form YBCO. High temperature X-ray diffraction experiments confirm that these results are applicable for thin film synthesis prepared from an aqueous fluorine-free sol-gel precursor.

Rapid formation of the Bi2-xPbxSr2Ca2Cu3Oy high Tc-phase, using spray-dried nitrate precursor powders

This study describes the use of spray-dried nitrate precursor powders in the synthesis of Bi-2223 high {Tc}-superconductors. The decomposition of the precursor powder is studied using TGA/DTA, XRD, IR, and nitrogen analyses. The particle size is determined using SEM. The low decomposition temperature of the nitrates ({approximately}600 C) and the small particle size of the spray dried powder ({approximately}3{center_dot}10{sup {minus}6} m), resulting in a lowering of the calcination temperature and a shortening of the sinter time, enabled the authors to synthesize a > 96% pure Bi-2223 phase (from XRD peak intensities) after a thermal process of 5h at 650 C and 60 h at 855 C.

Density functional theory study of La2Ce2O7: Disordered fluorite versus pyrochlore structure

The crystal structure of lanthanum cerium oxide (La