MULTI-LAYERED CONTROLLED-RELEASE METHYLPHENIDATE PELLET

摘要

The present invention relates to a type of controlled-release multi­layered methylphenidate pellet that does not need to be combined with another type of pellet. It allows the maintenance of therapeutic levels in the plasma during 12 hours with a single daily dose, avoiding repeated administrations throughout the day. The controlled-release multi-layered pellet is comprised of an inert core, a first layer that contains methylphenidate and an acid buffering system, a protective layer, a layer of ethylcellulose, that performs the function of controlling the extended release of most of the methylphenidate, and a second layer of methylphenidate, that is responsible for the immediate release of the aforesaid within one hour of administration. The weight ratio between the methylphenidate present in the first active layer and the ethylcellulose is between 1.40:1 and 1.90:1. The multi-layered pellet may possibly have an external coating to protect it from erosion during processing.