Factors influencing solubilization

The function of neutral carriers, such as the crown ether compounds discussed above, is to bind ions reversibly and to transport them across the aqueous/organic interface. The neutral carrier forms a solvation shell around a cation of appropriate charge and size, thereby solubilizing it in the organic phase. Some influencing factors are important, such as, steric interaction and the effect of the solvent on the metal cations (125). Ideally, these induce a selective permeation of one type... 

P Singh, S Desai, D Flanagan, A Simonelli, W Higuchi. Mechanistic study of the influence of micelle solubilization and hydrodynamic factors on the dissolution rate of solid drugs. J Pharm Sci 57 959, 1968. 

Microstructures of CLs vary depending on applicable solvenf, particle sizes of primary carbon powders, ionomer cluster size, temperafure, wetting properties of carbon materials, and composition of the CL ink. These factors determine the complex interactions between Pt/carbon particles, ionomer molecules, and solvent molecules, which control the catalyst layer formation process. The choice of a dispersion medium determines whefher fhe ionomer is to be found in solubilized, colloidal, or precipitated forms. This influences fhe microsfrucfure and fhe pore size disfribution of the CL. i It is vital to understand the conditions under which the ionomer is able to penetrate into primary pores inside agglomerates. Another challenge is to characterize the structure of the ionomer phase in the secondary void spaces between agglomerates and obtain the effective proton conductivity of the layer. 

In addition, the solubilized sulfonamides as a group diffuse very widely into the tissues, penetrating into all fluids, including urine, bile, and milk. The degree of tissue penetration is influenced by several factors, including the ionization state and lipophilicity of the particular sulfonamide, the vascularity of the absorption site, and the degree of protein binding. 

If MPT is solubilized in aqueous CTAB micelles together with a hydrophobic quencher, statistical and proximity effects will influence the efficiency and rate of the energy transfer in the same direction. Thus reaction 20 is enhanced in the confined space of a CTAB micelle by a factor of HO (19). 

The accepted rules for solubilizate position and the factors influencing solubilization are derived from many observations (Mukerjee, 1979 Sepulveda, 1974) (a) compounds such as acids, amines and alcohols with polar groups are located in the micellar soft-core, and nonpolar hydrocarbon groups at the micellar surface (b) nonpolar aliphatic hydrocarbons and aromatic hydrocarbons are located in the outer micellar surface. 

The total solubilizate concentration is a function of the stepwise association constant, K, between a solubilizate and a monomer concentration solubilizate. It is very useful to consider the factors influencing solubilization. These values determine the general behavior of solubilization as follows ... 

A number of factors influence formation of proteoliposomes with a low passive ion permeability. Lin et al. (1990) have reported that polyethylene glycol (PEG) treatment of proteoliposomes lowers passive permeability to small molecules, enabling the ion-gradient to be maintained for longer periods. In several ion-coupled carrier reconstitution procedures (Fafoumoux et al., 1989 Tamarappoo and Kilberg, 1991 Ramamoorthy et al., 1992 Ramamoorthy et al., 1993), solubilized proteins have been precipitated with PEG before incoiporation into lipid vesicles. Trace amounts of PEG associated with the proteoliposomes in these procedures may reduce passive permeability and lead to high levels of ion-coupled transport (Ramamoorthy et al., 1993). 

While electrokinetic treatment of soils looks promising, most of the work performed was bench-scale, under carefully controlled laboratory conditions. For electrokinetic remediation to be a viable alternative for in-situ cleanup of waste sites, a number of factors will have to be investigated. All of the work to date has dealt with uniformly contaminated soil samples. Studies performed on partially saturated soils will yield different results. Further studies on the removal of mixed metal contaminated soils, using different soil types, are needed. The presence of organic compounds in the soil will also influence successful treatment of real contaminated soils. The use of reagents which could increase desorption and/or solubilization (without further contaminating the soil matrix) may also be areas of future investigation. Finally, field tests need to be performed to substantiate studies accomplished on the bench scale. 

The solubilizing capacity for a given surfactant system is a complex function of the physicochemical properties of the two components which, in turn, influence the location or sites where the drug is bound to the micelle. The molar volume of the solubilizate together with its lipophilicity are important factors, the former reducing and the latter increasing solubilization. ... 

When a solid has been solubilized in the liquid prior to the introduction of the compressed gas, the volumetric expansion is accompanied by a decrease of the liquid solvent strength, which causes the solid to precipitate as ultra fine particles. The physicochemical properties of the solute of interest strongly influence the choice of a solvent/antisolvent pair. The antisolvent should have appreciable mutual solubility with the solvent and should have little or no affinity for the solute. As will be seen, the solute-solvent affinity is also an effective factor that can strongly influence the morphology of the end product. 

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