Solubility evaluation methods

The solubility measurement at several time points can be used for preliminary solution stability evaluation of new drug candidates. If degradation is observed during the solubility evaluation, further HPLC method development... 

Dickhut, R. M. Armstrong, D. E. Andren, A. W. The solubility of hydrophobic aromatic chemicals in organic solvent water mixtures - evaluation of 4 mixed solvent solubility estimation methods./. Environ. Toxicol Chem. 1991, 10, 881—889. 

The only evaluation method that unifies the contributions of these optimization goals is the total separation cost. The position of the optimum after a cost optimization depends heavily on the magnitude of each contribution relative to each other. If the price of adsorbent or fixed costs (maintenance and capital cost) is a dominant factor, then the cost optimum will coincide with the maximum productivity. For separation problems with low solubility of the components and/or very high eluent price, the cost optimum is approximately equal to the minimum of eluent consumption (i.e. very high number of stages). In other words, only the optimization of total separation cost leads to the real (economically) optimum of the separation problem (Fig. 7.15). 

The physical properties of all fats and oils, including cottonseed oil, are determined by their chemical composition. Physical characteristics are of practical importance because most applications depend on the melting behavior, solubility, flavor, density, appearance and on other physical properties to provide functionality in finished products. Appropriate analytical and physical evaluation methods are used to measure these attributes for identification, trading, and control purposes. 

A light scattering method has recently been described for the determination of the solubility of drugs, and its application to solubility evaluations of metastable phases has also been demonstrated [27]. Using this technique to deduce solubility data for theophylline anhydrate (metastable with respect to the monohydrate phase in bulk water at room temperature), agreement with the most reliable literature data was excellent. The light scattering method appears to be most useful in the determination of solubility data for metastable crystal phases in dissolution media in which they spontaneously and rapidly convert into a more stable crystal phase. 

Tager, A. A. Kolmakova, L. K. Solubility parameter, its evaluation methods, connection with polymers solubility. High-Molecular Compounds. A, 1980, 22(3), 483 96. Lee, H. -R. Lee, Y. -D. Solubility behavior of an organic soluble polyimide. J. Appl. 

In addition to overcoming all these problems in the actual measurement and in the evaluation method, this technique also avoids a series of chemical titration problems. These arise with other techniques when too large a solubility product or too small a complex formation constant in dilute solutions result in poorly defined end points in the usual titration curves. With the Gran method, with which an excess of titrating... 

It follows that the applicability of the nonane pre-adsorption method for the evaluation of microporosity is restricted to adsorptives such as nitrogen which are used at temperatures far below ambient and which have negligible solubility in soUd or liquid nonane. 

Thus, if Mp is known, from the initial mass of seeds plus the ehange in solubility over the temperature range, then the growth inerement AL and eonsequent produet CSD eould be evaluated. MeCabe (1929b) verified the method in experimental work. It was observed, however, that nueleation oeeurred despite operation at low supersaturation levels - subsequently referred to as seeond-ary nueleation i.e. nueleation in the presenee of erystals (Chapter 5). 

Beech, D. R. Bandyopadhyay, S. (1983). A new laboratory method for evaluating the relative solubility and erosion of dental cements. Journal of Oral Rehabilitation, 10, 57-63. 

Absorption across biological membranes is often necessary for a chemical to manifest toxicity. In many cases several membranes need to be crossed and the structure of both the chemical and the membrane need to be evaluated in the process. The major routes of absorption are ingestion, inhalation, dermal and, in the case of exposures in aquatic systems, gills. Factors that influence absorption have been reviewed recently. Methods to assess absorption include in vivo, in vitro, various cellular cultures as well as modelling approaches. Solubility and permeability are barriers to absorption and guidelines have been developed to estimate the likelihood of candidate molecules being absorbed after oral administration. ... 

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