Claims for Patent: 5,422,123

Summary for Patent: 5,422,123

Title:	Tablets with controlled-rate release of active substances
Abstract:	Tablets with zero order controlled-rate of release of the active substances, consisting of a core of defined geometrical form containing the active substance, polymer substances which swell on contact with aqueous liquids and polymer substances with gelling properties, and a support applied to said core to partly cover its surface, the support consisting of polymer substances which are slowly soluble and/or slowly gellable in aqueous liquids, plasticizing substances, and possibly substances with an adjuvant function.
Inventor(s):	Conte; Ubaldo (Busto Arsizio, IT), La Manna; Aldo (Pavia, IT), Colombo; Paolo (Pavia, IT)
Assignee:	Jagotec AG (Hergiswil, CH)
Application Number:	08/123,982
Patent Claims:	1. A system for the controlled-rate release of active substance which comprises: (a) a deposit-core comprising an effective amount of the active substance and having defined geometric form, and (b) a support-platform applied to said deposit-core, wherein said deposit-core contains at least the active substance, and at least one member selected from the group consisting of (1) a polymeric material which swells on contact with water or aqueous liquids and a gellable polymeric material wherein the ratio of the polymeric material which swells on contact with water or aqueous liquids to the gellable polymeric material is between 1:9 and 9:1, and (2) a single polymeric material having both swelling and gelling properties, and wherein the support-platform is an elastic support, applied to said deposit-core so it partially covers the surface of the deposit-core and follows changes due to hydration of the deposit-core and is slowly soluble and/or slowly gellable in aqueous fluids. 2. The system of claim 1, wherein said support-platform comprises a polymer substance which is slowly soluble or slowly gellable in aqueous liquids and a plasticizing substance. 3. The system as claimed in claim 2, wherein said plasticizing substance contained in said support-platform is selected from the group consisting of polyoxyethylene glycols, castor oil, hydrogenated castor oil, ethyl phthalate, butyl phthalate, natural glycerides, synthetic glycerides and semisynthetic glycerides. 4. The system as claimed in claim 3, wherein said plasticizing substance represents between 2 and 15% by weight of the support-platform. 5. The system as claimed in claim 2, wherein said support-platform comprises a substance acting as a binder selected from the group consisting of polyvinylpyrrolidone, methylcellulose, ethylcellulose, gum arabic, and alginic acid. 6. The system as claimed in claim 2, wherein said support-platform comprises a substance acting as a hydrophilic agent selected from the group consisting of mannitol, lactose, starch and colloidal silica. 7. The system as claimed in claim 2, wherein said support-platform comprises a substance acting as a hydrophobic agent selected from the group consisting of hydrogenated castor oil, magnesium stearate, a fatty substance, wax, natural glycerides and synthetic glycerides. 8. The system of claim 2, wherein the thickness of said support-platform is 0.5 to 0.8 mm. 9. The system of claim 2, wherein the thickness of said support-platform is about 1 mm. 10. The system as claimed in claim 2, wherein the support-platform remains intact until complete release of the active substance. 11. A process for preparing a system for the controlled-rate release of active substance having a deposit-core and a support-platform which comprises: granulating the deposit-core ingredients according to claim 2, and compressing said granular mixture to form a deposit-core of defined geometrical form; and screening and mixing the support-platform substances according to claim 2 to obtain an easily flowable homogeneous granular mixture and applying said easily flowable homogeneous granular mixture onto a portion of the surface of said deposit-core by compressing to form said support-platform partially covering said deposit-core of defined geometrical form, to prepare a tablet. 12. A tablet produced by the process of claim 11. 13. A system for the controlled-release of active substance which comprises: a deposit-core defined in geometrical form containing: a) an active substance in an amount between 1% and 95% of the weight of the deposit-core; b) a polymer substance which swells on contact with an aqueous liquid, which is selected from the group consisting of crosslinked sodium carboxymethylcellulose, crosslinked hydroxypropylcellulose, polyhydroxypropyl-methylcellulose having a molecular weight sufficiently high to result in swelling in aqueous liquids, carboxy-methyl starch, potassium methacrylate/divinylbenzene copolymer, crosslinked polyvinylpyrrolidone, and polyvinyl alcohol; and c) a polymeric substance with gelling properties which is selected from the group consisting of methylcellulose and non-crosslinked polyvinylpyrrolidone, wherein the ratio of b) to c) is between 1:9 and 9:1; and an elastic support-platform that follows any changes due to hydration of the deposit-core, applied to said deposit-core, which partially covers the surface of said deposit-core, wherein said support-platform comprises: 1) a polymer substance which is slowly soluble or slowly gellable in aqueous liquids which is selected from the group consisting of polyhydroxypropylmethylcellulose, polyvinyl alcohol, polyacrylate, polymethacrylate, polyhydroxypropylcellulose, and polysodium carboxymethylcellulose; and 2) a plasticizing substance selected from the group consisting of polyethylene glycol, castor oil, hydrogenated castor oil, ethyl phthalate, butyl phthalate and natural glycerides, synthetic glycerides and semisynthetic glycerides, and wherein said polymer 1) is between 30% and 90% by weight of said support-platform.