Solute aqueous solubility

From the standpoint of thermodynamics, the dissolving process is the estabHsh-ment of an equilibrium between the phase of the solute and its saturated aqueous solution. Aqueous solubility is almost exclusively dependent on the intermolecular forces that exist between the solute molecules and the water molecules. The solute-solute, solute-water, and water-water adhesive interactions determine the amount of compound dissolving in water. Additional solute-solute interactions are associated with the lattice energy in the crystalline state. 

Solubility The amount of mass of a substance or chemical that will dissolve in a unit volume of solution aqueous solubility is the maximum concentration of a chemical that will dissolve in pure water at a reference temperature. 

Solubility The amount of mass of a substance or chemical that will dissolve in a unit volume of solution aqueous solubility is the maximum concentration of a chemical that will dissolve in pure water at a reference temperature Solution A mixture in which the components are uniformly dispersed Solvent A liquid capable of dissolving or dispersing one or more chemical substances in certain instances the solvents can dissolve many different chemical substances—for instance, water, ethanol, acetone, hexane, and toluene Soot An agglomeration of particles of carbon impregnated with tar formed in the incomplete combustion of carbonaceous material Sorbent A solid or liquid medium in or upon which materials are retained by absorption or adsorption... 

The constant K is termed the distribution or partition coefficient. As a very rough approximation the distribution coefficient may be assumed equal to the ratio of the solubilities in the two solvents. Organic compounds are usually relatively more soluble in organic solvents than in water, hence they may be extracted from aqueous solutions. If electrolytes, e.g., sodium chloride, are added to the aqueous solution, the solubility of the organic substance is lowered, i.e., it will be salted out this will assist the extraction of the organic compound. 

Solvent Evaporation. This encapsulation technology involves removing a volatile solvent from either an oil-in-water, oil-in-oil, or water-in-oH-in-water emulsion (19,20). In most cases, the shell material is dissolved in a volatile solvent such as methylene chloride or ethyl acetate. The active agent to be encapsulated is either dissolved, dispersed, or emulsified into this solution. Water-soluble core materials like hormonal polypeptides are dissolved in water that contains a thickening agent before dispersion in the volatile solvent phase that contains the shell material. This dispersed aqueous phase is gelled thermally to entrap the polypeptide in the dispersed aqueous phase before solvent evaporation occurs (21). 

The steps involved in entry of a radical into the particle phase from an aqueous phase initiator have been summarized in Section 3.1.11. Aqueous phase termination prior to particle entry should be described by conventional dilute solution kinetics (Section 5.2,1.4.1). Note that chain lengths of the aqueous soluble species are short (typically <10 units). 

The synthetic approach is very simple and does not require any special set up. In a typical room temperature reaction, 1.0 mL aqueous solution of cadmium chloride was added to 20 mL aqueous solution of soluble starch in a 50 mL one-necked round-bottom flask with constant stirring at room temperature. The pH of the solution was adjusted from 6 to 11 using 0.1 M ammonia solution. This was followed by a slow addition of 1.0 mL colourless selenide ion stock solution. The mixture was further stirred for 2 h and aged for 18 h. The resultant solution was filtered and extracted with acetone to obtain a red precipitate of CdSe nanoaprticles. The precipitate was washed several times and dried at room temperature to give a material which readily dispersed in water. The same procedure was repeated for the synthesis of PVA and PVP - capped CdSe nanoparticles by replacing the starch solution with the PVA and PVP polymers while the synthesis of elongated nanoparticles was achieved by changing the Cd Se precursor ratio from 1 1 to 1 2. The synthesis of polymer capped ZnSe nanoparticles also follows the same procedure except that ZnCb solution was used instead of CdCb solution. 

To identify the major species in any aqueous solution, first categorize the solutes. A soluble salt, strong acid, or strong base generates the appropriate cations and anions as major species. Eveiy other solute generates its molecular species in solution. In addition, H2O is always a major species in aqueous solutions. Example provides practice in identifying the major species in solution. 

In an aqueous solubility reaction, a salt dissolves to yield ions in solution. The amount of a salt that dissolves in water varies over a large range, as the following examples show ... 

Most injections are formulated as aqueous solutions, with Water for Injections BP as the vehicle. The formulation of injections depends upon several factors, namely the aqueous solubility of the active ingredient, the dose to be employed, thermal stability of the solution, the route of injection and whether the product is to be prepared as a multidose one (i.e. with a dose or doses removed on different occasions) or in a singledose form (as the term suggests, only one dose is contained in the injection). Nowadays, most injections are prepared as single-dose forms and this is mandatory for certain routes, e.g. spinal injections such as the intrathecal route and large-volume intravenous infusions (section 2.2). Multidose injections may require the inclusion of a suitable... 

The generalization as to binned solubility ranges is based on experimental aqueous solubility assays that are primarily intended for early discovery use. Most often these assays employ a drug in DMSO stock solution rather than a powder... 

Medicinal chemists should be aware that inexperienced biologists can erroneously conclude that poorly aqueous soluble compounds are orally absorbed when compounds are dosed in pharmaceutically unacceptable solvents. Always ask what is the dosing vehicle Heroic combinations of DMSO, Cremophor, poly(ethylene glycol), Tween-80 and ethanol are unacceptable and misleading. In case of doubt consult with a pharmaceutical scientist colleague. The reliable standards are an aqueous solution (with perhaps a trace of DMSO) or a suspension (perhaps stabilized with an acceptable quantity of adjuvant, e.g. Tween-80). 

The intrinsic aqueous solubility S of a drug X is related to the Gibbs free energy AGs i of the transfer of the drug X from its lowest free energy crystalline form to a saturated solution of the neutral form of X in water by the simple equation ... 

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