Pharmacokinetics and bioavailability study on acetaminophen oral drop in healthy volunteers

The concentrations of acetaminophen in human plasma were determined by RP-HPLC after administration of a single oral dose of 1000 mg acetaminophen oral drop or tablet to eight normal male volunteers in a crossover study. The concentration vs time curves of acetaminophen all fitted the two compartment model. The C(max) in oral drop and tablet were 11.23 ± 0.93 and 8.79 ± 0.93 mg/L, respectively; T(max) were 0.86 ± 0.08 and 1.48 ± 0.39 h; T( 1/2 )β 3.03 ± 0.79 and 2.51 ± 1.10 h; AUC 42.35 ± 6.20 and 40.60 ± 6.79 mg/L · h. When AUC in tablet was 100%, the relative bioavailability of acetaminophen oral drop was 105.58%. The results showed that the oral drop and tablet are bioequivalent.