UV-Vis spectroscopic quantification of residual acetone during the development of nanoparticulate drug delivery systems.

Methods for nanoparticles preparation often employ organic solvents in order to solubilize the non-polar constituents of the final nanostructures. In the research process, nanoparticles are assayed as aqueous suspensions in several cases, so that an excessive residual concentration of the organic solvent needs to be avoided since may lead to undesired secondary effects during biological tests. Despite the importance, residual solvent concentration is rarely determined, making necessary the development of quantification methods suitable for this purpose.

Unusual alkaloids of the highland species Astragalus cryptanthus Wedd. (Fabaceae).

Two unusual caprolactam alkaloids, 3-(dimethylamino)hexahydro-2H-azepin-2-one and 3-(methylamino)-hexahydro-2H-azepin-2-one, were isolated from the aerial parts of Astragalus cryptanthus Wedd.; their structures were unambiguously determined based on data from extensive 1D and 2D NMR, GC-MS and FT-IR spectroscopic analyses. This is the first report of this alkaloid type in the genus Astragalus.