Modified release formulations containing drug-ion exchange resin complexes

A solid modified release methylphenidate tablet which provides at least about a 12 hour release profile and is suitable for oral ingestion which consists of methylphenidate particulates and pharmaceutically acceptable excipients compressed into a tablet, wherein said methylphenidate particulates comprise:

• (A) a modified release methylphenidate component having a single active drug consisting of a methylphenidate, said component consisting of
• (i) a particulate matrix comprising a particulate methylphenidate-ion exchange resin complex and a water insoluble polymer or copolymer, or hydrophilic polymer, said particulate matrix capable of passing through a number 40 mesh screen,
• said methylphenidate-ion exchange resin complex comprising a pharmaceutically acceptable methylphenidate bound to a pharmaceutically acceptable water insoluble ion exchange resin to form said methylphenidate-ion exchange resin complex, said ion exchange resin being a sulfonated copolymer comprising styrene and divinylbenzene,
• wherein said water insoluble polymer or copolymer, or hydrophilic polymer is present in an amount of about 3% to about 30% by weight, based on the weight of said methylphenidate-ion exchange resin complex,
• (ii) a cured, high tensile strength, water permeable, water insoluble, non-ionic polymeric diffusion barrier coating over said particulate methylphenidate-ion exchange resin complex-water insoluble polymer or copolymer, or hydrophilic polymer matrix defined in (i), said cured barrier coating applied as an aqueous dispersion and comprising
• (a) a polyvinylacetate polymer
• (b) a stabilizer, and
• (c) at least an amount of plasticizer effective to enhance the tensile strength of said cured barrier coating, whereby said barrier coating provides a modified release profile to said pharmaceutically acceptable methylphenidate in said methylphenidate-ion exchange resin complex-matrix and
• (B) a particulate uncoated methylphenidate-ion exchange resin complex comprising a pharmaceutically acceptable methylphenidate as the sole active drug in the complex bound to a pharmaceutically acceptable water insoluble ion exchange resin to form said methylphenidate-ion exchange resin complex, said ion exchange resin being a sulfonated copolymer comprising styrene and divinylbenzene.