Studies On Methylphenidate Hydrochloride Sustained-release Pellets

Objective: To prepare methylphenidate hydrochloride(MPH) sust -ained-release pellets and characterize the MPH release in vitro.Methods: The MPH sustained-release pellets were developed in fluidized-bed. High performan ce liquid chromatography method was developed to determine content and diss olution of MPH. A LC/MS/MS method was established to determine the plasm a concentration. Results: The final preparation consisted of the three different pellets: immediate-release pellets (content MPH 22%); one-layer sustained-releas -e pellets (content MPH 39%); two-layer extended-release pellets (content MPH 39%). The plasma concentration curve has two peaks: Tmax1 = 1h, Tmax2=6h,C_max1 = 1.001ng/mL C_max2= 1.721ng/ml. Conclusion: The release in vitro conform to first-order process. The relative bi-oavailability was 155%. Obvious correlation existed between absorption fraction in vivo and the release percentage in vitro.