Matrix compositions for controlled delivery of drug substances

A controlled release pharmaceutical composition for oral use in the form of a coated matrix composition, the matrix composition comprising

• (i) a mixture of a first polymer and a second polymer that have plasticizing properties and which have melting points or melting intervals of a temperature of at the most 200° C.,
• the first polymer being selected from the group consisting of polyethylene glycols and polyethylene oxides having a molecular weight of at least about 20,000 daltons in crystalline and/or amorphous form, or a mixture of such polymers, and
• the second polymer being selected from block copolymers of ethylene oxide and propylene oxide having an HLB value of at least 18, and
• (ii) a therapeutically, prophylactically and/or diagnostically active substance,
• wherein the concentration of the second polymer in the matrix composition is from about 5 to about 90% w/w,
• the matrix composition being provided with a coating which is substantially insoluble in and impermeable to body fluids during the intended release periods, the coating having at least one opening exposing one surface of said matrix,
• the coating comprising one or more coating polymers which can be processed by extrusion, solution, or in the form of a dispersion, the one or more coating polymers being selected from the group consisting of cellulose acetate, polyamide, polyethylene, polyethylene terephthalate, polypropylene, polyurethane, polyvinyl acetate, polyvinyl chloride, silicone rubber, latex, polyhydroxybutyrate, polyhydroxyvalerate, teflon, polylactic acid or polyglycolic acid and copolymers thereof, ethylene vinyl acetate (EVA) copolymers, styrene-butadienestyrene (SBS) copolymers and styrene-isoprene-styrene (SIS) copolymers.