Prolonged release microcapsules and their production
First Claim
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1. A prolonged release microcapsule having an average diameter of about 0.5 to 400 μ
- m for injection, which is produced by preparing a water-in-oil emulsion comprising an inner aqueous layer containing a water-soluble and non-polypeptidic drug, a drug retaining substance therefor selected from a member of the group consisting of gelatin, albumin, pectin and agar and an oil layer containing a polymer substance of lactic acid-glycolic acid copolymer or lactic acid polymer, then thickening or solidifying said inner aqueous layer to a viscosity of not lower than about 5000 centipoises and finally admixing the resulting emulsion with third aqueous layer to give a water/oil/water ternary layer emulsion and then desorbing the solvent in the oil layer.
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Abstract
A microcapsule produced by preparing a water-in-oil emulsion comprising an inner aqueous layer containing said water-soluble drug and a drug retaining substance therefor and an oil layer containing a polymer substance, then thickening or solidifying said inner aqueous layer to a viscosity of not lower than about 5000 centiposes and finally subjecting the resulting emulsion to in water drying gives prolonged release of water-soluble drug.
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13 Claims
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1. A prolonged release microcapsule having an average diameter of about 0.5 to 400 μ
- m for injection, which is produced by preparing a water-in-oil emulsion comprising an inner aqueous layer containing a water-soluble and non-polypeptidic drug, a drug retaining substance therefor selected from a member of the group consisting of gelatin, albumin, pectin and agar and an oil layer containing a polymer substance of lactic acid-glycolic acid copolymer or lactic acid polymer, then thickening or solidifying said inner aqueous layer to a viscosity of not lower than about 5000 centipoises and finally admixing the resulting emulsion with third aqueous layer to give a water/oil/water ternary layer emulsion and then desorbing the solvent in the oil layer.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for producing a prolonged release microcapsule having an average diameter of about 0.5 to 400 μ
- m for injection, which comprises preparing a water-in-oil emulsion comprising an inner aqueous layer containing a water-soluble and non-polypeptidic drug, a drug retaining substance therefor selecting from a member of the group consisting of gelatin, albumin, pectin and agar and an oil layer containing a polymer substance of lactic acid-glyucolic acid copolymer or lactic acid polymer, then thickening or solidifying said inner aqueous layer to a viscosity of not lower than about 5000 centipoises and finally admixing the resulting emulsion with a third aqueous layer to give a water/oil/water ternary layer emulsion and then desorbing the solvent in the oil layer.
Specification