Potassium release problem

Reserve slow release potassium chloride preparations for patients who cannot tolerate liquids or effervescent potassium preparations, or for patients in whom there is a problem of compliance with these preparations. 

The experiment was a failure. All that happened was that hydrogen was released at one electrode and oxygen at the other. But Davy was undaunted. If the experiment didn t work with a solution of potash, he could repeat it without the water. However, there was a problem. Cold, dry, caustic potash was an insulator it didn t conduct an electric current. So Davy tried melted potash instead. Finally in 1807, after a series of failures, he obtained a new metal from the potash, which he named potassium. 

The anomalous behaviour for potassium chloride matrices with a value <0.5 emphasizes the complex release of this drug. Peppas [8] did not interpret values of <0.5 but stated that such occurrences were an indication of statistical analysis problems or were due to diffusion through a polymeric network where diffusion occurred partially through a swollen matrix and partly through water-filled pores. In this case, in order to investigate the mechanism of release, the percentage release v. time profile was evaluated for goodness of fit. The details of the use of this statistical... 

In addition to deposits of crystalline potassium bitartrate, infrequent calcium tartrate deposits occur in wines. The calcium level of carefully produced wines is seldom high enough to cause stability problems. Occasionally, however, wines may extract calcium from improperly prepared filter materials. Prolonged storage in uncoated concrete tanks also will release calcium into wine. 

Soybean meal is generally low in minerals and vitamins (except choline and folic acid). About two-thirds of the P in soybeans is bound as phytate and is mostly unavailable to animals. This compound also chelates mineral elements including Ca, magnesium, potassium, iron and zinc, rendering them unavailable to poultry. Therefore, it is important that diets based on soybean meal contain adequate amounts of these trace minerals. Another approach to the phytate problem is to add phytase, a phytic acid degrading enzyme, to the feed to release phytin-bound P. A benefit of this approach is that less P needs to be added to the diet, reducing excess P loading into the environment. 

With all batch techniques, there is the common problem of not removing the desorbed species. This can cause an inhibition of further adsorbate release (Sparks, 1985, 1987a), promote hysteretic reactions, and create secondary precipitation during dissolution of soil minerals (Chou and Wollast, 1984). However, one can use either exchange resins or sodium tetraphenylboron, which is quite specific for precipitating released potassium, as sinks for desorbed species and still employ a batch technique (Sparks, 1986). Also, since in most batch methods the reverse reactions are not controlled, problems are created in calculating rate coefficients. This is particularly true for heterogeneous systems such as soils. 

More recently, the Tc(I) compound [Tc(C0)3(H20)3]+ has become an important starting material for labeling organometallic pharmaceuticals. The compound can be prepared in water and at normal pressure. The use of the toxic gaseous CO was a problem, but a kit has recently been developed using solid nontoxic potassium boranocarbonate, which releases CO when hydrolyzed and which can reduce Tc(VII) to Tc(I). Therefore this kit should increase drastically the use of the precursor [Tc(C0)3(H20)3]+ for Tc and Tc studies. The chemistry of this molecule will be discussed in more details in a later section. 

The main adverse effects of oral potassium salts are hyperkalemia, particularly when they are used in combination with potassium-sparing drugs, such as spironolactone and ACE inhibitors, and gastrointestinal ulceration and perforation, particularly with modified-release formulations. The problems surrounding enteric-coated potassium chloride tablets are unresolved. Despite recommendations that they be withdrawn, some are still available. The risks seem to be less with slow-release potassium chloride tablets. 

High localized concentrations of potassium chloride in the gastrointestinal tract can cause ulceration, hence the development of the many enteric-coated and wax matrix sustained-release preparations that are available.Although it is claimed that some formulations cause less ulceration than others, it is often preferred to administer potassium chloride as an aqueous solution. However, solutions have also been associated with problems, mainly due to their unpleasant taste. 

Notice that the reaction of potassium and water releases energy and increases disorder. This example and Sample Problem G show how to determine AG values at 25°C by using AH and A5 data. However, you can calculate AG in another way because lists of standard Gibbs energies of formation exist, such as Table 5. 

Consider the formulation Osmosin was a modified release preparation of indomethacin. It was designed to release the active drug under osmotic control. Instead it allowed its potassium content to be released in a way that caused perforation of the small bowel distal to the duodenum. The drug provides an example of the formulation causing the problem, and the drug serves as a reminder that consideration needs to be given to the formulation as a possible cause of trouble which can be remedied by reformulation. 

A related problem is ionization interference. If the analyte atoms are ionized in the flame, they cannot emit atomic emission wavelengths, and a reduction in atomic emission intensity will occur. For example, if potassium is ionized in the flame, it cannot emit at its atomic emission line at 766.5 nm and the sensitivity of the analysis will decrease. If a large amount of a more easily ionized element, such as cesium, is added to the solution, the cesium will ionize preferentially and suppress the ionization of potassium. The potassium ions will capture the electrons released by the cesium, reverting to neutral potassium atoms. The intensity of emission at 766.5 nm will increase for a given amount of potassium in the presence of an excess of cesium. The added cesium is called an ionization suppressant. Ionization interference is a problem with the easily ionized elements of groups 1 and 2. The use of ionization suppressants is recommended for the best sensitivity and accuracy when determining these elements. Of course, as ionization increases, ion emission line intensity increases. It may be possible to use an ionic emission line instead of an atomic emission line for measurements. 

In the United States, hypertension (high blood pressure) is the primary reason people visit doctor s offices, and more prescriptions are written for its treatment than any other health problem. In addition to the use of prescription drugs, hypertension is also usually treated by reducing or eliminating the dietary intake of sodium in the form of table salt (sodium chloride). Recently released research results indicate that combining an increase in dietary potassium intake with a reduction in sodium intake is probably the most important dietary decision (after excess weight loss) people can make to reduce cardiovascular diseases, including hypertension. 

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