Randomized two‐way cross‐over bioequivalence study of two amoxicillin formulations and inter‐ethnicity pharmacokinetic variation in healthy Malay volunteers

The objectives of this study were to develop a new deproteinization method to extract amoxicillin from human plasma and evaluate the inter-ethnic variation of amoxicillin pharmacokinetics in healthy Malay volunteers. A single-dose, randomized, fasting, two-period, two-treatment, two-sequence crossover, open-label bioequivalence study was conducted in 18 healthy Malay adult male volunteers, with one week washout period. The drug concentration in the sample was analyzed using high-performance liquid chromatography (UV–vis HPLC). The mean (standard deviation) pharmacokinetic parameter results of Moxilen® were: peak concentration (Cmax), 6.72 (1.56) µg/mL; area under the concentration–time graph (AUC0–8), 17.79 (4.29) µg/mL h; AUC0–∞, 18.84 (4.62) µg/mL h. Those of YSP Amoxicillin® capsule were: Cmax, 6.69 (1.44) µg/mL; AUC0–8, 18.69 (3.78) µg/mL h; AUC00–∞, 19.95 (3.81) µg/mL h. The 90% confidence intervals for the logarithmic transformed Cmax, AUC0–8 and AUC0–∞ of Moxilen® vs YSP Amoxicillin® capsule was between 0.80 and 1.25. Both Cmax and AUC met the predetermined criteria for assuming bioequivalence. Both formulations were well tolerated. The results showed significant inter-ethnicity variation in pharmacokinetics of amoxicillin. The Cmax and AUC of amoxicillin in Malay population were slightly lower compared with other populations. Copyright © 2014 John Wiley & Sons, Ltd.