Subjects will be randomized to Cohort 1 and cohort 2 in the study without crossover, Cohort 3-6 will be a dose-escalation manner. An effort will be made to balance the number of males and females in each cohort.~The first treatment cohort 1 and 2 will enroll 12 study volunteers. The volunteers of cohort 1 will receive Panadol® oral dosage form is 500 mg*2 tablets = 1,000 mg/ person every 6 hours daily of the multiple-dose treatment (Q6H, total 4 dosages, 8 tablets, 4,000 mg) (n = 6) and cohort 2 will receive SafeTynadol® oral dosage form is 500 mg*2 tablets = 1,000 mg/ person every 6 hours daily of the multiple-dose treatment (Q6H, total 4 dosages, 8 tablets, 4,000 mg) (n = 6) in an single-blind, randomized manner.~About one to three weeks later, cohorts 3-6 will be studied in an order of increasing dose of SafeTynadol® starting from 4,500 mg increment to a maximum dose of 8,000 mg of SafeTynadol® if the previous cohort do not meet the significant criteria of hepatotoxicity.~Cohort 3-6 will initially enroll 3 study volunteers. The volunteers of cohort 3 will receive SafeTynadol® oral dosage form is 500 mg*3 tablets at first dosage (1500 mg) and 500 mg every 6 hours *2 tablets at second to fourth dosage (1000 mg) person every 6 hours daily of the multiple-dose treatment (Q6H, total 4 dosages, 9 tablets, 4,500 mg) and cohort 4 will receive SafeTynadol® oral dosage form is 500 mg*3 tablets at first and second dosage (1500 mg) and 500 mg every 6 hours *2 tablets at third and fourth dosage (1000 mg) person every 6 hours daily of the multiple-dose treatment (Q6H, total 4 dosages, 10 tablets, 5,000 mg) and cohort 5 will receive SafeTynadol® oral dosage form is 500 mg*3 tablets = 1,500 mg/ person every 6 hours daily of the multiple-dose treatment (Q6H, total 4 dosages, 12 tablets, 6,000 mg) and cohort 6 will receive SafeTynadol® oral dosage form is 500 mg*4 tablets = 2,000 mg/ person every 6 hours daily of the multiple-dose treatment (Q6H, total 4 dosages, 16 tablets, 8,000 mg). In Cohort 3-6, liver function tests will be administered two hours after the third dose to confirm that the hepatotoxicity criteria are not met before the fourth dose can be administered and Cohort 6 will perform liver function tests two hours after the second dose administered to confirm that the hepatotoxicity criteria are not met before the third dose can be administered. After 3 study volunteers to confirm that did not meet significant hepatotoxicity occurs then another 3 study volunteers were included, study will in a dose-escalation manner.~Except at admission blood blank sampling to Clinical Research Center on day 1 at 10:00, sampling will be obtained at the following times last post dose: 0 (prior to the last dose), 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 24, 36, 48, 72, 96, 120, 144 and 168 hours after administration (21 samples) to assess acetaminophen concentrations and its metabolites concentrations. In addition, Cohort 1-6 blood sample for liver function test (ALT, AST, total bilirubinl) and PT(INR) will be obtained on day 1 (10:00) after admission, two hours after the third dose on day 2 and 24, 48, 72, 96, 120 and 144 hours after the last dose, Cohort 6 will increase the assessment of liver function tests two hours after the second dose. Blood samples for blood chemistry, PT(INR), hematology (CBC) and OGSP will be collected on 168 hours for post-study evaluation.
To investigate and compare the possible response of Panadol® and SafeTynadol® formulations in healthy volunteers and the safety in SafeTynadol® dose-limiting hepatotoxicity.