Electrostatic coating of substrates of medicinal products
AssigneeHoechst UK Limited
InventorsJohn N. Staniforth, Martin P. Grosvenor
Life of this patent
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Abstract
Method of coating cores of pharmaceutical tablets with a dry powder, wherein the cores are fed onto a conveyor, the dry powder is supplied to a region through which the cores are to be conveyed, and the cores are conveyed on the conveyor through the region with the cores maintained at a different electric potential from the dry powder. In this way, the dry powder is attracted to the exposed surfaces of the cores to form powder coatings thereon. The dry powder on the surface of the cores is then melted to convert the powder into fused film coatings secured to the cores.
Claims24
A method of coating cores of pharmaceutical tablets with a dry powder, said method comprising the steps of:
- feeding cores of pharmaceutical tablets onto a conveyor;
- supplying dry powder to a region through which said cores are to be conveyed on said conveyor;
- conveying the cores through said region with said cores supported by said conveyor and with said cores maintained at a different electric potential from that of said dry powder, whereby said dry powder is attracted to exposed surfaces of the cores to form partially coated cores having powder coatings thereon, and melting said dry powder coatings of the partially coated cores to convert the dry powder into fused film coatings secured to the cores, thereby forming partially coated cores.
A method of coating cores of pharmaceutical tablets with a dry powder, said method comprising the steps of:
- feeding cores of pharmaceutical tablets onto a conveying means;
- supplying dry powder to a region through which said cores are to be conveyed on said conveying means;
- conveying the cores through said region with said cores supported by said conveying means and with said cores maintained at a different electric potential from that of said dry powder, whereby said dry powder is attracted to exposed surfaces of the cores to form partially coated cores having powder coatings thereon;
- melting said dry powder coatings of the partially coated cores to convert the dry powder into fused film coatings secured to the cores, thereby forming partially coated cores;
- feeding said partially coated cores onto a further conveying means with the fused film coatings adjacent to the further conveying means and with that surface of the core that was adjacent to the conveying means during said conveying step exposed;
- supplying further dry powder with which the exposed surfaces of the partially coated cores are to be coated to a region through which the further conveying means carrying the partially coated cores passes;
- conveying the partially coated cores through the region with said partially coated cores supported by the further conveying means and with the partially coated cores maintained at a different electric potential from the dry powder, whereby the further dry powder is attracted to the exposed surfaces of the partially coated cores, and
- melting the further dry powder to convert the further dry powder into fused film coatings secured to the cores, thereby forming coated cores.
Dependencies are inferred from the claim text.