Isotonic solutions are necessary when working with cellular elements such as blood, sperm or tissue. An isotonic solution limits osmotic injury to cells, while the addition of other biochemicals may help preserve cellular function.
Some isotonic solutions:
(1) normal saline (0.85%)
(2) Locke's solution
(3) Ringer's solution
(4) Tyrode's solution (used in tissue culture)
where:
• These solutions are unbuffered.
• Ringer's lactate contains lactate (as a source of bicarbonate), magnesium chloride, and different levels of the other salts in Ringer's solution.
|
grams per liter |
Saline |
Ringer's |
Locke's |
Tyrode's |
|
sodium chloride |
8.5 |
8.6 |
9.0 |
8.0 |
|
potassium chloride |
|
0.3 |
0.42 |
0.2 |
|
calcium chloride anhydrous |
|
0.25 (1) |
0.24 |
0.20 (2) |
|
sodium bicarbonate |
|
|
0.1 – 0.3 |
1.0 |
|
D-glucose |
|
|
0.1-2.5 |
1.0 |
|
magnesium chloride |
|
|
|
0.1 |
|
monosodium phosphate |
|
|
|
0.05 |
where:
• Footnote 1: calcium chloride dihydrate 0.33 g/L (ratio dihydrate to anhydrous = 1.32)
• Footnote 2: The Sigma-Aldrich Products for Life Science Research Catalogue (2000-2001 page 376) uses 0.24 g of calcium chloride dihydrate, equivalent to 0.18 g of the anhydrous form.
Specialty: Clinical Laboratory
