| 摘要 |
A dosage unit form, for the oral administration of medicaments and diagnostic agents, which swells without breaking when in contact with gastric juice, to such a size as to be mechanically ruptured on passage through the pyloric sphincter, comprises one or both of (a) a substance or mixture evolving gas on contact with gastric juice, and (b) a substance exerting an osmotic pressure in aqueous solution; sealed hermetically in a polymeric semi-permeable film which is resistant to attack by, but permeable to, gastric juice. Suitable such films are made of gelatine, partially or wholly hydrolised polyvinyl acetate, vinyl acetate-vinyl alcohol copolymers, ethers or esters of cellulose, or plant mucilages, or mixtures of such materials, which have been hardened to give them the required resistant but semi-permeable properties. Such hardening may be effected by treatment with formaldehyde (which is preferably afterwards removed by washing with ethanol or inactivated with ammonia or salts thereof) or by treatment with tannic acid, glutaraldehyde or ethylene oxide. Suitable gas-evolving substances are sodium bicarbonate, alone or admixed with citric or tartaric acid; osmotic-pressure-producing substances may be water-soluble salts (e.g. sodium or potassium chloride), or sugars (e.g. sucrose, lactose, or mannitol). Forms taken by the dosage units are sealed capsules, preferably not less than 20 mms. in length, and made of the said materials; and easily disintegrated compressed tablets enclosed in a continuous film of these materials. Examples are given for capsules containing the said ingredients with, as a medicament, disodium glycyrrhetinic acid hemisuccinate (carbenoxolone sodium); and, as a diagnostic agent, barium sulphate; together with ethyl hydroxyethyl cellulose as a thickening agent.
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