Patent GB-931149-A (GB)
Title: Dual coating process
IPC: A61K9/50
Filed: 1959-10-28
Abstract: Solid particles are pre-coated with a solid lipid material and then capsulated by phase separation from an aqueous solution.  The first coating may be of a wax, a fatty acid, a fatty acid ester, a fatty alcohol or a sterol; many examples are specified.  The second coating may be of a gelable hydrophilic colloid; of two or more colloids of which at least one is gelable and at least one has an electrophoretic charge opposite to others in the system; of a synthetic linear macromolecular polymer of which the recurrent units comprise both lipophilic and hydrophilic units; or of a styrene-maleic acid copolymer and a gelable hydrophilic colloid of opposite electrophoretic charge.  The second coating may be hardened by chemical treatment, drying or irradiation.  The first coating may be applied melted or in organic solution, and the coated particles then introduced into the aqueous solution of the second coating material, or the particles may be suspended in the molten lipid material and the suspension introduced into the aqueous solution of the second coating material.  In each case the second coating material is caused to separate as a solute-rich aqueous phase which surrounds the pre-coated particles, by adjusting the pH of the aqueous solution or by adding thereto a non-solvent for the coating material which is miscible with water. Examples are given of coating wax-coated methionine with gelatine and with a mixture of gelatine and acacia, for addition to animal feeding-stuffs; of coating calcium carbonate particles pre-coated with glyceryl monostearate with a mixture of gelatine and acacia; of coating ascorbic acid pre-coated with glyceryl tri-palmitate, with gelatine, for use in medicine: of coating wax-coated sodium fluoroacetate with gelatine for use in rat poisons; of coating methylrosaniline chloride, pre-coated with ceresine, with gelatine, as an anti-helmintic preparation for humans or animals: of coating ammonium nitrate pre-coated with stearic acid, with acacia-gelatine mixture for use as a fertiliser: of coating neomycin sulphate, pre-coated with spermaceti, with acacia-gelatine mixture, for addition to hand lotions, creams and soaps: of coating calcium arsenate, pre-coated with cetyl alcohol, with acacia-gelatine mixture, for use in insecticides: of coating caffeine, pre-coated with sitosterol, with a styrene-maleic acid co-polymer, for use in medicine; and of coating urea, pre-coated with stigmasterol, with styrene-maleic acid co-polymer for addition to animal feeds. Specifications 751,600, 929,225, 929,226 and 931,148 are referred to.ALSO:Solid particles are pre-coated with a solid lipid material and then capsulated by phase separation from an aqueous solution. The first coating may be of a wax, a fatty acid, a fatty acid ester, a fatty alcohol, or a sterol; many examples are specified.  The second coating may be of a gelable hydrophilic colloid; of two or more colloids of which at least one is gelable and at least one has an electrophoretic charge opposite to others in the system; of a synthetic linear macromolecular polymer of which the recurrent units comprise both lipophilic and hydrophilic units; or of a styrene-maleic acid copolymer and a gelable hydrophilic colloid of opposite electrophoretic charge.  The second coating may be hardened by chemical treatment, drying or irradiation.  The first coating may be applied melted or in organic solution, and the coated particles then introduced into the aqueous solution of the second coating material, or the particles may be suspended in the molten lipid material and the suspension introduced into the aqueous solution of the second coating material.  In each case the p  second coating material is caused to separate as a solute-rich aqueous phase which surrounds the pre-coated particles, by adjusting the pH of the aqueous solution or by adding thereto a non-solvent for the coating material which is miscible with water. Examples are given of coating wax-coated methionine with gelatine and with a mixture of gelatine and acacia, for addition to animal feeding-stuffs; of coating calcium carbonate particles pre-coated with glyceryl monostearate with a mixture of gelatine and acacia: of coating ascorbic acid pre-coated with glyceryl tri-palmitate, with gelatine, for use in medicine; of coating wax-coated sodium fluoroacetate with gelatine for use in rat poisons; of coating methylrosaniline chloride, pre-coated with ceresine, with gelatine, as an anti-helmintic preparation for humans or animals: of coating ammonium nitrate pre-coated with stearic acid, with acacia-gelatine mixture for use as a fertilizer; of coating neomycin sulphate, pre-coated with spermaceti with acacia-gelatine mixture, for addition to hand lotions, creams and soaps; of coating calcium arsenate, pre-coated with cetyl alcohol, with acacia-gelatine mixture, for use in insecticides; of coating caffeine, pre-coated with sitosterol, with a styrene-maleic acid copolymer, for use in medicine; and of coating urea, pre-coated with stigmasterol, with styrene-maleic acid copolymer for addition to animal feeds. Specifications 751,600, 929,225, 929,226, and 931,148 are referred to.