2. Pharmacokinetic tests(single/multiple dose) .(1)Single dosing pharmacokinetic tests.36 eligible healthy subjects are selected. Each group has 12 people, evenly composed of men and women. After taking 80mg/160mg/320mg of PNA orally in fasting state, blood and urine samples are taken to be tested and analyzed, in order to study the pharmacokinetic characteristics of single-dose administrations.(2)Multiple dosing pharmacokinetic tests.In the single-dose administration trial, respectively choose 10 subjects (evenly composed of men and women) in middle and high-dose group (160mg qd、320mg qd).After the single-dose administration,inspecte the pharmacokinetic characteristics with 6-day continuous administration. Blood samples are taken to test the trough drug concentration of pre-dose in the morning of the 3rd, 4th, 5th day after administration, and the 6th morning before and after the administration, to study the steady state concentration and the fluctuation coefficient of the trough to peak drug concentration after multiple-dose, and to find out whether there exists the effect of drug storage and / or induction of drug enzyme.