Fabrication and characterization of drug particles produced by electrospraying into reduced pressure

In the present study, electrospraying was used in drug particle-production. The objective of the research was to establish whether electrospraying can be carried out in reduced pressure in order to improve the drying process of the droplets. By this method, it is possible to produce drug particles relatively uniform in size, crystallinity and porosity. Drying the droplets in a reduced pressure is a more sensitive way to remove the solvent from the particles than, for example, the addition of heat. The efficiency of this drying method and particle morphology were studied using SEM, DSC, and XRD. Another objective was to workout whether the size of the produced particles can be estimated by a simple method. The maximum particle size was defined theoretically and compared to experimental results with good agreement.     

Alkynyl-Protected Chiral Bimetallic Ag22Cu7 Superatom with Multiple Chirality Origins

Understanding the origin of chirality in the nanostructured materials is essential for chiroptical and catalytic applications. Here we report a chiral AgCu superatomic cluster, [Ag₂₂Cu₇(C≡CR)₁₆(PPh₃)₅Cl₆](PPh₄), Ag₂₂Cu₇ , protected by an achiral alkynyl ligand (HC≡CR: 3,5-bis(trifluoromethyl)phenylacetylene). Its crystal structure comprises a rare interpenetrating biicosahedral Ag₁₇Cu₂ core, which is stabilized by four different types of motifs: one Cu(C≡CR)₂, four −C≡CR, two chlorides and one helical Ag₅Cu₄(C≡CR)₁₀(PPh₃)₅Cl₄. Structural analysis reveals that Ag₂₂Cu₇ exhibits multiple chirality origins, including the metal core, the metal-ligand interface and the ligand layer. Furthermore, the circular dichroism spectra of R/S-Ag₂₂Cu₇ are obtained by employing appropriate chiral molecules as optical enrichment agents. DFT calculations show that Ag₂₂Cu₇ is an eight-electron superatom, confirm that the cluster is chirally active, and help to analyze the origins of the circular dichroism.