Evaluation of Solubility Limits

CHAPTER 8 An evaluation of solubility limits on maximum uranium... 

An Evaluation of Solubility Limits on Maximum Uranium Concentrations in Groundwater... 

Solubility phenomena between solid and aqueous phases are treated in the chapters Leaching from cementitious materials used in radioactive waste disposal sites by Kosuke Yokozeki, An evaluation of solubility limits on maximum uranium concentrations in groundwater by Teruki Iwatsuki and Randolf C. Arthur, and The solubility of hydroxyaluminosilicates and the biological availability of aluminium by Christopher Exley. 

An Evaluation of Solubility Limits on Maximum Uranium Concentrations in Groundwater by Teruki Iwatsuki and Randolf C. Arthur. Email iwatsuki.teruki jaea.go.jp... 

Interaction characteristics in polymer-related areas frequently make use of solubility parameters (16). While the usefulness of solubility parameters is undeniable, there exists the limitation that they need to be estimated either by calculation or from indirect experimental measurements. The thermodynamic basis of IGC serves a most useful purpose in this respect by making possible a direct experimental determination of the solubility parameter and its dependence on temperature and composition variables. Price (17) uses IGC for the measurement of accurate % values for macromolecule/vapor pairs, which are then used for the evaluation of solubility parameters for a series of non-volatile hydrocarbons, alkyl phthalates, and pyrrolidones. It may be argued that IGC is the only unequivocal, experimental route to polymer solubility parameters, and that its application in this regard may further enhance the practical value of that parameter. Guillet (9) also notes the value of IGC in this regard. 

A wide variety of physical properties are important in the evaluation of ionic liquids (ILs) for potential use in industrial processes. These include pure component properties such as density, isothermal compressibility, volume expansivity, viscosity, heat capacity, and thermal conductivity. However, a wide variety of mixture properties are also important, the most vital of these being the phase behavior of ionic liquids with other compounds. Knowledge of the phase behavior of ionic liquids with gases, liquids, and solids is necessary to assess the feasibility of their use for reactions, separations, and materials processing. Even from the limited data currently available, it is clear that the cation, the substituents on the cation, and the anion can be chosen to enhance or suppress the solubility of ionic liquids in other compounds and the solubility of other compounds in the ionic liquids. For instance, an increase in allcyl chain length decreases the mutual solubility with water, but some anions ([BFJ , for example) can increase mutual solubility with water (compared to [PFg] , for instance) [1-3]. While many mixture properties and many types of phase behavior are important, we focus here on the solubility of gases in room temperature IFs. 

Static test results may be evaluated by measurement of change of mass or section thickness, but metallographic and X-ray examination to determine the nature and extent of attack are of greater value because difficulty can be encountered in removing adherent layers of solidified corrodent from the surface of the specimen on completion of the exposure, particularly where irregular attack has occurred. Changes in the corrodent, ascertained by chemical analysis, are often of considerable value also. In view of the low solubility of many construction materials in liquid metals and salts, changes in mass or section thickness should be evaluated cautiously. A limited volume of liquid metal could become saturated early in the test and the reaction would thus be stifled when only a small corrosion loss... 

The advantages of developing such correlations is that once any of the parameters is known it is then a simple process to estimate the others. This is particularly useful in early evaluation of chemical partitioning in the environment. From a limited amount of information on a chemical, for example, its vapor pressure, water solubility and melting point, other partitioning parameters can be estimated and used in simple ecosystem models to evaluate the chemical s expected environmental distribution. 

One approach to the study of solubility is to evaluate the time dependence of the solubilization process, such as is conducted in the dissolution testing of dosage forms [70], In this work, the amount of drug substance that becomes dissolved per unit time under standard conditions is followed. Within the accepted model for pharmaceutical dissolution, the rate-limiting step is the transport of solute away from the interfacial layer at the dissolving solid into the bulk solution. To measure the intrinsic dissolution rate of a drug, the compound is normally compressed into a special die to a condition of zero porosity. The system is immersed into the solvent reservoir, and the concentration monitored as a function of time. Use of this procedure yields a dissolution rate parameter that is intrinsic to the compound under study and that is considered an important parameter in the preformulation process. A critical evaluation of the intrinsic dissolution methodology and interpretation is available [71]. 

In a limited independent evaluation of GastroPlus , Hendriksen et al. [22] used literature data on solubility together with calculated human permeability values to predict the human Fabs for 21 drugs for which observed human FabS... 

In general, the biological evaluation of hypericin in various test models is limited by its poor water solubility. It was shown in in vitro as well as in vivo studies (18,78) that the water solubility of hypericin was remarkably enhanced in the presence of procyanidins or flavonol glycosides of SJW extract. In a recent pharmacokinetic study in rats, it was shown that procyanidin B2 as well as hyperoside increased the oral bioavailability of hypericin by approximately 58% (B2) and 34% (hyperoside) (Fig. 5) (19). Procyanidin B2 and hyperoside had a different influence on the plasma kinetics of hypericin median maximal plasma levels of hypericin were detected after 360 minutes (Cmav 8.6 ng/mL) for B2, and after 150 minutes... 

Bikiaris, D., G. Z. Papageorgiou, A. Stergiou, E. Pavlidou, E. Karavas, F. Kanaze, and M. Georgarakis. 2005. Physicochemical studies on solid dispersions of poorly water-soluble drugs. Evaluation of capabilities and limitations of thermal analysis techniqiT ffirmochnica Act 39 58-67. 

Official methods have been published for the determination of nitric-perchloric acid-soluble lead [111] and ammonium pyrrolidine dithiocarbamate-extractable lead [ 112] in soil. Atomic absorption spectrometric evaluations of the digest or extract is conducted at the 217 nm emission line from a lead hollow cathode lamp. Rigin and Rigina [122] determined lead in soil by flameless atomic fluorescence using electrolytic preconcentration. The limit of detection is 15 pg lead and the standard deviation is not greater than 0.04. 

---