Search

Summary: Objective: We investigated the synovial and plasma glucosamine concentrations in osteoarthritic patients following oral administration of crystalline glucosamine sulphate at the therapeutic dose of 1500mg once-a-day for 14 days. Design: Twelve osteoarthritic patients (six males and six females) received 14 consecutive once-daily oral administrations of crystalline glucosamine sulphate soluble powder (1500mg), in an open fashion. Plasma and synovial fluid were collected simultaneously from the same patient, at baseline and, at steady state (3h after the last dose). Glucosamine was determined in plasma and synovial fluid by liquid chromatography–tandem mass spectrometry. Results: Median endogenous glucosamine concentrations in plasma and synovial fluid were 52.0ng/ml (0.29μM) and 36.5ng/ml (0.21μM), respectively (P =0.001), and varied substantially among patients (41–121ng/ml and <10–67ng/ml, respectively). Three hours after the last dose, glucosamine concentrations resulted increased from baseline in all patients with median increases of 20.5 and 21.5 folds in plasma and synovial fluid, respectively, the difference being not statistically significant (P =0.11). In plasma, the median post-treatment value was 1282ng/ml (7.17μM) and ranged from 600 to 4061ng/ml (3.35–22.7μM). The median post-treatment synovial glucosamine concentration was 777ng/ml (4.34μM), i.e., significantly lower than in plasma (P =0.001), and ranged from 577 to 3248ng/ml (3.22–18.1μM). Plasma and synovial glucosamine concentrations were highly correlated and were in the 10μM range. Conclusions: Glucosamine is bioavailable both systemically and at the site of action (the joint) after oral administration of crystalline glucosamine sulphate in ostaeoarthritis patients. Steady state glucosamine concentrations in plasma and synovial fluid were correlated and in line with those effective in selected in vitro studies. [Copyright &y& Elsevier]

Abstract: A new HPLC method for the determination of glucosamine (2-amino-2-deoxy-d-glucose) in human synovial fluid was developed and validated. Synovial fluid samples were analyzed after a simple protein precipitation step with trichloroacetic acid using a polymer-based amino column with a mobile phase composed of 10mM ammonium acetate (pH 7.5)–acetonitrile (20:80, v/v) at 0.3mL/min flow rate. d-[1-13C]glucosamine was used as internal standard. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in positive ionization mode and in multiple reaction monitoring acquisition (m/z 180→72 and 181→73 for glucosamine and internal standard, respectively). The limit of quantification (injected volume=3μL) was 0.02ng, corresponding to 10ng/mL in synovial fluid. Calibration curves obtained using matrix-matched calibration standards and internal standard at 600ng/mL were linear up to 2000ng/mL. Precision values (%R.S.D.) were ≤14% in the entire analytical range. Accuracy (%bias) ranged from −11% to 10%. The recoveries measured at three concentration levels (50, 800, and 1500ng/mL) were higher than 89%. The method was successfully applied to measure endogenous glucosamine levels in synovial fluid samples collected from patients with knee osteoarthritis and glucosamine levels after oral administration of glucosamine sulfate (DONA®) at the dose of 1500mg/day for 14 consecutive days (steady-state). [Copyright &y& Elsevier]