Glucosamine is used by patients with osteoarthritis and rheumatoid arthritis. Wide variety of simple or complex Glucosamine products are offered with great different prices in Iranian pharmacies. Glucosamine is a small molecule therefore its absorption and bioavailability after oral administration is nearly complete and irrelevant to its formulation. The aim of this report is to consider Glucosamine content of such products and have a comparison to discuss if generics are as effective as brand ones.
A total of 15 products containing Glucosamine were assessed to measure Glucosamine content, at first derivatization was performed by adding phenylisothiocyanate. Then phenylthiourea derivative of Glucosamine was determined by spectrophotometer at 240 nm. To ensure non-interference of other substances, Glucosamine content of complex products also were determined with high-performance liquid chromatography (HPLC), C18 column and mobile phase phosphate buffer/acetonitrile (90/10 1 ml/min) with UV detector at 240 nm.
Glucosamine compared with amount had been mentioned in label was ranging from 93.22% to 125.14%. Almost 85% of products had active ingredient more than amount claimed on label. Comparison of HPLC analysis with spectrophotometric data indicated acceptable selectivity of spectrophotometric method for Glucosamine determination in two sample products and those containing Glucosamine plus other active ingredients such as chondroitin and methylsulfonylmethane (MSM).
One way analysis of variance (ANOVA) performed for comparison of means achieved after several Glucosamine determinations in one brand. In the basis of our study and appropriate bioavailability of Glucosamine, generic products of that also would be acceptable despite lower prices.