Home About us Contact
|
Home About us Contact | ||
|
|
||
Solubility Method (solubility + method)
Selected AbstractsXRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007E. Ramachandran Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of the nature and concentration of substrates in aqueous solutions on the solubility of aroma compoundsFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2005Marco Covarrubias-Cervantes Abstract The solubility of nine aroma compounds (acetone, 2-butanone, 2-hexanone, 2-octanone, ethyl acetate, ethyl butanoate, ethyl hexanoate, n -hexanal, and n -hexanol) in both water and various aqueous solutions was measured at 25 °C using the mutual solubility method. The aqueous solutions consisted of sucrose, glucose, sorbitol, glycerol, polyethylene glycol 200, or maltodextrins at different concentrations. Aroma solubility in water decreased with increased hydrophobicity. For aroma molecules which have the same number of carbon atoms in their structure, aqueous solubility decreased as follows: aldehyde > methyl ketone > alcohol > ethyl ester. When using a group contribution method, the estimated solubility of ethyl esters and methyl ketones in water was, respectively, underestimated and overestimated. Compared to water, the solubility of the volatile molecules in aqueous solutions was higher in the aqueous polyols solutions than in the carbohydrate solutions, although solubility decreased as substrate concentration increased. Aqueous solutions properties, such as water activity, also in,uenced aroma compound solubility. Copyright © 2004 John Wiley & Sons, Ltd. [source] Characterization of non-covalent complexes of rutin with cyclodextrins by electrospray ionization tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2004Mingquan Guo Abstract Electrospray ionization tandem mass spectrometry (ESI-MSn) and the phase solubility method were used to characterize the gas-phase and solution-phase non-covalent complexes between rutin (R) and ,-, ,- and ,-cyclodextrins (CDs). The direct correlation between mass spectrometric results and solution-phase behavior is thus revealed. The order of the 1 : 1 association constants (Kc) of the complexes between R and the three CDs in solution calculated from solubility diagrams is in good agreement with the order of their relative peak intensities and relative collision-induced dissociation (CID) energies of the complexes under the same ESI-MSn condition in both the positive and negative ion modes. Not only the binding stoichiometry but also the relative stabilities and even binding sites of the CD,R complexes can be elucidated by ESI-MSn. The diagnostic fragmentation of CD,R complexes, with a significant contribution of covalent fragmentation of rutin leaving the quercetin (Q) moiety attached to the CDs, provides convincing evidence for the formation of inclusion complexes between R and CDs. The diagnostic fragment ions can be partly confirmed by the complexes between Q and CDs. The gas-phase stability order of the deprotonated CD,R complexes is ,-CD,R > ,-CD,R > ,-CD/R; ,-CD seems to bind R more strongly than the other CDs. Copyright © 2004 John Wiley & Sons, Ltd. [source] Comparison of a miniaturized shake-flask solubility method with automated potentiometric acid/base titrations and calculated solubilitiesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2005A. Glomme Abstract Solubility is one of the most important parameters for lead selection and optimization during drug discovery. Its determination should therefore take place as early as possible in the process. Because of the large numbers of compounds involved and the very low amounts of each compound available in the early development stage, it is highly desirable to measure the solubility with as little compound as possible and to be able to improve the throughput of the methods used. In this work, a miniaturized shake-flask method was developed and the solubility results were compared with those measured by semiautomated potentiometric acid/base titrations and computational methods for 21 poorly soluble compounds with solubilities mostly in the range 0.03,30 ,g/mL. The potentiometric method is very economical (approximately 100 ,g of a poorly soluble compound is needed) and is able to create a pH/solubility profile with one single determination, but is limited to ionizable compounds. The miniaturized shake-flask method can be used for all compounds and a wide variety of media. Its precision and throughput proved superior to the potentiometric method for very poorly soluble compounds. Up to 20 compounds a week can be studied with one set-up. Calculated solubility data seem to be sufficient for a first estimate of the solubility, but they cannot currently be used as a substitute for experimental measurements at key decision points in the development process. © 2004 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:1,16, 2005 [source] | ||||||||||