An in vitro Method to Determine Intestinal Bioavailability of Glucosamine Salt Mixture

Glucosamine is an amino sugar commonly used to improve joint health. It is often available for consumers as specialized supplements, the matrixes of which are formulated with components that facilitate enhancing functionality of the bioactive glucosamine. The primary objective of this study was to determine the in vitro bioaccessibility and bioavailability of a commercial glucosamine sulphate supplement, formulated with a mineral clay mixture. We used a modified a 3-step in vitro digestion procedure that included oral, gastric, and gastrointestinal digestions to assess bioaccessibility. Bioavailability followed using a Caco2 cell permeability test. Glucosamine bioaccessibility was not affected by gastric digestion and only marginally affected by gastrointestinal digestion (e.g., > 90% recovery). Bioavailability was dramatically lower, averaging approximately 15%, but similar for both the glucosamine reference standard and clay mineral mix glucosamine formulated product. Our in vitro bioavailability measurement of glucosamine, corrected for bioaccessibility, agree with values from in vitro rodent models. We conclude that the in vitro 3-step digestion of glucosamine, used to mimic gastrointestinal digestion, followed by the Caco2 permeability assay represents an alternative method to assess digestibility and bioavailability of formulated glucosamine products. Keywords: Glucosamine; Clay Mineral Mix; Bioaccessibility; Bioavailability