Two solutions having the same osmotic pressure across a semipermeable membrane is referred to as isotonic solution. It has the same osmolarity (solute concentration), as another solution.
- A solution is isotonic when its effective mole concentration is the same as that of another solution.
- This state provides the free movement of water across the membrane without changing the concentration of solutes on either side.
- Some examples of isotonic solutions are 0.9% normal saline and lactated ringers.
- When a solution has a higher solute concentration than the solution present across the semi-permeable membrane, it is known as a hypertonic solution.