Degree of binding

Materials may be absorbed by a variety of mechanisms. Depending on the nature of the material and the site of absorption, there may be passive diffusion, filtration processes, faciHtated diffusion, active transport and the formation of microvesicles for the cell membrane (pinocytosis) (61). EoUowing absorption, materials are transported in the circulation either free or bound to constituents such as plasma proteins or blood cells. The degree of binding of the absorbed material may influence the availabiHty of the material to tissue, or limit its elimination from the body (excretion). After passing from plasma to tissues, materials may have a variety of effects and fates, including no effect on the tissue, production of injury, biochemical conversion (metaboli2ed or biotransformed), or excretion (eg, from liver and kidney). 

Information over the state of oxidation and degree of binding Determination of the activity of the free ion (important in physiology)... 

Indeed, the degree of binding of the counterions to the micellar surface, even in the largest aqueous core, is found to be 12% [2,94]. This means that virtually all counterions are confined in a thin shell near the surface (about 4 A), the concentration of ions in this domain is very high, and a nearly ordered bidimensional spherical lattice of charges is formed at the water/surfactant interface of ionic surfactants. 

Addition reaction of peroxide-generated macroalkyl radicals with the reactive unsaturation in MA is shown in reaction scheme 4. The functionalised maleic-polymer adduct (II, scheme 4) is the product of hydrogen abstraction reaction of the adduct radical (I, scheme 4) with another PP chain. Concomitantly, a new macroalkyl radical is regenerated which feeds back into the cycle. The frequency of this feedback determines the efficiency of the cyclical mechanism, hence the degree of binding. Cross-linking reaction of I occurs by route c ( scheme 4). 

The presence of an active site in the modifier is essential for the formation of polymer-modifier adduct by the in-situ method (method 2) above. Figure 3 compares the degree of binding which can be achieved... 

Recently, another interaction was reported between an intracellular pathogen and the key regulator system of intracellular iron concentration, i.e. the degree of binding of the IRPs to IRE (see Chapter 7). In extracts from Leishmania tarentolae, a protein has been detected that binds specifically to the mammalian IRE. However, the exact nature and function of this protein is unclear up to now. In contrast to mammalian IRPs, the L. tarentolae IRE-binding activity was not induced by growth in iron-depleted medium (Meehan et ah, 2000). 

Degree of binding of chemical to plasma proteins (i.e., agent affinity for proteins) and tissues. 

Diffusion of chemical into the tissues or organs and degree of binding to receptors that are and are not responsible for the drug s beneficial effects. 

It may be important to determine the degree of plasma protein and red blood cell binding of the test substance calculation of blood clearance rates using plasma or serum concentrations of the substance that have not been adjusted for the degree of binding may under or over-estimate the true rate of clearance of the test substance from the blood. This is usually done through experiments in vitro. 

Some biomarkers are more remote from the clinical benefit endpoint (e.g., the degree of binding to a receptor or inhibition of an agonisf). 

The relationship between substrate concentration ([S]) and reaction velocity (v, equivalent to the degree of binding of substrate to the active site) is, in the absence of cooperativity, usually hyperbolic in nature, with binding behavior complying with the law of mass action. However, the equation describing the hyperbolic relationship between v and [S] can be simple or complex, depending on the enzyme, the identity of the substrate, and the reaction conditions. Quantitative analyses of these v versus [S] relationships are referred to as enzyme kinetics. 

In previous publications (10,16) we have described the procedure used to obtain the degree of binding, 6, defined as... 

Multiple drug interactions can occur with the TCA drugs. Because of their high degree of binding to plasma proteins, competition for binding sites can exist between TCAs and phenytoin, aspirin, phenothiazines. 

Various degrees of binding the extractant to the polymeric membrane [87]. 

The unit cell is trigonal, with a = b = 1.28 nm and c = 2.74 nm. Two chains, each with a 3(— 0.913) helix, pass through the unit cell. All three axes of the unit cell are shorter than those observed for the sodium salt formBS 69 (a = b = 1.45 nm, and c — 2.88 nm). This was attributed to the greater degree of binding of calcium ion to the polysaccharide chain, compared to that of the sodium ions. 

Arfellini et al. (1984) reported a greater degree of binding to DNA in organs (liver, kidneys, lung and stomach) of mice than in those of rats (1.45-2.26-fold) 22 h after intraperitoneal administration of equivalent single doses of 8.7 pmol/kg bw. 

Lornoxicam reaches peak plasma concentrations within 2 to 6 h and shows high degree of binding to plasma protein (99.7%). In contrast to other oxicams, lornoxicam has a short plasma elimination half-life of about 4 h (Olkkola et al., 1994) and is metabolised mainly to the inactive compound 5 -hydroxy-lornoxicam (Dittrich et al., 1990) and excreted in the urine ( 33%) and faeces ( 66%) (Hitzenberger et al., 1990). 

The peak plasma concentration is reached 2 h after oral administration. The degree of binding of phenylbutazone to plasma proteins is 98%. The long elimination half-life of phenylbutazone (mean -70 h) exhibits large interindividual and intraindividual variation. It is metabolized in the liver by oxidation and glucuronidation and excreted in the urine and to a lower degree (-25%) in the faeces (Aarbakke, 1978). Oxyphenbutazone is an active metabolite of phenylbutazone. The metabolic pathway of phenylbutazone is shown in Scheme 72. 

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