Preventing Crystal Agglomeration of Pharmaceutical Crystals Using Temperature Cycling and a Novel Membrane Crystallization Procedure for Seed Crystal Generation
In this work, a novel membrane crystallization system was used to crystallize micro-sized seeds of piroxicam monohydrate by reverse antisolvent addition. Membrane crystallization seeds were compared with seeds produced by conventional antisolvent addition and polymorphic transformation of a fine powdered sample of piroxicam form I in water. The membrane crystallization process allowed for a consistent production of pure monohydrate crystals with narrow size distribution and without significant agglomeration. The seeds were grown in 350 g of 20:80 w/w acetone-water mixture. Different seeding loads were tested and temperature cycling was applied in order to avoid agglomeration of the growing crystals during the process. Focused beam reflectance measurement (FBRM); and particle vision and measurement (PVM) were used to monitor crystal growth; nucleation and agglomeration during the seeded experiments. Furthermore; Raman spectroscopy was used to monitor solute concentration and estimate the overall yield of the process. Membrane crystallization was proved to be the most convenient and consistent method to produce seeds of highly agglomerating compounds; which can be grown via cooling crystallization and temperature cycling.
Antisolvent Crystallization of Indomethacin from a Ternary Solvent System with High Productivity, Better Polymorphism, and Particle Size Control
Antisolvent crystallization of indomethacin (IMC), a nonsteroidal anti-inflammatory drug, from a ternary solvent system (acetone–methanol–water) has been investigated in this work. The acetone–methanol (66.5–33.5 wt %) binary mixture was selected as a solvent on the basis of the solubility of IMC reported earlier. Water was selected as an antisolvent on the basis of the solubility of IMC measured in acetone–methanol–water mixtures at 25 °C. Unseeded and seeded antisolvent crystallization was carried out for two initial concentrations of IMC (C0,1 and C0,2) with the stepwise addition of antisolvent. The acetone solvate of IMC was crystallized during the unseeded experiments, while the desired γ-IMC was obtained with a bimodal particle size distribution (PSD) during the experiments seeded with γ-IMC. A significant increase in the productivity was observed because of increased crystal yield and faster crystallization kinetics as compared to those of the crystallization processes reported earlier for the prod...
Gender and History in Medieval English Romance and Chronicle
New York, Bern, Berlin, Bruxelles, Frankfurt/M., Oxford, Wien. This reading of canonical texts of medieval English literature - Sir Gawain and the Green Night and Chaucer's Man of Law's Tale - alongside Geoffrey of Monmouth's Historia regum Britanniae and other Anglo-Norman and English chronicles offers a broader context for reading the romance narratives and re-evaluates romance conventions in light of the genealogical priorities of these chronicles. By arguing that maternity is featured as a position of power, Gender and History in Medieval English Romance and Chronicle adds to our understanding of women and sovereignty, and the ways gender and authority were rhetorically linked to medieval texts.