Isotone

In addition to these forms of water, several other official aqueous vehicles can be used. These are isotonic injections that can be sterilised, eg, sodium chloride. Ringer s, dextrose, dextrose and sodium chloride, and lactated Ringer s. Addition of water-miscible solvents such as ethanol or propylene glycol increases solubiUty and stabiUty. 

Mineral oil and paraffins should not be used, because these are not metabolized and may irritate tissue. Various other additives are needed for stabiUty, stefihty, and isotonicity antimicrobial preservatives, antioxidants (qv), chelating agents (qv), and buffers. No parenteral container material is completely inert to parenteral solvent systems. 

Ophthalmic Dosage Forms. Ophthalmic preparations can be solutions, eg, eye drops, eyewashes, ointments, or aqueous suspensions (30). They must be sterile and any suspended dmg particles must be of a very fine particle size. Solutions must be particle free and isotonic with tears. Thus, the osmotic pressure must equal that of normal saline (0.9% sodium chloride) solution. Hypotonic solutions are adjusted to be isotonic by addition of calculated amounts of tonicity adjusters, eg, sodium chloride, boric acid, or sodium nitrate. 

Ophthalmic ointments usually contain petrolatum as the base. The petrolatum is sterilized by dry heat and combined with the sterile dmg powder under aseptic conditions. Ophthalmic suspensions contain very fine (- 10 ji) particle sized soHds suspended in an aqueous vehicle. The vehicle is adjusted to isotonicity and viscosity-increasing excipients, chelating agents, and surfactants also may be needed. The aqueous vehicle in these cases is generally autoclaved and mixed with sterile dmg powder asceptically (30). 

Aperture impedance measurements of cell volume must take into account the osmolaUty and pH of the medium. A hypotonic medium causes cells to swell a hypertonic medium causes them to shrink. Some manufacturers of aperture impedance counters deHberately provide hypertonic electrolytic media for red blood cell measurements. The shmnken red cells not only become more nearly spherical and thus less affected by orientation, but also less deformable than cells in isotonic media and thus less affected by differences in hemoglobin content. 

Iso-polysaure,/. isopoly acid, -purpurinskure, /. isopurpuric acid. -saccharinsaure, /. isosaccharinic acid, isosmotisch, a. isosmotic. iso-therm, -thermisch, a. isothermal. Iso-therme, /. isotherm, -thlocyanat, -thio-cyanid, n. isothiocyanate, -thiocyansaure, f. isothiocyanic acid, -tonie, /. isotonicity. 

Calf kidneys, dog kidneys and rhesus monkey kidneys were treated with trypsin to give suspensions of cells. The suspensions were centrifuged and the packed cells diluted with 400 volumes (calf cells) or 200 volumes (dog cells and rhesus monkey cells) of a growth medium consisting of 5% horse serum and 0.5% lactalbumen hydrolysate in Earle s saline, with 100 units/ml each of penicillin and streptomycin. These media were used separately to produce Semliki Forest/calf interferon, Semliki Forest/dog interferon and Semliki Forest/rhesus monkey interferon. The cell-containing growth medium was dispensed into 500 ml medical flat bottles (70 ml in each). The cultures were incubated at 36°C. Confluent sheets of cells (monolayers) were formed in 5 to 6 days. The growth medium was then removed and the monolayers were washed with isotonic phosphate-buffered saline, pH 7.5. 

A 0-9% salt solution is considered to be isotonic with blood. Other electrolytes present include bicarbonate ions (HCOj ) and small amounts of potassium, calcium, magnesium, phosphate, sulphate and organic acid ions. Included among the complex compounds and present in smaller amounts are phospholipids, cholesterols, natural fats, proteins, glucose and amino acids. Under normal conditions the extracellular body fluid is slightly alkaline with a pH of 7-4. ... 

A careful examination has been made of the properties of / films when immersed in solutions of electrolytes. It was found that when a film of a pentaerythritol alkyd varnish was transferred from 0-001 N KCl to 3-5 N KCI its resistance rose, fell upon returning it to the 0-001 N KCl, rose again to the same high value when immersed in a sucrose solution isotonic with 3 - 5 N KCl and fell to the original value when returned to the dilute KCl solution (Fig. 14.3). It was concluded that the changes in resistance were dependent only upon the available water in the solution and were associated, therefore, with the entry of only water into the varnish film . 

Nutrient solutions used in intravenous feeding must be isotonic with blood that is, they must have the same osmotic pressure as blood. If the solution is too dilute, its osmotic pressure will be less than that of the fluids inside blood cells in that case, water will flow into the cell until it bursts. Conversely, if the nutrient solution has too high a concentration of solutes, water will flow out of the cell until it shrivels and dies. 

Aqueous solutions introduced into the bloodstream by injection must have the same osmotic pressure as blood that is, they must be isotonic with blood. At 25°C, the average osmotic pressure ofblood is 7.7 atm. What... 

Refer to Problem 55 and determine the concentration of a glucose solution isotonic with blood. 

While the osmotic concentration of renal cortical tissue is isotonic, interstitial solute concentration begins to rise at the border between renal cortex and renal medulla to... 

Blood and lymph are approximately isotonic to a cell so that cells do not gain or lose liquid when bathed in these fluids. Pure water is hypotonic and may cause cells to swell and burst. During intravenous feeding, injections, and storage of cell tissue, a salt (saline) solution is used with a concentration of solutes that is essentially isotonic with blood (and hence, with the cell) to prevent cell damage. 

Sports drinks provide water to the body in the form of an isotonic solution (one having the same total molar concentration of solutes as human blood). These drinks contain electrolytes such as NaCI and KCI as well as sugar and... 

The dangers of shock are avoided or treated by intravenous infusion of large volumes of a salt-containing solution that is isotonic with blood (has the same osmotic pressure as blood), usually one known as lactated Ringer s solution. The added liquid increases blood volume and blood flow, thereby improving oxygen delivery. The HCO / H2C03 ratio then increases toward normal and allows the severely injured person to survive. 

Which isotopes of nickel and chromium are isotones (see Exercise 17.3) of iron-56 ... 

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