Pharmacokinetics and bioequivalence of two N‐acetylcysteine tablets in healthy Chinese volunteers under fasting and fed conditions

N-acetylcysteine (NAC) is a derivative of cysteine with potent mucolytic and antioxidant properties. However, the pharmacokinetics of NAC tablets remain unclear in healthy Chinese subjects. This study aimed to assess the pharmacokinetics, bioequivalence, and safety of a domestically manufactured NAC tablet (600 mg) compared with the reference formulation in healthy Chinese volunteers under both fasting and fed conditions. A single-dose, randomized, open-label, two-formulation, crossover bioequivalence study was conducted, using a two-period, two-sequence design under fasting conditions and a four-period, fully replicated crossover design under fed conditions. Blood samples were collected at predetermined time points and analyzed using a validated liquid chromatography-tandem mass spectrometry method. The 90% confidence intervals for the geometric mean ratios (test/reference) of the maximum plasma concentration, the area under the concentration-time curve from time zero to the last measurable concentration, and from time zero to infinity were all within the accepted bioequivalence range of 80%-125%. Furthermore, both the test and reference formulations were well tolerated, and no serious adverse events were reported. These results demonstrate that the test and reference NAC tablets are bioequivalent and exhibit similar pharmacokinetic profiles and safety in healthy Chinese subjects under both fasting and fed conditions.