A total 80 healthy subjects will be enrolled in both sites, both male and female, age 18-45 years old. Half of them will be healthy Chinese volunteers, both male and female; will be recruited to obtain at least 36 evaluable volunteers in Chinese site of CTC, PUTH. The other half will be healthy Caucasian volunteers, both male and female; will be recruited to obtain at least 36 evaluable volunteers in the U.S. site of Spaulding Clinical Research LLC. An evaluable subject is defined as a volunteer completing all study procedures from the screening period to the final ECG nominal time-point for QTc interval measurement and final blood sampling for plasma levels of Moxifloxacin on the last study day (Day 2 of the second period).~Study Objective:Primary Objective:To compare the difference of ΔΔQTcF (Baseline-adjusted, placebo-corrected effect on QTcF) between Chinese group and Caucasian group under the same exposure (Cmax) of Moxifloxacin.Secondary Objectives:1)To compare the difference of ΔΔQTcF, heart rate, PR, RR, QRS and Moxifloxacin plasma concentration between Chinese group and Caucasian group.2)To compare slopes of Moxifloxacin plasma Concentration/QTcF value between healthy Chinese volunteers and Caucasian Volunteers.
A double-center, randomized, double-blinded, 2-way crossover, placebo-controlled Study: Comparison of single oral dose 400mg Moxifloxacin-induced QT prolongation between healthy Chinese volunteers and Caucasian Volunteers Study Objective:Primary Objective:To compare the difference of ΔΔQTcF (Baseline-adjusted, placebo-corrected effect on QTcF) between Chinese group and Caucasian group under the same exposure (Cmax) of Moxifloxacin.Secondary Objectives:1)To compare the difference of ΔΔQTcF, heart rate, PR, RR, QRS and Moxifloxacin plasma concentration between Chinese group and Caucasian group.2)To compare slopes of Moxifloxacin plasma Concentration/QTcF value between healthy Chinese volunteers and Caucasian Volunteers.