Also during the 6-hour study period , each of pH > 2 , 3 , 3.5 , 4 , and 5 was maintained for a longer duration after administration of esomeprazole 20 mg than after administration of omeprazole 20 mg ( median : 75.4 % vs. 53.8 % , p = 0.0138 ; 52.1 % vs. 33.4 % , p = 0.0188 ; 45.8 % vs. 28.2 % , p = 0.0262 ; 42.5 % vs. 20.7 % , p = 0.0414 ; 35.8 % vs. 11.6 % , p = 0.0262 ; respectively ) .