We present for the first time a peculiar concentration effect on competitive adsorption of a binary mixture at the liquid/solid interface, which we attribute to the existence of pseudopolymorphism and its concentration dependence. These results are helpful for the understanding of phase behavior of multi-component systems at the interface.
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http://dx.doi.org/10.1039/c0cc03445b | DOI Listing |
Biomicrofluidics
December 2021
Complex Fluid Processing, Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands.
Solid State Nucl Magn Reson
April 2020
Nanocrystallography Unit, RIKEN-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan; NMR Division, SPring-8 Center, RIKEN, Yokohama, Kanagawa, 230-0045, Japan; JEOL RESONANCE Inc., Akishima, Tokyo, 196-8558, Japan. Electronic address:
Atomic-level characterization of active pharmaceutical ingredients (API) is crucial in pharmaceutical industry because APIs play an important role in physicochemical properties of drug formulations. However, the analysis of targeted APIs in intact tablet formulations is less straightforward due to the coexistence of excipients as major components and different APIs at dilute concentrations (often below 10 wt% loading). Although solid-state (ss) NMR spectroscopy is widely used to investigate short-range order, polymorphism, and pseudo-polymorphism in neat pharmaceutical compounds, the analysis of complex drug formulations is often limited by overlapped signals that originate from structurally different APIs and excipients.
View Article and Find Full Text PDFArch Pharm Res
April 2016
College of Pharmacy, Duksung Women's University, 419, Ssangmun-Dong, Dobong-Gu, Seoul, 132-714, Korea.
Rebamipide is marketed as a peptic ulcer agent under the trade name Mucosta(R). The objective of this work was to investigate the existence of polymorphs and pseudopolymorphs of rebamipide. Two crystal forms of rebamipide were isolated by recrystallization and characterized by differential thermal analysis (DTA), thermogravimetric analysis (TG), powder X-ray diffractometry, infrared spectrometry, and nuclear magnetic resonance.
View Article and Find Full Text PDFInorg Chem
August 2014
Departamento de Quı́mica-Centro de Sı́ntesis Quı́mica de La Rioja (CISQ), Universidad de La Rioja , Madre de Dios, 51, 26006 Logroño, Spain.
Two types of Pt2Pb luminescent clusters were successfully prepared by the reaction of [Pt(C6F5)(bzq)(OCMe2)] (1) and [Pt(C6F5)(ppy)(dmso)] (2) with [Pb(SpyR-5)2] (R = H, CF3). Thus, whereas 5 (ppy, Spy) is generated through coordination of the pyridine-N atoms to the Pt centers, the formation of 3, 4 (bzq), and 6 (ppy, SpyCF3) is accompanied by a formal thiolate transfer from Pb(II) to Pt(II), keeping the two N atoms in the primary environment of the lead. In 5, the neutral Pb center adopts a rather stable and symmetrical "Pt2S2" coordination sphere supplemented by two Pb··Fo contacts, whereas for the remaining species several pseudopolymorphs were found depending on the solvent (3, 4) and crystallization conditions (6).
View Article and Find Full Text PDFInorg Chem
June 2014
Institute of Inorganic Chemistry, Christian-Albrechts-University of Kiel, Max-Eyth-Str. 2, Kiel 24118, Germany.
The distinct control of the synthesis parameters achieved crystallization of five new inorganic-organic hybrid tin sulfides with 1,10-phenanthroline (phen) as the organic component: {[Mn(phen)2]2(μ2-Sn2S6)} (1, 3), {[Mn(phen)2]2(μ2-Sn2S6)}·phen (2), {[Mn(phen)2]2(μ2-Sn2S6)}·phen·H2O (4), and {[Mn(phen)2]2[μ-η(2)-η(2)-SnS4]2[Mn(phen)]2}·H2O (5). Compounds 1, 3, and 4 occur successively under static conditions by increasing the reaction time up to 8 weeks. Stirring the reaction mixtures and keeping the educt ratio constant allow preparation of distinct phase pure samples within very short reaction times.
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