Preparation and in vitro Release Behavior of Methylphenidate Hydrochlori Desustained-release Capsules

Objective To prepare a kind of methylphenidate hydrochloride(MPH) sustained-release capsule, and make a comparative study of controlled release tablets in vitro with imported drug release. Methods Using fluidized bed coating technology, we prepared a kind of capsule which contains 3 different release-rate pellets. Drug-loaded pellets packed protective layer made of as the quick-release pellets; use ethylcellulose(Surelease) as coating material to make sustained-release pellets. Double-layer extended-release pellets were prepared using Opadry-7006( the main component of low-viscosity HPMC) as inner swelling layer and Surelease as outer controlled release layer. Results Pellets actual drug loading was 6.85%. The technology and formulation of pellets were optimized. Weight of sustainedrelease pellets coating increased 14%. Weight of double-layer extended-release pellets which with swelling layer coating increased 16%, and the weight of controlled release layer coating increased 22%. The double-layer pellets had a 3.5-hour lag time. Three kinds of pellets were mixed in the following proportions loaded capsules: quick-release pellets(containing MPH 22%); sustained-release pellets(containing MPH 39%); double-layer extended-release pellets(containing MPH39%). The 1-hour release of MPH from the self-made preparation was about 25%; 4-hour release was about 50%; 12-hour release was more than 95%. Conclusions We prepared a kind of sustained-release capsule which could continue releasing MPH for 12 hours. This preparation process is simple. The self-made capsule with reference preparation has the same effect on in vitro release.