Relative Density Test

CD Formulation provides services to determine the physical parameters of drugs, in addition to drug characterization and impurity analysis, all of which can reflect the actual situation of drugs. By knowing these information about the drug, we can better develop the drug. Here, we provide services for the measurement of relative density, which is commonly used.

Relative Density Test

About Relative Density Measurement

Relative density is the ratio of the density of a substance to the density of water under the same conditions of temperature and pressure. The relative density of a pure substance is a constant under certain conditions. However, if the purity of the substance is not enough, the measured value of its relative density will change with the change of purity. Therefore, the determination of the relative density of a drug can be used to check the degree of purity of the drug.

Factors Affecting the Relative Density Measurement

Air bubbles

A small bubble with a diameter of 1 mm can produce an increase of 0.5 mg, while a small bubble with a diameter of 2 mm can produce an increase of 4 mg. Therefore, make sure that solid objects or sinkers immersed in liquids are not adhered by air bubbles.

Solid material samples

A very large volume of sample immersed in fluid will result in an increase in the fluid level in the glass jar.


Solids are usually not affected by temperature changes and therefore the corresponding density changes are irrelevant. However, according to Archimedes' principle, the temperature of a liquid or solid is taken into account when determining its density.

Testing Services for Relative Density

Liquid specific gravity meter: It is an instrument used to determine the relative density or specific gravity. It works on the model of Archimedes' principle. Archimedes' principle states that any object partially or completely immersed in water is subjected to an upward force called buoyancy. This force is equal to the weight of the liquid displaced by the object immersed in the water. A pharmaceutical liquid specific gravity meter is kept in a liquid specific gravity tank containing the liquid. When the level of the sample liquid in the jar is aligned with a point on the scale of the liquid specific gravity meter, this indicates the relative density of the pharmaceutical liquid.

Relative Density Test

Specific gravity bottle: This device is used to determine the specific gravity of various pharmaceutical liquids. The procedure for determining the relative density of pharmaceutical liquids requires that the empty flask be measured first. The flask is weighed with the reference liquid and finally weighed with the test liquid. Specific gravity flasks can also be used to measure the density of solids and gases.

Relative Density Test

Applications of Relative Density Testing Services

  • Measurement of the relative density of pharmaceutical products.
  • Used to determine the density of an unknown substance from the known density of another substance.
  • To test the purity of pharmaceutical products.

About CD Formulation

CD Formulation's business covers all aspects of drug formulation, drug ingredients, drug development, drug testing, drug optimization, etc. We provide one-stop integrated services from pre-clinical to commercial manufacturing for our global pharmaceutical and biotech partners. In the future, we will continue to strengthen our technological barriers and enhance our R&D production and service capabilities to provide quality and diversified services to more new drug development start-ups, medium and large companies as well as pharmaceutical companies around the world. If you have a requirement about our services, please contact us by phone or email, our colleagues will reply to you within three working days.

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Please note: Our products and services are not intended to be used directly in diagnostic or therapeutic procedures.
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