Abstract: A system for the controlled release of an active agent to an environment of use, said system having a predetermined release rate of the active agent to the environment of use, comprising: a) a shell comprised of a wall formed of a water-insoluble material which is permeable to the passage of an external fluid, and b) a core which is surrounded by said shell, said core comprised of i) a water-soluble active agent, and ii) a soluble polymeric adjuvant capable of unlimited swelling.

Abstract: A drug formulation administrable by mouth for the treatment of central dopamine deficiency condition, said formulation comprising100 to 250 parts by weight of levodopa,10 to 25 parts by weight of carbidopa,a polymer mixture in an amount of 10 to 200% based on said drugs, said polymer mixture consisting of:0 to 100 parts by weight of a completely saponified polyvinyl alcohol having 0 to 3% residual acetyl content, a mean molecular weight of 60,000 to 80,000 and a total surface area of 0.1 m.sup.2 /g to 0.18 m.sup.2 /g, and0 to 100 parts weight of a partially saponified polyvinyl alcohol having 10 to 18% residual acetyl content, a mean molecular weight of 80,000, a total surface area of 0.5 m.sup.2 /g to 0.69 m.sup.2 /g, and a specific pore volume of 0.2 cm.sup.3 /g to 0.36 cm.sup.3 /g,and an effective amount of customary galenic adjuvants.