A crossover study to evaluate the pharmacokinetics and bioequivalence of hydroxychloroquine tablets in healthy Chinese subjects

Hydroxychloroquine (HCQ) has a high variability and a long half-life in the human body. The purpose of this study was to evaluate the bioequivalence of a generic HCQ tablet (test preparation) versus a brand HCQ tablet (reference preparation) under fasting and fed conditions in a crossover design. This was an open-label, two-period randomized, single-dose, crossover study in 47 healthy Chinese subjects who were sequentially and randomly allocated either to the fed group (high-fat meal; n = 23) or the fasting group (n = 24). Participants in each group were randomized to the two arms to receive either a single 200-mg dose of the test preparation or a 200-mg dose of the reference preparation. The application of the two preparations in each patient was separated by a 28-day washout period, regarded as sufficiently long to avoid significant interference from residual drug in the body. Whole blood samples were collected over 72 hours after drug administration. A total of 23 subjects completed both the fed and the fasting parts of the trial. There were no significant differences in C , AUC , and T between the test and reference preparation (p > 0.05). Food had no significant effect on C and T (p > 0.05), but AUC values were significantly reduced under fed condition compared to fasting condition (p < 0.05). The 90% confidence intervals (CIs) for the geometric mean ratios (GMRs) of C and AUC were 0.84 - 1.05 and 0.89 - 0.98 in the fed study, and 0.97 - 1.07 and 0.97 - 1.05 in the fasting study, respectively. The carryover effect due to non-zero blood concentrations resulted in higher AUC values in the second period for both test and reference formulations and had no effect on the statistical results. No serious adverse events were reported. The investigation demonstrated that the test and reference preparations are bioequivalent and well tolerated under both fasting and fed conditions in healthy Chinese subjects.