Chondroitin Sulfate Testing (USP)

Chondroitin Sulfate belongs to a group of complex polysaccharides known as glycosaminoglycans (GAGs) or mucopolysaccharides. GAGs are present in the tissue of vertebrate animals (e.g., bovine trachea) and have mainly a linear structure with a repeating unit containing D-glucuronic acid and N-acetylgalactosamine. The N-acetylgalactosamine is either sulfated in the C-4 position (Chondroitin Sulfate A) or the C-6 position (Chondroitin Sulfate C). Chondroitin Sulfate, in conjunction with glucosamine and MSM, is used as a dietary supplement to slow the progression of osteoarthritis.

Due to the complexity of Chondroitin Sulfate, many different analytical techniques are used for its characterization and determination of purity. Eurofins Scientific offers the following tests for Chondroitin Sulfate to clients requiring characterization of their material according to the USP monograph:

• ID by IR

• Residue on Ignition

• Heavy Metals

• Loss on Drying

• Clarity and Color of Solution

• Microbial Enumeration

• pH

• Limit of Protein

• OVIs

• Specific Rotation

• Sulfate

• Content of Chondroitin Sulfate

• Sodium <191>

• Chloride

• Electrophoretic Purity

The content of chondroitin sulfate (total glycosaminoglycans) are determined using a Brinkmann / Metrohm titrator and probe colorimeter. This instrumentation has been set up to do the CPC (cetylpyridinium chloride) turbidimetric titration. In this procedure the anionic Chondroitin Sulfate forms an insoluble complex with the cationic CPC. After the end point, where the Chondroitin Sulfate is completely complexed, the addition of more CPC causes flocculation. Typically a 5g sample is sufficient for analysis using this method. In addition, the titration can be used to analyze simple finished products, for example chondroitin sulfate / glucosamine tablets. Since we started using the titration, over 10 years ago, the results for a raw material control sample have shown a precision of 1.5% (RSD).

The CPC titration effectively compliments other Chondroitin Sulfate purity determinations offered by Eurofins Scientific. Specifically, these are AOAC enzymatic HPLC and carbazole reaction. These techniques can be used to confirm the results from the CPC titration or help resolve differences when comparing data from other methods. For a complex natural material like Chondroitin Sulfate, the highest quality results are obtained when data from different methods / techniques agree.

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