Hypo-osmolar

Q74 Patients using oral rehydration salts should be advised that after reconstitution, any unused solution should be discarded no later than 1 hour after preparation unless stored in a refrigerator. Oral rehydration solutions should be slightly hypo-osmolar. 

Oral rehydration salts should be reconstituted with water. Patients are advised to put the reconstituted solution in the fridge or else it should be used up to 1 hour after reconstitution. Oral rehydration solution should be slightly hypo-osmolar to decrease the electrolyte and water loss from the intestines. 

The syndrome of inappropriate antidiuretic hormone (SIADH) secretion is a condition in which secretion of ADH continues despite serum hypo-osmolarity. This results in fluid retention and hyponatremia that can lead to brain oedema, mental confusion and coma. The causes are hypothalamic-pituitary tumours or an ectopic vasopressin-secreting tumour. 

After one minute, however, all the experimental studies have demonstrated the ineffectiveness and even harmfulness of eye rinsing with water or with the other isotonic solutes (isotonic to blood). In fact, these aqueous solutions dilute the chemical substance and facilitate the release of the active ions of the corrosive or irritating product. In addition, being hypo-osmolar to the cornea, aqueous solutions create flows from tissue surface to the inside, favoring the penetration of the chemical into ocular tissue (see Chaps. 5 Physiopathology and 6 Eye Rinsing Solutions ). 

Q7 An excess of vasopressin produces a hypo-osmolar condition with excessive water retention. This greatly dilutes the sodium content of plasma and causes an overall dilution of the extracellular fluid (ECF), which can lead to tissue swelling, for example in the brain. Mental symptoms such as confusion, irritability, seizures and coma can occur when ECF sodium falls below 120 mEq l-1. 

Hull M, Kottlors M, Braune S. Prolonged coma caused by low sodium and hypo-osmolarity during treatment with citalopram. J Clin Psychopharmacol 2002 22(3) 337-8. 

The ideal cerumenolytic preparation (a hypo-osmolar, alkaline, aqueous solution) has not yet been developed. It should be able to lyse the keratin cells of cerumen and allow for easy disimpaction. ... 

Fig. 2 Fractograms were obtained with a Sd-FFF apparatus (77 X 1 X 0.0125 cm), (a) RBC elution profile on a new or properly washed FFF channel. Elution conditions flow injection of 5 X 10 RBCs (1/20 dilution of total blood in phosphate buffer saline pH 7.4/0.1 % of bovine albumin) external field 9.45g (1 g = 9.81 cm/s ) flow rate 0.7 mL/min, photometric detection at A = 313 nm. (b) Channel poisoning effect observed after 47 identical injections Idescribed in (A)], (c) Two sequences of RBC elution and channel cleaning procedure. Each sequence is RBC fractogram (flow injection of 5 X 10 RBCs (1/20 dilution of total blood in phosphate buffer saline pH 7.4), external field 25.7g, flow rate of 1.02 mL/min, photometric detection at A = 313 nm), external field stopped (S.R.), hypo-osmolar shock with doubly distilled water, cleaning agent (C.A.) signal, second water washing, (d) Example of fragile nucleated cells eluted in Sd-FFF neuroblasts (NB) case. Elution conditions flow injection of 1.5 X 10 neuroblasts in phosphate buffer saline pH 7.4/0.1 % of bovine albumin), external field 60.0g, flow rate of 1.25 mL/min, photometric detection at A = 254 nm. (e) Separation of components from an artificial mixture of neuroblasts and RBC. Elution conditions flow injection of 1.5 X 10 neuroblasts and 5 X 10 RBC in phosphate buffer saline pH 7.4/0.1 % of bovine albumin, external field 50.0g, flow rate of 1.25 mL/min, photometric detection at A = 254 nm.

Hypo-osmolar A fluid is a lower concentration of particles of solute than water. Osmolality less than 275 mOsm/dg. 

Hypotonic The concentration is less than the concentration of intracellular fluid (hypo-osmolar range less than 240 mOsm/L). Moves fluid from extracellular space into inside cells. 

Huang YN, Hagiwara A, Wang W, et al. Local injection of M-CH combined with i.p. hyperthermic hypo-osmolar infusion is an effective therapy in advanced gastric cancer. Anticancer Drags 2002 13 431-435. 

Various conditions and agents may change the osmolarity within the developing embryo and thereby disrupt embryogenesis. Thus, induction of hypoxia may cause hypo-osmolarity,... 

Osmolarity. Hypo-osmolarity wiU promote brain swelling. Patients with ischemic stroke at risk of ischemic brain swelling should be treated with isosmolar or hyperosmolar fluids (e.g., normal saline). Dehydration should be avoided as it promotes coagulation, lowers left ventricular volume, and may reduce cerebral blood flow (CBF). The objective is to obtain and maintain euvolemia and eunatremia with fluids containing little or no free water. 

Normal semm has an osmolality of between 275 and 295 mOsm/dg. Less than 275 mOsm/dg is hypo-osmolar and greater than 295 mOsm/dg is hyper-... 

Fluids and electrolytes are stored in two compartments intracellular (inside the cell) and extracellular (outside the cell). The amount of electrolytes in fluid is called a concentration. There are three types of fluid concentrations iso-osmolar (same concentration), hypo-osmolar (low concentration), and h) er-osmolar (high concentration). These concentrations are used to describe IV solutions as isotonic (iso-osmolar), hypotonic (hypo-osmolar), and hypertonic (hyper-osmolar). 

Ruid regulation depends on the sensing of the osmolality, or solute concentration, of the blood. As more water is retained in the body solutions, the osmolaUty is decreased and can result in hypo-osmolar fluid that has a lower amount of solute than water. When water is lost from the body, the osmolality of body fluids increases and can result in hyperosmolar fluid that has a higher amount of solute than water. The body responds to an increase in osmolality by stimulating the release of ADH, which causes the retention of fluid and lowers the osmolality of body fluids. 

Wakim, K.G. Predominance of hyponatremia over hypo-osmolarity in simulation of the dialysis disequilibrium syndrome. Mayo Clin. Proc. 44, 433-460(1969)... 

With the aid of the three methods described in Sect. 18.5.4 it can be calculated whether or not a pharmaceutical preparation is iso-osmotic. Hypo-osmolarity can usually be avoided as it can be compensated by the addition of excipients in calculated quantities. Hyper-osmolarity may be inevitable due to dosage reasons, for example when a high dose of an active substance has to be administered in a small volume. The extent to which hyper-osmolarity is tolerated will depend on the route of administration and administration site. The tolerance for parenteral administration, for example, increases in the order subcutaneous < intramuscular < intravenously. This has to do with the fact that of these three routes, the intravenously administered dose spreads most rapidly, and thus dilutes most rapidly in the body and the subcutaneously administered dose most slowly. For the same reason, the tolerance is greater when the solution is injected into a large blood vessel than in a small blood vessel. The tolerance is also determined by the volume infused. In Sects. 

If two solutions contain the same number of particles they may be said to be iso-osmotic, or simply isosmotic, with respect to each other. If one solution exhibits a greater osmolarity than another solution it is hyperosmotic with respect to the less concentrated solution. If one solution has a lower osmolarity than another solution then it is hypo-osmotic or hyposmotic, with respect to the more concentrated solution. Iso-, hyper- and hypo-osmolarity should always be stated with respect to another solution. 

Countercurrent exchange. This is a passive process which occurs in the presence of ADH. ADH renders the walls of the distal part of the tubules and the collecting ducts permeable to water. The hypo-osmolar fluid produced as a result of countercurrent multiplication is therefore concentrated. 

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