Coating for medical compound

Abstract

Abstract Medicinal tablets, intended to dissolve only on reaching a predetermined part of the digestive tract, are coated with a water-insoluble and indigestable base composition having incorporated therein an agent which, when acted upon by moisture, expands or is effervescent so as to disrupt the coating. Bases specified are stearic acid, carnauba wax, petroleum jelly, mixtures of these three substances, hydrogenated vegetable oil, shellac, cellulose products such as nitro cellulose lacquer or a solution of celluloid in methyl acetone or solutions such as are used for preparing "Cellophane" (Registered Trade Mark), gum mastic, and gum benzoin. Substances causing disintegration of the coating are agar, powdered elm, cinnamon bark, corn-meal, thyme, kaolin, and mixtures of tartaric acid with sodium bicarbonate. Choice of particular bases and of the added ingredients and the proportions in which they are mixed permit the period between ingestion and disruption of the coating to be varied. According to one example, agar is mixed with a melted base consisting of carnauba wax, petroleum jelly and stearic acid. The tablets may be coated by dipping, or the mixture may be allowed to set, pulverized and applied, in a rolling pan to tablets which have been coated with an adhesive such as shellac. More than one such coating may be applied and the coated tablets may be used directly, or may be passed under a flame to seal them by fusing the surface of the coating. In other methods, the tablets are coated with shellac and rolled in a pan with powdered agar, or are dipped in a solution of celluloid in methyl acetone to which tartaric acid and sodium bicarbonate have been added. Reference has been directed by the Comptroller to Specification 427,106,

Inventors

No inventors recorded.

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