Glucosamine and Joint Health: Pharmacologic Research Ongoing

Canadian researchers recently compared the pharmacologic properties of two different forms of glucosamine--hydrochloride and sulphate. They measured significantly higher levels of glucosamine in synovial fluid samples from horses receiving the oral glucosamine sulphate formulation as compared to synovial fluid levels in horses receiving oral glucosamine hydrochloride.

Glucosamine is a common ingredient in oral joint health supplements that are widely administered to horses with osteoarthritis. Glucosamine is available in a number of different forms including hydrochloride, sulphate, and N-acetyl-D-glucosamine. To date, there is conflicting evidence surrounding the use of glucosamine for the management of osteoarthritis, regardless of species.

"It has been proposed that the type of glucosamine used may impact efficacy," explained Sheila Laverty, MVB, Dipl. ACVS, professor and specialist in equine surgery in the University of Montreal's Veterinary School. Laverty is also a member of the Canadian Arthritis Network.

A recent review article suggests that the most favorable clinical trial results of osteoarthritis in humans were associated with the use of glucosamine sulphate, which is currently available for human use by prescription only in European countries.

In the study by Laverty and colleagues, horses were administered clinically relevant doses of glucosamine hydrochloride or glucosamine sulphate (20 mg/kg) via nasogastric intubation. They administered the preparation of glucosamine sulphate reported to be beneficial in Europe. Both types of glucosamine were absorbed and were measurable in synovial fluid at one, six, and 12 hours after administration.

"Following administration, synovial levels of glucosamine were significantly higher at one and six hours post-administration of glucosamine sulphate compared to glucosamine hydrochloride," summarized Laverty. Pure glucosamine hydrochloride was employed, but the investigators were unable to obtain commercially available pure glucosamine sulphate for their study.

Laverty pointed out that there were substances to improve palatability included with the glucosamine sulphate preparation they studied. She suggested that these substances might have enhanced the absorption of the glucosamine molecule. In addition, it is not clear whether these differences in synovial fluid levels will have a real, clinical impact on horses with osteoarthritis. Further research is required.

The study, "Comparison of pharmacokinetics of glucosamine and synovial fluid levels following administration of glucosamine sulfate or glucosamine hydrochloride," will be published in an upcoming edition of the journal Osteoarthritis and Cartilage.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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