Chloride plasma concentration

In blood plasma, the chloride ion concentration is sufficiently large (about 100 mAf) to prevent cis-Pt hydrolysis, and the neutral platinum species most likely crosses the cell membrane. Inside the cell the chloride ion concentration is much lower (about 4mM), which allows for hydrolysis (35, 37). Because water is a far better leaving group than chloride or hydroxide (38, 39), the aqua species are most likely the reactive form of cis-Pt in vivo. Thus hydrolysis is the rate-limiting step in the reaction of cis-Pt with biomolecules such as proteins, RNA, and DNA (40). 

The influence of some of the aforementioned factors on aluminum absorption is further illustrated by the findings of two animal studies which estimated bioavailability differences by comparing areas under plasma concentration-time curves (AUC) after oral and intravenous dosing (Yokel and McNamara 1988). Using a single oral dose of aluminum chloride, aluminum absorption was estimated to be 0.57% in... 

At 104 mM chloride ion, typical of the plasma, for both cA-DDP and its trans-isomer, the species distribution as a function of pH is similar to that depicted earlier with the dichloro and chloro-hydroxo complexes being the dominant species at pH 7.4 [18]. Both dominant species are relatively inert kinet-ically. This reference also shows a plot of mole fraction vs. chloride-ion concentration at pH 7.0. Only at lower chloride-ion concentrations do the more reactive species containing an aqua ligand appear to a significant extent. 

Table 3. Weighted Relative Rates for Reaction of Complexes (NH3)2Pt11 with Inosine N(7) at pH 7.4 at Plasma and Nuclear Chloride-Ion Concentrations...

Sustained-release (oral) preparations can reduce the frequency of medication to once a day, and compliance is made easier for the patient. Most long-term medication for the elderly can now be given as a single morning dose. In addition sustained-release preparations may avoid local bowel toxicity due to high local concentrations, e.g. ulceration of the small intestine with potassium chloride tablets, and may also avoid the toxic peak plasma concentrations that can occur when dissolution of the formulation, and so absorption of the drug, are rapid. Some sustained-release formulations also contain an immediate-release component to provide rapid, as well as sustained, effect. 

Potassium. Even if plasma potassium is normal or high, patients have a substantial total body deficit, and the plasma concentration will fall briskly with i.v. saline (dilution) and insulin which draws potassium into cells within minutes. Potassium chloride should be added to the second and subsequent litres of fluid according to plasma potassium (provided the patient is passing urine) ... 

Furosemide (frusemide) produces a rapid decrease in the plasma and blood volumes and a concomitant increase in the total protein concentration. This effect is maximal about 30 min after its i.v. administration but is attenuated, in part, over the next few hours by fluid shifts into the vascular compartment from the intestinal tract and intracellular and interstitial fluid spaces (Hinchcliff Mitten 1993). The changes in the plasma and blood volumes are accompanied by decreases in the plasma concentrations of potassium, chloride, calcium and hydrogen ions (a mild metabolic alkalosis is produced). In contrast, the sodium ion concentration remains essentially unchanged (Hinchcliff Mitten 1993). These electrolyte changes can be exacerbated and a mild decrease in the sodium ion concentration may also be observed if horses are allowed to replace water losses by drinking. 

Amphetamines increase the concentration of free fatty adds. Morphine increases the activity of amylase and lipase, alanine and aspartate aminotransferases, ALP and the serum bilirubin concentration. The concentrations of gastrin, TSH, and prolactin are also increased. In contrast the concentrations of insulin, norepinephrine, pancreatic polypeptide, and neurotensin are decreased. Heroin increases the plasma concentrations of cholesterol, thyroxine, and potassium. PCO2 is increased but PO2 is decreased. The plasma albumin concentration is also decreased. Cannabis increases the plasma concentrations of sodium, potassium, urea, chloride, and insulin but decreases those of creatinine, glucose, and urate. 

Schwertner et al. introduced a salting-out procedure, in combination with single extraction using chloroform-isopropanol (95 5). 100 pi plasma samples could be effectively extracted with 2 ml chloroform-isopropanol. Theophylline was derivatized with pentafluoroben-zyl chloride, and 3-isobutyl-l-methylxanthine was used as an internal standard. This standard is similar to theophylline in extractability, derivatization rates, stability and chromatographic properties. Accurate measurements of plasma concentrations ( + 0.22 ug/ml) could be obtained with little or no interference from theophylline metabolites and other coextract-able material. A packed column with 3 OV-17 on Gas Chrom Q and temperature programming from 150°C to 250°C was used in combination with an electron capture detector. 

Antitumor Pt(II) complexes exist In human blood plasma In an ambient chloride Ion concentration of 103 mM. A much lower value of only 4 mM Cl" occurs within many cells. Equilibrium and rate constants have been reported for substitution of Cl" by H2O In els (NH3)2PtCl2. The successive equilibrium constants for formation of aquo and els dlaquo complexes are 3.3 and 0.4mM, respectively ( ). Similar values are found for enPtCl2 (O. The above values are used herein as prototypes for els Pt(II) amines. 

The effects of pH and Cl ion concentration on the species distribution of platinum compounds have been used to fashion the following plausible argument for the chemistry of cw-DDP in vivo. With the use of thermodynamic data for the ethylenediamine (en) analogue [Pt(en)Cl2], the relative concentrations of hydrolyzed species at pH 7.4 were estimated (see Table 9.3) for blood plasma and cytoplasm (Figure 9.7). The higher chloride ion concentration in... 

Both cis- and trans-DDP are small, neutral molecules that retain their coordination environment in circulating plasma, where the chloride ion concentration is —100 mM. Once passing through the cell membrane into... 

Although changes in urinary pH can affect the amount of mexiletine lost in the urine, the effect of diet or the concurrent use of alkalinisers (sodium bicarbonate, acetazolamide) or acidifiers (ammonium chloride etc.) on the plasma concentrations of mexiletine does not appear to be predictable. There appear to be no reports of adverse interactions but concurrent use should be monitored. The UK manufacturer of mexiletine recommends that the concomitant use of drugs that markedly acidify or alkalinise the urine should be avoided. ... 

When I plotted the data according to equation (1-2), they fitted a straight line at plasma concentrations below 3 mN but fell below the straight line at concentrations greater than 3 mN (Fig. 1 -15C). At concentrations below 3 mN the gastric mucosa concentrates iodide above that concentration, iodide in addition enters the gastric juice in replacement of chloride. The ratio of iodide to chloride in gastric juice then approaches the ratio in plasma. 

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