A Saline solution prepared in labs is a mixture of salt and water. Here, sodium chloride act as a solvent and water is a solvent in this aqueous solution. This mixture of Normal saline is a mixture of 0.9% sodium chloride and 0.1% of water and which is isotonic (solution having same osmotic pressure) Or which is similar to the concentration of sodium in blood and tears.
Saline solution is usually called NORMAL SALINE, but it’s sometimes referred to as PHYSIOLOGICAL or ISOTONIC SALINE. It is applied to the affected area, it is useful in cleaning wounds, helps in removing contact lenses, and helps with the problems of eyes (dry eyes),also used as an injection into a vein which implicitly helps in the treatment of dehydration .
This 0.9% saline solution is a prescribed medicine which is used for fluid and electrolyte restoration for intravenous administration.
On intravenous administration of normal saline ,it provides a source of water and electrolytes. Solutions which provide combinations of hypotonic or isotonic concentrations of sodium chloride are satisfactory for parenteral (Parenteral drug administration means any non-oral means of administration) maintenance or resuscitation of water and electrolyte requirements.
Isotonic concentrations of sodium chloride are suitable ,And on the other hand hypotonic concentrations of sodium chloride are suitable for parenteral maintenance of water requirements when only a small amount of salt is needed. In water sodium chloride dissociates to release sodium (Na+) and chloride (Cl–) ions. In the extracellular fluid the principal cation is sodium (Na+) and plays a huge part in the therapy of fluid and electrolyte disturbances.
The buffering action when oxygen and carbon dioxide exchange takes place in the red blood cells is done by Chloride (Cl-).The apportionment and excretion of sodium (Na+) and chloride (Cl–) are mostly under the regulation of the kidney which regulates and maintains a balance between intake and output. Approximately 70% of total body weight is accounted for by water which is an essential constituent of all body tissues. The daily requirements of an average normal adult varies from two to three liters (1.0 to 1.5 liters each for insentient deprivation of water by perspiration and urine production).
There are various regulatory mechanisms for the maintenance of water balance. In the body compartments the Water distribution is dependent primarily on the electrolytes concentrations, and here sodium (Na+) also plays a major role.
These physiologic or isotonic salines are already present in the market commercially, but obviously, this solution of Normal saline can also be prepared manually in the laboratory whenever it is required.
Protocol for the preparation of Normal saline in lab
In the above section it is already defined that -what is a Normal saline? ✓A Normal saline solution is a mixture of 0.9% sodium chloride and 0.1% of water, or a normal saline is an aqueous solution of 0.9% sodium chloride.
The preparation of this 0.9% sodium chloride normal saline can be achieved in the laboratory by dissolving the calculated amount of sodium chloride crystals in the required quantity that is equal to it’s gram formula weight (1 mole of NaCl)to 1 liter of solution. Gram formula weight of sodium chloride (NaCl) is 58 g. On adding the atomic masses of Na and Cl together (23 g + 35 g = 58 g), one can determine it. Then, diluting 58 g of NaCl to 1 L in water gives us a 1 M NaCl solution.
Molarity can be determined by a physiological saline solution by dividing 9 g by 58 g… No. Of moles =given mass of the substance/molecular weight of the substance on solving, saline has 0.154 moles of NaCl per liter.
It signifies that Physiological saline (0.9% NaCl) has a molarity of 0.154 molar. Elucidated as 0.154 M… or 154 millimolar (154 mM).
A 0.9% NaCl and a 0.154 M NaCl solution are the same thing ( physiologic)
How to make 1L of 0.9% (w/v)Normal saline solution?
Calculation :
‘0.9% (w/v) NS’ – this tells that normal saline can be prepared by dissolving 0.9 g of NaCl to a final volume of 100 ml’s in water or solvent. It is similar to diluting 9 g of NaCl to a final volume of 1 liter in water. The desired quantity of sodium chloridecan be calculated by using the formula- W1/V1=W2/V2
- W1 = amount of sodium chloride for 100 ml NS = 0.9gm
- V1 = volume for 0.9gm sodium chloride to make NS = 100 ml
- W2 = amount of Sodium chloride to make the desired quantity of Normal Saline solution
- V2 = 1000 ml (or required quantity of Normal saline to be prepared)
Substitute the values in the formula:
- 0.9 grams / 100 millilitres = W2 grams / 1000 millilitres
- 0.9 grams × 1000 millilitres = W2 × 100 millilitres
- W2 = 0.9 × 1000 ml / 100 ml
- W2 = 9 gm
Hence, for the production of 1 litre of normal saline solution ,first of all, weigh 0.9 gram of sodium chloride crystals by using an electric balance,and then dissolve it in 1000ml of deionized water.
Apparatus/Instruments Required:
- Measuring/weighing scale
- Volumetric flasks or beaker
- Funnel
- Stirring rod
Chemicals Required for Normal saline solution:
- Nacl/sodium chloride/common salt
- Deionized/Distilled water
Note: This solution will be used for various microbiological, and pathological purposes, so make sure that all glassware/plasticware is clean and free of chemical residue.
Procedure For Normal Saline Solution as follows:
- Weigh 0.9gm the calculated and required quantity of Sodium chloride (NaCl) with the help of a weighing/ measuring scale.
- Take a Volumetric flask or a beaker . And 500 ml of distilled water in the flask or beaker.Now add 0.9gm NaCl to this.
- Mix the contents of flask by gently swirling the flask or stirring with the help of stirrer in the case if the solution is being prepared in a beaker.
- On complete dissolution of NaCl add the measured quantity of distilled water and make the final volume of Normal saline solution to 1 liter by adding water to it.
- Cover the mouth of the volumetric flask with an air-tight stopper and make the solution homogeneous by gently swirling the solution in flask or stirring the solution well using a stirrer if a beaker has been used.
Note: For using the solution immediately, it does not need to be sterilized. Although, for storing it long term, it is highly recommended to sterilize by autoclaving for 15 minutes at 121°C or Passing it through a .45 or .22 micron sterile filter.
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