GB368423A - Improvements in gelatinous foam-developing preparations for medicinal and like purposes - Google Patents

Abstract

Solid preparations, stable at ordinary temperature, but developing foam when melted by mere warming in the absence of liquids, for example on application to the body, are made by adding a gelatine solution, containing one of the gas-evolving ingredients and on the point of setting, to a set and comminuted or otherwise preformed gelatine solution containing the other gas-evolving ingredient. Suitable gas-evolving ingredients are: (1) tartaric acid, or an acid salt such as aluminium sulphate, and sodium carbonate or bicarbonate, producing carbon dioxide; (2) tartaric acid and sodium sulphide or nitrite, producing hydrogen sulphide and nitric oxide respectively; (3) hydroxylamine hydrochloride and sodium nitrite, producing nitrous oxide. Medicinal, antiseptic, insecticidal or like substances, for example bismuth subgallate, iodoform, nicotine sulphate, may be incorporated in one or both gelatine solutions. The preparations may be made, by moulding, into rods, globules or other shaped bodies suitable for application to wounds, bodily cavities, such as the nose, ear or stomach, to tooth cavities, or as suppositories. Separation of the gelatine components until reaction is required may be further assured by reducing the contact surface between them, as by making the shaped bodies in two parts only, or by separating the individual particles, or the two parts, by solid gelatine, a concentrated gelatine gel, a wafer, a fat or wax, or merely by a binding agent such as gum arabic. The stability, density and tenacity of the foam may be increased by the addition to the preparations of up to about 10 per cent of starch, albumen or other colloid. The concentrations of the two gelatine solutions employed may be so chosen as to make their melting points, which are affected by the added ingredients, substantially the same. When used as insecticides the preparations may be applied to the bark of trees in order to foam when warmed by the sun or atmosphere. An example of the invention is as follows-30 gms. of gelatine are dissolved in 50 gms. of warm water, 50 gms. of glycerine added, and, after cooling to 37-38 DEG C., 15 gms. of sodium bicarbonate stirred in: the mixture is allowed to set, comminuted, and the comminuted mass placed in a mould and cooled to 4 DEG C.; a solution, containing 40 gms. of gelatine, 50 gms. of water, 50 gms. of glycerine, and 15 gms. of tartaric acid, and cooled to 37 DEG C., is then poured in, and the whole allowed to set to produce a shaped body melting at 35 DEG C.