GB454813A - An improved process for obtaining therapeutically valuable metal compounds of keratinic acids - Google Patents

Abstract

Metal keratinates are prepared by treating alkali metal keratinates, which are obtained from the non-reduced hydrolysis products of keratin, in weakly alkaline or acidic solution with so much of a salt of gold, silver, mercury, zinc, bismuth, antimony or copper that the product, when precipitated by addition of acid or organic solvents, contains at least 20 per cent of metal in the case of gold and bismuth and at least 12 per cent in the case of the remaining metals. The products possess therapeutic properties. According to the examples: (1) a gold compound is obtained by adding an auric chloride solution slowly to a weakly alkaline solution of a keratinate prepared according to Specification 247,944, [Class 2 (iii)], until the precipitate just goes into solution; the solution is made weakly alkaline by addition of caustic soda solution and auric chloride solution again added until the precipitate dissolves; this process is repeated until, after precipitation with ethyl alcohol, a product is obtained containing 30 per cent of gold; (2) a bismuth compound containing 30 per cent of the metal is prepared by adding bismuth ammonium citrate to a weakly alkaline keratinate solution prepared according to Specification 247,944 and completing the precipitation with glacial acetic acid; (3) sodium antimonyl tartrate is added to a weakly alkaline keratinate solution prepared according to Specification 370,295; on stirring into alcohol, solid antimony keratinate settles out. The alternate addition of alkali and metal salt solution is advantageous not only in the preparation of the gold compounds but also when using silver, mercury, zinc and copper salts. In the preparation of the bismuth and antimony compounds, the use of the organic metal double salts is desirable. Specifications 357,189, 412,366, and 437,769 also are referred to. The Specification as open to inspection under Sect. 91 also includes examples of the preparation of silver, mercury and lead keratinates by adding silver nitrate, mercury acetate and lead acetate solution respectively, alternately with soda lye, to a weakly alkaline solution of sodium keratinate and precipitating the product with alcohol. This subject-matter does not appear in the Specification as accepted.