ABSTRACT
Objective To study the pharmacokinetic parameters of riluzole tablets and commercial riluzole capsules in Beagle dogs,and evaluate the correlation between the release rate in vitro and the absorption in vivo, and calculate the relative bioavailability of riluzole tablets. Methods Six Beagle dogs were treated with 50 mg of riluzole tablets or capsules,and then cross-treated by the other drug after 14-days wash out period. Blood concentration of riluzole was measured by high performance liquid chromatography ( HPLC ) . The atrioventricular model was used to calculate the pharmacokinetic parameters and Wanger-Nelson method was applied to assess the correlation between the release rate in vitro and the absorption in vivo. Results The t1/2 ,tmax ,Cmax ,AUC0-72 and AUC0-∞ in the tablet and capsule groups were (12. 43±3. 87) and (12. 57±3. 25) h,(6. 00±2. 60) and (6. 23±2. 72) h,(56. 24±16. 51) and (60. 82±18. 13) ng·mL-1 ,(1 255. 83±311. 39) and (1 283. 50±313. 81) ng·mL-1 ·h, (1 282. 57±322. 64) and (1 297. 22±297. 39) ng·mL-1 ·h,respectively. The relative bioavailability of capsules versus tablets was (105. 9±30. 6 )%. Conclusion HPLC method can be applied to measure the concentration of blood riluzole with little interference and high levels of repeatability and accuracy. The absorption in Beagle dogs between riluzole tablets and capsules was equal,and a good correlation between the in vivo absorption and in vitro release has been found in this study.