Mean C ( max ) values were 49.2 , 32.6 , and 28.4 ng/mL for the low - , intermediate - , and high-level coating hydrocodone ER tablet prototypes , respectively , and 37.3 ng/mL for the hydrocodone IR/APAP tablet ; respective median t ( max ) values were 5.9 , 8.0 , 8.0 , and 1.0 h. Total systemic exposure to hydrocodone ( AUC ( 0 - ) ) was comparable between hydrocodone ER tablet prototypes ( 640 , 600 , and 578 ngh/mL , respectively ) and hydrocodone IR/APAP ( 581 ngh/mL ) .