Analysis of Glucosamine and Chondroitin Sulfate Content in Marketed Products and the Caco-2 Permeability of Chondroitin Sulfate Raw Materials

Abstract

Objective: The purpose of this report is to evaluate and present the results of analysis of actual contents of several products in the marketplace containing glucosamine and/or chondroitin sulfate and to determine if they significantly deviate from label claim. In addition, the study examined the intestinal transport of several marketed sources of chondroitin sulfate. Methods: A total of fourteen products containing glucosamine hydrochloride or sulfate and eleven products containing chondroitin sulfate were evaluated using a UVHPLC method. In addition, a total of 32 products containing chondroitin sulfate were tested using a titration method. The permeability of various marketed sources of raw materials of chondroitin sulfate across Caco-2 cell monolayers were assessed. This analysis was an attempt to evaluate whether different suppliers of chondroitin sulfate use different grades of material. Results and conclusions: The amounts of glucosamine and chondroitin found after analysis were significantly different from the label claim in some products, with deviations from label claims ranging from as low as 0% to over 115%. Products with a retail price of less than or equal to one dollar per 1200 mg of chondroitin sulfate were found to be seriously deficient in meeting label claim (less than 10% of label claim). The permeability of the different molecular weight chondroitin sulfates was found to be significantly different (p<0.05), with the permeability coefficient increasing with decreasing molecular weight. This suggests that molecular weight of chondroitin sulfate could be a possible predictor of permeability.