Dual mechanism controlled release system for drug dosage forms
AssigneeBiosytes USA, Inc.
InventorRobert Goldman
Life of this patent
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Abstract
A dual mechanism polymer mixture composed of pH-sensitive enteric materials and film-forming plasticizers capable of conferring permeability to the enteric material, for use in drug-delivery systems; a matrix pellet composed of a dual mechanism polymer mixture permeated with drug and sometimes covering a pharmaceutically neutral nucleus; a membrane-coated pellet comprising a matrix pellet coated with a dual mechanism polymer mixture envelope of the same or different composition; and a pharmaceutical dosage form containing matrix pellets. The matrix pellet releases acid-soluble drugs by diffusion in acid pH and by disintegration at pH levels of nominally about 5.0 or higher.
Claims25
An oral dosage form comprising at least one pellet prepared from a delivery system for a pharmaceutical drug of pH-dependent solubility, said delivery system consisting essentially of a pH-sensitive film forming coating composition, said coating composition consisting essentially of:
- A. a pH-sensitive enteric coating material selected from the group consisting of cellulose acetate phthalate, polyvinyl acetate phthalate, hydroxypropyl methylcellulose phthalate, methacrylic acid copolymers, and mixtures, in an amount of up about 95% by weight;
- and
- B. an accessory film forming coating material having the properties of being a film former in its own right, acting as a plasticizer to said enteric coating material, and rendering said enteric coating material permeable to said pharmaceutical drug, said accessory coating material selected from the group consisting of hydroxyethyl cellulose, hydroxypropyl cellulose, shellac, and mixtures, capable of plasticizing and conferring permeability to said enteric coating material, said accessory coating material present in an amount less than that of said enteric coating material;
- C. wherein said accessory coating material modifies the properties of said enteric coating material, so that said enteric coating material forms a coating that is plasticized and does not exhibit embrittlement, and that functions as a pH-dependent dialytic membrane with controlled permeability for the gradual release of said pharmaceutical drug by diffusion at pH values at which the drug is water soluble, while at the same time possessing the ability of an enteric coating to release said pharmaceutical drug by disintegration at higher pH values when the drug becomes inadequately soluble to release by diffusion;
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- D. wherein said coating composition dispenses said pharmaceutical drug in metered fashion when said pH is below about 5.0, and acts as a pH sensor and promotes the complete release of said pharmaceutical drug by disintegration when said pH rises above about 5.0.
An oral dosage form comprising at least one pellet prepared from a pharmaceutical composition for the controlledrelease delivery of a pharmaceutical drug of pH-dependent variable solubility, said pharmaceutical composition consisting essentially of:
- A. A pH-dependent film forming coating composition, said coating composition consisting essentially of:
- i. a pH-sensitive enteric coating material selected from the group consisting of cellulose acetate phthalate, polyvinyl acetate phthalate, hydroxypropyl methylcellulose phthalate, methacrylic acid copolymers, and mixtures, in an amount of up about 95% by weight;
- and
- ii. an accessory film forming coating material having the properties of being a film former in its own right, acting as a platicizer to said enteric coating material, and rendering said enteric coating material permeable to said pharmaceutical drug, said accessory coating material selected from the group consisting of hydroxyethyl cellulose, hydroxypropyl cellulose, shellac, and mixtures, capable of plasticizing and conferring permeability to said enteric coating material, said accessory coating material present in an amount less than that of said enteric coating material;
- iii. wherein said accessory coating material modifies the properties of said enteric coating material, so that said enteric coating material forms a coating that is plasticized and does not exhibit embrittlement, and that functions as a pH-dependent dialytic membrane with controlled permeability for the gradual release of said pharmaceutical drug by diffusion at pH values at which the drug is water soluble, while at the same time possessing the ability of an enteric coating to release said pharmaceutical drug by disintegration at higher pH values when the drug becomes inadequately soluble to release by diffusion;
- and
- iv. wherein said coating-composition dispenses said pharmaceutical drug in metered fashion when said pH is below about 5.0, and acts as a pH sensor and promotes the complete release of said pharmaceutical drug when said pH rises above about 5.0;
- and
- B. A pharmaceutical drug having pH-dependent solubility impregnated therein.
Dependencies are inferred from the claim text.