Fourier-transformed infrared spectroscopy, physicochemical and biochemical properties of chondroitin sulfate and glucosamine as supporting information on quality control of raw materials

Background: Chondroitin sulfate (CS) and glucosamine (GLcN) are recommended for the restoration of the articular cartilage surface in patients affected by osteoarthritis. They are commercialized as pharmaceutical-grade products and as food supplements, and there are reports that they do not undergo the strict quality controls of pharmaceuticals. Herein, we evaluated the physicochemical parameters of two raw materials (CS and GlcN) obtained from two distinct suppliers in Brazil and compare the obtained data with the product specification provided by the manufacturer. Also, the homogeneity and purity grade of samples were analyzed by FT-IR spectroscopy. Results: The organoleptic properties and solubility of CS and GlcN samples obtained from pharmacy analyses and the supplier's specifications are in accordance with the standards required by the Brazilian Health Regulatory Agency (ANVISA). However, the intraclass correlation coefficient (ICC) and Bland Altman analysis of pH and the density values of samples are statistically different between the suppliers. In addition, FT-IR analyses indicated that there is non-homogeneity in the CS and GlcN samples tested, showing that both manufacturers distribute the drugs in different concentrations, although both declare the same concentration in the product technical specifications. Conclusion: In summary, our study demonstrated that physicochemical parameters are insufficient to ensure product quality, and it is necessary to implement a more efficient protocol to ensure the quality of the final product.