초록 ▼

A microcapsule composition comprising a core material in a matrix of polymorphic shell material, releases said core material in an aqueous environment in accordance with zero order linear release profile. A preferred composition comprises a core material having a degree of water solubility entrapped

A microcapsule composition comprising a core material in a matrix of polymorphic shell material, releases said core material in an aqueous environment in accordance with zero order linear release profile. A preferred composition comprises a core material having a degree of water solubility entrapped in a beta crystalline matrix of water insoluble shell material which matrix may, optionally, be surrounded by a contiguous core material-free layer of water insoluble shell material. Also disclosed is a process for the preparation of microcapsules comprising subjecting a flowable mixture of core material and a first amount of water insoluble shell material to a pressure force to form a pressure-treated mixture, and passing said pressure-treated mixture through a spray nozzle into a chilling zone to form a solidified composition. A special embodiment of the method providing for the long term moisture stability of the resulting microcapsules subjects the microcapsules prepared in the first step to a second coating with a second amount of water insoluble shell material.

대표청구항 ▼

A microcapsule composition comprising a core material in a matrix of polymorphic shell material, releases said core material in an aqueous environment in accordance with zero order linear release profile. A preferred composition comprises a core material having a degree of water solubility entrapped

A microcapsule composition comprising a core material in a matrix of polymorphic shell material, releases said core material in an aqueous environment in accordance with zero order linear release profile. A preferred composition comprises a core material having a degree of water solubility entrapped in a beta crystalline matrix of water insoluble shell material which matrix may, optionally, be surrounded by a contiguous core material-free layer of water insoluble shell material. Also disclosed is a process for the preparation of microcapsules comprising subjecting a flowable mixture of core material and a first amount of water insoluble shell material to a pressure force to form a pressure-treated mixture, and passing said pressure-treated mixture through a spray nozzle into a chilling zone to form a solidified composition. A special embodiment of the method providing for the long term moisture stability of the resulting microcapsules subjects the microcapsules prepared in the first step to a second coating with a second amount of water insoluble shell material. to claim 9 wherein the melting point of said shell composition starts at about 106 degrees F. and is substantially complete at about 135 degrees F. 20. A sodium bicarbonate microcapsule produced in accordance with claim 1. 21. A sodium bicarbonate microcapsule in accordance with claim 20 characterized in that said capsule releases less than about 2.5% of bicarbonate in an aqueous medium at room temperature in about one hour. 22. A microcapsule comprising a core material in a matrix of polymorphic shell material, where, in an aqueous environment, said core material is released from said microcapsule in accordance with zero order linear release profile. 23. A microcapsule according to claim 22 wherein said core material is an acid or basic salt of an organic compound. 24. A microcapsule according to claim 23 wherein said core material has a mean particle size of between about 250 to about 400 microns. 25. A microcapsule according to claim 24 wherein said microcapsules are substantially spherical. 26. A microcapsule according to claim 25 wherein said shell material is a polymorphic wax or a mixture of polymorphic waxes. 27. A microcapsule according to claim 25 wherein said organic compound is released from said shell at a substantially linear rate for about 8 to about 24 hours. 28. A storage stable microcapsule composition comprising a core material in a beta crystalline matrix of water insoluble polymorphic material which matrix is surrounded by a contiguous layer of water insoluble polymorphic material free of core material, wherein said core material is capable of being released from said microcapsule in a pre-defined temperature range. 29. A storage stable composition according to claim 28 wherein said core material is a water soluble inorganic compound. 30. A composition according to claim 29 wherein said core material comprises solid particles having a mean particle size of from about 5 to about 100 microns.