Comparison of dissolution profiles of Ibuprofen pellets

In this work we use both model dependent and independent techniques to assess the difference between dissolution profiles in which ibuprofen, in the form of uncoated pellets, is used as a model drug. The choice of a proper regression function, the relevance of the estimated parameters and the influence of the choice of dissolution points in the assessment of differences is discussed. The results obtained via mean dissolution times (MDT) and fit-factors (f1 and f2) are also discussed and a non-quantitative method based on profiles correlation with graphical representation (concentration vs. concentration and rate vs. rate) presented. The tested methods discriminate similarly between curves, although not in all cases, but those based on modeling, MDT and fit-factors have shown to be less informative than the correlation approach.http://www.sciencedirect.com/science/article/B6T3D-48CT09D-6/1/963a3879961981b265df020d3ac842f

The intersecting-state model: a link between molecular spectroscopy and chemical reactivity

The intersecting-state model is applied to calculate the energy barriers and rates of atom transfers, SN2 reactions, proton transfers and electron transfers, including electron transfer at the metal-electrolyte interface. The calculated rates are usually within one order of magnitude of the experimental ones. These applications of the model reveal the main factors that influence the rates of these chemical reactions. The structural and electronic properties of reactants that are used in the calculations are the reaction energy, the hypervalency at the transition state, the bond lengths and for constants of the reactive bonds.http://www.sciencedirect.com/science/article/B6TGS-435M5SD-3/1/77dc7dce5b87eab97a0480c42652da0

Science indicators and science patterns in Europe

http://www.sciencedirect.com/science/article/B83WV-4VK69B2-1/2/857bd537a0546fe2cb394c525b44341

Room temperature and low-temperature absorption and emission spectra of some polypyridylruthenium(II) 3.2.1 complexes

Electronic absorption and luminescence spectra are reported for a series of complexes of type [Ru(tpy)(L-L)(py)]2+, where tpy and py are 2,2',2''-terpyridine and pyridine, and L-L represents the bidentate ligands bipyridyl, 4,4'-dimethylbipyridyl, 4-nitrobipyridyl, oxalate and acetylacetonate. The effect of solvent polarity and temperature on their spectral and light emission properties is studied. Energies are reported for the lowest-energy 3MLCT* excited state, and on the basis of these it is suggested that the complexes may make good triplet energy acceptors for use in organic and polymeric light emitting devices.http://www.sciencedirect.com/science/article/B6TGS-433W90H-F/1/6603da98c21c7d9749d77de81e9a042