| 摘要 |
Therapeutically active albuminous substances are separated from aqueous thyroid extracts by addition of a saturated aqueous solution of ammonium sulphate or other easily soluble salt in a series of steps. The extract is first treated with 40 to 45 per cent by volume of the saturated salt solution to precipitate inactive matter, which is removed and discarded, and then one or more further additions up to a total of about 80 per cent are made to precipitate active fractions. The active precipitates are removed by filtration, freed from the precipitating salt by dialysis whereby the precipitates are re-dissolved, and the dialysate evaporated in vacuo. Zinc sulphate, dimethylamine hydrochloride, diethylamine hydrochloride, or other easily soluble di-, tri- or tetra-alkyl-ammonium salts may be used in place of ammonium sulphate. According to examples (1) an aqueous extract of the glands is treated successively with 45, 60, and 80 per cent by volume of saturated ammonium sulphate solution of the same hydrogen-ion concentration as the extract; (2) glands are extracted with water at a low temperature, the turbid juice obtained by percolation is clarified by centrifuging and treating successively with 40 to 45 and 60 per cent by volume of saturated ammonium sulphate solution. The Specification as open to inspection under Sect. 91 (3) (a) refers to the use of saturated salt solution up to 100 per cent by volume of the extract and includes examples according to which (1) frozen sheep thyroids are ground and extracted with water at 10 DEG C., the extract is purified by percolation and centrifuging, and successive additions of saturated zinc sulphate solution are made up to a total of 70 per cent by volume; (2) an aqueous extract of pig's thyroids is treated first with 20 per cent and then with 60 per cent by volume of a concentrated solution of dimethylamine hydrochloride; (3) thyroids of cattle are extracted with water containing sodium chloride and the extract treated successively with 20 to 25 per cent and 70 per cent of concentrated diethylamine hydrochloride. This subject-matter does not appear in the Specification as accepted.
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