Molar Concentration of Osmotic Pressure Test

What Is Molar Concentration of Osmotic Pressure?

Molar Concentration and Osmotic Pressure are two concepts related to the properties of a solution. Molar Concentration refers to the value of moles of solute per liter of solution with units in mol/L. For example, if 0.1 moles of sodium chloride (NaCl) are dissolved in one liter of water, the molar concentration of this solution would be 0.1 mol/L.

Osmotic Pressure is the pressure created when a solvent passes through a semipermeable membrane. For instance, if pure water and brine (NaCl aqueous solution) are separated using a semipermeable membrane, the solvent (water molecules) on the lower concentration side (pure water) will diffuse into the brine (this process is called osmosis). The resistance created on the brine side is known as osmotic pressure and is measured in Pascals (Pa).

The unit of Molar Concentration of Osmotic Pressure is mOsmol/kg, and the calculation formula is:

Milliosmolality (mOsmol/kg) = (grams of solute dissolved per kilogram of solvent/molecular weight) × n × 1000

n is the number of particles formed when a solute molecule dissolves or dissociates. For example, n=2 in brine.

Why Measure Molar Concentration of Osmotic Pressure?

Molar Concentration of Osmotic Pressure is a crucial parameter in pharmaceutical research and development, particularly for drugs like injectables and eye drops. Biological membranes in the human body, such as cell membranes and capillary walls, exhibit semipermeable characteristics.

If the osmotic pressure of a drug is inappropriate, it can cause discomfort in the eyes or, in the case of injectables, cell dehydration or rupture (hemolysis). The osmotic pressure of intravenous fluids should be kept the same as that of blood as much as possible, and the osmotic pressure of eye drops should be the same as that of tears.

Hemolysis caused by inappropriate osmotic pressure.Fig. 1 Hemolysis caused by inappropriate osmotic pressure.

Services at Protheragen-ING

Initial Consultation

Our process begins with a comprehensive consultation to understand clients' specific needs and requirements. This includes the nature of the sample, the type of solutes involved, and any particular conditions relevant to the investigation (as needed).


This test uses an osmolality meter that uses the freezing point depression principle. It utilizes the principle that the freezing point drop of the solution is proportional to the molar concentration of the solute. According to the Vantoff equation, the osmotic pressure molar concentration of the solution can be calculated from the freezing point drop value.

Data Analysis & Reporting

We will provide comprehensive reports that include not only the Milliosmolality data but also any other parameters measured such as environment temperature.

Follow-up Support

After we deliver the results, we are still available for any follow-up consultations or support that clients may require. We aim to address any questions or concerns to ensure clients have a complete understanding of the analysis and its implications.

If you are interested in our Molar Concentration of Osmotic Pressure services or need more information, please contact us, we will respond promptly and provide assistance within 2-4 working days.


Daily: 9.30 AM–6.00 PM
Sunday : 9.30 AM–1.00 PM
Holidays: Closed

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