Solubility principles

The earlier researches of Charabot have shown that the essential oil of the flowers is richer in menthone than the essential oil of the leaves. And it is in spite of a circulation of menthol, a soluble principle, from the leaf to the inflorescence, that this latter organ contains an essential oil particularly rich in menthone. It must therefore be that the menthol is there converted into menthone by oxidation. 

The differences in composition between the two essential oils examined show well, if they be compared with those which exist between the essential oils of the leaves and the inflorescences, that the distribution of the odorous principles between the leaf, the organ of production, and the flower, the organ of consumption, tends to take place according to their relative solubilities. But this tendency may be inhibited, or on the other hand, it may be favoured by the chemical metamorphoses which the substances undergo at any particular point of their passage or at any particular centre of accumulation. Thus, in the present case, some of the least soluble principles, the esters of menthol, are most abundant in the oil of the leaves, whilst another, menthone, is richest in the oil of an organ to which there go, by circulation, nevertheless, the most soluble portions. This is because this organ (the flower) constitutes the. medium in which the formation of this insoluble principle is particularly active. 

Sweetana, S. and Akers, M.J., Solubility principles and practices for parenteral drug dosage form development, /. Pharm. Sci. Technol., 50, 330, 1996. 

Meat extracts are more or less concentrated aqueous extracts of muscular flesh freed from coagulable albuminoid substances. They contain, therefore, in a more or less reduced volume, all the water-soluble principles of lean meat, and they have the appearance of a stiff, reddish-brown mass, with a rather bitter taste and a peculiar, not unpleasant odour Liebig s extract type). 

Qualitative chemistry is an area of chemistry concerned with identifying substances. In Activity 9.1 you will perform a qualitative analysis to detect the presence of certain ions that, in turn, may reveal an art forgery. The ions could come from paints that were not available at the time of the artwork. In this qualitative analysis, metal ions (cations) and nonmetal ions (anions) are reacted with solvents and with each other. Then the cations and anions present are identified by the products produced. In addition, flame tests and pH determinations are used to identify ions. Qualitative analysis is an engaging opportunity for you to develop experience with chemical change and review solubility principles. Nowadays, however, most of the time a chemist analyzes a substance to detect ion content using quantitative analytical computerized instruments. 

Mechanism of Soluble Principle Active Propranolol Hydrochloride and Lobenzarit Disodium from Dextran Tablets... 

The solubilities of salts in water (clearly of importance in aquatic, analytical, and geochemistry) can be fairly well predicted and explained using two principles later we shall return to the more familiar of these, the hard soft acid base (HSAB) principle (see Hard Soft Acids and Bases). To control this principle, we must first consider oifly salts of anions that are hard bases, that is, salts of 0x0 and fluoro anions, and oxides, hydroxides, and fluorides. The solubilities of salts of these anions can be fairly well predicted and explained on the basis of the acidity classification of the cation and the basicity classification of the anion, that is, on a principle of acid base strength. The numerous solubility rules taught in General Chemistry could be replaced with four solubility principles (Table 4), two of which are quite reliable and two of which are less reliable, for known reasons. 

Table 4 Solubility principles for salts of hard-base anions...

Whether a vitamin is fat soluble (it dissolves in organic media) or water soluble can be determined by applying the solubility principles discussed in Section 3.4C. Vitamins A and C illustrate the differences between fat-soluble and water-soluble vitamins. 

Solubility principles and the pollutants MTBE and PCBs in the environment (Section 3.4C)... 

Resins Solid preparations consisting chiefly of the resinous principles from vegetable bodies. The officially prepared resins differ from alcoholic extracts in that the latter contain all of the alcohol-soluble principles in the drugs, whereas the resins contain only the alcohol-soluble principles that are insoluble in water. The term probably arose from the Greek rheos, to flow, referring perhaps to the flow of pine resin commonly observed. ... 

Identify applications of solubility principles, and relate them to polarity and intermolecular forces. 

Sweetana S and Akers MJ. Solubility Principles and Practices for Parenteral Drug Dosage Form Development. PDA JPharm Set Technol 1996 50 330-342. 

Solubility Principles for Proteins and Practical Parameters Influencing Protein Solubility... 

Spirit of Peppermint, An alcoholic soln contg psr liter 100 ml oil of peppermint and the alcohol-soluble principles from 10 g of powdered peppermint previously macerated with water. 

Highly crystalline polymers, viz. PE or PTFE are insoluble at room temperature, but they obey the solubility principles at T > 0.9 T, i.e., at temperatures not more than 10% (in Kelvin) above their melting temperature [Leung et al., 1987]. 

Herriott (1957) has reviewed the use of the solubility diagram as a tool for detecting the presence of impurities in soluble substances, particularly proteins. In these days of advanced types of instrumentation and sophisticated methods, it is worth recalling the use of a method that depends on solubility principles and is not difficult to apply. The method is based on application of the phase rule, but one need not apply the phase rule or even understand it to determine whether a preparation contains one or more components. Herriott has discussed the general procedure, the interpretation of results, the quantitative limitations of the method, the conditions and details of technique, and the separation of protein components by methods based on the solubility diagram. 

In Part E, you will perform several exercises that involve the application of the solubility principles learned in Parts A-D of this experiment. Part F is a unique nanotechnology experiment that also relates to solubility. 

Differential (Phase Rule) solubility principles have been applied extensively to the determination of purity of purified proteins (486, 592) but only in a few oases to amino acids (209, 225). In order to determine the purity of an amino acid by the differential solubility method, minimum requisites are solubility values determined in duplicate on at least two levels of solute in excess of the solubiliiy amoimt. The attainment of solubility equilibrium should be established on the basis of the constancy of the solubility data at each level of solute either by measuring solubilities of samples brought initially to a temperature below and one above that of the thermostat or equilibrated for increasing times. 

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