Background: Glucosamine sulfate is used for the treatment of arthrosis, especially osteoarthritis of the knee joint. The available evidence suggests differences in its pharmacokinetics in Chinese subjects compared with non-Chinese subjects.
Objective: The aim of this study was to compare the pharmacokinetics and relative bioavailability of a test and reference formulation of glucosamine sulfate 500 mg after single oral administration in healthy Chinese volunteers.
Methods: This open-label, randomized-sequence, single-dose, 2-way crossover study was performed at the First Hospital of Nanjing Medical University, Nanjing, China. Eligible subjects were healthy male volunteers who were randomly assigned at a 1:1 ratio to receive a single 500-mg dose of the test or reference capsule formulation, followed by a 1-week washout period and administration of the alternate formulation. The study drugs were administered after a 12-hour overnight fast. Glucosamine sulfate was assayed using a liquid-chromatography tandem mass spectrometry method. For analysis of pharmacokinetic properties, including C(max), AUC(0-t), and AUC(0-infinity)), blood samples were obtained at intervals over a 14-hour period after study drug administration. The formulations were considered bioequivalent if the log-transformed ratios of C(max) and AUC were within the predetermined equivalence range (70%-143% for C(max) and 80%-125% for AUC) as established by the State Food and Drug Administration (SFDA) of China. Tolerability was assessed by monitoring vital signs and laboratory tests (hematology, blood biochemistry, hepatic function, and urinalysis), and by questioning subjects about adverse events (AEs).
Results: Twenty-two healthy male Chinese subjects were enrolled (mean [range] age, 24 [22-26] years; weight, 63.9 [58.5-69.3] kg; height, 172 [167-177] cm); all completed the study. No period or sequence effect was observed. The 90% CIs for the log-transformed ratios of C(max), AUC(0-t), and AUC(0-infinity)) were 93.4 to 127.3, 92.4 to 114.5, and 92.7 to 114.6, respectively (all, P = NS). The AUC(0-infinity) of the test and reference formulations was 1.83 (0.66) and 1.77 ( 0.72) microg/h/mL, respectively. No AEs were observed or reported during the study.
Conclusions: In this small study in healthy male Chinese volunteers, a single 500-mg dose of the test formulation met the SFDA's regulatory definition for bioequivalence to the reference formulation. Both formulations were well tolerated.